CO2 affecting Earth‘s climate in a very negative way is a well-known fact. However, it seems we have been underestimating how much CO2 may be affecting our climate. Now new research from Binghamton University is demonstrating that climates on ancient Earth might have been more sensitive to carbon dioxide than it was previously thought.
Scientists got such results by examining nahcolite crystals found in Colorado’s Green River Formation, formed 50 million years old during a hothouse climate. During previous experiments it was predicted that CO2 levels at that time were about 1,125 parts per million (ppm).
However, new experiments show that they were nearly half as high, only at 680 ppm. This data suggests that previous calculations did not allow for accurate evaluation of climate change during that particular time. Furthermore, Earth’s climate may be much more sensitive to increased carbon dioxide that it was previously believed.
In short, this means that 50 million years ago Earth did not have nowhere near as much CO2 as it was believed, but still was significantly warmer that it is today. Nowadays, in comparison, carbon dioxide levels are 400 ppm. Scientists calculate that if we double this factor, global average temperature will raise by 3 degrees Centigrade. This is why scientists now say that currently we are underestimating effect CO2 has on our climate.
Professor Tim Lowenstein, one of the authors of the study, said: “Take notice that carbon dioxide 50 million years ago may not have been as high as we once thought it was. We may reach that level in the next century, and so the climate change from that increase could be pretty severe, pretty dramatic. CO2 and other climate forcings may be more important for global warming than we realized.”
Scientists are able to measure ancient CO2 levels by investigating ice cores. However, this method allows for measurements of only 1 million years old. Now scientists are working on developing methods that would calculate CO2 levels using indirect proxies. In other words, scientists would use laboratory experiments to replicate ancient conditions and CO2 levels as well. Understanding how carbon dioxide levels effect climate is very important, but it seems that currently we are underestimating sensitivity of our climate for CO2.