UN Report: Cut Emissions 18 Percent by 2030 to Limit Overshoot
The emissions gap report says the world must cut emissions by 2030 to keep the overshoot of the 1.5 degree limit small and short.
Global greenhouse gas emissions have to fall 18 percent by 2030 and 45 percent by 2035 if the overshoot of the 1.5-degree Celsius limit is to remain small and short, the United Nations Environment Programme said on Wednesday, October 21, in its annual Emissions Gap Report.
The agency does not claim the limit itself can still be held. Its finding is that the chance of staying under 1.5 degrees with little or no overshoot is gone. What remains is damage control. The lowest-overshoot pathway peaks at 1.7 to 1.8 degrees, requires a 69 percent cut by 2040 at 2025 levels, reaches net-zero carbon dioxide around 2050, and depends on large-scale carbon control from the atmosphere to bring temperatures back to 1.5 degrees by 2100.
Inger Andersen, the agency’s executive director, put it bluntly. Governments had been warned for years, she said, and the world once had a chance to stay within the limit through an extraordinary global effort that was never made. “We procrastinated, and now we are saying this window has closed.” Even so, she urged countries to keep the goal, which remains central to the Paris Agreement, and said the point of return begins “now, not later.” United Nations Secretary-General António Guterres, in a video message, said overshoot “is not surrender” and that temperatures can still be brought back to 1.5 degrees by the end of the century.
The direction of travel is a different matter. Existing policies point to about 2.8 degrees of warming by 2100, and full delivery of the latest national pledges would still leave the world near 2.6 degrees. A year ago, the agency put the pledge-based figure at 2.3- 2.5 degrees. Anne Olhoff, a co-author, said the outlook worsened because the United States formally left the Paris agreement and because historical emissions were revised upward. National plans now on the table deliver cuts of only 11 to 15 percent by 2035.
Emissions in 2025 were broadly in line with 2024, a result some might call a peak. Geopolitical uncertainty, continued dependence on fossil fuels, and the risk that emissions rise again despite rapid growth in renewable energy all argue for caution. The report estimates that every five-year delay locks in roughly another 0.1 degrees of warming.
The report identifies weaker international leadership as a key factor, with the United States singled out for particular criticism. Under President Donald Trump, the country has withdrawn from the Paris climate agreement and is now threatening to reverse its long-term decline in greenhouse gas emissions. The US remains the world’s second-largest emitter, after China.
Bill Hare, chief executive of the Climate Analytics think tank, said that while every government has a responsibility to act, major fossil fuel producers such as the United States and Saudi Arabia bear particular responsibility. Together, they account for an estimated 20 to 25 percent of global fossil fuel production. He said these countries should confront the scientific evidence rather than continue expanding fossil fuel output.
Other governments have also held back. At the COP30 climate summit in Brazil last November, countries were expected to bring stronger measures and policies for carbon emissions control. What they submitted fell far short of what scientists say is needed.
The Paris Agreement has a way to close that gap: a regular review of collective progress known as the global stocktake, next due in 2028. It is now in doubt. The Intergovernmental Panel on Climate Change suspended a meeting in Addis Ababa last Friday without agreeing on when to publish its next assessment. A coalition of 30 countries fears the science will not be ready for the 2028 talks. India, Kenya, Saudi Arabia, Russia and China want more time.
Johan Rockström, director of the Potsdam Institute for Climate Impact Research, said the dispute over timing must not hold up government action. If every current national commitment is carried out, he said, emissions would reach about 50 gigatons of carbon dioxide equivalent a year by 2035, when they should be below 35 gigatons. “The science is already clear,” he said.
Scientists add that each further step beyond 1.5 degrees raises the risk of irreversible tipping points, among them major changes to ice sheets, ocean circulation and ecosystems.
There is some good news. Since 2015, renewable electricity capacity worldwide has grown three times faster than expected, and solar power deployment has risen sevenfold compared with projections made a decade ago. Mohamed Adow, director of the think tank Power Shift Africa, said the failure is political and not technological, because governments are still not moving away from fossil fuels quickly enough.
Cutting methane is one of the fastest ways to slow the warming, the agency said. Over 20 years, the gas is roughly 80 times more powerful than carbon dioxide, and the largest reductions are available in fossil fuel operations, agriculture and waste.
