Climate: Catastrophic consequences may occur… According to a study
Devastating effects. A warming of the planet above 1.5°C, the most ambitious objective of the Paris agreement, could trigger several climate “tipping points” that would generate catastrophic chain reactions, according to a study published Thursday in the journal Science.
And rising temperatures threaten to initiate five of these breakpoints, including the Antarctic and Greenland ice sheets, warn the study, but believe it is not too late to act. “For me, it will change the face of the world — literally, if you look from space,” with rising sea levels or destruction of forests, said Tim Lenton, one of the study’s leading authors. It had signed the first major publication on the subject in 2008.
Sixteen ‘tipping points’
A ‘tipping point’ is ‘a critical threshold beyond which a system reorganizes itself, often abruptly and/or irreversibly’, as defined by the UN Climate Expert Group (IPCC). These break points are phenomena that inextricably and independently trigger other cascading consequences. While early analyzes estimated the threshold to trigger warming within a range of 3-5°C, progress in climate observations and modeling, as well as in the reconstruction of past climates, has drastically lowered this assessment.
The study published in Science is a synthesis of more than 200 scientific publications, conducted in order to better predict the triggers of these breaking points. The authors identify nine major “tipping points” globally and seven regionally, sixteen in total. Of these, five are likely to be triggered by current temperatures, which have increased by nearly 1.2°C on average since the pre-industrial era: ice caps in Antarctica and Greenland, a sudden thaw of permafrost, the cessation of heat transfer in the Labrador Sea and the extinction of coral reefs. With warming to 1.5°C, four more points are changed from “possible” to “probable”, and five more become “possible”, according to the study.
“Sociological tipping point”
For the West Antarctic and Greenland ice sheets, crossing the breakpoint estimated by scientists would contribute, over hundreds of years, to a 10-meter rise in sea levels, says Tim Lenton of the British University of Exeter. If the destruction of coral reefs has already begun, rising temperatures could make the destruction permanent, affecting the 500 million people who depend on it. About 20 Minutes.
In the Labrador Sea, a heat exchange (or convection) phenomenon that brings warm air to Europe could be disrupted, with colder winters, as the continent had known during the small ice age. An accelerated thaw of permafrost would release huge amounts of greenhouse gases and profoundly alter landscapes in Russia, Canada and Scandinavia. With warming to 1.5°C, a major Atlantic marine current (AMOC) would be disrupted and at 2°C, monsoons in West Africa and the Sahel and the Amazon forest would be disrupted, which could then turn into savannah.
A “sociological tipping point”
These devastating effects depend on how long the warming lasts, says lead author David Armstrong McKay: if 1.5°C sets in for 50 or 60 years, the planet will face the worst consequences. But these “tipping points” will do little to worsen warming itself, he adds, believing that humanity can still limit the damage for the future. “It’s always worth cutting our emissions as quickly as possible,” the scientist pleads.
Tim Lenton, one of the world’s leading experts on the topic, wants to believe that this concept of rupture can translate more positively in the fight against the climate crisis, as a “sociological tipping point” that encourages action. “That’s how I get up in the morning,” he says. “Can we change, transform our lifestyles? Thinking systemically, with this idea of breaking point, gives us a glimmer of hope.”
