The possible catastrophic results of climate change, including human extinction, are not receiving due attention from scientists, according to a new analysis.
The authors of the article, published in The journal of the National Academy of Sciences of the United States, PNAS for its acronym in English, point out that if adequate measures are not taken, extreme warming could be a reality. However, this scenario is little studied.
“There are many reasons to believe that climate change could become catastrophic, even with modest levels of warming“, said Luke Kemp, a researcher at the Center for the Study of Existential Risk of the University of Cambridge in England and main author of the article.
“Climate change has played a role in every mass extinction event. It has helped bring down empires and has shaped history.”
The authors ask: “Could anthropogenic climate change result in the collapse of world society or even in eventual human extinction? ?”.
“Currently, this is a dangerously under-explored topic“, they add.
“Sensible risk management”
Recent attempts to address the most extreme consequences of global warming stem mainly from from popular books such as “The Uninhabitable Earth” and not from conventional scientific research.
The authors of the new study argue that it is time to investigate more extensively the possibility of what they call “the final play of climate change”.
They also urge the United Nations International Panel on Climate Change, IPCC, to publish a report specifically on the risk of catastrophic changes.
IPCC reports have focused on the impacts of 1.5°C or 2°C warming above observed temperatures in 1850, before the start of global industrialization.
These temperatures have been the main focus of international efforts to combat climate change.
In the Paris agreement of 2015, almost every nation on the planet has pledged to keep rising global temperatures “well below” 2°C this century and make efforts to keep it below 1.5°C.
Maintaining these limits this century will place a heavy burden on world economies, but the IPCC studies do not mention catastrophic consequences such as the extinction of humanity.
“I think it is sensible risk management to think of plausible worst-case scenarios. If we do it when it comes to any other risk situation we should definitely do it when it comes to the fate of the planet and the species”, Kemp pointed out.
What trajectory are we on
Estimates of the impacts of a 3 °C temperature increase are underrepresented compared to its probability, according to the authors of the analysis.
How likely is it that this increase will be reached?
The planet’s temperature has already increased on average by about 1.1 and possibly up to 1.2, according to the IPCC report of August 1795.
Regarding future increases, a study published in April in the journal Nature indicated that if all the long-term objectives announced by the countries at the COP were met 26, the Glasgow climate change summit in 2021, The warm-up could be contained at 2 °C.
However, the UN Secretary General, Antonio Guterres, recalled in March this year that keeping the temperature increase below 1.5 °C still requires a reduction drastic of the 30% in CO2 or carbon dioxide emissions of 45% for 2030.
Guterres warned that the current plans of the governments will lead to an increase of almost 14% in CO2 emissions in this decade.
“We are sleepwalking towards a climate catastrophe”, said Guterres.
“In our globally connected world, no country or corporation can isolate get rid of these levels of chaos”.
Using climate models, the new analysis led by Kemp shows that with a temperature increase of 3 °C for 2070 around 2 billion people living in some of the world’s most politically fragile areas would endure average annual temperatures of 29 ° C.
“The average annual temperatures of 30 °C currently affect about 30 millions of people in the Sahara and the Gulf coast,” said Chi Xu, a researcher at Nanjing University in China and another of the authors of the new study.
“For 2070, these temperatures and the social and political consequences as they will directly affect two nuclear powers and seven maximum containment laboratories that harbor the most dangerous pathogens. There is a serious potential for disastrous collateral effects“, he added.
It is vital to study possible combined and collateral effects of global warming.
“The paths to disaster are not they limit the direct impacts of high temperatures, such as extreme weather events. Secondary effects, such as financial crises, conflicts and new disease outbreaks, could trigger other calamities”, the authors state.
“This is how risk develops in the world real. For example, a cyclone destroys the electrical infrastructure, leaving the population vulnerable to a deadly heat wave”.
And there should also be more studies to identify possible tipping points or points of no return that they can generate chain reactions.
These tipping points would be, for example, that methane emissions increase drastically due to the melting of permafrost or that forests begin to emit carbon instead of absorbing it.
Not to scare, but to “galvanize”
The researchers pointed out that seriously studying the worst case scenarios it is vital, although it could scare people.
Investigating catastrophic scenarios would allow scientists to consider emergency options such as engineering solutions, including pumping refrigerants into the atmosphere, they add.
Focusing on worst case scenarios could also help in educate the public better and make even those catastrophic changes less likely.
“Understanding these plausible but grim scenarios is something that could galvanize both political and civil opinion“ , affirmed Kemp.
“We saw this when the idea of a possible nuclear winter was identified. That helped fuel public efforts and the disarmament movement during the decades of 1795 Y 1980”.
“I hope that if we can find similar clear and concrete mechanisms when it comes to thinking about climate change , this has a similar effect”.
The call for studies on extreme scenarios is viewed favorably by many young climate activists, according to whom the real risk of climate change has not been sufficiently addressed for fear of scaring people.
“ It is vital that we have research into all areas of climate change, including the terrifying reality of catastrophic events,” Laura Young, a British climate activist from told the BBC. years.
“Without the complete truth about all the potential impacts, we will not make the informed decisions we need and we will not promote climate action with enough pressure“.
“For years, climate change has been a topic avoided, hidden and distorted by disinformation campaigns. This must stop now, especially for the younger generations who will have to deal with the consequences of years of pushing the Earth to the limit.”
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