SUBSCRIBE TO OUR FREE NEWSLETTER
Daily news & progressive opinion—funded by the people, not the corporations—delivered straight to your inbox.
5
#000000
#FFFFFF
To donate by check, phone, or other method, see our More Ways to Give page.
Daily news & progressive opinion—funded by the people, not the corporations—delivered straight to your inbox.
"Only by doing much more in this critical decade to bring emissions down and peak temperatures as low as possible, can we effectively limit damages."
Just over a month away from the next United Nations climate summit, a study out Wednesday warns that heating the planet beyond a key temperature threshold of the Paris agreement—even temporarily—could cause "irreversible impacts."
The 2015 agreement aims to limit global temperature rise this century to 1.5ºC, relative to preindustrial levels.
"For years, scientists and world leaders have pinned their hopes for the future on a hazy promise—that, even if temperatures soar far above global targets, the planet can eventually be cooled back down," The Washington Post detailed Wednesday. "This phenomenon, known as a temperature 'overshoot,' has been baked into most climate models and plans for the future."
"The earlier we can get to net-zero, the lower peak warming will be, and the smaller the risks of irreversible impacts."
As lead author Carl-Friedrich Schleussner said in a statement, "This paper does away with any notion that overshoot would deliver a similar climate outcome to a future in which we had done more, earlier, to ensure to limit peak warming to 1.5°C."
"Only by doing much more in this critical decade to bring emissions down and peak temperatures as low as possible, can we effectively limit damages," stressed Schleussner, an expert from Climate Analytics and the International Institute of Applied Systems Analysis who partnered with 29 other scientists for the study.
The paper, published in the peer-reviewed journal Nature, states that "for a range of climate impacts, there is no expectation of immediate reversibility after an overshoot. This includes changes in the deep ocean, marine biogeochemistry and species abundance, land-based biomes, carbon stocks, and crop yields, but also biodiversity on land. An overshoot will also increase the probability of triggering potential Earth system tipping elements."
"Sea levels will continue to rise for centuries to millennia even if long-term temperatures decline," the study adds, projecting that every 100 years of overshoot could lead seas to rise nearly 16 inches by 2300, on top of more than 31 inches without overshoot.
The scientists found that "a similar pattern emerges" for the thawing of permafrost—ground that is frozen for two or more years—and northern peatland warming, which would lead to the release of planet-heating carbon dioxide and methane. They wrote that "the effect of permafrost and peatland emissions on 2300 temperatures increases by 0.02ºC per 100 years of overshoot."
"To hedge and protect against high-risk outcomes, we identify the geophysical need for a preventive carbon dioxide removal capacity of several hundred gigatonnes," the authors noted. "Yet, technical, economic, and sustainability considerations may limit the realization of carbon dioxide removal deployment at such scales. Therefore, we cannot be confident that temperature decline after overshoot is achievable within the timescales expected today. Only rapid near-term emission reductions are effective in reducing climate risks."
In other words, as co-author and Climate Analytics research analyst Gaurav Ganti, put it, "there's no way to rule out the need for large amounts of net negative emissions capabilities, so we really need to minimize our residual emissions."
"We cannot squander carbon dioxide removal on offsetting emissions we have the ability to avoid," Ganti added. "Our work reinforces the urgency of governments acting to reduce our emissions now, and not later down the line. The race to net-zero needs to be seen for what it is—a sprint."
While the paper comes ahead of COP29, the U.N. conference in Azerbaijan next month, co-author Joeri Rogelj looked toward COP30, for which governments that have signed the Paris agreement will present their updated nationally determined contributions (NDCs) to meet the climate deal's goals.
"Until we get to net-zero, warming will continue. The earlier we can get to net-zero, the lower peak warming will be, and the smaller the risks of irreversible impacts," said Rogelj, a professor and director of research for the Grantham Institute at Imperial College London. "This underscores the importance of countries submitting ambitious new reduction pledges, or so-called 'NDCs,' well ahead of next year's climate summit in Brazil."
The U.N. said last November that countries' current emissions plans would put the world on track for 2.9°C of 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.
The study in Nature was published as Hurricane Milton—fueled by hot waters in the Gulf of Mexico—barreled toward Florida and just a day after another group of scientists wrote in BioScience that "we are on the brink of an irreversible climate disaster. This is a global emergency beyond any doubt. Much of the very fabric of life on Earth is imperiled."
Those experts emphasized that "human-caused carbon dioxide emissions and other greenhouse gases are the primary drivers of climate change. As of 2022, global fossil fuel combustion and industrial processes account for approximately 90% of these emissions, whereas land-use change, primarily deforestation, accounts for approximately 10%."
The release of mercury from permafrost "could take a huge toll on the environment and the health of those living in these areas," said a co-author of the new study.
A study published Thursday in Environmental Research Letters warns that Arctic warming could unleash toxic mercury currently contained in rapidly thawing permafrost, potentially threatening the region's food supply and water quality.
Researchers from the University of Southern California's Dornsife College of Letters, Arts, and Sciences noted in the new study that the Arctic is "warming four times faster than the global average, destabilizing permafrost soils that have remained frozen for two or more years and that underlie much of the Arctic."
Mercury (Hg) deposits in the region's permafrost have "accumulated over thousands of years," the study authors noted, "and Hg in the top meter of Arctic soils potentially exceeds the total amount stored in the atmosphere, ocean, and all other soils."
Josh West, professor of Earth sciences and environmental studies at USC Dornsife and a study co-author, said in a statement that "there could be this giant mercury bomb in the Arctic waiting to explode."
The study notes that "a range of processes" can release mercury from permafrost, including riverbank erosion.
"The rivers are reburying a considerable amount of the mercury," West said. "To really get a handle on how much of a threat the mercury poses, we have to understand both the erosion and reburial processes."
Isabel Smith, a doctoral candidate at USC Dornsife and another study co-author, warned that "decades of exposure" to the toxic element, "especially with increasing levels as more mercury is released, could take a huge toll on the environment and the health of those living in these areas."
The study was published as parts of the Arctic experienced what The Washington Post's Ian Livingston described as "exceptionally high temperatures—up 30 to 40 degrees above normal."
"And it's happening as the National Oceanic and Atmospheric Administration just announced July was the 14th successive month with record-high global temperatures," Livingston wrote earlier this week. "Over the past week, temperatures soared to nearly 100 degrees Fahrenheit in Norman Wells, Canada, just 90 miles south of the Arctic Circle. Locations in Alaska set numerous record highs."
"Off the coast of Greenland, Longyearbyen, Norway, the northernmost city on Earth with a sizable population, witnessed its warmest August day, with a high of nearly 70," he added.
As our world continues to warm up, vast areas of permafrost are rapidly melting, releasing material that's been trapped for up to a million years. This includes uncountable numbers of microbes that have been lying dormant for hundreds of millennia.
To study these emerging microbes, scientists from the French National Center for Scientific Research have now revived a number of these "zombie viruses" from the Siberian permafrost, including one thought to be nearly 50,000 years old - a record age for a frozen virus returning to a state capable of infecting other organisms.
The team behind the study, led by microbiologist Jean-Marie, says these ancient viruses are potentially a significant threat to public health, and further study needs to be done to assess the danger that these infectious agents could pose as the permafrost melts.
The researchers warned it may just be the tip of the iceberg:
"One-quarter of the Northern Hemisphere is underlain by permanently frozen ground, referred to as permafrost," researchers wrote in the paper.
"Due to climate warming, irreversibly thawing permafrost is releasing organic matter frozen for up to a million years, most of which decomposes into carbon dioxide and methane, further enhancing the greenhouse effect. Part of this organic matter also consists of revived cellular microbes (prokaryotes, unicellular eukaryotes) as well as viruses that remained dormant since prehistorical times."
\u201cA 48,500-year-old virus has been revived from Siberian permafrost\nSeven viruses from the Siberian permafrost have been revived and replicated themselves in the lab \u2013 including the oldest revived so far\nhttps://t.co/mMGMXEBdsy\u201d— Samuel Jacobs (@Samuel Jacobs) 1669399746
According to Global News:
In 2014, the same researchers unearthed a 30,000-year-old virus trapped in permafrost, the BBC reported. The discovery was groundbreaking because after all that time, the virus was still able to infect organisms. But now, they've beaten their own record by reviving a virus that is 48,500 years old.
"If the authors are indeed isolating live viruses from ancient permafrost, it is likely that the even smaller, simpler mammalian viruses would also survive frozen for eons," virologist Eric Delwart from the University of California, San Francisco told New Scientist.
\u201cOkay. I've seen this movie and it didn't end well...and seriously what's that name again?\n\nPandoravirus? \ud83d\ude2c\n\n"The revived virus has been given the name Pandoravirus yedoma, which acknowledges its size and the type of permafrost soil that it was found in."\nhttps://t.co/F5yHqCTZv9\u201d— Chris Hendel (@Chris Hendel) 1669408433