The Weight of Nature: How a Changing Climate Changes Our Brains

By Karen Melton, Sylvanian and Southeastern Pennsylvania Group Volunteer

“It is no surprise that when the world breaks, we break along with it. The environment – the ground, the horizon, the sky, as perceived by all our senses – is our reference point.”

Clayton Aldern is a neuroscientist and widely published author who focuses a fascinating and unusual lens on climate change -- its effects on our mental health and functioning.

According to Aldern, most of us believe that we humans are in control of our behavior and our minds, but he spends several chapters laying out the evidence and physiology for the effects of excessive heat,ozone or particulates on both behavior and capabilities. People become demonstrably less productive, more fatigued, more irritable, and prone to aggression. Chess players make more mistakes, parole boards grant fewer paroles, students score lower on important entrance exams, pitchers intentionally hit more batters, and immigration judges rule favorably for fewer asylum seekers.

Shifting Baselines

“The climate can’t change if you don’t know what it felt like to begin with.”

As climate activists we are used to seeing charts showing Co2 and average temperatures going back 100 years. But, Aldern explains that key standards-setting groups such as the World Meteorological Organization, report 30-year averages, and they shift their base year forward every 10 years. So an extraordinarily warm year historically, such as 2023, begins to look fairly normal. The explanation for this is that averages from this organization are used to predict averages going forward, so an adjusted baseline is more useful.

Another example Aldern discusses of moving baselines is the understanding wildlife biologists have of changing norms. Although most fish species are smaller on average than they were a generation ago, scientists tend to consider the norm to be what they observed at the start of their careers. So, the dramatic change that has actually occurred becomes less obvious and less reported in the scientific literature.

He writes that the World Wildlife Fund’s Living Planet Index, tracking 32,000 species, reports that wildlife populations across all species have declined an average of 70% since 1970. Again, if you consider the norm to be the population observed over your career, this kind of shifting baseline makes target setting for conservation or rehabilitation ill-founded.

“The greenhouse gases we’ve sent aloft on the wings of industry return to us as extreme weather events, forcing millions from their homes in an echo of our own actions: a planetary feedback loop that spares no one.”

Aldern explores many other ways climate change is affecting our minds – PTSD as a response to catastrophic fires and extreme weather events: a notably higher incidence of depression experienced by people living in mountaintop removal communities, links between environmental degradation and anxiety more broadly, the pain of climate migrants, and the loss of identity by entire communities of people as their languages and cultures disappear.

Everyone working on behalf of nature will find this book both sobering and enlightening -- it is deeply thoughtful and beautifully written.


This blog was included as part of the May 2024 Sylvanian newsletter. Please click here to check out more articles from this edition!