For the first time, the world is able to limit global warming to below 2C, according to the first in-depth analysis of the net zero promises made by nations at the UN Cop26 climate summit in December.
Prior to these promises, temperatures above 2 ° C were more than likely to rise at the height of the climate crisis, with more serious consequences for billions of people. Now the peak temperature rise is more likely to be around 1.9C.
However, researchers said it was up to all nations to keep their promises on time and in full, and warned that policies were not in place. Promises include those that developing countries have said will not happen without more financial and technical support.
Achieving the promises needed to limit the 2C was a “historic milestone” and good news, scientists said. However, they said the bad news is that the currently planned global emissions cuts by 2030 are far from the way to keep the peak below 1.5C. This is the global goal, but there is currently less than a 10% chance of achieving that goal.
People around the world are already facing intensifying heat waves, floods and storms with 1.2 C heat caused by human emissions so far, and the Intergovernmental Panel on Climate Change (IPCC) warned in 2018 of much more bad if the heating lasts more than 1.5 C.
Access to the 2C border was “big news,” said Christoph McGlade of the International Energy Agency, a member of the team behind the new analysis. “This is the first time that governments have come up with specific goals that can keep global warming below the symbolic level of 2C.
“These results are clearly a cause for optimism,” he added. “We have come a long way since the signing of the Paris Agreement in 2015. But now the real work must begin. Promises are not yet backed by the strong and credible short-term policies needed to make them a reality. “
Professor Malte Meinshausen of the University of Melbourne, Australia, another member of the team, said the apparent limitation of 2C was a “historic milestone”.
But he said: “Our study also clearly shows that increased action is needed during this decade. Otherwise, we will break the remaining carbon budget by 1.5C. ” A major IPCC report earlier in April said global emissions must peak and begin to fall within 30 months to keep the 1.5C target alive.
The new analysis, published in the journal Nature, is the first peer-reviewed study to assess the peak temperature rise that would result from the fulfillment of the parties’ promises. It uses two independent modeling approaches, one of which evaluates more than 1,400 different scenarios and includes recent promises on emissions from shipping and aviation.
By the end of Cop26, 153 nations had made new climate promises at the United Nations, with countries responsible for 75% of global greenhouse gas emissions committed to reaching zero between 2050 and 2070. This made it possible to limit 2C, although scientists warned that uncertainty about how the planet reacts to rising emissions means there remains a 5% chance of temperatures above 2.8C.
Climate policies that are actually being implemented today would mean a peak of around 2.6 C, which will lead to “huge climate damage around the world,” McGlade said. The commitments made by the countries so far by 2030 have only reduced this peak to 2.4C. The IPCC said limiting heating to 1.5C requires a 45% reduction in CO2 emissions by 2030 compared to 2010.
But emissions are set to rise by 7-15% by 2030, a “sobering estimate,” scientists said, with any delay in action putting 1.5C “out of range.” If the world goes beyond this goal, then securing a “livable future” will rely on the massive deployment of technologies that can suck CO2 out of the air, as well as large-scale afforestation.
The new study gave a much clearer picture of our likely climate future, said Francis Moore of the University of California and Ziek Hausfater, head of climate research at Stripe, in a comment to Nature. They said this showed that the goal of strengthening the initial climate promises made in 2015 in Paris had been “partially realized”.
“But optimism must be contained until promises to reduce emissions in the future are backed by stronger short-term action,” they said. “It is easy to set ambitious climate goals for 30, 40 or even 50 years in the future, but it is much more difficult to implement policies [needed] today. ”
Moore and Hausfater also warned of the danger of geopolitical tensions, including Russia’s war in Ukraine: “It would be a mistake to rule out a future of resurgent nationalism that strains global cooperation and increases dependence on local fossil fuel resources. and a corresponding increase in emissions. “
“Politicians are at a crossroads,” McGlade said. “We can choose to limit emissions and deepen the energy crisis. Or we can use this moment to take an honest step towards a cleaner and safer future. “
McGlade said there are many policies that could have immediate or short-term effects on energy and climate crises, including reducing speed limits on roads, speeding up the deployment of renewable energy and electric vehicles, and halting methane emissions. greenhouse gas. , from oil and gas production facilities and instead put it into delivery.
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