COP31 kicks off as planet faces imminent overshoot of 1.5°C climate target

The United Nations annual climate meeting starting today is the first to take place after confirmation that global warming will overshoot the headline limit of 1.5 °C. The aim of keeping warming within 1.5 °C above pre-industrial temperatures was set out in the 2015 Paris agreement.

As tens of thousands of delegates and observers arrive in Antalya, Turkey, for the COP31 meeting, some scientists and climate advocates say the 12-day event must discuss how to deal with the overshoot. Along with cutting emissions, this includes practical ways of removing massive volumes of carbon dioxide from the atmosphere.

The UN Environment Programme last month acknowledged that, under all plausible emissions trajectories, the world will surpass the 1.5 °C target agreed at COP21 in Paris. Its Limiting Overshoot report is the first UN report to state explicitly that overshoot is now inevitable. It also laid out how to bring temperatures back below the 1.5 °C target this century.

In addition to slashing emissions to near-zero levels, the report confirmed the need to remove hundreds of billions of tonnes of CO₂ from the atmosphere this century, either using CO₂ removal technologies or nature-based approaches such as reforestation. “[K]eeping 1.5 °C within reach requires climate policy to evolve to include the removal of already emitted [greenhouse gases],” the report states.

This idea to limit the “magnitude and the duration” of overshooting 1.5 °C is expected to shape discussion among parties at the COP meeting, says Clea Schumer, a research associate at the World Resources Institute, an environmental research and advocacy organization in Washington DC. Some language on limiting overshoot was included in the final decision of the COP30 summit last year in Belém, Brazil, but CO₂ removal has mostly gone unmentioned.

Most governments “are happy that they finally don’t have to pretend any more that we will make it” to 1.5 °C, says Oliver Geden, a researcher at the German Institute for International and Security Affairs in Berlin. They now want to limit overshoot, “but how we actually do that, nobody is talking about”, he adds.

Steve Smith, a climate researcher at the University of Oxford, UK, agrees. CO₂ removal has sparked controversy in the past over concerns that it might distract from the need to cut emissions. But it is possible that CO₂ removal could move up the agenda amid discussions about the necessary return from overshoot, he says.

Environmental advocacy groups, such as New York-based Natural Resources Defense Council (NRDC), that had been skeptical of CO₂ removal, have now changed their position. A report from the organisation in September called on environmentalists to support CO₂ removal in the same way they supported renewable energy and electrification.

“It is now time to set the stage for another—an industry that removes carbon dioxide from the atmosphere—to contribute to the fight for climate stability,” the report says

However, so far, no country has included clearly quantified CO₂ removal targets in climate commitments submitted to the UN, says Smith. Such targets would be necessary to achieve the large scales of CO₂ removal that could bring warming back below 1.5 °C. “We really want governments to cut emissions and set out clear plans for scaling up CO₂ removal,” says Smith

COP out

Some scientists say the failure to cut emissions fast enough to avoid overshoot is a sign that there need to be reforms to COP meetings.

“We need to first recognize that global policy has failed. This is a moment of self-critique,” says Johan Rockström, a climate scientist at the Potsdam Institute for Climate Impact Research in Germany.

Rockström leads a group of scientists advising a coalition of around 60 countries working in parallel to the COP. The coalition wants the world to move faster to transition away from fossil fuels, and met for the first time in April in Santa Marta, Colombia.

Rockström, together with other prominent climate scientists and diplomats, has argued for some years that the COP process needs reform. Ahead of COP31, he told Nature that a top priority should be to allow for decisions to be made by majority votes among parties. Currently, agreements must involve all countries coming to a consensus. In the past, this has meant that a small number of states can block decisions backed by the majority. “Overshoot gives even more impetus for the need for reform. It shows that we’ve not been able to make the progress that we need,” says Rockström.

However, that doesn’t mean COP meetings don’t still have an important role, say climate advocates. “COP gatherings have had a massive impact,” says Yamide Dagnet, a senior vice-president in Washington DC at the NRDC. “But their success has increasingly been measured in degrees averted,” she adds.

When the Paris agreement was signed in 2015, the world looked likely to reach around 4 °C of warming this century. Under current policies, the UN Emissions Gap report found that has declined to between 2.6 and 2.8 °C of warming this century, with a small chance of reaching significantly hotter temperatures.

Climate researchers say it is unrealistic to expect the COP meetings to shift the trajectory of the world’s countries on their own. “Action, in the end, has to be national,” says Ed Carr, senior scientist at the Boston, Massachusetts, office of the Stockholm Environment Institute, a non-profit research organization.