The rate at which the greenhouse gas CO2 is naturally removed from the Earth’s atmosphere is not constant, but can slow down or accelerate, new research by earth scientists from Utrecht University shows. This natural thermostat of Earth’s climate severely faltered some forty million years ago when concentrations of CO2 increased, which led to a global hothouse that lasted for hundreds of thousands of years. The findings, published online in Nature Communications, offer perspectives for other periods of extreme climate change in the geological past – and possibly for climate change in the future.
The new results show how forty million years ago the Earth’s climate warmed gradually in response to an increase of greenhouse gases emitted by volcanoes. However, the Earth’s natural mechanism to remove CO2 from the atmosphere could not keep up with the pace of warming. The faltering thermostat of the Earth allowed for a prolonged accumulation of CO2 in the atmosphere, resulting in a transient hothouse climate. Only 500 thousand years later the Earth began to slowly cool down.