Rising Carbon Dioxide Levels Could Make Us Dumber


Tom Hale

Senior Journalist

clockApr 27 2020, 18:41 UTC

Lika Koltyrina / Shutterstock

Not only will our planet’s fossil fuel addiction lead to a climate crisis, but it might even harm our ability to think. 

New research has suggested that carbon dioxide concentrations in our indoor spaces could lead to impaired human cognition by the end of the century. Of course, this dreary fate could be avoided if the world successfully curtails carbon emissions, although ironically this hidden impact of climate change could actually hamper our ability to solve the problem itself.


Air with a high concentration of carbon dioxide can lift the carbon dioxide levels in our blood, reducing the amount of oxygen that reaches our brain, increasing our sleepiness, levels of anxiety, and impairing our cognitive function. It’s an effect similar to the cloudy-headed, sleepy feeling you get after sitting in a stuffy room for hours. 

Ever since we started rampant fossil-fuel burning in the 19th century, levels of carbon dioxide in our atmosphere have been creeping upwards and currently stand at over 410 parts per million (ppm), higher than at any point in at least the past 800,000 years. By 2100, outdoor carbon dioxide levels could be as high as 930 ppm if current emission trends continue, while indoor concentrations could be as high as 1400 ppm – a level far higher than levels ever experienced by humans. 

Reported in the journal GeoHealth, scientists led by the University of Colorado Boulder believe this latter indoor level of carbon dioxide will be more than enough to see some decline in cognitive function. By their estimates, basic decision-making skills could be reduced by around 25 percent and complex strategic thinking could be reduced by 50 percent.


"At this level, some studies have demonstrated compelling evidence for significant cognitive impairment," co-author Anna Schapiro, assistant professor of psychology at the University of Pennsylvania, said in a statement. "Though the literature contains some conflicting findings and much more research is needed, it appears that high-level cognitive domains like decision-making and planning are especially susceptible to increasing CO2 concentrations."

The research team looked at current global emission trends and localized urban emissions to see how this would affect indoor and outdoor carbon dioxide levels and, in turn, the impact on human cognition. They concede this is a complex problem, so their research might not take into account every variable. However, they note there's currently not much research on the connection between cognitive function and rising carbon dioxide emissions. 

"This is a complex problem, and our study is at the beginning. It’s not just a matter of predicting global (outdoor) CO2 levels," Kris Karnauskas, lead author and associate professor at CU Boulder.


"We need even broader, interdisciplinary teams of researchers to explore this: investigating each step in our own silos will not be enough," he added.

  • tag
  • climate change,

  • brain,

  • pollution,

  • oil,

  • gas,

  • carbon dioxide,

  • carbon emissions,

  • fossil fuel,

  • cognitive function,

  • air