A firefighter works to contain a tactical fire in Louchats, as wildfires continue to spread in the Gironde region of southwestern France, July 17, 2022

Catastrophic effects of climate change ‘dangerously underexplored’

Image credit: Reuters/Sarah Meyssonnier

Climate scientists have warned in a new report that far too little work has gone into understanding the risks global warming might pose to the survival of humanity.

The authors of the study said the potential for climate change to lead to worldwide societal collapse or even human extinction is a “dangerously underexplored topic”.

According to the authors, although the catastrophe has a small chance of occurring, given the uncertainties in future emissions and the climate system, we should not rule out cataclysmic scenarios.

“Facing a future of accelerating climate change while blind to worst-case scenarios is naïve risk management and fatally foolish at worst,” the scientists said, adding that there were “ample reasons” to suspect global heating could cause an apocalyptic disaster.

The international team of experts argues the world needs to prepare for the possibility of a “climate endgame”. “Analysing the mechanisms for these extreme consequences could help galvanise action, improve resilience, and inform policy,” they said.

The extensive analysis proposes a research agenda, which includes what the researchers call the “four horsemen” of the “climate endgame”: famine, extreme weather, war, and disease.

“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,” he added. “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.”

A dozen scientists reviewed the analysis, published in the journal Proceedings of the National Academy of Sciences. It argues that the consequences of global heating beyond 3°C have been under-examined, with few quantitative estimates of the total impacts.

Using climate models, the analysis shows that extreme heat - defined as an annual average temperature of more than 29°C - could affect two billion people living in some of the most politically fragile areas of the world by 2070, if carbon emissions continue.

“Such temperatures currently affect 30 million people in the Sahara and Gulf Coast,” said Chi Xu, at Nanjing University in China, who was part of the team. “By 2070, these temperatures and the social and political consequences will directly affect two nuclear powers, and seven maximum containment laboratories housing the most dangerous pathogens. There is serious potential for disastrous knock-on effects.”

It’s not just high temperatures that are the problem, it’s the compound and knock-on effects such as food or financial crises, conflicts or disease outbreaks that have the potential for disaster, according to the report.

The researchers also stressed there should be more focus on identifying potential tipping points, where increasing warmth triggers another natural event that drives temperatures up even more – such as methane emissions from melting permafrost or forests that start emitting carbon rather than soaking it up.

Carrying out the research would allow scientists to consider emergency options such as climate engineering which might involve pumping coolants into the atmosphere, according to the researchers.

Furthermore, the analysis may also pave way for researchers to carry out a risk analysis for these drastic interventions compared to the worst effects of climate change. Focusing on the worst-case scenarios could also help inform the public – and might actually make the outcomes less likely.

To properly assess all these risks, the team is calling for the Intergovernmental Panel on Climate Change to carry out a special report on the issue. The IPCC report on the impacts of just 1.5°C of heating drove a “groundswell of public concern”, the researchers said.

“The more we learn about how our planet functions, the greater the reason for concern,” said Professor Johan Rockström, at the Potsdam Institute for Climate Impact Research in Germany. “We increasingly understand that our planet is a more sophisticated and fragile organism. We must do the maths of disaster in order to avoid it.”

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