Carbon Dioxide Could Make It Harder to Think

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Climate change is ruining our air quality and contributing to a public health catastrophe. But there’s more. Researchers are warning in a new paper that the very greenhouse gas that’s driving most of our global warming—yes, carbon dioxide—is also diminishing indoor air quality. And it may be messing with our ability to make decisions and think strategically.

The research was presented at this year’s annual American Geophysical Union fall meeting and submitted to the journal GeoHealth for peer review. The findings focus on students of the future. Today’s students already face obstacles due to the increased risk of classroom heat in a warmer world. It turns out rising carbon dioxide could only make things worse.

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Previous research has looked at the impact of indoor air pollution and carbon dioxide levels on test scores. Carbon dioxide levels tend to build up in confined spaces (especially ones with poor ventilation) because we all exhale it. Improving ventilation solves that by bringing in more air from outside, and research shows that reducing levels could improve math scores. But in a world ravaged by extreme carbon emissions, improving ventilation might actually make the situation worse.

That led the researchers on the new study to develop a model to see what the future might hold. That model includes the typical number of students in a classroom, the size of a classroom, the usual ventilation rates, and the impact each has on cognitive functioning. The paper then ran that model under at least two commonly used climate scenarios, including one where the world cuts carbon emissions start in mid-century and another where they continue to rise dramatically.

The findings show that basic decision-making ability in people in a classroom setting could decrease by about 25 percent by 2100 due to increased carbon dioxide in the worst-case scenario. Students’ complex strategic thinking abilities may drop by some 50 percent by the end of the century if carbon emissions continue to increase under the business-as-usual carbon emissions scenario. The youth are the future, and one with a bunch of kids struggling to get an education doesn’t sound like a great one. Shelly Miller, a co-author and professor of environmental engineering at the University of Colorado at Boulder, told Earther that it also raises questions about how ventilation should be designed in the future to ensure it’s not doing more harm than good.

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While a future of continually rising emissions sounds terrible, the study also found, however, that “these results are almost entirely avoidable by reducing global CO2 emissions.” 

Researchers used to see carbon dioxide as a sign of poor ventilation but never as the culprit of reduced health impacts, Joel Kaufman, a professor of environmental health sciences at the University of Washington, said in an email to Earther. Instead, they focused on the impact of volatile organic compounds and other signs of indoor air pollution. But research is beginning to show carbon dioxide may actually be a part of the problem.

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General air pollution has been linked to decreased brain function. Research looking at the impact of carbon dioxide on learning specifically dates back to at least 1967, but it’s only taken off in the last few years as it’s become increasingly clear how much carbon dioxide exposure may rise if world leaders fail to act on the climate crisis.

There have been experiments in controlled settings where researchers have adjusted ventilation rates in rooms or straight up had participants breathe in carbon dioxide-enriched air. A 2011 paper where participants inhaled carbon dioxide through a face mask found that their anxiety levels increased afterward. In 2016, Harvard researchers elevated carbon dioxide levels as well as volatile organic compounds in environmentally controlled office spaces to see the impact on participants’ focus levels and crisis response. They found each had “significant, independent impacts” on cognitive function.

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“It is concerning, and yet it’s not clear what’s the mechanism,” Miller said.

Figuring out this mechanism is key. Some research has found that even a 5 percent increase in carbon dioxide reduces oxygen and brain activity. Still, the body of research includes some inconsistent findings, William Fisk, a senior scientist at the Lawrence Berkeley National Laboratory’s Indoor Environment Group, wrote in an email to Earther. And the research has yet to look at the impacts of long-term exposure, which is the future we all potentially face.

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What researchers do know is this: Humans have never experienced the atmospheric levels of carbon dioxide this high, let alone if the worst-case scenario comes to fruition. We already know so much about the risks carbon pollution poses to the climate. But we still have so much learn about how it could affect other things, and that’s in part why Miller looked more closely at the potential impact on cognitive functioning. And it only adds to the growing list of reasons for why climate change requires urgent action.

“I want to try to gather these important facts and associations in science to say, ‘There’s a lot happening here, and you should care, and maybe you’ll care more if you know this,’” she said.

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About the author

Yessenia Funes

Senior staff writer, Earther. The one who "pulls the race card" in the name of environmental justice. You dig?

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