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15 May 2024

The curse of climate brain

Global warming is not only destroying our environment; it is altering the way we think and act – for the worse.

By Philippa Nuttall

 “I don’t seek to leave you in the foetal position,” writes Clayton Page Aldern, a neuroscientist turned environmental journalist. The Weight of Nature, his elegant, convincingly argued book about how climate change is altering our minds, bodies and brains, didn’t make me want to curl up silently; it made me want to shout, to rouse people from their slumber. Aldern asks whether we are awake. The answer for most of us is no. Too many people, especially politicians, seem unable or unwilling to comprehend the dangers posed by a warming world and prefer to carry on, head in the sand, with business and life as usual. Aldern shows us that the world we knew has gone. The choice he offers us is to continue to make things worse, or to confront the crisis and work together to reduce harm and become more resilient.

The book opens in California with Dezaraye Bagalayos, mother to a six-year-old daughter, watching in sufferance as the Sacramento-San Joaquin River Delta, which once provided water for “the breadbasket of the world”, dries up. “My daughter has no future,” says Bagalayos. “Our days on this planet are numbered, I don’t think how we will all die will be pleasant, and nothing and no one is moving fast enough to stop it.” The delta is drying up because of the vast amounts of water required for the industrial quantities of nuts, fruits and vegetables grown in the valley and because climate change means less rain and higher temperatures. In response, farmers are drilling down “as deep as two thirds of a mile – to tap Joaquin’s aquifers”.

Bagalayos’s troubling prognosis sets the tone for the rest of the book. By page five, Aldern is evoking “the ragged trauma of a hurricane, wildfires that melt people… the abyssal depression that descends with landscape loss; the cortex-rotting diseases provoked by warming waters… brain-eating amoebae and plummeting test scores and the shrunken brains of chronic stress”. All are the result of the climate and biodiversity crises.

While studies and headlines often focus on the visible impacts of climate change – destroyed homes and infrastructure after extreme-weather events – Aldern’s interest is how a warming world is upsetting what goes on unseen inside our heads. The natural world exerts “an invisible but unmistakable nudge” on our minds, he argues, and as climate change disrupts nature, it also disturbs our mental state.

“The effects of climate change on our brains constitute a public health crisis that has gone largely unreported,” he writes. Aldern cites various concrete examples – that “immigration judges are more likely to reject asylum applications on hotter days” or that “some drugs that act on the brain aren’t as effective at higher temperatures” – but also more insidious changes. “Climate change causes amnesia,” he writes. We forget how the seasons were, what constitutes “normal” numbers of birds, bees or butterflies – references that, suggests one psychologist he quotes, are important for “accessing and structuring memory”.

In an already deeply divided world, climate change increases inequality. “As temperatures rise, opportunity falls,” writes Aldern. “Our brains don’t work as well when it’s hot out.” Everybody is more likely to do worse in an exam when the mercury rises, but as Aldern points out, in reality it is the less well-off who suffer most – in the US at least, the poorer schools are less likely to be air-conditioned.

Heat is a “subtle poison”, “regressive and silent”, writes Aldern, “it is cognitive death by a thousand cuts”. He underlines the violence it can engender: “Riots are more likely at higher temperatures, as are incidents of intimate-partner violence and aggravated assault.” Pinpointing the exact relationship between deaths and heat is impossible, he suggests, but he cites research indicating that the number of people whose lives will end early in some way because of violence associated with global warming will reach the hundred thousands or millions in the US alone between now and the end of the century.

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Maybe climate scientists, instead of talking about the likelihood of more or less rain or the expected increase in heatwaves as climate change gathers pace, should also talk more about what is emerging from the “Pandora’s box of [climate] horrors”. There’s the spread of cyanobacteria blooms – the blue-green algae that increasingly covers lakes, rivers and coastlines as summers get hotter. Aldern raises the alarming theory that the toxin in these blooms might be airborne and could be linked to neurodegenerative diseases such as Parkinson’s and Alzheimer’s. There’s also the poisonous mercury leaking from thawing permafrost as the Greenland ice sheet melts, “like some kind of cartoonish sludge zombie” – and, of course, the brain-eating amoeba. In the summer of 2009, ten-year-old Philip Gompf was wakeboarding with his cousins in Florida; a week later he was dead. Deadly amoeba had entered his brain through his nose during a fall in the lake. As waters warm, the amoeba wake up. In the US, those suffering this horrific fate are often children, particularly boys, innocent youngsters jumping into fresh water to cool off from the heat.

Even the unborn are not safe. Aldern highlights studies showing that children who were in utero during Hurricane Sandy in 2012 “carry a severely disproportionate risk of psychiatric conditions”. Girls who were in the womb of mothers in the eye of the storm have “a twenty-fold increase in anxiety and a thirty-fold increase in depression” and boys “a sixty-fold increased risk of ADHD and a twenty-fold increase in conduct disorder” compared to their peers.

Perhaps the ultimate example of those who are mentally impacted by our increasingly unstable world are climate migrants. Forced to leave their homes, they suffer “a dissonance between our innate longing for home – for continuity – and the imperatives of survival in a changing world”, writes Aldern, whose previous book was about the housing crisis in the US. “Every family hearth extinguished fractures the continuity of lived experience and intergenerational memory, echoing a loss as profound as the extinction of a species.”

Though its subject matter is heavy, the book is lifted by the lightness of Aldern’s prose, his honesty and the maturity of his reflection. He refuses to romanticise the past or to disregard people’s fears. There are solutions to cut emissions and better ways to live, but climate change is here and we will have to manage its impacts. Aldern’s is a calm voice in a world of chaos. He wants action, but he also wants us also to be able to sit and accept what is happening.

“The brain diseases of climate change are coming, but we can meet them head on,” writes Aldern. “Pretending they don’t exist – as in the case of, say, municipal policies that sweep homeless encampments out of sight without implementing permanent housing solutions – isn’t going to help.” He describes his book as “a hand reaching out” – gentle but firm and, I’d like to hope, impossible to ignore.

The Weight of Nature: How a Changing Climate Changes Our Minds, Brains and Bodies
Clayton Page Aldern
Allen Lane, 336pp, £25

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[See also: The lonely land]

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This article appears in the 15 May 2024 issue of the New Statesman, The Great Stink