The possibility of a chain of disasters from global warming is “dangerously underexposed” by the international community, scientists warn in a study published Tuesday. They are calling on the world to consider the worst in order to better prepare for it.
In an article published in the journal PNAS (Proceedings of the National Academy of Sciences), the researchers argue that too little work has been done on the mechanisms that can lead to risk “catastrophic” and “irreversible” for humanity: for example, if the temperature rises are worse than expected or if they cause a cascade of events not yet foreseen, or both.
“It’s about the scenarios that matter most, that we know least”writes Luke Kemp of the Center for the Study of Existential Risk in Cambridge.
The more research into global climate tipping points – such as the irreversible melting of the ice sheets or the loss of the Amazon rainforest – increases, the more it becomes necessary to consider risk scenarios in climate modeling. , explains Johan Rockström, director, of the Potsdam Institute for Climate Impacts and co-author.
“The roads to disaster are not limited to the direct effects of high temperatures, such as extreme weather conditions. Ripple effects such as financial crises, conflicts and new epidemics can lead to further calamities and hinder recovery from potential disasters such as nuclear war.”adds Luke Kemp.
In response, the team proposes a research program to help governments combat the “four horsemen” of the “climate apocalypse”: famine and malnutrition, extreme weather, conflict and vector-borne diseases.
The authors point out that successive scientific reports from UN climate experts (IPCC) have focused mainly on the predicted effects of a warming of 1.5 to 2°C.
But current government actions are instead putting the Earth on a trajectory of 2.7°C of warming by the end of the century, far from the 1.5°C targeted by the Paris Agreement in 2015.
The study suggests that a certain scientific tendency to “prefer the least worst case scenario” has led to insufficient attention for the possible effects of a warming of 3°C or more.
These researchers calculated that extreme heat zones – with an average annual temperature of more than 29°C – could affect two billion people by 2070.
These temperatures pose a major risk of “breadcrumbs” from droughts such as those currently in Western Europe and heatwaves such as those that hit the wheat crop in India in March/April.