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  1. Jan 2021
    1. Scientists at Lawrence Livermore National Laboratory in collaboration with colleagues from Nanjing University and Texas A&M University have re-evaluated how much future global warming is in the pipeline if atmospheric greenhouse gas concentrations were to remain fixed at present-day levels, a quantity known as committed warming. Their new analysis accounts for the fact that surface warming to date has been large in certain regions but small in others, which has temporarily allowed Earth to shed heat more efficiently. Ignoring this “pattern effect”, as has been done in previous studies, gives the false impression that Earth’s energy budget is nearly balanced and implies that committed warming is only about 1.3°C (2.3°F) above pre-industrial levels. The team’s updated estimate is substantially larger, with a most likely value of 2.3°C (4.1°F). 
    1. 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.
    1. Bericht über eine Fernsehsendung mit Michael Mann, bei der es insbesondere darum geht, dass ein rascher stop der CO2 Emissionen schon in wenigen Jahren dazu führen kann, dass sich die globale Erhitzung nicht länger fortsetzt.
