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Global warming is expected to exceed the threshold set by the 2015 Paris Agreement, but the extent to which this will occur is unknown.
A new study by scientists at the Department of Energy’s Pacific Northwest National Laboratory, the University of Maryland, and the U.S. Environmental Protection Agency finds that current climate pledges are insufficient to meet the goals of the 2015 Paris Agreement. , global warming exceeds 1.5 degrees[{” attribute=””>Celsius limit.
The research suggests that the only way to minimize the extent of this overshoot is for countries to adopt more ambitious climate pledges and decarbonize their economies at a faster pace. This will help to reduce the amount of time that the planet spends in a warmer state.
While exceeding the 1.5-degree limit appears inevitable, the researchers chart several potential courses in which the overshoot period is shortened, in some cases by decades. The study was published recently published in the journal Nature Climate Change.
“Let’s face it. We are going to breach the 1.5 degrees limit in the next couple of decades,” said corresponding author and PNNL scientist Haewon McJeon. “That means we’ll go up to 1.6 or 1.7 degrees or above, and we’ll need to bring it back down to 1.5. But how fast we can bring it down is key.”
PNNL researchers Gokul Iyer and Yang Ou, authors of the new study, reveal their findings.Pacific Northwest National Laboratory
Reducing overshoot by even a second means less time to deal with some of the most damaging effects of global warming, from extreme weather to rising sea levels. Abandoning or delaying more ambitious goals could lead to “irreversible and adverse effects on human and natural systems,” says the Joint Global Change Institute, a partnership between PNNL and the University of Maryland. said lead author Gokul Iyer, who is working alongside his McJeon on .
“Moving fast means reaching net-zero pledges sooner, accelerating decarbonization and meeting more ambitious emissions targets,” said Iyer. “Even a little bit helps. Everything has to be combined. But our results show that the most important thing is to do it early. We’re doing it now, really.”
During COP26 in 2021, the same research team found that the then-renewed pledges could significantly increase the chances of limiting warming to 2 degrees Celsius above pre-industrial levels. In their new paper, the authors take additional steps to answer the question of how to move the needle from his 2 degrees to his 1.5 degrees.
“Our 2021 pledges don’t add up to nearly 1.5 degrees. says. “Here, we seek to provide scientific support to help answer the following question: What type of ratchet mechanism will return us to 1.5 degrees or less of his? That’s the motivation behind the paper.”
way to proceed
The authors model the scenarios, modeling a total of 27 emission pathways according to their respective targets, to see how much warming will follow what course of action. At a basic level, the authors assume that countries will meet their emissions commitments and long-term strategies on schedule.
In a more ambitious scenario, the authors model how much warming would be limited if countries accelerated decarbonisation and brought forward their net-zero pledge dates. Their results underscore the importance of “stepping up short-term targets”, which entails rapidly reducing carbon emissions from all sectors of the energy system immediately and by 2030. I’m here.
For example, if countries maintain their nationally determined contributions until 2030 and follow a minimum decarbonization rate of 2%, global carbon dioxide levels will not reach net zero during this century.
However, the most ambitious path outlined could lead to net zero carbon emissions by 2057. Such a path, the authors write, will be marked by “rapid transformation of the entire global energy system” and “expansion of low-carbon technologies.” These include renewable energy, nuclear energy, and carbon capture and storage. ”
“Technologies that can help us achieve zero emissions include renewable energy, hydrogen, electric vehicles, etc. Of course they are important players,” Iyer said. “Another important piece of the puzzle is technology that can remove carbon dioxide from the atmosphere, such as direct air capture or nature-based solutions.”
The most ambitious scenarios outlined in their work are intended to show the paths offered. But a key point is clear through all the scenarios modeled. After temperatures rise above 1.5 degrees soon, he will need more ambitious climate pledges to re-reach 1.5 degrees.
See: “Ratcheting of Climate Commitments Needed to Limit Global Warming Peaks” Gokul Iyer, Yang Ou, James Edmonds, Allen A. Fawcett, Nathan Hultman, James McFarland, Jay Fuhrman, Stephanie Waldhoff, and Haewon By McJeon, 10 Nov 2022, nature climate change.
DOI: 10.1038/s41558-022-01508-0
This research was funded by the US Environmental Protection Agency.
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