Studies suggest that elevated carbon dioxide concentrations can have detrimental effects on our health. One problem it appears to cause is oxidative stress, which is thought to underlie many of the health problems we face. Carbon dioxide exposure in an office environment at levels above 1000 parts per million leads to elevated levels of urinary 8-OHdG, compared to exposure at levels below 600 parts per million. The size of the effect is comparable to that of being a tobacco smoker. Other studies confirm that signs of oxidative stress begin to increase, long before concentrations of 1000 parts per million are reached.
If carbon dioxide exposure leads to increased urinary 8-OHdG levels, this is very worrying, as 8-OHdG is commonly used as an indicator of a variety of health problems. Elevated levels are indicative of atherosclerosis risk, cancer risk and complications seen in diabetes. Elevated levels of this marker of oxidative stress are also found in male patients suffering from low fertility. It’s notable that human sperm counts are believed to have decreased by 50% during the 20th century.
The question we have to ask ourselves is: What kind of future are we setting ourselves up for? Even our best case scenarios lead to levels above 500 parts per million, before 2100. Shell no longer believes that temperature increase will be kept below two degree Celsius, rather it predicts an increase of four degree Celsius, later rising to six degree Celsius.
A rise in temperatures by six degree Celsius, also means an increase in atmospheric carbon dioxide levels to above 1000 parts per million. In such a world, humans are chronically exposed to high levels that are known to detrimentally affect our mental abilities. We would feel continually uncomfortable and unable to think clearly. If carbon dioxide is responsible for oxidative stress symptoms, a world with such high CO2 concentrations would be one where people age prematurely and chronic disease affects us at ever younger ages. It’s difficult to see how humans could ever survive on such a planet.