The temperature on Earth is rising more rapidly than previously thought due to increased carbon dioxide (CO2) in the air. Current levels of carbon dioxide in the atmosphere have not been reached in 14 million years on Earth. This is what a group of scientists published on Thursday in the Science journal. The study results from seven years of work by eighty researchers in sixteen countries.

Climate scientists have always wondered how much the Earth would warm up if the amount of CO2 in the air were to double. Until now, this so-called ‘climate sensitivity’ was usually estimated somewhere between 1,5 and 4,5 degrees Celsius on a time scale of decades or centuries.

66 million years on Earth

However, a new study reveals that the Earth responds much more strongly, and could lead to a warming of 5 to 8 degrees Celsius. It is clear that pumping CO2 into the air, for example, by burning fossil fuels, warms the Earth.

Climate researchers look into the past to analyze how the Earth responds to this. They study ocean sediments, fossil plant leaves, and geological samples, such as ancient air bubbles in ice cores from Antarctica. Some samples are up to 66 million years old.

One year of commuting

Researchers filtered the least reliable data from earlier studies thanks to the latest technologies. Now, they have a more correct picture of Earth’s sensitivity to increased atmospheric CO2 over long timescales, hundreds of thousands of years.

In the meantime, the Dutch Knowledge Institute for Mobility Policy (KiM) has calculated that CO2 emissions from Dutch vacationers are approximately the same as the emissions from one year of commuting.

‘Holiday emissions’

Almost three-quarters (74%) of ‘holiday emissions’ come from air travel. In their spare time, people emit much more greenhouse gases by getting in a car or on a plane. “Recreational trips” account for 12,6 megatons of CO2.

Of all holiday trips, beach holidays cause the most emissions. Dutch people travel more than 2 000 kilometers for a beach holiday. Almost half (49%) of domestic recreational activities do not produce any CO2 emissions during the trip because they’re done on foot or by bicycle.