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Scientists call for studies on ‘climate endgame’

Could global warming be the end of humanity? It’s possible, researchers say, but remains largely unexplored.

(CN) — A team of international researchers want the global scientific community to investigate potential “climate endgame” scenarios, as current studies tend to take an optimistic focus on limiting global warming to 2.7 to 3.6 degrees Fahrenheit above pre-industrial levels.

The Proceedings of the National Academy of Sciences published “Climate Endgame: Exploring catastrophic climate change scenarios” on Monday, which addresses the lack of research on how anthropogenic — human-caused — climate change can result in worldwide societal collapse or human extinction.

“The best way of summarizing our perspective piece is that it’s a call for seriously considering and studying the plausible catastrophic scenarios of climate change,” said Luke Kemp, lead author and Research Associate at Centre for the Study of Existential Risk at the University of Cambridge.

“Despite 30 years of efforts and some progress under the United Nations Framework Convention on Climate Change (UNFCCC) anthropogenic greenhouse gas (GHG) emissions continue to increase,” the authors wrote. “Even without considering worst-case climate responses, the current trajectory puts the world on track for a temperature rise between 2.1 degrees Celsius (3.8 degrees Fahrenheit) and 3.9 degrees Celsius (7.02 degrees Fahrenheit) by 2100.”

Such temperatures have not been sustained on Earth’s surface since before the Pleistocene Epoch 2.6 million years ago. But even if humans manage to cap global warming at a 3.78 degree increase by 2100, the paper highlights how the world could face interacting risks and knock-on effects from famine, undernutrition, extreme weather events, human conflict and vector-borne disease. Such effects, Kemp noted, are rarely studied together and especially for global warming scenarios.

Climate-induced morbidity and mortality are just one aspect of understudied risks associated with climate change, as well. Societal fragility plays a key role in determining whether we’re headed for global catastrophe, while “extreme Earth system states” could heighten the likelihood of a mass extinction event.

“Research suggests that previous mass extinction events occurred due to threshold effects in the carbon cycle that we could cross this century,” the authors wrote. “Key impacts in previous mass extinctions, such as ocean hypoxia and anoxia, could also escalate in the longer term.”

According to the article, should global warming exceed 3.6 degrees Fahrenheit, research models of the West Antarctic ice sheet indicate irreversible loss we will not be able to restore even if temperatures returned to present state. “At a 6 degrees to 9 degrees Celsius (10.8 to 16.2 degrees Fahrenheit) rise in global temperature, slow, irreversible loss of the East Antarctic ice sheet and over 40 m (131.23 feet) of sea level rise equivalent could be triggered," the authors wrote.

Analyzing risks associated with societal fragility is even more complex, yet it provides a more realistic idea of what to expect with extreme climate change: conflict, disease, political change and economic crises. Among researchers, Kemp explained, “There’s a general consensus that climate impacts can worsen preexisting conflict, or even trigger it, especially in cases with ethnic tensions and poor governance.”

He added: “We don’t know how the relationship between climate and conflict unfolds at higher levels of warming."

But while researchers don’t know the relationship between how climate and conflict unfold at higher levels of warming, Kemp expects the risks to increase exponentially. “Which is what we see for numerous potential damages with climate change,” said Kemp.

Why the lack of research?

The lack of present research on worst-case scenarios is likely due to a few reasons, according to Kemp. “The goals of the 2015 Paris Climate Agreement have focused the scientific community on lower end warming, the merchants of doubts and the fossil fuel lobby make any talk of worse case scenarios automatically labeled as alarmism, and the fact that talking about pale risks of climate change is just much more difficult. It requires a more complex and intricate form of analysis.”

The way the global community addresses climate change is also impeding risk analysis of worst-case warming. “Right now, there’s a mismatch between what we know and what we need to know,” said Kemp. “The scenarios we have the most knowledge about tend to be the most. When you look at more extreme scenarios of, say, warming of up to 4 degrees Celsius (7.2 degrees Fahrenheit) or above, that is going to be much more impactful.”

He added: “If you’re doing any kind of risk management or analysis, you need to understand these possible catastrophic scenarios. They are vital to thinking about risk management and also the ones we know least about. That’s not a good basis for thinking about the future or making decision about climate change.”

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