Scientists from the Potsdam Institute for Climate Impact Research in Germany succeeded to do a computer simulation that fits ocean floor sediment data of climate evolution over this period of time. The study found that ice age onset, and the start of the glacial cycles from cold to warm and back, was mainly triggered by a decrease of CO2-levels. Today, it is the increase of greenhouse gases due to the burning of fossil fuels that is fundamentally changing our planet, according to the study.
Global mean temperatures never exceeded the preindustrial levels by more than 2 degrees Celsius in the past three million years, the study shows. The current climate policy inaction, if continued, would exceed the 2 degrees limit already in the next 50 years, researchers said.