Acceleration of changes in global surface temperature after the Earth system has crossed a tipping point

Abstract

Global surface temperature is an important indicator of climate change. Its long-term shifts reflect changes in the balance between absorbed global mean solar radiation and emitted thermal infrared radiation to space, plus natural climatic variability. Earth’s energy imbalance and the responses and feedbacks from many different and interacting Earth systems are all affecting global temperature, but the rhythms and sequence of events behind the ongoing trajectory of this key indicator remain elusive. Here we provide novel analyses of global surface temperature anomalies (GSTA) over the period 1880–2022 by means of a framework based on indicators of critical transition (multiscale variability, variance, autocorrelation and trend). Our analyses indicate that a tipping point was already crossed between 1965 and 1977 and that the climatic system has moved to a phase of critical transition. We identify a sequence of events that punctuate the transition and reveal that changes in global temperature are now severely accelerating. Theory indicates that, in the absence of large reductions in greenhouse gas emissions, the current global warming trend is expected to continue to escalate until an inflection point is eventually reached. These results are important because they suggest that regional consequences of global climate change on the different natural and human systems of our planet, including biodiversity, human health, socio-economic and geopolitical systems, may rapidly intensify and reach levels unseen in recent human history.