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As climate change continues to warm the planet, ice sheets and ocean currents can destabilize each other, resulting in a climate domino effect that affects 40% of the world’s population, according to new research.
These effects can be seen at much lower temperatures than previously thought.
Scientists conducted 3 million computer simulations of a climate model, and found that nearly a third resulted in catastrophic domino effects even when temperature increases were less than 3.6 degrees Fahrenheit (2 degrees Celsius) above pre-industrial levels, the upper limit set by the Paris Agreement. .
Climate tipping points are points of no return in the climate system. Once crossed, extreme and accelerating changes in the climate systems that support life on Earth could become irreversible, according to a report from the United Nations’ Intergovernmental Panel on Climate Change (IPCC). Live Science previously reported that some of these tipping points, such as the collapse of the West Antarctic ice sheet, may have already been passed.
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In order to simulate Earth’s climate on a computer, the researchers created a simplified model that focuses on how specific “dominoes” interact in global climate systems. Some of those dominoes were things like ice sheets, ocean currents, or weather patterns like El Nino, and the model basically simulated how to flip them — for example, by melting major ice sheets or slowing down the Atlantic conveyor belt that helps cool Europe’s climate — It will affect the other dominos in the chain. The model simulated more than 3 million possible scenarios, in which some dominoes more or less strongly interacted with each other.
The new study finds that collapsed ice sheets, such as those in West Antarctica and Greenland, were likely the starting point for upsurge of waterfalls. In one alarming scenario, cold waters and melting ice slowed the Atlantic current and then – by affecting the El Niño Southern Oscillation – dramatically reduced rainfall in the Amazon rainforest, potentially turning much of it into the savannah.
In another scenario, significant melting of Greenland’s ice sheet would release fresh water into the ocean and slow the Atlantic currents that transport heat from the tropics to the Arctic. This current slowdown will cause the Southern Ocean to warm, destabilizing the Antarctic ice sheets, which in turn will send meltwater into the ocean and eventually cause sea level to rise. The sea level rise will in turn cause more melting of the Greenland ice sheet.
And in many future simulations, climate changes have significantly affected coastal regions, where 2.4 billion people, or 40% of the world’s population, lived in 2017, according to the United Nations.
“We’re changing the odds, not in our favour – the risk obviously increases as our planet gets warmer,” said co-author Jonathan Donggs, a physicist at the Potsdam Institute for Climate Impact Research (PIK) in Germany. in the current situation. “It goes up dramatically between 1 and 3 [degrees] c. If greenhouse gas emissions and the resulting climate change cannot be stopped, the upper level of this warming range is likely to be exceeded by the end of this century. As temperatures rise, more inversion is expected, with devastating long-term effects.”
And we might already be on our way to some of those choppy streaks. In May, a separate study published in the Proceedings of the National Academy of Sciences showed that the Greenland Ice Sheet, the world’s second largest, is on the cusp of accelerated melting. The ice sheet lost 586 gigatons (532 gigatons) of mass in 2019, according to an August 2020 study. Another study published in the same month stated that the ice sheet may have already passed the point of no return.
The researchers say their research may actually underestimate how close Earth’s climate is to these tipping points, and that aggressive and rapid reductions in carbon dioxide emissions are vital to avoiding them.
“Our analysis is conservative in the sense that many interactions and transformation components have not yet been considered,” said study co-author Ricarda Winkelmann, professor of climate system analysis at the Potsdam Institute for Climate Impact Research (PIK) in Germany. statement. “It would therefore be a bold bet to hope that uncertainties play a good role, given what is at stake. From a precautionary perspective, rapid reduction of greenhouse gas emissions is indispensable to reduce the risk of crossing tipping points in the climate system, and potentially It causes domino effects.”
According to a 2018 report from the Intergovernmental Panel on Climate Change, compiled by the world’s leading climate scientists, carbon dioxide emissions must be halved by 2030 if the world is to remain within 2.7°F (1.5°C) of global warming – The threshold beyond which global ecosystems are crossed, food webs will be under severe pressure and small islands will be inundated. Leaders of the Group of Seven nations are meeting at a summit in Cornwall, England, this week, and will also meet in November in Glasgow, Scotland, at the United Nations Climate Change Conference, to further negotiate a path forward.
The researchers published their findings June 3 in the journal Earth System Dynamics.
Originally published on Live Science
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