History Is Shaped by Germs Not By Humans

 
   

In his new book  Pathogenesis Dr Jonathan Kennedy argues that Infectious diseases have been the driving forces of human history.  Diseases have shaped humanity, from the development of agriculture to the global rise of religion, he says. Dr Kennedy is a visiting fellow at Queen Mary University, London where he teaches in global health policy.
 
The dominance of homo sapiens and extinction of Neanderthals was likely the result of disease, he told Kim Hill.
 
“I always went along with the dominant view that homo sapiens survived, whereas Neanderthals became extinct, because we were more intelligent.
 
“This is such a dominant argument that it's even inherent in the name that we give to ourselves, homo sapiens or wise humans, whereas the Neanderthals, in the 19th century were sometimes even referred to as homo stupidness. Stupid man or stupid humans.”
 
Over the last 20 years there's been an increasing amount of evidence that shows Neanderthals weren't that different to us, he says.
 
“They painted on cave walls, they used medicinal herbs to treat various illnesses, they buried their dead, they talked to one another.”
 
So why did they disappear 50,000 years ago? Most likely homo sapiens gave them diseases for which they had no resistance, he says.
 
“We had been separated from Neanderthals for over half a million years, we'd been living in tropical Africa, and they'd been in western Eurasia.
 
“We'd been living in totally different disease environments. And when we started to push out of Africa 60,000 years ago, we were carrying diseases that the Neanderthals hadn't developed any resistance to.”
 
When we met with the Neanderthals in the eastern Mediterranean, they died out, and we survived as homo sapiens came from a more tropical; microbe rich environment, he says.
 
Thousands of years later in the 14th century infectious disease wiped out two thirds of the world’s population, but the cataclysm of the Black Death also unleashed a period of extraordinary innovation and social change, he says.
 
“It basically kickstarted a series of events that over decades, and even hundreds of years created the world in which we now live, a world in which it's no longer a feudal society where you have these warring Lords a bit like Game of Thrones, and then at the bottom of the social pyramid, you have serfs who are working on their, on their little strips of land and just trying to try to scratch a living.”
 
Feudal society couldn’t function without plenty of serfs to exploit, he says.
 
“The serfs realised that suddenly labour was in great demand. And cultivatable land was really, really plentiful, so they struggled for the better terms.
 
“And certainly, in England, this led to a situation where 100 years after the Black Death, the vast majority of serfs have won their freedom.”
 
Human history from the adoption of agriculture about 12,000 years ago is punctuated by these devastating pandemics, he says.
 
“Infectious diseases have been one of the real driving forces of human history. And I think this is an interesting way to think about the world because often when we think of history, we focus on the role of great men and great women in really kind of rushing historical change.
 
“But actually, when we look at history through this perspective, we see that in many ways, infectious diseases, are the real tidal force that's pushing the past forward.”
 
Just as disease has shaped human society, so too has human collaboration, he says. Overcoming the squalor that accompanied the industrial revolution in England is an example.
 
“The industrial revolution reaches its height in the middle of the 19th century and you have unprecedented economic growth, you have this massive creation of wealth.
 
“But at the same time, health among the majority of the population, in Liverpool and Manchester, which are the centres of the Industrial Revolution, life expectancy for factory workers falls to 15 in Liverpool and 17 in Manchester. This is really, really catastrophic.”
 
The only way to overcome this massive public health crisis was through democratisation, he says.
 
“These new local politicians that were really driven by an ethos of public service. And they directly tax the middle classes and indirectly taxed the lower classes, the factory workers, and they spent enormous amounts of money on sanitation systems and drinking water, and then later improving health systems.
 
“And this is what enabled the UK to kind of have this massive transformation in life expectancy at the end of the 19th. And the first half of the 20th century, this this massive investment in public health and wellbeing.”
 
Covid reminds us, he says, that collaboration on that scale will be needed in the future with scientists predicting another Covid-like pandemic could emerge in the next 50 years.
 
“I'm certainly not the first person to say it but we need to rethink the focus that we have on economic growth and think about how that economic growth can be used to improve the health and wellbeing of the majority of the population because money in and of itself is of no use. If you're dying at a young age or living a very unhealthy life.”

 Listen to the full conversation  on the podcast.

 
Jonathan Kennedy: how germs made history. By Kim Hill. Radio New Zealand, May 6, 2023.
 

Instant Genius is a bite-sized masterclass in podcast form. And in this episode, we're exploring how human diseases have shaped global history.

Over time, we have become infected with various viruses, bacteria and other microorganisms, which have had a huge impact on our evolution. Dr Jonathan Kennedy, a reader in politics and global health, tells us about the close links between disease and colonialism, how infection shaped the migration of humans out of Africa, and what we can all learn from the COVID pandemic.

 Instant Genius Podcast: How human disease changed history, with Dr Jonathan Kennedy. By Alice Lipscombe-Southwell.  BBC Science Focus,   April 3, 2023

Forget ‘great men’ – infection and disease are the really important forces in the development of humankind, believes public health specialist Jonathan Kennedy
 
Barts pathology museum is usually open to the public only by special appointment. But today, I’m in luck. I find myself with an unexpected open sesame in the form of Dr Jonathan Kennedy, the director of the MSc and iBSc global public health programmes at Barts and the London Medical School, and while he has his photograph taken up on one of its mezzanine floors, I’m free to wander around alone. (At least, I think I’m alone; the museum is nothing if not ghostly.)
 
On the same site as the hospital in the City of London, this purpose-built, glass-roofed Victorian building is home to about 4,000 medical specimens, the majority of them displayed on open shelves. Every part of the body is represented and every kind of illness and injury – though tracking down a particular condition can be tricky for the non-medical. When I finally find the gnarled, yellow spine of a patient who suffered from tuberculosis – I was after something that speaks to Kennedy’s new book, which is about infectious disease and its effect on human civilisation – it’s largely down to luck. The vertebrae in question just happen to be next to the museum’s most famous exhibit: the skull of John Bellingham, who assassinated the British prime minister, Spencer Perceval, in 1812.
 
In Pathogenesis: How Germs Made History, there is no mention of Perceval. But Bellingham’s skull, preserved after the dissection of his body that followed his hanging, inevitably brings to mind Kennedy’s chapter on the Industrial Revolution – a period when previously uncommon pathogens such as TB and cholera began to thrive in our cities (cholera did not appear in Europe until the 1830s, having hitched a lift in both the guts and the linen of travellers from south-east Asia). Not only did infectious diseases then account for 55% of deaths in London; cholera epidemics in particular also led to a rise in the public’s distrust of doctors, who were sometimes attacked as they transported suspected sufferers to hospital for isolation.

 
Murderers’ bodies were sent for dissection by law, as Bellingham’s had been; the medical profession was hungry for cadavers and this ensured a supply line. However, as Kennedy notes, the 1828 murders committed by William Burke and William Hare, who sold their victims’ bodies to Edinburgh University’s medical school, caused people to believe that cholera patients, removed from their communities by doctors, were about to be similarly dispatched. The “anatomists”, of course, were absolutely right to compel isolation, but most of their patients would indeed die, even if they didn’t kill them personally. So far as treatments went, doctors were clueless. One of their more bizarre cures involved injecting turpentine and mutton stew into the patient’s intestines via the anus.
 
Kennedy’s book, which aims to show how infectious disease has shaped us from the time of the Neanderthals to the era of Covid-19, is full of amazing facts like these. For days after I read it, I kept thinking of Pope Clement VI who, when the Black Death reached 14th-century Avignon (where he was exiled), retired on the advice of his physician to his chamber, seeing nobody, and spending all day and all night between two great fires – the flames of which kept the rats that were carrying the disease at bay. Clement did very well to survive. It’s estimated that somewhere in the region of 60% of the population of Europe (about 50 million out of 80 million people) died from the plague between 1346 and 1353. Meanwhile, the economy more or less ground to a halt.
 
Kennedy is a sociologist who somehow ended up – he describes “a meandering intellectual journey” – in public health. “Before coronavirus, I published a paper looking at the links between populism and vaccine confidence,” he says. “So when the outbreak started, the rational thing to do as an academic might have been to get my hands dirty working on Covid-19. But actually, I struggled with the way my work was suddenly the news and so I went in a slightly different direction.
 
“With Pathogenesis, I wanted to broaden [the discussion] out. In the pandemic, most experts stopped saying ‘this is an aberration’ pretty early on, for the simple reason that if you look back, you can see that it really isn’t exceptional. Over the course of human history, it has been normal to have these pandemics that not only kill a lot of people and bring civilisations crashing down, but which also, sometimes, create space for new kinds of societies to emerge. The book is an intellectual response to the slightly myopic way some people viewed the pandemic. It’s a long view, one that we couldn’t perhaps take at the time because everyone was in such a panic.”
 
It’s hard to overstate the role that infectious diseases played in the foundation of the Spanish empire
Pathogenesis doesn’t only cover thousands of years of history – it seeks radically to alter the way the reader views many of the (often very well-known) events it describes. Having read recent research by scientists, archaeologists and anthropologists, for instance, Kennedy suggests that Homo sapiens became the dominant species of human not as a result of any inherent intellectual superiority over Neanderthals, but because our immune system was better suited to adapting to pathogens as we migrated north from Africa. He also looks at the role disease played in colonisers’ ability (or not) to govern their empires.
 
It’s generally accepted that Rome fell partly because of plague (probably smallpox), its armies weakened by illness. But by his telling, had it not been for an Ebola-like pandemic in the second century, Christianity would never have become so widespread – a slightly more surprising analysis. What part, he asks, did pathogens play in the near-miraculous victories of conquistadors such as Hernán Cortés and Francisco Pizarro in Central and South America in the early 16th century? Kennedy, as you will have gathered, doesn’t believe in the so-called great man theory of history. He believes in the sick man theory of history, for no soldier can march if he is dying and no king can rule who is weakened by infection.
 
With this book, he set himself a mammoth task. Where on earth did he start? “Well, I guess my starting point was microbes,” he tells me (we’re in a seminar room now, far away from all the pickled lungs and hearts). “Within us, there are 40 trillion bacteria. They’ve evolved over millions of years and we now know they’re playing all sorts of roles in our lives. This blows my mind and the question I wanted to ask as a sociologist was: if these tiny things have such an influence on our bodies, what kind of effect might they have on the body politic, the body social, the body economic? Humans make history, but not in circumstances of their own choosing. Microbes are a huge force in creating those circumstances.”

 
Together, we roam haphazardly over some of the history in his book. I want to know what he found most mind-boggling. “One thing that really came out of the whole project was the absolute baselessness of white ideology,” he says. “Obviously, that comes to the fore when we’re discussing colonialism. It seems bizarre to me now that people would put down Pizarro’s conquering of the Inca empire with only 168 troops to the fact that he had superior weapons. It’s hard to overstate the role that infectious diseases played in the foundation of the Spanish empire.” The Spanish brought smallpox with them, among other diseases, which devastated the Indigenous population. This was followed by measles, an infection now thought to have been similar to salmonella, and flu. Local populations fell by 90%. The Spanish invaders interpreted all this as a sign that God supported them.
 
Yet we cling to assumptions about superiority. “Ever since we discovered the Neanderthals were a separate species, we have dehumanised them, seeing them as these brutish cave men,” Kennedy goes on. “But it seems like they were just as smart as us. They could talk, they created cave art. They buried their dead and observed rituals. To realise that Homo sapiens were migrating out of a tropical region, and that they were carrying more microbes, and that the Neanderthals further north struggled to deal with those… it’s a neat reflection of the arguments about colonialism.”
 
In the context of our own times, Neanderthal man is particularly interesting to him. We now know that Homo sapiens and Neanderthals interbred, with the result that we carry their genes. The Neanderthal genome has, moreover, been sequenced (by Prof Svante Pääbo, the winner of the 2022 Nobel prize for physiology), and papers published since have shown that Neanderthal gene variants in the contemporary population have had an impact on responses to Covid (those carrying one such variant were 22% less likely to end up in intensive care compared with infected people of the same age). “It’s crazy to think that something that happened 60,000 years ago impacts on whether or not we have a really terrible reaction to Covid,” says Kennedy.
 
But if he is fascinated by the past, he’s also concerned about the future. “We’re living in a golden age for microbes. Population densities are increasing, people are moving more quickly around the world, the climate is changing. We’ve seen the emergence not just of Covid, but of HIV/Aids, Zika, Dengue fever, Sars and Ebola. It seems now that we won’t be able to conquer infectious diseases. Rather, we’re going to have to learn to deal with the new diseases that periodically arrive to threaten us.” If history teaches us anything, he believes, it’s that things will only change in terms of health if we stick together: “These are global societal issues. If one rich country tries to save itself, it’ll still be doomed.”
 
Has writing Pathogenesis made him feel pessimistic? On balance, it hasn’t. While antibiotics may soon cease to be effective in treating some illnesses, a prospect he finds frightening and “hard to fathom”, in the future microbes may themselves provide the solution: “Viruses might be the new antibiotics. They kill about half the bacteria in the world every day. It’s about finding the right one to target the right bacteria.”

 
He thinks of Antonie van Leeuwenhoek, the 17th-century Delft haberdasher who pioneered the microscope. “No more pleasant sight has ever come before my eyes,” wrote Van Leeuwenhoek, enraptured by the teeming new world he saw beneath his lens. There is, Kennedy says, still so much to discover. “We’re incredibly vulnerable as a species, but we’re also incredibly ingenious. A hundred and fifty years ago, we didn’t even know that microbes cause infectious diseases. Now we’re analysing Neanderthal DNA.”
 
 
‘We’re in a golden age for microbes’: the man rewriting history from the perspective of germs. By Rachel Cooke. The Guardian, April 2, 2023.

Penguin

The evangelical right is always waiting for the Apocalypse, counting the days, charting signs and wonders, making calculations as to the time and hour of the end times. One would think that in 2020, when the world was faced with a global catastrophe and a complete breakdown in the normal order of things, they would seize on Covid-19 as a sure sign that those days had come. But for the most part, they chose to deny rather than embrace the coronavirus: Their president and their pastors downplayed its severity and its impact, claimed numbers of deaths were exaggerated, and ridiculed those taking it seriously. Rather than embrace the end of days, they demanded a return to the way things were.
 
Perhaps this has to do with the realization that many of us faced in those early months of 2020: that we were suddenly and radically living on the virus’s terms, not our own. Instead of a grand battle of good and evil with humans at the center of the action, we were obligated to learn and adapt our behavior to a nonhuman organism whose motives and purpose were incomprehensible to us. How was it possible, in such an ordeal, to maintain the supposed truth of Genesis 1:26, that God intended humanity to have dominion over livestock and all of nature? Perhaps the coronavirus had dominion over us, and we were the livestock?
 
Jonathan Kennedy’s Pathogenesis: A History of the World in Eight Plagues takes this idea as its inspiration, asking us to rethink our relationship to the bacteria and viruses that drive pandemics. Perhaps, Kennedy suggests, we are not the grand protagonists to our story; perhaps we are just bit players in a larger drama. He retells the story of human civilization from its earliest prehistoric roots to the current decade, not from the perspective of its Great Men so much as its Great Diseases—the bacteria and viruses that have dogged us since Homo sapiens emerged as a species. For Kennedy, it is smallpox, yellow fever, and malaria that matter far more than Charlemagne, Cortes, or Napoleon; he argues not only that “humans have a far less significant place in the world than we used to think” but also that “microbes play a much more important role than we would have believed just a few years ago.”
 
Quoting Stephen Jay Gould, who wrote that “on any possible, reasonable, or fair criterion, bacteria are—and always have been—the dominant form of life on earth,” Kennedy argues that we are as much a product of disease as we are of any conscious decisions. “Outbreaks of infectious diseases have destroyed millions of lives and decimated whole civilizations,” he writes in his introduction, “but the devastation has created opportunities for new societies and ideas to emerge and thrive. In this way, pathogens have been the protagonists in many of the most important social, political, and economic transformations in history.” A radical thought: What if we, for all our hopes, dreams, and best laid plans, are nothing more than the raw material used by bacteria and viruses to shape the world in their image?
 
Kennedy lays this argument out through reframing well-known historical events in terms of the diseases and epidemics that led to them. The rise and fall of empires, the brutal conquests of colonial powers, the map as we now know it—all this has depended far more on disease than we may have thought. Some of this may sound familiar: for example, the fact that European settlers in North America, both intentionally and unintentionally, used smallpox to wipe out Indigenous populations, to make the work of colonizing easier. Entirely new to North America, smallpox “raced ahead of the Spanish,” in Kennedy’s words, devastating whole communities. The disease proved decisive: “Without the help of Old World pathogens,” he argues, “early efforts to colonize the American mainland foundered.” Take, for example, the Spanish conquistadors’ attempts to take Tenochtitlan. The first try failed, but a second expeditionary force arriving a year later brought with it smallpox, which devastated the city and brought the Spanish victory.
 
More subtle was the arrival of the Puritans and the settlement of Plymouth Colony. Earlier attempts to build colonies in New England had faced fierce resistance from the Indigenous peoples already living there. The Popham Colony in southern Maine failed after 14 months; the French trading post near Cape Cod also fell to Native attacks. But these earlier attempts laid the groundwork for the Puritans by spreading disease; when the Pilgrims got there, they found abandoned villages with grain and beans that they used to get through their first winter, the remnants of Native communities destroyed by smallpox. While these Europeans claimed this food as “God’s good providence,” Kennedy suggests instead that “their gratitude at Thanksgiving should be directed to the Old World pathogens that made the settlement of Plymouth Colony possible.” The rest, unfortunately, is history—crucially, in Kennedy’s version of events, the real colonizer of the Americas was the variola virus, with the Spanish and English as merely its unwitting hosts.

 
Other examples that Kennedy invokes may be more surprising. Despite the Roman Empire’s vaunted aqueduct and sewer systems, he explains, Romans’ lack of any understanding of germ theory meant that their water infrastructure festered with disease, hastening the empire’s downfall. Citing Kyle Harper’s The Fate of Rome, Kennedy argues that “pandemics caused immense damage and played a crucial role in weakening the Roman Empire,” far more so, he claims, than the “Barbarians” at the gates.
 
Pathogenesis also convincingly argues that the birth of the nation of Haiti, and perhaps even the rise of the United States in its current shape, can be traced to yellow fever and the humble mosquito, Aedes aegypti, its primary host. In 1802, about a decade after the outbreak of the Haitian Revolution, Napoleon sent an expeditionary force of some 30,000 troops to its former colony Saint-Domingue, hoping to retake the land and reimpose slavery. The freed Haitians, however, defeated them not with military might but with disease. As the rebels’ commander, Jean-Jacques Dessalines, told his troops in March 1802, “The whites from France cannot hold out against us here in Saint-Domingue. They will fight well at first, but soon they will fall sick and die like flies.” Dessalines’s army used the island’s yellow fever against the invading French: It avoided a straightforward conflict when Napoleon’s troops first arrived in spring, drawing them into a quagmire that lasted until summer, when the rains came. With the rains came standing water, the perfect breeding ground for Aedes aegypti, the mosquito that carried yellow fever and proved a crucial ally against the French. According to one historian’s estimate, of the 65,000 French soldiers sent to recapture the colony, more than 50,000 died, overwhelmingly from yellow fever.
 
Unable to maintain their Caribbean outpost, the French ultimately sold the sprawling Louisiana territory to the United States; a fact that leads to Kennedy’s conclusion that the U.S. as it exists today owes a great debt of gratitude to Haiti’s mosquito population.
 
Again and again, Pathogenesis suggests that the course of history has less to do with our own volition and more to do with the ways in which different diseases fared in different climates. In places where Europeans were less susceptible to disease, such as North America, colonizers brought families and established settlements that eventually became wealthy democracies. In places were Europeans were more susceptible to pathogens, such as sub-Saharan Africa, they built rapacious, extractive industries meant to maximize profit with minimal exposure to the environment, men plundering all they could before returning to their families in Europe healthy and wealthy. What they left behind were landscapes ripped of natural resources and countries that, decades later, still struggle to achieve any kind of remote economic parity with former colonial powers.
 
At times, the thesis seems stretched a little thin—Kennedy argues that the rise of Christianity over Roman pagan religions can be traced to its version of the afterlife, an afterlife that became attractive in the face of repeated plagues and pandemics. But it would seem that if the issue here is simply mortality, the Roman Empire’s ceaseless warfare might drive soldiers into embracing Christianity’s afterlife as well. At other times, Kennedy’s desire to offer pandemics as the key behind all of human history means Pathogenesis can veer into the same territory as the kinds of books he critiques—Yuval Noah Harari’s Sapiens and Stephen Pinker’s Enlightenment Now: The Case for Reason, Science, Humanism, and Progress, among them—books that offer “this one weird trick” to explain all of human history.
 
But this quibble doesn’t detract from the main idea that drives Pathogenesis. What the book reveals is the plain fact that humans are often not the only actors on the great stage of history that we assume we are, and that we may not even be the most important. We have used and been used by diseases so repeatedly that, by the end of Kennedy’s book, one begins to wonder if we may exist primarily to spread and promulgate microscopic organisms and viruses. And if that isn’t our main purpose, it certainly remains something we are exceedingly good at—a true calling, you could say.
 
Our diseases, ourselves. For pathogens need us as much as we need them; the story here is of the interdependence of us and the microbes inside us. Rather than showing how insignificant humans are in the grand scheme of the universe, the true effect of Kennedy’s Pathogenesis may be to invite us to further rethink our long held binary that attempts to separate the human from the rest of the living organisms on this planet.
 
It also helps to put the last few years in greater context. If one sees human history as more or less constantly engaged in a complicated dynamic with microbes, creating and responding to pandemics, then the Covid-19 outbreak is less of an apocalyptic interruption in the world, heralding the end times, and instead the latest way in which humans have played hosts to yet another player on the world stage.
 
Are Germs the Main Characters in History? Outbreaks of disease may have had a greater effect on the course of events than the actions and plans of humans. By Colin Dickey. The New Republic  ,May 3, 2023. 

Most accounts of humanity’s origins, and our evolution since, have understandably put Homo sapiens center stage. It was our ingenuity, our tools, our cultural savvy that enabled our species to survive long past others—that allowed wars to be won, religions to blossom, and empires to rise and expand while others crumbled and fell. But despite what the schoolbooks tell us, humans might not be the main protagonists in our own history. As Jonathan Kennedy argues in his new book, Pathogenesis: A History of the World in Eight Plagues, the microscopic agents behind our deadliest infectious diseases should be taking center stage instead. Germs and pestilence—and not merely the people who bore them—have shaped inflection point after inflection point in our species’ timeline, from our first major successful foray out of Africa to the rise of Christianity, to even the United States’ bloody bid for independence.
 
Three years after the outbreak of a devastating infectious disease with a staggering death toll, spending time with a book that vividly details the microbial richness of human history might not rank high on most people’s must-do lists. But those with enough of an epidemiological appetite to pick up Kennedy’s new book will be gratifyingly—if not necessarily cheerfully—rewarded with the knowledge that their read was at least well timed. Epidemics, Kennedy reminds us, are not aberrations in our overstuffed, interconnected, climate-change-fractured world. And when the next one arrives, as it surely will, our response to it will be better if we remember, and avoid, the many mistakes of the past.
 
Kennedy’s book isn’t meant as revisionism; the broad strokes of history remain intact. But it gently sidelines humans—and, in doing so, humbles them. In the grand scheme of things, he writes, we have far less influence over the fate of our own species than we might like to think: “Very often we don’t make history in circumstances of our own choosing, but in circumstances created by microbes.” Humans aren’t alone, even in their own tale. We’re constantly being puppeteered by our viral, bacterial, and parasitic passengers—simply riding a narrative arc that’s been constantly bent by our bugs.
 
Consider, for instance, the vanishing of the Neanderthals, one of the early human species that lived alongside and interbred with ours. Neanderthals were once perceived as brutish and dumb—intellectual inferiors who whimpered out after our ultra-brainy species spread over the globe. Decades of scientific findings now exist to refute that notion, showing that Neanderthals were extraordinarily sophisticated—painting caves, lighting fires, even making use of medicinal plants. What snuffed them out wasn’t their lack of smarts but a lack of immunity to the (likely viral) diseases that Homo sapiens introduced to them as the two species mingled.
 
That same tragic motif plays out repeatedly over some 60,000 years, as Kennedy points to the cast of microbes that played startlingly prominent roles in several otherwise-familiar chapters of our history. Neolithic farmers may have edged out their hunter-gatherer predecessors with the help of hepatitis B, tuberculosis, measles, and a bevy of mosquito-borne viruses; diseases such as typhus and smallpox may have helped turn the tide against Athens in the Peloponnesian War. Spanish conquistadors appear to have been aided in their obliteration of the native populations by smallpox—an inadvertent weapon at least as powerful as any tool forged by hand. And although it’s clear that various sociopolitical factors were key to the ultimate founding of the United States, it’s also a bit fun to cheekily consider malaria-carrying mosquitoes as among the “founding mothers of the United States,” as the historian John McNeill once put it. The parasitic disease—which established itself in the American South prior to the Revolution—killed eight times more British troops than did American guns, potentially enough to substantially tilt the odds.
 
Other societal forces such as religion and politics have infectious roots too. Horrific bouts of plague, Kennedy writes, were major catalysts for the global spread of both Islam and Christianity—religions that were able to find massive audiences only after large sectors of the global population had died off, and survivors had begun to lose faith in the efficacy of local religious practices. Perhaps Christianity offered a more soothing balm for mortality than paganism at a time when painful deaths were terrifyingly common. And maybe “the lethal effects of Yersinia pestis,” the bacterial pathogen behind the plague, truly were what helped Islam develop into “a major religion practiced by almost a quarter of the world’s population.”
 
There was little awareness of the deus ex microbe as these events unfolded—which is understandable, given that it took until the end of the 19th century for germ theory to gain traction among leading scientists. But Kennedy makes a compelling case that historical ignorance has left behind some pretty sinister vestiges. Neanderthals, ravaged by disease, are still regularly cast in modern terms as dumb brutes; the native peoples of South America, technologically advanced but beaten down by foreign epidemics, imagined themselves disfavored in the eyes of the gods, who instead took the side of the colonizers who ravaged them with diseases.
 
Pathogenesis even implicates infectious disease in the reinforcement of—maybe even the genesis of—certain racial stereotypes. West Africans trafficked to the Americas initially labored alongside white slaves and indentured servants. But when diseases ferried over from Africa began to obliterate those lighter-skinned people, the darker-skinned people who’d already built up immunity were spared—leaving a population of almost entirely Black slaves. Abruptly, the region’s conceptions of slavery became linked to melanin, a stereotype that has insidiously stuck. It was a horrible irony: The movement of pathogens put a premium on protection against them—but ended up saddling survivors with horrific consequences. Our notion of superiority over certain groups, Kennedy suggests, is at least as misguided as our smugness about our supremacy as a species in this world.
 
Kennedy’s point isn’t that we’re powerless against infectious disease. (Nor are microbes unilateral villains: The opening to Pathogenesis painstakingly details the many ways in which the benign ones have benefited us—including aiding the evolution of the placenta, a vital mammalian organ that is thought to have co-opted genetic material from an ancient virus that infected our ancestors.) But, he suggests, humans will remain vulnerable to pathogens’ formidable powers if we continue to ignore them and not learn from the past responses of people in similar circumstances. The ongoing coronavirus pandemic, after all, is not the first time that people have concertedly pushed back against calls for face masks; nor is it the first time the public has bought into lethal misinformation. As Kennedy writes, the cholera outbreaks in 19th-century Europe sparked rumors that the public-health officials and doctors trying to enforce quarantines, travel restrictions, and isolation for the sick were a front—a plot to “poison the urban poor.” Locals rebelled, and governments capitulated, abandoning the very interventions that might have saved countless more lives.
 
Those missteps are important to keep in mind as we look ahead. Our modern habits are technologically advanced but epidemiologically dangerous. As the globe’s population has grown, infections have gotten easier to spread; as we’ve domesticated animals, we’ve carved new conduits for microbes to travel across species lines. Climate change is also pushing wild creatures into new habitats, where they’re more likely to encounter us. Disease spillovers into humans will keep happening; in just the past two decades, three have occurred with coronaviruses alone. That’s a grim fact to consider. And yet, Kennedy’s book manages to end on a somewhat hopeful note. Yes, our trajectory is defined by microbes. But it’s also influenced by our reactions to them—and our acknowledgment of their power. This current pandemic may be tilting toward a slow end. As much as we may want the crisis to disappear in the rearview, the coda of one outbreak is an ideal time to prepare for the next, inevitably on its way.

A History of Humanity in Which Humans Are Secondary.  A new book tells the story of our past from the perspective of the bugs that have shaped it. By Katherine J. Wu. The Atlantic, April 18, 2023. 

In the first chapter of Jonathan Kennedy’s Pathogenesis, he singles out Yuval Noah Harari’s Sapiens as a history that strays too far from scientific facts in service of a grand narrative. This is before Kennedy, a sociologist and lecturer in public health, has even begun constructing his own scientific-historical case: that germs — bacteria, viruses, and other communicable pathogens — have been a powerful and yet-unrecognised driver of human history. Later, he takes Jared Diamond’s Guns, Germs, and Steel to task for giving insufficient credit to the germ part of the triad — suggesting that “germs, germs, germs” is closer to the truth.
 
In an era in which authors tend to offer nothing but unreserved praise of each other via book cover blurbs, it’s refreshing to see a first-time writer take aim at what he sees as the failings of two of the best-read popular history titles of the past 30 years. It also draws the battle lines for Kennedy’s project. Germs, he contends, are a very big deal.
 
His basic thesis is that our intentions (or rather, those of any “great men” of history) mattered less than they or we ever thought. A true “history from deep below” should recognise, as he puts it, that “the modern world has been shaped by microbes as much as by women and men”. This isn’t an entirely new idea — many histories consider the powerful effects of disease — but the perspective is novel. To Kennedy, pathogens aren’t understood simply as catastrophes visiting destruction upon us but as complex living beings with their own history irrevocably intertwined with our own.
 
Kennedy argues this in chapters clustered roughly by era, where he revisits familiar events armed with a microscopic lens. He suggests that 8,000-9,000 years ago, as farming spread into Europe from what is now Turkey, hunter-gatherers weren’t supplanted via conquest or culture, but by farmers incubating novel diseases such as tuberculosis in their densely packed, settled communities. After centuries, farmers finally emerged with stable immunity — which their hunting and gathering cousins didn’t have once they began encountering those same diseases.
 
The book shines when it brings cutting-edge science to bear on these questions, something that Kennedy treats with great care. There are studies emerging that swab ancient tooth pulp and sequence the genes of bacterial fragments within them, showing which Neanderthal or homo sapiens ancestor died by which bug, where, and at what time. Like a map of temperatures or ancient waterways, we may come to see cycles of disease and immunity as equally strong shapers of early human settlement.
 
When the book fails, it is usually because the germ explanation becomes stale. Kennedy labours to prove that the bubonic plague, which probably arrived in Europe in the mid-1300s via Eurasian trade routes, is responsible for everything from capitalism, to Protestantism, to the modern university system. The death of more than 50mn people clearly threw the continent into turmoil, but extrapolating out from it in too many directions causes the book to lose its focus.
 
In the strongest sections, like those covering colonialism and slavery, germs feel powerfully alive and at work in history. Yellow fever and malaria kept colonisers out of much of Africa for centuries. But when mosquitoes carried yellow fever across the colonised Caribbean, and malaria to the American South in the 17th century, they disproportionately struck down the indentured European labourers. Plantations’ horrific embrace of African slave labour, Kennedy suggests, was partly a question of finding labourers immune to specific diseases. By mining the grim statistics of colonial bureaucracies, the book convincingly traces the ways cycles of disease and immunity shaped the outcomes of expeditions, trade, wars and ultimately entire civilisations.
 
Microbes existed well before humans. And their domain extends from parts of Earth we have never reached to the inside of our own bodies. Despite this, they often appear in circumscribed form in our histories — plagues arising and receding from some outside place, almost at random. Pathogenesis shows a microbial world that is as complex, dynamic, and alive as the human one, and just as consequential.
 
Pathogenesis — a history of microbes and men.  Jonathan Kennedy argues that germs have shaped our world more than humankind has — and it’s time we took notice. By Stephen Buranyi. Financial Times, April 12, 2023. 

On Tuesday afternoons, pathology teaching at medical school required me to peer down a microscope for two hours, screwing my inactive eye ever more tightly shut as if that would make the looking eye suddenly see clearly. Each eosin-stained slide with its pink and purple lines and splodges of diseased cells was as legible to me as a barcode. The tiny world beneath my lens created an illusion of human supremacy, a world where the truth was small, immobilised and bored of itself.
 
Pathogenesis – the cause of disease, its development and the impact it has on cells and organisms – is thankfully not what Pathogenesis is about. Jonathan Kennedy is a sociologist, not a microbiologist, and his unit of interest is the epidemic event, not the single bacterium. Where tales of great white men, great inventions and great power once populated the history books, Kennedy argues that great plagues are what really matter. Immunity has been the unifying asset of survivors and victors. The historical sweep of his pen could not be wider, from pre-history to post-Covid. Three hundred-odd pages roam through 50,000 years, and by the last it’s almost impossible to disagree that infectious diseases are our permanent companion and ultimate adversary.
 
Humans are not always in competition with pathogens, though. In fact our existence is indebted to them. A viral infection hundreds of millions of years ago might have enabled our brains to form memories, because of the insertion of a heritable piece of DNA that codes for ‘tiny protein bubbles’ to assist information transmission between neurons. Moreover, the fact that we’re not nibbling at the shells of our mothers’ eggs is because ‘a shrew-like creature developed the capacity to gestate her young inside her own body’. Thanks to a retrovirus, mammals were gifted the placenta and the relative safety of pregnancy.
 
As possibly the only person not to have read the 2014 mega-hit Sapiens, I was intrigued by the more speculative sections of deep history on different human species. For 250,000 years, Homo sapiens lived alongside other humans, including Homo erectus, Neanderthals and Denisovans. It was only 40,000 years ago that Homo sapiens spread across the world while fellow species became extinct. Emerging evidence suggests Homo sapiens in fact reproduced with other human species, and today approximately 2 per cent of our genes comes from Neanderthals. We know about these meet-cutes because of archaea found in calcified plaque on Neanderthal teeth, which could speculatively have been transmitted through kissing, and this same archaeon is a cause of modern gum disease. The evolutionary advantage of genetic mixing of the two species’ microorganisms gave Homo sapiens resistance to unfamiliar diseases and a lifeline for survival and dominance.
 
The fluency of Kennedy’s narration is remarkable, weaving Tolkien, Game of Thrones and Monty Python into memorable and accessible explanations of genetics, evolutionary biology and demography. Whether looking at hunter gatherers overwhelmed by new zoonotic diseases, Thucydides’ account of the Peloponnesian War and the role of plague in Sparta’s victory, or the 60 per cent decline in Europe’s population from 1348 due to the Black Death, each era in history seems to hinge on infectious disease as a ‘devastating weapon of mass destruction’. The result of recurrent infections and exterminations is that ‘contemporary Europeans are neither genetically “pure” nor are they the region’s indigenous people. Even white Europeans are mongrel immigrants.’
 
Events across the Atlantic further strengthen Kennedy’s point. When the Spanish arrived in the New World, their exposure to domesticated animals and denser populations back home gave them the upper hand in encounters with natives who didn’t enjoy such immunity. Kennedy perhaps oversimplifies this ‘virgin soil hypothesis’, as historians of medicine have emphasised the role of social factors and living standards too. But Old World pathogens did result in a 90 per cent fall in the population across the Americas, far outranking damage from imperial force. Smallpox, malaria, yellow fever and measles were the true, though unconscious, armamentarium of the colonisers. African immunity to malaria went on to fuel the racist ideology used to justify human trafficking across the Atlantic during the slave trade and became the foundation for economic arguments to exploit their labour.
 
Kennedy wears his politics on his sleeve, as well as his despondency. The idealism that inspired the WHO, established in 1948, was corroded when the US and UK in the 1980s, under Reagan and Thatcher, reduced their contributions to addressing the global burden of disease. Today, ‘vaccine colonialism’ means that antiretroviral drugs are stockpiled in wealthy nations, but are relatively scarce in poorer ones. Inequality also thrives at home, where a man’s life expectancy in Blackpool is 27 years less than a man living in Kensington and Chelsea – the same difference between the UK and the most deprived countries in Africa. However, the West’s big killers are cardiovascular disease, cancer and Type 2 diabetes. Although not transmitted like a virus, these noncommunicable conditions are socially contagious.
 
As impressive and enjoyable as Pathogenesis is, Kennedy openly concedes that his argument is not new. Historiographically, the idea of pathogenic supremacy has had several outings, most notably in William McNeill’s Plagues and Peoples (1976), which offered a radically novel interpretation of world history through the impact of disease. A new edition in the 1980s was prompted by Aids, just as Kennedy rightly justifies the need for his book with the impact of Covid, discoveries about the microbiome and the new technologies available for recovering the pathogenic signatures of the past. What is recurrently appealing and somewhat horrifying to new audiences about this strain of history is the way it destabilises human agency to such an extent that the purpose of our endeavours is thrown into question. If the bugs write the script, what chance do we have? A microbe-centric approach tends towards biological determinism and nihilism, carrying the risk, once again, of dismissing and underfunding the social determinants of health.
 
Ironically, we have reached the Anthropocene, when human action is finally changing the course of our planet’s history. Emissions in the atmosphere and the misuse of antibiotics have introduced the two urgent threats of global heating and antimicrobial resistance. The pair also interact. Warmer climates invite new pathogenic dangers, as anyone who has watched the trailer for HBO’s The Last of Us will know.
 
Small changes can lead to massive storms, but this could also be a reason for optimism. Pathogenesis might perhaps be read as an invitation to refocus on the minute particulars of our actions, and the billions of encounters between the human and natural world that occur every day. There is an opacity and unpredictability to both evolution and history that can never be fully recovered in our accounts of either. The famous Darwinian tree of descent, which Kennedy describes, is in fact more like a wild root system. As Deleuze and Guattari wrote in 1987: ‘We no longer follow models of arborescent descent going from the least to the most differentiated, but instead a rhizome.’ These tangled interactions show that while Pathogenesis is a humbling story for humankind, it is also one of radical contingency.
 
Great men don’t shape history – but tiny microbes do. By Kate Womerlsy. The Spectator, April 8, 2023. 

The Covid-19 pandemic has wreaked extraordinary destruction and misery, killing nearly 7 million people worldwide thus far and devastating the lives of many more. And yet, viewed through the long lens of human history, writes the public health sociologist Jonathan Kennedy, “there is little about it that is new or remarkable”. Previous pandemics have killed many more, both in absolute numbers and as proportions of populations, and so may future ones. Covid should be a wakeup call that helps us manage deadlier plagues in the future. But will we heed it?

 
Our very existence and success as a species, Kennedy argues in this fascinating book, has been shaped by bacteria and viruses. Where, for example, did all the other species of humans go? At one time, early Homo sapiens shared the Earth (and interbred with) the stronger, larger-brained and equally artistic Neanderthals, as well as the hobbit-like Denisovans. What happened to them? It could be, as some argue, that we simply killed them all, or that they were somehow less well able to adapt to climate change. But Kennedy explores the possibility that roving Homo sapiens from Africa, who had acquired strong immune systems on their travels, might have simply infected the already settled Neanderthals of Europe with a novel pathogen that they couldn’t fight off – just as the colonising Spanish, tens of thousands of years later, decimated the Aztec population with smallpox as much as with weapons.
 
A similar dynamic repeats itself over and over in human history, in Kennedy’s telling, even if some of the details remain speculative. Why, for example, were dark-skinned Neolithic hunter-gatherers such as the celebrated “Cheddar Man”, who first settled the British Isles after the last ice age, replaced throughout Europe by light-skinned farmers of Mediterranean origin? “The most likely answer,” the author suggests, is that the farmers carried infectious diseases to which they had, over time, become immune, but which devastated the indigenous populations. Those farmers were in turn almost completely replaced by another wave of migrants, shepherds from the Eurasian steppe – thanks, perhaps, to a Neolithic wave of bubonic plague in Europe. Kennedy does not shy away from emphasising the point most relevant to modern politics: “Contemporary Europeans are neither genetically ‘pure’ nor are they the region’s indigenous people.” Modern genetic analysis shows that even the people who built Stonehenge were completely wiped out and replaced by a new wave of migration. As Spinal Tap so clairvoyantly put it: “The druids. No one knows who they were, or what they were doing.”
 
We can be more confident, at least, about the geopolitical effects of disease once we enter the era of written history. An epidemic of either typhus or smallpox devastated Athens from BC430, which “undermined Athens’s capacity to fight against the Spartans and had a profound impact on the course and outcome of the Peloponnesian War”. A series of plagues beginning in 65AD, meanwhile, might have weakened the Roman empire to an extent that contributed to its eventual fall. Medieval waves of the Black Death, it is salutary to be reminded, killed astonishing numbers of people – as much as 60% of the entire population of Europe succumbed in a single decade of the 14th century.
 
The subsequent introduction of rules of quarantine and cordons sanitaires, Kennedy argues, can be seen as marking the beginnings of the modern state, extending as they did its power into ordinary human life in unprecedented ways. Meanwhile, the shortage of agricultural labour caused by devastating recurrences of the plague was perhaps instrumental in the collapse of feudalism in favour of a capitalist system of flexible employment. Later on, the susceptibility to malaria of northern soldiers in the American civil war “probably delayed victory by months or even years”, possibly giving Lincoln time to come round to the idea of abolishing slavery.
 
The book thus performs that satisfying trick of encouraging the reader to think differently about familiar topics, though its ideas are inevitably variable in their persuasiveness. Among the most conjectural, for example, is the suggestion that the rise of Christianity in the imperial Roman era might itself have depended on the prevalence of disease, because of its consoling message. “The Christian faith skyrocketed because it provided a more appealing and assuring guide to life and death than paganism during the devastating pandemics that struck the Roman empire in the second and third centuries CE,” Kennedy suggests. Well, maybe. But the conversion of Constantine, briefly mentioned on the same page, was surely the nearer and sufficient cause.
 
There is, too, occasionally a slightly po-faced attitude to Kennedy’s discussions, as when he cites the “What have the Romans ever done for us riff” from Life of Brian. (There is “something unsettling about a group of white, Oxford- and Cambridge-educated men extolling the virtues of colonialism, albeit for comedic effect,” he complains piously.) And the depredations of “capitalism” come to figure, in this story, as a villain as evil as any virus. The economic growth driven by the Industrial Revolution, Kennedy claims, did not, as is usually thought, increase welfare through improved living standards, though here his disagreement seems to be merely about timescales. (It didn’t overall at first because many of the new cities and working environments were filthy and unsanitary, but it sure did in the long run.)
 
The author seems to approve considerably more of capitalism with Chinese characteristics, celebrating the undoubted improvement in living standards of many millions of people in China over the last few decades. He is also curiously happy to accept the official Chinese figures on Covid death rates in order to argue that the US and “liberal democracy” in general are not obviously superior systems.
 
Kennedy is convincing, though, in his emphasis on the way that disease can intersect and interact with social inequality, both globally – most sub-Saharan Africans remain unvaccinated for Sars-Cov-2, the rich countries having kept multiple doses for their own citizens – and within countries, where health outcomes are shockingly dependent on socioeconomic status. What is sometimes called “shit life syndrome” will harm you as surely as many infectious diseases, and “pathogens thrive on inequality and injustice”.
 
So what will we do now? Perhaps, as Kennedy suggests, the recent, comparatively mild pandemic will cause us to rethink “how humans see their place in the world”, to stop creating super-pathogens with our incontinent use of antibiotics, and to realise that “if we Homo sapiens don’t strive to live in balance with the other living things on our planet, we face a very bleak future”. That, however, is a tall order, and not just politically. Bacteria alone make up an estimated 13% of the biomass of Earth, while humans represent a mere 0.01%. In the war against disease, we are massively outnumbered.
 
Pathogenesis by Jonathan Kennedy review – in sickness and in health. By Steven Poole. The Guardian, April 6, 2023.

Migration is the Planet’s Connective Tissue

 

                                                                       mosaic-tailed rat

On about 3.6 per cent of the planet's surface, geographic barriers prevent wild species from migrating as effectively as the desert borderlands barred the polo-shirted young man. Take, for example, the mosaic-tailed rat, which lived on tiny Bramble Cay, an uninhabited island on the northern edge of the Great Barrier Reef off the coast of Australia. Increasingly violent storm surges steadily wiped out the island's plant life. But like other terrestrial creatures living on remote islands, or at the top of mountains, the mosaic-tailed rat had nowhere to go. The rodents' numbers diminished. By 2002 there were only 10 mosaic-tailed rats left on the island. A fisherman spotted one in 2009, but when scientists returned in 2016 to survey the island, they couldn't find even one. In 2019, with 97 per cent of the vegetation on the island destroyed, officials in Australia declared Melomys rubicola, the Bramble Cay mosaic-tailed rat, officially extinct. It was the first mammal we know of to be wiped out by climate change. Experts agreed it would not be the last.

 The more potent barrier to wild species' movement is us. So far, our cities, towns, farms, and sprawling industrial infrastructure have swallowed up over half the planet's land surface. We transformed another 22 per cent of the earth's habitable land in just the last decades, mostly by cutting down forests and turning them into farms, as a recent analysis of satellite images from 1992 to 2015 showed. Our massive footprint makes life impossible for so many wild species that an estimated 150 go extinct every day, speeding up the background rate of extinction by a factor of one thousand. Species that have not lost their habitats entirely must move through a landscape disfigured by human developments. Black bears in the hardwood swamps of Louisiana must cross a highway to reach others in their population. Instead of striking out across the highway to find new mates, they've started to mate with those in their own cut-off group, becoming increasingly inbred. Cougars living in the mountains around Los Angeles must cross two freeways, including one with eight lanes of speeding traffic, to meet others of their kind. None of the cougars that scientists fitted with GPS collars could do it. Four died attempting the crossing, five turned back, and one was shot by police. Birds on the wing smash into industrial structures, each building regularly racking up corpses, like the half-dozen or so birds felled every week by the Thurgood Marshall Federal Judiciary building in Washington, D.C.

 Migrating butterflies, lured off course by electric lighting, perish and flutter to the ground. A 2018 paper in Science analyzed the movements of fifty-seven different mammal species outfitted with GPS devices over landscapes rated according to a "human footprint index," which incorporated data on human population density, the extent of built land, roads, nighttime lighting, and the like. New York City garners a score of 50, while the vast and wild tropical wetlands of the Brazilian Pantanal scores 0. The bigger the human footprint, the researchers found, the more constrained animal movements became. In places with the largest footprints, animals managed to cover as little as a third of the distance of those in places with little or no human impact.

 Besides the inadvertent obstacles of geography and industrial development, the next great migration must overcome purposeful barriers. Before 2001 fewer than 20 of the invisible boundaries that define nearly two hundred nation-states were physically marked by fences or walls. Animals, winds, currents, and waves could freely travel across their imaginary lines. In 2015 an unprecedented surge in construction of new border walls began. By 2019 newly built walls, fences, and gates had risen over 60 international boundaries, blockading the movements of over 4 billion people around the world. More borders are fortified by walls and fences today than at any time in history. Tunisia has built a wall of sandbanks and water-filled trenches along its border with Libya. India and Myanmar have fenced their borders with Bangladesh. Israel has enclosed itself with razor wire, touch sensors, infrared cameras, and motion detectors. Hungary's fence along its border with Croatia, built by prisoners, delivers electric shocks to any migrant foolhardy enough to touch it. Security officials patrol the barrier, tear gas canisters in hand. Austria has built a fence along its border with Slovenia. Britain plans another one along the channel separating it from France. Norway has fortified its border with Russia. In the United States, the hundreds of miles of sixteen-foot-high concrete and steel walls marking the southern border would be extended with even taller, longer, more impregnable walls, U.S. president Trump insisted, perhaps even the entire length of the two-thousand-mile border. Walls don't necessarily function as the impregnable barricades they're meant to.

 In one study, for example, researchers set up camera traps along the U.S.-Mexico border, tracking the movement of people and wild species across open stretches and comparing their movement across stretches blocked by border walls. The walls effectively deterred the pumas and coatis. According to conservation biologists, the extended walls proposed for the U.S.-Mexico border, for which the government has waived scores of environmental regulations, will endanger the life-saving movements of most of the 93 species that live on either side of it. But in the study comparing open and walled stretches of the border, the walls had no effect on people's movements. Whether crossing the border means scaling a wall or not, people keep moving, regardless. If border obstructions fail to stifle movements, they do effectively deflect them. People on the move take more circuitous routes than they otherwise would in order to circumvent barriers, moving like water around a boulder in a stream. Attempting to bar migration, a European border official said, "is very much like squeezing a balloon. When one route closes, the flows increase on another."

 This World Hates Migrants, Human And Otherwise. By Sonia Shah.  Mid-day, August 2 , 2020.

 Excerpt  from The Next Great Migration: The Story of Movement on a Changing Planet by Sonia Shah.

 

 

                                                             Charles Elton 

Biologists such as Elton and others who’d dismissed migrants as suicidal zombies and mindless invaders never really examined migrants’ behaviour itself nor considered in any depth how it might have evolved. What drives creatures to move into new territories, away from where they were born? Leaving behind the known comforts of a home habitat, migrants strike out into the unknown. They forsake the help of kin who stay behind. In return, they may not find anywhere suitable to live at all.

 And yet they do it anyway.

 Baleen whales migrate thousands of miles from their rich feeding grounds in the far north to the warm waters of the tropics. Zooplankton migrate vertically between the depths and the surface the migrant formula in sync with the fluctuating light. Forests move over thousands of years with the advance and retreat of glaciers. In jungle-dripped Hawaii, tiny goby fish migrate from the open Pacific Ocean back to their birthplaces at the tops of waterfalls. The journey requires swimming against ocean currents into fresh waters and climbing up cliffs. They use suckers on the undersides of their bodies to do it.

 In humans, the origin and ecological role of migration continue to be shrouded in controversy and contention. But biologists have forwarded a clear idea about its provenance in animals.

 Migration experts such as Hugh Dingle say that migration most likely evolved as an adaptive response to environmental change. Migratory behaviour is more common among species that depend on resources exposed to environmental variations than in those whose livelihoods are more buffered from environmental change. Arthropods that live in temporary habitats such as shallow pools and seasonal ponds, for example, are more likely to migrate than those that live in relatively stable environments such as forests and salt marshes. Species that live in places with erratic rainfall or that feed on patchily distributed resources such as fruit and flowers are more likely to migrate than those that live in relatively stable places such as alpine tundra or deep lakes, where a disproportionate number of insect species don’t even have wings. Species that live on the edges of forests or in their canopies are more likely to migrate than those that live in their interiors. Bird species that feed on fruit, which is available only seasonally, tend to migrate more than bird species that feed on insects in the interior of forests, which are not. Bats that roost in trees, where they’re more exposed to the cold and the rain, migrate more than bats that roost in caves, which protect them from the elements.

 Even within species, individuals that live in habitats exposed to change migrate more than those less exposed. The migratory behaviour of white-tailed deer, for example, correlates with the size the next great migration of their forest patches: deer that live in small patches more exposed to changing conditions migrate more frequently than deer that live in large patches.

 For creatures that live in habitats subject to environmental change, survival rests on one of two strategies: either go dormant and wait for the altered conditions to recede or migrate. Again and again, those creatures capable of movement have opted for migration, despite the costs. Dingle distilled a formula that predicts the emergence of migratory behaviour. It lies in the ratio between the time it takes to reproduce a new generation and the stability of the environment. If that ratio is less than one—if, say, it takes a couple of years to reproduce the next generation but the habitat, say a vernal pond, lasts only for a season—migration is likely to emerge. And so as the northern hemisphere tilts away from the sun, lengthening shadows and shortening days, creatures of all kinds prepare to move. Physiological changes transpire inside their bodies, hormones spiking and nervous systems mobilizing. Sap-sucking rosy apple aphids birth special forms with wings. Salmon on the verge of migration experience spikes of hormones such as prolactin and cortisol. Baby eels metamorphose into transparent forms that prefer fresh water to salt water. In preparation for their travels, migratory birds and insects build up fat stores that can comprise more than 50 per cent of their body mass, and plants produce tough coats on their seeds. The proportion of fat they deposit in their seeds correlates to the distance the seeds are likely to travel.

 As the time to leave approaches, a restlessness sets in. Migratory birds trapped in cages will flutter repeatedly to one side of a cage, jumping off their perches and crashing to the side. Which side depends on the direction it faces: whichever matches that of their migratory path. Scientists named their agitation Zugunruhe, German for “migratory restlessness.”

 It’s hormonal. Remove the gonads of sparrows in the spring, and they’ll be less restless; castrate the migrant formula a migratory bird, and it will still migrate, but in a different direction.

 Migratory journeys are not simple extensions of everyday movements, like flying from one tree to another or moving from one cave to the next. In birds, you can tell as soon as they leave, from their rate of climb and the altitude they achieve, that their migratory flights are something different. While en route, their behaviour and bodily functions are fundamentally altered. Unlike during ordinary movements, during migrations their bodies halt their own growth and development. They ignore stimuli they’d ordinarily respond to, passing by appealing foods and breeding spots.

 But while migration is driven by physiological changes, it is not necessarily the result of some fixed itinerary instilled into the bones or some blueprint encoded in genes, propelling creatures in fixed directions at standardized times. The physiological states required for migration can be flexible and dynamic, too. The muscles that power the wings of migratory aphids, for example, start to break down after migration, the proteins diverted to reproduction instead. Animals’ sensitivity to the quivers and trembles of our pulsating planet—not predetermined internal programs— drives their behaviour and movement.

 Wild animals’ sensitivity to environmental perturbances is the stuff of legend. Anecdotal stories of animals apparently sensing impending environmental disruptions hours or days before they’re detectable to humans stretch back to ancient times. Pliny the Elder described birds’ restlessness before earthquakes. Geese detected the arrival of an invading army of Celts in 387 BCE. Rome before the sleeping residents did, their quacking alerting them to the impending onslaught. In 1975 snakes outside the city of Haicheng in China emerged from their hidden shelters and froze to death in the winter’s cold, in advance of a 7.3 magnitude quake.

 How the urge to migrate is coded in our genes. By Soniah Shah.  Daily O, July 24, 2020.

Excerpt  from The Next Great Migration: The Story of Movement on a Changing Planet by Sonia Shah.

                                                            Kon Tiki raft

When people start moving, we call it a “migrant crisis”. It’s reflexive. And it happens regardless of whether host societies have the capacity to absorb migrants or whether migrants themselves and the societies they enter and leave would be better or worse off because of their movements.

 In part, that’s because we’ve long misunderstood the scale and meaning of movement on our shared planet.

 In the 18th century, the founder of modern taxonomy, Carl Linnaeus, characterised the natural world as essentially still. Each animal belonged where it was found and hadn’t moved from one place to another; each human population was similarly fixed in place on the planet. Thanks to Linnaean taxonomy, we name things based on their fixed places and where they “belong”: the Canadian goose, the Japanese maple. We use animals to stand in for places, as if they are one and the same: the camel stands in for the Middle East; the kangaroo for Australia – as if they have been there from time immemorial and could never shift.

 Linnaeus decided that people who lived in different continents had been so biologically isolated from each other that they were separate subspecies, creating a human taxonomy which separated people by colour, continent, and his sense of their morals. He relied heavily on folklore and myth about tailed men and African women with bizarre genital growths (his taxonomy was famously based on sexual characteristics, which is why it was controversial and called “loathsome harlotry”). Elevating the degree of differentiation between us obscured our common origin and our shared migratory history. Nevertheless, his ideas formed the foundation for modern ideas about racial difference, which are used to justify anti-migrant policies to this day.

 We’ve minimised the role and scope of migration ever since. For example, Europeans refused to believe Polynesian people’s story of prehistoric migrations to the Pacific Islands by canoe from Asia. They thought that purposeful long-distance movements were only possible with modern Western technology. In the 1940s, the Norwegian explorer Thor Heyerdahl theorised that the only way people could have gotten to the remote Pacific islands was by floating there on a raft from Peru. He was so convinced of his theory that he tried it himself on the Kon Tiki raft, which became a popular movie and book. Up until the 1960s, top geographers said that migration has played such a minor role in human history that the people who lived on different continents had actually evolved there.

 Today’s policymakers similarly underestimated the pace of human movements when they claimed they could arrest the spread of novel coronavirus by closing the borders, seemingly unaware that seven million people had already left the city of Wuhan before it was locked down. It was only after the borders slammed shut that it became clear that our movement patterns made even our most stringent efforts to stop the microbe’s dispersal futile.

 Our underestimation of the scope of migration has been coupled with an outsized focus on migration’s disruptive effects. We call the movement of wild species into novel habitats “invasions” of unwanted “aliens,” even though according to a general rule in invasion biology, only 10 per cent of alien species establish themselves in new habitats and only 10 per cent of those are likely to cause unwanted harm to economies, ecosystems or human health.

 Human migrants are blamed for all manner of social ills, from the spread of crime and terror to disease. One result is that today, more borders are fortified with walls and fences than at any time in history.

 But new findings made possible by advancements in genetics and navigation are upending conventional notions of migration as rare and disruptive, revealing migratory capacities more extensive and more deeply embedded in history and nature than ever before imagined.

 Ancient DNA shows that we’ve continuously migrated. We didn’t just disperse out of Africa into an empty planet and then stop moving until modern times. We migrated out of Africa into Eurasia and then back again; we moved from Eurasia into South Asia; we migrated into the Americas and then back to Europe. Some of the most forbidding migrations, such as into the Tibetan plateau and the remote Pacific had been accomplished not just once but multiple times.

 A revolution in animal tracking thanks to GPS and solar technology has revealed that animal movements are much more expansive in scale and more complex and responsive than ever before imagined, too. The movements of mountain goats is shaped by the timing of volcanic eruptions, which they detect six hours before seismologists can. The flight paths of swans curve according to cold snaps, and could forecast outbreaks of avian influenza days before traditional methods of influenza surveillance. The creep of thousands of species toward the poles and into the heights tracks the shifting climate.

 We live in a world on the move. And nature depends on our journeys. Ecosystems depend on the biological connections provided by wild species on the move. Over 90 per cent of the trees in rainforests, for example, rely on the movements of birds and other animals to disperse their seeds. Human mobility is fundamental to our biological resilience. Our capacity to co-operate across geographic barriers relies on the cultural connections forged by people on the move, injecting genetic and cultural diversity into otherwise insular societies.

 Migration is the planet’s connective tissue. It’s not the crisis we reflexively imagine it to be. In a rapidly changing world, migration may be just the opposite: the solution.

 “Migration is the planet’s connective tissue” By Sonia Shah.  The Big Issue , June 26, 2020.

 

 

How should countries protect citizens from deadly diseases? The most promising solution is often not the most popular, explains author Sonia Shah.

 In her forthcoming book, The Next Great Migration: The Beauty and Terror of Life on the Move, Shah explores whether, in a world of disruptive and deadly biota on the move, there is any lasting solace in closed borders and isolated societies—or whether our survival depends on just the opposite.

 On April 23, 2020, Shah joined the Pulitzer Center for a discussion of her past and present reporting as part of the Talks @ Pulitzer Science and Health Series. Her latest book grew out of a Pulitzer Center-supported investigation into contagions facing Syrian and Afghan refugees trapped in Greece.

 The following is an edited transcript of the Question & Answer segment of Shah's Talks @ Pulitzer, moderated by Ann Peters, the Center's university and community outreach director. Also included are several audience questions that were not presented during the 45-minute webinar due to time constraints, but were answered by Shah after the session via email communication.

 The post-session answers are indicated by an asterisk*. Portions of this text have been revised for clarity and/or length.

 Question: You said that flight paths affect the spread of pathogens. If nations across the world would have shut down traveling faster, do you think the coronavirus would not have become such a large pandemic?

 Answer: I don’t think that there’s been any respiratory pathogen that we’ve been able to contain as such in the history of pandemics. Look at the seasonal flu virus, for example: We have that every year, and even though we have some degree of herd immunity that we’ve acquired at a great cost to our health, even though we have a scientific establishment that creates a cool new flu vaccine every year, we still lose billions and billions of dollars to sickness and we lose half a million people every year to flu. Given that example, I think the idea of containing a respiratory pathogen that spreads just from people moving around and talking to each other, the social contacts that happen, is really difficult. We’ve never been able to do it even though we’ve had lots of opportunity to try and lots of incentive to try.

 Q: What has your research shown in terms of migration harming a country’s health care system?

 A: It’s exactly the opposite. A lot of political leaders think migrants are coming into their societies because they’re attracted by some special benefits that they’ll get from getting there. ‘They’re coming to steal our jobs, they’re coming to get our healthcare,’ there’s all these attractives that pull them in, and so when they don’t want them to come policies of deprivation get put into place. And we see that across countries—the ordinary health care that’s available to citizens is not available to newly arrived people and migrants, whether they’re documented or not documented. Even things that would protect all of us better like vaccination programs [are not available]. Undocumented children across Europe don’t get the routine vaccinations in a lot of countries that residents do. I think it comes out of this idea about migration as being this negative phenomenon that we have to deter. Also, that if we don’t give them any ‘goodies’ and deprive them then they’re going to stop coming, which is not what I’ve found at all. It’s exactly the opposite.

 Q: Is there a solution to create equity across the world so that migration can be reduced and made less risky? Does not access to natural resources often drive migration?*

 A: Migration is shaped by many factors, not just the availability of resources or even jobs, which is why poor countries situated next to wealthier ones with porous borders are not depopulated. In fact most international migration in the world occurs between poor countries. Still, migration can be made a lot more orderly, safe, and humane. The UN's Global Compact on Safe, Orderly and Regular Migration provides a roadmap.

 Q: Did you come across any interesting research about vaccines for animals? If so, do they make a difference (positive or negative) in preventing disease outbreaks?

 A: One point to clarify is that these microbes that become pathogens in humans are not pathogenic in animal reservoirs—they’re harmless to the animals. So there wouldn’t be any role of vaccination because the animal already has the immunity. The bats are not falling sick with Ebola, they’re the reservoir of Ebola. In terms of antibiotic consumption in agriculture, it’s a huge driver of antibiotic-resistant pathogens. Here in the United States, about 80 percent of the antibiotics that we consume as a country are used in commercial applications in agriculture. And we know that in countries where that practice is not allowed, that they don’t have problems with antibiotic-resistant bacteria the way we do here in the United States. It’s really something that scientists realized in the very beginning—if you use them in ways that are not medically necessary, you will provoke the evolution of antibiotic-resistant bacteria. That’s basically what we have been doing here in the United States over the past decades. I think it’s a ticking bomb, really.

Q: Are CAFOs (concentrated animal feeding operations) in the U.S. part of this current contagion?*

 A: Industrial livestock farming is a known driver of pathogens with pandemic potential. The use of antibiotics for growth promotion in livestock contributes to the spread of antibiotic-resistant bacterial pathogens, for example; poultry farms where thousands of captive chickens are crammed together allow avian influenza viruses to replicate, amplify, and become more virulent. Here in the U.S., about half of all cattle on feedlots are infected with Shiga-toxin producing E. Coli (STEC). Because cattle waste so often contaminates our food and water, hundreds of thousands of American fall ill with STEC every year.

Q: Can you explain the positive migration benefits in the context of invasive species? Especially in vulnerable areas?*

A: There's no doubt that migration is disruptive and in some cases, such as for invasive species, the costs might outweigh the benefits. But these are a tiny fraction of introduced species. There's no reason to make the problem of invasives the centerpiece of our policies toward species on the move. They should be managed as outliers, and dealt with on a case-by-case basis.

Q: Could you describe your research and reporting processes?

A: In a nutshell, my process is to do a ton of background research before I go into any of these places. I do all of the background reading and to talk to all the experts I can on the phone in the places that I’m going to before so I have established my background level of understanding of the communities and what their own priorities are. I’ve also established social contact with the leaders in those communities so that when I go there I can concentrate once I’m on the ground. The other part is just making enough time to really listen. It’s not the most efficient thing to do, but if you go to, say, a hurricane shelter where you have traumatized people who have lost everything and you just need information about one part of their experience, you can’t just extract that. You have to sit down and establish trust and really listen to what people want to say because people want to be listened to but they dont wanna just give you the one piece of information you want. So, you have to have the patience to sit there and really listen to all of it and absorb it and respond in a humane way. That’s how you get a more complete picture of what’s going on, even if you’re just looking at one angle of the experience.

 Q: Can you share some policies or advocacy that offer some hope for tackling these issues?

A: I do see hopeful signs everywhere and the one thing I keep in mind is that history doesn’t progress in a linear fashion. There’s always unexpected outcomes and little things that can have outside effects in ways you can’t imagine. We’ve seen backlash against science around the world with right-wing populist leaders coming into power saying ‘we don’t need to do vaccines, we don’t need to listen to the science, we don’t need experts, we don’t need all these environmental regulations,’ or whatever it is, and I think it grows in part out of the elitism that is inherent in the scientific establishment. The establishment itself is complicit, to some extent, in trying to elevate its authority and saying ‘we’re going to speak in lingo that none of you people can understand and you have to study for years and years to even know what we’re talking about,’ and I think that dynamic is not helpful for us as a society. I’m very hopeful about the fact that that’s starting to change. I think scientists themselves are starting to get involved in the political process—we’ve seen scientists running for office and they’re speaking out more. On the other side, we’re seeing the democratization of science. This is coming out of the climate movement, I think, where people are learning about atmospheric chemistry, and how energy works, and thermodynamics—now that’s all stuff we have to know about. We’re seeing that now with public health: We’re all getting a crash course in epidemiology right now which I think just a few years ago would have been considered a very obscure part of the scientific establishment that we didn’t have to think about. And I think what my work has always been about is that civil society has to be part of the scientific process—it shouldn’t be two separate things. So the fact that these things are colliding and starting to meld a little more, I think that’s a hopeful movement that’s happening right now.

Anne Peters talks with Sonia Shah.

Talks @ Pulitzer: Author Sonia Shah on Migration Patterns and Fighting Diseases.  By Holly Piepenburg. Pulitzer Centre , April 24, 2020.

 

 

                                                                   Carl Linnaeus

Climate change has put organisms on the move. In her new book, The Next Great Migration, Science writer Sonia Shah writes about migration — and the ways in which outmoded notions of "belonging" have been used throughout history to curb what she sees as a biological imperative.

 There is a tendency to view plants, animals and people who cross into a new territory as a threat to the current habitat. But Shah says there's another way to think about these "invaders."

 Humans "thrive in such widely variable places — from the Tibetan plateau to the middle of rainforests," she says. "You have to think about the whole picture of, why did we evolve this way? It's because its benefits outweighed its risks over the long term."

 Shah's 2016 book, Pandemic, explored the increasing threat of viral outbreaks.

 Interview Highlights

 On the origins of the idea that human migration was problematic

 I traced most of these ideas back to Carl Linnaeus, who's considered the father of modern taxonomy. He's this 18th-century Swedish naturalist, and he kind of decided for all of us: Where does everything belong? He named everything. He came from a very Christian household, and like most naturalists of the time, he was very religious. He thought of nature as an expression of God's perfection. So everything was in its rightful place for him. ...

 Wherever he found things, that's where they "belonged," and that extended to his human taxonomy. So he decided that the people in Africa belong in Africa, that people in America, they belong in America, etc., to such an extent that he decided that all of these different peoples on different continents didn't have a shared ancestry, a shared migration history, but were actually separate subspecies of humans. And, in fact, he called Africans even less than human, that they were sort of a hybrid between real humans and this other archaic, mythical human that he called "troglodytes."

 But those ideas were incredibly influential because we see them today in our ideas about race and about where people belong and where wild species belong. When a wild creature crosses from a different place into a new territory, we think of it as an invasive; we call it an alien. We see hints of all of that in the way we make policy around immigration and newcomers in places around the world.

 On how Linnaeus' ideas opened the door for junk "race science" within the scientific community

 [The "race" scientists] really felt like immigration would cause a biological catastrophe, because they thought that people from Africa or Polynesia or elsewhere in the world were biologically distinct. And so if they came into our country and started to partner with "native" people, with local people, that they would have these hybrid children that would be like deformed, essentially degenerated and deformed. They did all this science to try to prove that, which, by modern standards is not scientific, as we understand it at all. But they were scientists. So they had that kind of authority of being people who are looking into this really deeply.

 But even leading people in the American Public Health Association and President Calvin Coolidge actually wrote about what he called "biological laws," according to which divergent people could not mix or blend. And the Public Health Association said that if we allowed immigrants in, and these are people who are of different subspecies to mix with native people, that would lead to hybrid generations that would lead to, I think the quote, was "absolute ruin" for American society.

 On what we've learned from tracking the migrations of animals

 With solar technology and GPS, we can track animals 24/7 over the course of their lifetimes, sort of continuously. So you can see the full picture of the way they move. And what they're finding is that these creatures are moving farther and faster and in more complex and responsive ways, dynamic ways than anyone ever thought before. What's funny is we've created all these parks and reservations to kind of protect animals, and when we've actually now studied well, where do they actually go? It turns out the giraffes, they're supposed to stay in the park in Ethiopia that we set aside for them, in fact, they're crossing borders and going much farther than that. The turtles are swimming well beyond the boundaries of the marine protected-zones we've made up for them. We see animals are moving sort of en masse now because of the climate crisis.

 On rethinking invasive species like "murder hornets" and lanternflies

 I don't deny that those disruptions are occurring, but I dispute what the reason is behind it. There's so many species that are moving around, and to think that every newcomer who comes into your territory is sort of alien to it as opposed to the natives who belong there, I think that's where we go wrong. I mean, it's interesting with the hornets. This is very typical of how we respond to new novel creatures that we think are out of place. I mean, we were calling these hornets, "murder hornets," which is a very pejorative way to talk about anything, really. Lions also are predators, we don't call them "murder cats." ...

 What they're really threatening is honeybees and stuff, which are also not native either. They're from Europe. So, I'm not saying the disruption doesn't exist — but it's the way we think about it. What we know is that only 10 percent of species that move into new places are able to establish themselves. And then only 10 percent of those become sort of pests, cause disruptions, unwanted effects on either human health or our economies or on already resident species. So we're talking about one percent of all the species that are moving around actually causing these problems of what we call invasiveness. And yet we have this approach that's embedded in our conservation policies, like the Convention on Biological Diversity, which recommends that we detect species that are new in our environments early, that we repel them and that we eradicate them before they are able to establish themselves. And the idea there is that you get rid of them because you're presuming that they're going to cause problems. And so that presumption, I think, is what is problematic, because especially right now, because the climate is changing, and we need species to move into new places and we don't want to repel them as invaders or aliens just because they're moving into new places, which is what's going to allow them to survive.

 On going to borders to report on human migration

 Right now, we have more borders around the world ... fortified with walls and other barriers than ever before. And ... it hasn't repelled movement. It hasn't made people stay home. It's just made migration a lot more deadly. So people are risking their lives now to find refuge from bombs and beheadings and poverty and the rest of it. So that was what was most striking to me. And the thing about reporting on migration is you basically can go anywhere because there's migration happening sort of behind-the-scenes everywhere you go. So what I wanted to do is look at, well, where are people getting stuck? Whether it's refugee camps or border checks or dying in the desert on the U.S.-Mexico border.

 On the underlying biodiversity crisis behind the coronavirus and other pathogens

 New Coronavirus 'Won't Be The Last' Outbreak To Move From Animal To Human

I think we need to look more deeply at the way we're interacting with nature. We need to look more deeply at the crisis of biodiversity, which is really the fundamental driver of all of these spillover pathogens coming into human populations. I mean, it's not just the novel coronavirus. It's also Ebola and Zika and HIV in the 1980s and West Nile Virus and new kinds of Lyme disease, a tick-borne disease. We have a whole host of these pathogens that are coming out of animal populations into humans because we are destroying wildlife habitat at such a huge rate. We're losing 150 species every day. So this biodiversity crisis is the fundamental driver. So we need to, I think, look at that more deeply and consider human health to be connected to the health of our livestock, our wildlife and our ecosystems more generally.

 New Book Argues Migration Isn't A Crisis — It's The Solution.  Dave Davies talks with Sonia Shah.

 NPR  , June 2, 2020. 

                                        lifejackets abandoned by migrants on the Greek island of Lesbos

This fascinating study debunks false narratives about immigration and finds that, in common with other species, the urge to move is written in our genes

 Sonia Shah’s last two books Pandemic, published in 2016, and The Fever, published in 2010, introduced her as a storyteller in a novel genre: travel books that went in search of the spread of disease - cholera in the former, malaria in the latter. That literature of track and trace, part detective story, part reportage, took Shah to remote corners of the world and to distant grid references of history. Her books were also prescient case studies of the way that human progress has been shaped by its love-hate relationship with microbes – how disease has caused empires to rise and fall and economies to stutter and implode.

 This book – a wandering narrative about why people wander – is likely to prove equally prophetic in the coming months and years, since it asks two questions that are already shaping our geopolitics: what causes human beings to migrate? And is such mass movement beneficial to more settled communities and nations?

The “next great migration” has been predicted by many – and feared by some – ever since the end of the cold war. The national security expert Robert D Kaplan described it in a 1994 Atlantic magazine article as “the coming anarchy” – the binary superpowers had held borders mostly in check, now people would start to move. “There would likely be 50 million on the move by 2020, experts at the United Nations University projected. Two hundred million by 2050, the environmental security analyst Norman Myers announced. One billion! the NGO Christian Aid projected.” One result of those alarmist predictions had been the populist politics that has emerged with a single purpose in mind: how to make those people stay still. “End freedom of movement!”; “build the wall!”

Shah begins her history with a series of observations that become parables from the natural world. The first concerns the habits and behaviour of the checkerspot butterfly. The checkerspot, most abundant on the west coast of America, is not a powerful creature. It flies very low to the ground and only lives for 10 days. Because of its sensitivity to changes in habitat and environment, it also proved one of the first bellwethers of climate change. A celebrated paper in Nature in 1996 showed that in response to warming temperatures the edges of the population of checkerspots were moving northwards at a rate of 20km per decade. Shah joined the butterfly hunters marking that progress and along the way found evidence that myriad other species are also checking out of familiar territories: Atlantic cod, for example, are moving at a rate of 200km a decade toward the cooler poles.

Shah confesses to a certain kinship with those migrations. Her parents – alone among their siblings – moved from India 50 years ago to fulfil a need for doctors in New York City, in the first wave of legal migration from the subcontinent. That migration instilled in Shah “an acute feeling of being somehow out of place”; despite having been born American, “I didn’t consider myself as being ‘from’ that place, even though I’d borne both of my children there”. For a few years, she and her husband left to live in Australia and became doubly “alien”. These feelings prompted questions in Shah: where did that concept of home originate? And was that a learned or an innate understanding?

Her compulsive investigation into these questions becomes a political history of the human urge to move from one place to another. It begins with the “mitochondrial Eve” identified as the African ancestor of all human societies – the prime mover of a species hardwired to migrate – and ends in the determined and futile efforts of contemporary politicians to deny that instinct in individual refugees with nowhere to go except somewhere else.

 Shah identifies the emergence of biological taxonomy, the naming of things, as the historical moment when we decided that nature, which had never stopped moving and evolving, was actually fixed. Carl Linnaeus, “the sex-crazed Swedish taxonomist”, becomes the founding father of a political principle of nativism that can be summed up simply: “We belong here. They belong there.” She shows how this enlightenment control freakery gave rise not only to eugenics and “race science” but also to the underpinnings of fascism. Heinrich Himmler, in addition to masterminding the genocide of millions, issued rules for landscape design: “The head of the Reich central office for ‘Vegetation Mapping’ called the delicate flowering herb Impatiens parviflora a ‘Mongolian invader’ and recommended its extermination.”

 Having established this history, Shah unpicks its pernicious effects on contemporary false narratives about immigration and the re-emergence of supremacist racial rhetoric in the political mainstream. It is only two decades since Bill Clinton stood on the White House steps and announced the sequencing of the human genome, which offered incontrovertible proof that we not only have infinitely more in common than that which divides us – “The sequencers had found [that] a paltry 0.1% of the 3bn nucleotides strung together on our strands of DNA differed from any one person to the next” – but that encoded in our DNA was the age-old urge to mix and move about.

 Towards the end of this fascinating study, Shah travels to some of the frontlines of the denial of that instinct. She meets the gravediggers of the Greek island of Lesbos, who bury the migrants who wash up on their shores, many of them children, in unmarked graves. She has no easy answers, except to argue that our biology and our history tell us a very different story to our politicians. Nigel Farage’s efforts to police the English Channel are about as likely to succeed as those of King Canute. “Life is on the move, today as in the past,” Shah insists. “For too long, we’ve suppressed the fact of the migration instinct, demonising it as a harbinger of terror. We’ve constructed a story about ourselves, our history, our bodies, and the natural world around us in which migration is the anomaly. It’s an illusion. And once it falls, the entire world shifts.” 

 The Next Great Migration by Sonia Shah review – why people wander.  By Tim Adams. The Guardian, June 7, 2020.

 

                                                              checkerspot butterfly

“A wild exodus has begun,” writes Sonia Shah early on in The Next Great Migration. “It is happening on every continent and in every ocean.” In response to the climate crisis, plants and animals that until recently scientists thought were fixed to a particular habitat have been seeking out different surroundings. Butterflies and birds have been edging their way towards the Earth’s poles; frogs and fungi are slowly climbing mountain ranges – while in the oceans, even some coral reefs are moving at the rate of a few kilometres per year. And where wild species go, humans may follow, Shah suggests, noting that more people already live outside their countries of birth than ever before, some of them pushed by war, floods, rising seas and creeping deserts.

 It sounds apocalyptic. But are we wrong to think so? Shah, a US science journalist, argues in a deeply researched and counterintuitive history that much received wisdom about migration – human or otherwise – rests on a series of misconceptions. We tend to see migration as unwelcome and rare, a flight from hardship or a burden for the place of arrival. But techniques including genetic history, navigational mapping and climatology have revealed that migration and mixing are far more central to life on Earth than previously thought. They may, in fact, “be our best shot at preserving biodiversity and resilient human societies”.

In making this argument, Shah takes on the dominant view of displacement as an overwhelming tide of human misery that will threaten global stability. Over the past few decades, this perspective has shaped national security policy in powerful countries such as the US, as well as the approach of international institutions such as the UN. Migration, crudely put, equals disorder.

If we are to escape this way of thinking, we will have to dispense with the deep-seated assumption that peoples and species are fixed to specific parts of the planet; a “stillness”, as Shah puts it, that sits “at the centre of our ideas about the past”. To make her point, she takes the reader through a history of modern biology, beginning with the 18th-century European naturalists whose effort to categorise the world went hand in hand with the exploration and colonisation of large parts of the globe. From the start, the idea that humans could be divided into a distinct set of biologically different types, each linked to one of the world’s continents, came with value judgments. White Europeans were generally seen as superior, and mixing as undesirable. Shah traces the development of 19th century race science, and how that in turn came to inform political arguments in favour of immigration control. (Arguments in America, at least: while Shah tells a global story in terms of biology, the political narrative is constructed mainly with a US readership in mind.)

Ideas about wild species also informed attitudes to humans. Chief among them, in Shah’s account, is the relationship between population and habitat. A mistaken belief among some 20th-century zoologists that nature was essentially “filled up” – each species occupying its own ecological niche, vulnerable to disruption from invasive outsiders, or to self-destruction through overbreeding – led some to imagine migration as “a vector of death”. In the 1960s, a number of ecologists and other scientists began to voice concerns about the supposed destructive effects of human overpopulation, an argument that gained mass appeal through the 1968 bestseller The Population Bomb, by Paul and Anne Ehrlich, which predicted widespread famine and social unrest unless drastic action was taken to limit the world’s population. Although the authors didn’t link this to an explicit call for immigration control, others who followed them did, giving weight to criticism that this was a form of Malthusianism, where “population control really meant controlling certain populations and not others”. Inferior foreigners and the poor, in other words.

Yet although Shah is firm in pointing out where scientists have got it wrong, she has faith in science. Animal populations fluctuate, move and adapt their bodies according to the availability of resources. When human population numbers rise, people often work together to find innovative solutions: Shah gives the example of Mexico, where a rising population prompted farmers to improve the efficiency of wheat production, and of cross-border cooperation over water shortages.

Perhaps the most groundbreaking discoveries of recent years have been in genetic history. It has already been several decades since the study of DNA revealed how little substance there was to claims of racial difference. Study of genetic material found in ancient bones also suggests that, rather than a single migration out of Africa, humans populated the globe in waves that intermingled, coming back as well as going forwards. “We weren’t migrants once in the distant past and then again in the most recent era,” Shah writes. “We’ve been migrants all along.”

 That general truth might not be enough to defuse conflicts over migration by itself. But Shah’s tone is neither smug nor triumphalist. She is clear about the power and the danger of xenophobic politics, tracing the anti-refugee backlash that has been mobilised by the right, as well as the threat to our lives posed by the climate emergency. Hers is an optimistic book nonetheless, because it tells us that this is just the latest chapter in a long story of survival and adaptation. Climate change will cause people to move, she argues, but it won’t necessarily be in the way we think: extreme weather, for instance, generally prompts people to move short distances; longer migrations are the result of more gradual change. Migration is disruptive, “but the next great migration will not unfold as an unstoppable physical phenomenon, like a cold front sweeping in from the north”.

This is a vivid and engaging story that weaves in the accounts of refugees Shah has met to illustrate the harm done by today’s border controls. As a writer, she has an eye for the visual metaphor, likening anti-immigration arguments to puffball mushrooms, which grow huge, then burst to release their spores, leaving “an empty, crinkled shell”. Those arguments may indeed be hollow but they spread their spores nonetheless: we need books such as this to expose them.

 The Next Great Migration by Sonia Shah review – movement is central to human history.  By Daniel Trilling. The Guardian, June 26, 2020.

 

                                              The U.S - Mexico border

The Edith’s checkerspot butterfly is a delicate insect, with a wingspan less than a thumb’s length and a tendency to hide from the rain. For many years, these butterflies were thought to be “the entomological equivalent of homebodies,” science journalist Sonia Shah writes in her new book, The Next Great Migration. Researchers hardly ever saw them stray far from the places where they were born. As cities encroached on the species’ habitats and climate change made it harder to survive, many believed they were destined for extinction.

 But in the mid-1990s, a Texas biologist named Camille Parmesan made a startling discovery. After gathering data on their habitats, she found that these fragile little animals weren’t homebodies at all: they had been shifting their range in response to climate change, moving north and to higher altitudes in order to survive. Parmesan’s discovery brought about a revolution in climate science, and soon researchers found legions more species that were migrating in response to climate change, including corals, red foxes, and even fungi.

 This is the anecdote that opens The Next Great Migration, an ambitious work of journalism that argues migration has played a vital role in our planet’s history. For centuries, Shah writes, scientists and political leaders have portrayed migration as something “unnatural” and “disruptive,” clinging to the idea that people, plants, and animals aren’t meant to move. But in reality, she argues, movement is completely natural, and we’ve been doing it for millennia. And while it’s sobering to know that our changing climate has disrupted so many species’ way of life, Shah sees reason for hope. “A wild exodus has begun,” she writes. “It is happening on every continent and every ocean.” In the coming years, as climate change threatens human and animal habitats, migration “may be our best shot at preserving biodiversity and resilient human societies.” In other words, it has the power to save all our lives.

Shah makes her case by moving nimbly between scientific history, scenes from her travels with ecologists, and occasional stories from refugees around the world. She takes a reportorial approach, mostly staying out of the picture, but she does briefly wrestle with her own experience as a daughter of Indian immigrants who spent many years feeling “somehow out of place” in the United States. “As a child, I was ashamed of even small things, like my preference for suspiciously fruity strawberry ice cream over the unimpeachably American chocolate for which the other children clamored,” she writes. It’s only after starting to research migration as an adult that she begins to feel like she truly belongs. 

Scientists have been depicting migration as a destructive force since at least the 18th century, Shah writes, when the Swedish botanist Carl Linnaeus invented modern taxonomy. Linnaeus believed that all the world’s species had left the Garden of Eden long ago—and then stayed put for centuries. The notion of mass migration was unthinkable: like many of his contemporaries, Linnaeus assumed birds hibernated for the winter, diving to the bottom of lakes or hiding out in caves. Accordingly, Linnaeus developed a system for classifying plants, animals, and people based on their geographic location. Humans who lived on different continents, he believed, were separate subspecies. It was a false idea, but a politically expedient one: “From a colonial perspective, it was more convenient to cast foreigners as so strange as to be unrelated or perhaps not even human at all,” Shah notes. Using Linnaeus as a jumping-off point, Shah surveys the vast legacy of scientific xenophobia, showing how the idea that migration is unnatural went on to influence eugenicists and the Nazis, along with prominent biologists and even U.S. presidents.

Along the way, Shah offers an important reminder that the history of American conservation movements can’t be separated from that of anti-immigrant politics. Madison Grant, who played a key role in developing the national park system, was also a white supremacist who shaped U.S. immigration policy. John Tanton, a conservationist who started a chapter of the Audubon Society, was a racist thinker who launched a network of anti-immigration groups that continue to influence the Trump administration today. Even David Brower, the famous Sierra Club leader, tried to push his organization to adopt an anti-immigration platform as recently as the late 1990s. (Tanton also participated in that effort.) Brower was one of a group of environmentalists at the time who were obsessed with the false idea that migration would lead to overpopulation and destroy the planet. 

 In the latter half of the book, Shah presents a skillful rebuke to the long line of scientists, environmentalists, and elected officials who’ve advanced such xenophobic thinking. In recent years, scientists have begun to discover the full extent of ancient human migration: we now know that early humans traveled out of Africa in several waves and back again, moving continuously between continents throughout the course of history. “Migration is not an exception to the rule,” she writes. “We’ve been moving all along.”

She also wades into the debate about invasive species, arguing that migratory plants and animals have been unfairly maligned. It turns out many scientists think that only about one percent of nonnative species pose a threat to resident plants and animals—the rest tend to increase biodiversity, if they have any impact at all. Moreover, leading biologists say that migration “most likely evolved as an adaptive response to environmental change.” That’s why creatures like the checkerspots move as the earth gets warmer, and why migration will play a critical role in the planet’s future.

 In this last part of the book, you get the sense that Shah is rushing a little—I wish she’d spent more time exploring the complicated contemporary science of wildlife migration. She also gives a brief overview of the ways we’re seeing climate change influence human movement today, but she doesn’t go into much depth on the topic. Despite the book’s title, The Next Great Migration focuses more on the past than on the future.

But maybe it’s inevitable that you can’t cover everything when you’re trying to wrangle hundreds of years of human and environmental history into a book that’s just over 300 pages. Shah has done a remarkable job, distilling complex ideas from a variety of disciplines into concise and elegant prose. She has a knack for summing up a big idea in a punchy sentence, but she also knows how to linger on a lovely scene, transporting the reader from the jungles of Hawaii to the Himalayan foothills.

 Prior to The Next Great Migration, Shah wrote a book about pandemics, and she admits that her work in that field once contributed to her “sense of movement as aberrant, something anomalous that needed to be examined and explained.” In the past few months, politicians have been especially eager to exploit Americans’ heightened fear of movement. We’ve seen Trump use COVID-19 as an excuse to push through draconian measures—like indefinitely closing the border to asylum seekers—that have nothing to do with stopping the virus.

In this time of rampant xenophobia, Shah’s book offers a call to “reclaim our history of migration and our place in nature as migrants like the butterflies and the birds.” It’s a powerful invitation, and one that’s never been more urgent.

A Science Writer Makes the Case for Embracing Migration. By Sophie Murguia. Outside , July 30, 2020.