Greater committed warming after accounting for the pattern effect

Our planet's energy balance is sensitive to spatial inhomogeneities in sea surface temperature and sea ice changes, but this is typically ignored in climate projections. Here, we show the energy budget during recent decades can be closed by combining changes in effective radiative forcing, linear radiative damping and this pattern effect. The pattern effect is of comparable magnitude but opposite sign to Earth's net energy imbalance in the 2000s, indicating its importance when predicting the future climate on the basis of observations. After the pattern effect is accounted for, the best-estimate value of committed global warming at present-day forcing rises from 1.31 K (0.99-2.33 K, 5th-95th percentile) to over 2 K, and committed warming in 2100 with constant long-lived forcing increases from 1.32 K (0.94-2.03 K) to over 1.5 K, although the magnitude is sensitive to sea surface temperature dataset. Further constraints on the pattern effect are needed to reduce climate projection uncertainty. Earth's energy budget depends on the global sea surface temperature pattern, which is currently counteracting warming more strongly than expected in the future. Including this pattern effect in projections causes committed warming with present-day forcing to exceed the Paris goals, implying less leeway than anticipated.

Automated summary

The Earth's energy budget is influenced by spatial inhomogeneities in sea surface temperature and sea ice changes, as well as the pattern effect of global sea surface temperature. Ignoring these factors could lead to overestimation of future climate warming and increased uncertainty in climate projections. Including the pattern effect in projections indicates a stronger counteracting force against warming than expected, potentially exceeding current climate goals.