Making sense of palaeoclimate sensitivity
Many palaeoclimate studies have quantified pre anthropogenic climate change to calculate climate sensitivity (equilibrium temperature change in response to radiative forcing change) but a lack of consistent methodologies produces a wide range of estimates and hinders comparability of results. Here we present a stricter approach, to improve intercomparison of palaeoclimate sensitivity estimates in a manner compatible with equilibrium projections for future climate change. Over the past 65 million years, this reveals a climate sensitivity (in K W 1 m2) of 0.3 1.9 or 0.6 1.3 at 95% or 68% probability, respectively. The latter implies a warming of 2.2 4.8 K per doubling of atmospheric CO2, which agrees with IPCC estimates.
Nature