Carbon emissions have long been linked to climate change and various health problems. Now, new evidence shows it could also negatively affect how humans think.
A new study, published in the journal GeoHealth, found that indoor carbon dioxide could reduce human cognition. It also predicts that by the end of the century, heavily exposed populations may become dumber.
Higher carbon dioxide levels in the blood could reduce the amount of oxygen in the brain. Researchers said the decrease causes sleepiness, higher levels of anxiety and impaired cognitive function.
The global carbon levels started to significantly increase when the industry started to use more fossil fuels in the 19th century. The carbon dioxide in the atmosphere has already reached more than 410 parts per million (ppm), a figure significantly higher than records in the past 800,000 years, IFLScience reported Monday.
Emissions around the world are expected to continue growing. Researchers estimated that outdoor carbon levels could climb to 930 ppm by 2100. In the same period, indoor concentrations may also increase to 1400 ppm.
Exposure to carbon dioxide at such levels may have a significant impact on the human brain. Researchers said humans may reduce basic decision-making skills by nearly 25 percent and complex strategic thinking could drop by 50 percent.
“At this level, some studies have demonstrated compelling evidence for significant cognitive impairment,” Anna Schapiro, study co-author and 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 findings come from the analysis of current global emission trends and localized urban emissions. However, the team noted more studies are required to confirm the effects of carbon exposure on how people think.
“This is a complex problem, and our study is at the beginning,” Kris Karnauskas, lead author and associate professor at University of Colorado Boulder, said. “We need even broader, interdisciplinary teams of researchers to explore this: investigating each step in our own silos will not be enough.”