Scientists say there are ample reasons to suspect global heating could lead to catastrophe
The risk of global societal collapse or human extinction has been “dangerously underexplored”, climate scientists have warned in an analysis.
They call such a catastrophe the “climate endgame”. Though it had a small chance of occurring, given the uncertainties in future emissions and the climate system, cataclysmic scenarios could not be ruled out, they said.
“Facing a future of accelerating climate change while blind to worst-case scenarios is naive risk management at best and fatally foolish at worst,” the scientists said, adding that there were “ample reasons” to suspect global heating could result in an apocalyptic disaster.
The international team of experts argue the world needs to start preparing for the possibility of the climate endgame. “Analysing the mechanisms for these extreme consequences could help galvanise action, improve resilience, and inform policy,” they said.
Explorations in the 1980s of the nuclear winter that would follow a nuclear war spurred public concern and disarmament efforts, the researchers said. The analysis proposes a research agenda, including what they call the “four horsemen” of the climate endgame: famine, extreme weather, war and disease.
They also called for the Intergovernmental Panel on Climate Change to produce a special report on the issue. The IPCC report on the impacts of just 1.5C of heating drove a “groundswell of public concern”, they said.
“There are plenty of reasons to believe climate change could become catastrophic, even at modest levels of warming,” said Dr Luke Kemp at the University of Cambridge’s Centre for the Study of Existential Risk, who led the analysis. “Climate change has played a role in every mass extinction event. It has helped fell empires and shaped history.
“Paths to disaster are not limited to the direct impacts of high temperatures, such as extreme weather events. Knock-on effects such as financial crises, conflict and new disease outbreaks could trigger other calamities.”
The analysis is published in the journal Proceedings of the National Academy of Sciences and was reviewed by a dozen scientists. It argues that the consequences of global heating beyond 3C have been underexamined, with few quantitative estimates of the total impacts. “We know least about the scenarios that matter most,” Kemp said.
A thorough risk assessment would consider how risks spread, interacted and amplified, but had not been attempted, the scientists said. “Yet this is how risk unfolds in the real world,” they said. “For example, a cyclone destroys electrical infrastructure, leaving a population vulnerable to an ensuing deadly heatwave.” The Covid pandemic underlined the need to examine rare but high-impact global risks, they added.