Can global warming be limited to below 2°C?

The goal of limiting global warming to 1.5°C will fail unless immediate action is taken, scientists warn.

For the first time, the world is in a position to limit global warming to below 2C, according to the first in-depth analysis of the net zero pledges made by nations at the COP26 United Nations climate summit in December.

Before these promises, it was more than likely that at the height of the climate crisis, there would be a temperature increase of more than 2°C, leading to more severe impacts for billions of people. The maximum temperature increase is now more likely to be around 1.9°C.

However, the researchers said that depended on all nations fully and on time implementing their pledges, and warned that the policies to do so did not exist. Pledges also include those that developing countries believe will not materialize without more financial and technical support.


A small big step

Achieving the promises needed for the 2C limit was a “historic milestone” and welcome news, the scientists said. However, they said the bad news was that the global emissions cuts currently projected for 2030 fell far short of keeping the peak below 1.5C. This is the global target, but there is currently less than a 10% chance of achieving this target.

People around the planet are already facing increasingly intense heat waves, floods and storms with the 1.2°C warming caused by humanity’s emissions to date, and the Panel intergovernmental experts on climate change (IPCC) warned in 2018 of much worse things if warming continues above 1.5C

Good news on global warming

The 2C limit of global warming within reach was “great news”, said the International Energy Agency’s Christophe McGlade, a member of the team behind the new analysis. “This is the first time that governments have come up with specific targets that can keep global warming below the symbolic level of 2C.”

“These results clearly give rise to optimism,” he added. “We have come a long way since signing the Paris Agreement in 2015. But now the real work must begin. The promises have not yet been backed by the strong and credible short-term policies needed to deliver them.

Professor Malte Meinshausen, from the University of Melbourne, Australia, another member of the team, said having the 2C limit in sight was a “historic milestone”.

But he said: “Our study also clearly shows that further action is needed in this decade. Otherwise, we’re going to blow the remaining carbon budget by 1.5C.” A major IPCC report released in early April said global emissions must peak and start falling within 30 months to maintain the 1.5C target. ° C alive.

The new analysis on global warming

Published in the journal Nature, it is the first peer-reviewed study to estimate the maximum temperature increase that would result if countries met their pledges. It used two independent modeling approaches, one of which assessed over 1,400 different scenarios and included recent commitments on shipping and aviation emissions.

By the end of COP26, 153 nations had submitted new climate pledges to the UN, with countries responsible for 75% of global greenhouse gas emissions pledging to reach net zero between 2050 and 2070. makes the 2C cap a possibility, although scientists have warned that uncertainties over how the planet responds to rising emissions mean there remains a 5% chance the temperature will rise above 2.8C.

Climate policies currently in place would mean a peak of around 2.6C, causing “massive climate damage worldwide”, McGlade said. Commitments made by countries until 2030 have only reduced this peak to 2.4°C. The IPCC said limiting heating to 1.5°C requires reducing CO2 emissions by 45% by 2030 compared to 2010.

But emissions were on track to increase between 7% and 15% by 2030 – a “sobering assessment”, the scientists said – and any delay in action would put 1.5C “out of reach. “. If the world exceeds this target, ensuring a “sustainable future” will depend on a massive deployment of technologies capable of absorbing CO2 from the air, as well as large-scale reforestation.

The new research has given a much clearer picture of our likely climate future, said Frances Moore of the University of California and Zeke Hausfather, head of climate research at Stripe, commenting in Nature. They said it showed the goal of building on the initial climate commitments made in 2015 in Paris had been “partially achieved”.

Geopolitics jeopardizes everything

“But optimism must be curbed until pledges to cut emissions in the future are backed by stronger near-term action,” they said. “It is easy to set ambitious climate goals 30, 40 or even 50 years into the future, but it is much more difficult to implement the policies [necesarias] today”.

Moore and Hausfather also warned of the danger of geopolitical tensions, including Russia’s war in Ukraine: “It would be wrong to reject a future characterized by a resurgence of nationalism that strains global cooperation and leads to greater dependence on resources”. fossil fuels and a corresponding increase in emissions”.

“Policymakers are at a crossroads,” McGlade said. “We can choose to block emissions and make the energy crisis worse. Or we can use this moment to take an honest step towards a cleaner, safer future.

McGlade said many policies could have immediate or short-term impacts on the energy and climate crises, including lowering speed limits on highways, accelerating the rollout of renewables and electric vehicles, and halting venting methane, a potent greenhouse gas. , oil and gas production facilities and supply them instead.

By Damien Carrington. Articles in English

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