Climate activists are urging strong action from the delegates arriving at Belém for COP30.Credit: Eraldo Peres/AP/Alamy
It’s been ten years since Laurent Fabius, then the foreign minister of France, gavelled the United Nations 21st conference of the parties on climate change (COP21), bringing the 2015 Paris climate agreement into existence. It is an imperfect pact, not least because the initial commitments it enshrined were woefully inadequate. But it set an important goal: to avert planetary-scale ecological, economic and social disruptions by reining in greenhouse-gas emissions and limiting global warming to 2 °C — and, ideally, 1.5 °C — above preindustrial levels. To get there, countries agreed to an iterative pledge-and-review process that would, in theory, build confidence and trust alongside progress and momentum.
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As representatives of governments convene in Belém, Brazil, for COP30, it is reasonable to question whether this process is delivering as promised. Globally, greenhouse-gas emissions have increased by 10% since 2015, hitting a new peak equivalent to the emission of some 53 billion tonnes of carbon dioxide last year.
Average global temperatures have also continued to increase, and the world is seeing the long-predicted impacts: more-extreme wildfires, storms, floods and droughts. Just last month, Derek Manzello, a researcher at the US National Oceanic and Atmospheric Administration, and his colleagues reported that an unprecedented marine heatwave in 2023 drove a pair of iconic corals that have served as primary reef builders off the coast of Florida for the past 10,000 years to “functional extinction” (D. P. Manzello et al. Science 390, 361–366; 2025). Researchers at Imperial College London estimate that global warming made Hurricane Melissa, the monster storm that rampaged through the Caribbean last month, four times more likely to occur.
Many countries are taking action, whether through mitigation measures, such as using more clean energy, or through financial investments to adapt and prepare for a changing climate. And there is little doubt, as our latest News Feature makes clear, that the engines of a low-carbon economy are revving up across the world — despite the anti-climate policies being put in place in the United States, the world’s largest economy and second-largest emitter, which has withdrawn from the Paris agreement.
The UN climate secretariat in Bonn, Germany, which monitors the state of national climate policies, is finding signs of progress: countries are creating stronger, more comprehensive climate action plans, called Nationally Determined Contributions (NDCs), than those drafted in 2020, the last time countries had to submit them. Three-quarters of the 64 plans analysed by the climate secretariat address adaptation and resilience (see go.nature.com/56hj7). Roughly 90% of the submitted plans laid out comprehensive, economy-wide emissions goals.
Warning signals
But the UN report also rang alarm bells, warning that commitments are still too few and too weak to achieve the Paris goals. This remains true even when considering targets that have been announced — but not formally submitted as NDCs — by two of the world’s largest emitters: China and the European Union.
These iconic corals are nearly extinct due to heatwaves: can they be saved?
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