Yves here. As Helene and Milton deliver a one-two punch to the Southeast US, and many parts of the world are besieged by record heat and widespread flooding and crop damage, new research provides further assurance that we cannot afford more climate inaction. or rationalizations. Exceeding the global temperature increase limit of 1.5°C will have very long-term consequences and is likely to cause declines such as methane emissions from melting permafrost.
By Jessica Corbett, staff writer at Common Dreams. Originally published in Common Dreams
With more than a month to go until the next United Nations climate conference, a study released Wednesday warned that heating the planet above the Paris accord’s critical temperature limit—even temporarily—could cause “irreversible impacts.”
The 2015 agreement aims to limit global warming this century to 1.5ºC, compared to pre-industrial levels.
“For years, scientists and world leaders have pinned their hopes for the future on a bleak promise—that, even if temperatures rise above the global target, the planet may be brought down again,” The Washington Postdetailed on Wednesday. “This phenomenon, known as a temperature ‘overshoot’, is included in many climate models and projections for the future.”
As lead author Carl-Friedrich Schleussner said in a statement, “This paper dispels any idea that overshooting will bring the same climate effect in the future where we did more, in the past, to ensure a reduction in peak temperatures to 1.5°C.” .”
“Only by doing more in this critical decade to reduce pollution and extreme temperatures, we can effectively reduce the damage,” emphasized Schleussner, an expert in Climate Analytics and the International Institute of Applied Systems Analysis in collaboration with 29 others. research scientists.
The paper, published in a peer-reviewed journal The environmentstates that “in the chain of climate impacts, there is no expectation of immediate reversal after the rain has passed. These include changes in ocean depth, marine biogeochemistry and abundance of animal species, land-based biomes, carbon stocks, and crop yields, but also biodiversity on Earth. The overshoot will also increase the likelihood of triggering potential Earth system events.”
“Sea levels will continue to rise for centuries to millennia even if long-term temperatures decline,” the study adds, noting that every 100-year flood could lead to sea levels rising by about 16 centimeters by 2300, more than -31 without skipping.
The scientists found that “the same pattern is emerging” of melting permafrost—soil that has been frozen for two years or more—and the warming of northern peatland, which could lead to the release of planet-warming carbon dioxide and methane. They write that “the output of permafrost and peatland at 2300 degrees Celsius increases by 0.02ºC per century of extreme warming.”
Paper inside @Imvelo raises concerns about the growing use and acceptance of climate change scenarios, where warming is allowed to temporarily exceed the Paris limit of 1.5 °C. pic.twitter.com/IM2zR2UdVU
— Nature Portfolio (@NaturePortfolio) October 9, 2024
“In order to hedge and protect against high-risk impacts, we see a geophysical need to limit carbon dioxide emissions by several hundred gigatonnes,” the authors note. “However, technical, economic, and sustainability considerations may limit the detection of carbon dioxide emissions at such scales. Therefore, we cannot be sure that the temperature drop after overshooting can be achieved within the time frames expected today. Only near-term emissions reductions are effective in reducing climate risks.”
In other words, as the author and analyst of the study of Climate Analytics Gaurav Ganti, put it, “there is no way to remove the need for large energy net negative emissions, so we really need to reduce our remaining emissions.”
“We cannot waste carbon dioxide emissions on offset emissions that we have the power to avoid,” added Ganti. “Our work reinforces the urgency for governments to play a role in reducing our pollution now, not later. The net-zero race needs to be seen for what it is—a race.”
While this paper comes before COP29, the UN conference in Azerbaijan next month, co-author Joeri Rogelj looks to COP30, where the governments that have signed the Paris agreement will present their updated nationally determined contributions (NDCs) to meet the goals of the climate agreement. .
“Until we reach net-zero, warming will continue. “If we get to net-zero sooner, the lower the temperature will be, the less the risk of irreversible impacts,” said Rogelj, professor and director of research at the Grantham Institute at Imperial College London. “This underscores the importance of countries delivering new ambitious reduction pledges, or so-called ‘NDCs,’ ahead of next year’s climate conference in Brazil.”
New study: “hitting past climate goals is more dangerous than first thought”. My sense is that they are right. There are many bottlenecks in the climate system that may not be reversible except on very long time scales.
— Jonathan Overpeck (@GreatLakesPeck) October 9, 2024
The UN said last November that current emissions plans would put the world on course for 2.9°C warming by 2100, nearly double the Paris target. Since then, scientists have confirmed that 2023 was the hottest year in human history and warned that 2024 is expected to set a new record.
Research on The environment was published as Hurricane Milton—fueled by warm waters in the Gulf of Mexico—struck Florida and just a day after another group of scientists wrote BioScience that “we are on the brink of an irreversible climate crisis. This is a global emergency without a doubt. A large proportion of life on Earth is at risk.”
Those experts emphasize that “human-caused emissions of carbon dioxide and other greenhouse gases are the main cause of climate change.” As of 2022, global fossil fuel burning and industrial processes account for about 90% of these emissions, while land-use change, primarily deforestation, accounts for about 10%.