A study published in Nature Communications recalculates climate sensitivity to the balance of the Planet and brings new estimates on the link between CO2 increase and global temperature growth. Original news the IPCC estimates that to double the CO2 ports to the maximum to +4,5°C, while the Dutch researchers speak of +7,2°C
The IPCC estimates of the consequences of doubling CO2 in the atmosphere are too optimistic
Doubling CO2 in the atmosphere will increase global warming twice as much as we thought. This is suggested by the analysis of sediments in an area of the Pacific off the coast of California, thanks to which researchers of the Royal Netherlands Institute for Sea Research have recalculated one of the main indicators of the sensitivity of the Earth’s climate system.
According to the study, published in Nature Communications, the climatic sensitivity to the equilibrium of the Planet would not be included in the range of 1.5 – 4.5°C, estimated by the IPCC, but would reach up to 7,2°C. This indicator measures the relationship between CO2 increase and global temperature increase and is one of the most important for determining the evolution of global warming, its impacts, future emissive scenarios and the speed and depth of the necessary mitigation measures.
The ratio of CO2 in the atmosphere to global temperature
Understanding this relationship is complex because there are many factors involved whose actual scope is not yet entirely clear. The basic idea is that the increase in CO2 leads to a corresponding increase in temperature over several centuries, which depends on the amount of solar radiation that accumulates on the Planet due to greenhouse gases instead of being reflected in space. Accumulation creates an imbalance in the Earth’s climate system, which then tends to change until it reaches a new – even radically different – state of equilibrium.
If, therefore, we get to double the amount of CO2 in the atmosphere – today we are about 1.5 times compared to the levels of the pre-industrial period – we should expect not +4.5ºC of global warming, as predicted by the IPCC in the worst case scenario, but well over 7 degrees.
The study comes to this new estimate from the evolution of the Earth’s climate over the last 18 million years, reconstructed thanks to the composition of the archaea, microorganisms contained in the “carrot” of marine sediment analyzed, whose chemical composition is considered a reliable proxy for changes in CO2 and temperature.
