Carbon dioxide pollution dulls the brain

CO2 levels rise in confined spaces like submarines. Image: By David A Levy, US Navy (public domain), via Wikimedia Commons

Carbon dioxide pollution slows our thinking. It could get bad enough to stop some of us thinking our way out of danger.

LONDON, 27 April, 2020 – If humans go on burning ever-greater quantities of fossil fuels, then tomorrow’s children in badly-ventilated classrooms or workers in crowded offices could find their wits dulled: the predicted concentrations of carbon dioxide pollution by 2100 could reduce the ability to make decisions by 25%, and cut the capacity for complex strategic thinking by as much as half.

That is, global warming driven by greenhouse gas emissions wouldn’t just be bad for the planet and its oceans: it would also make Homo sapiens measurably less sapient.

Although outdoor CO2 levels could more than triple – and at 930 parts per million (ppm), this would be far higher than humans have ever experienced – concentrations in enclosed spaces could rise much higher.

Research on seamen aboard submarines and in astronaut tests have confirmed that CO2 builds up in confined spaces, to limit the supply of oxygen to the brain. As this happens, people in such conditions have problems responding to any stimulus or even recognising a threat.

City atmospheres normally have higher carbon dioxide concentrations than in the countryside. And in poorly-ventilated city buildings, higher carbon dioxide levels could begin to limit human potential.

Direct effect

“It’s amazing how high CO2 levels get in enclosed spaces,” said Kris Karnauskas, of the University of Colorado, Boulder and the author of a new study in the journal Geohealth.

“It affects everybody – from little kids packed into classrooms to scientists, business people and decision makers, to regular folks in their houses and apartments.”

Other researchers have repeatedly warned that any steps to reduce emissions would more than pay off in terms of advancing human health and wealth, and that conversely expanding fossil fuel emissions could only increase damaging atmospheric pollution, along with potentially life-threatening extremes of summer heat.

But these are indirect effects of carbon dioxide concentration: Dr Karnauskas and his colleagues were more interested in a direct effect.

They report that they looked simply at climate scenarios, including the notorious business-as-usual prediction in which humans go on destroying forests, burning coal and oil, and making cement to build ever-expanding cities.

“It’s amazing how high CO2 levels get in enclosed spaces. It affects everybody – from little kids to scientists, business people and decision makers, to regular folks in their houses and apartments”

In this scenario, carbon dioxide concentrations – at around 280 ppm for most of human history, but already past the 400ppm mark – will rise to 930ppm by the end of the century.

If that happens, then indoor concentrations could quickly reach 1400ppm. And this could, on some research findings, begin to compromise what psychologists call high-level cognitive domains. So basic decision-making ability could falter by a quarter, and concentration on complex problems by 50%.

Quite literally, carbon dioxide build-up could reduce the capacity to think clearly. Such an outcome is far from certain, and the Geohealth researchers recognise this.

“This is a complex problem, and our study is at the beginning,” said Dr Karnauskas. “It’s not just a matter of predicting global outdoor CO2 levels. It’s going from global background emissions, to concentrations in the urban environment, to the indoor concentrations and finally the resulting human impact.

“We need even broader, interdisciplinary teams of researchers to explore this.” – Climate News Network