UN chief urges 'rapid' emission cuts to curb climate change

The head of the United Nations called Thursday for "immediate, rapid and largescale" cuts in greenhouse gas emissions to curb global warming and avert climate disaster.

Ahead of the annual U.N. General Assembly meeting next week, Antonio Guterres warned governments that climate change is proceeding faster than predicted and fossil fuel emissions have already bounced back from a pandemic dip.

Speaking at the launch of a UN-backed report summarizing current efforts to tackle climate change, Guterres said recent extreme weather - from Hurricane Ida in the United States to floods in western Europe and the deadly heatwave in the Pacific Northwest showed no country is safe from climate-related disasters. "These changes are just the beginning of worse to come," he said, appealing to governments to meet the goals of the 2015 Paris climate accord.

"Unless there are immediate, rapid and large-scale reductions in greenhouse gas emissions, we will be unable to limit global heating to 1.5 degrees Celsius (2.7 Fahrenheit)," said Guterres. "The consequences will be catastrophic."

In their report, titled United in Science 21, six U.N. bodies and scientific organizations drew on existing research to argue that there is a direct link between human-caused emissions, record high temperatures and disasters that have a tangible impact on individuals and societies, including "billions of work hours (...) lost through heat alone." Because of the long-lasting effects of many emissions already released into the atmosphere, further impacts are inevitable, they noted.

"Even with ambitious action to slow greenhouse gas emissions, sea levels will continue to rise and threaten low-lying islands and coastal populations throughout the world," the authors wrote.

University of Michigan environment dean Jonathan Overpeck, who wasn't part of the report, said scientists have said this before but it's important: "The situation is getting bad, we know why and we know how to solve it in ways that leave us, and future generations, with a better, healthier, more sustainable world." Guterres urged governments to put forward more ambitious plans for cutting emissions by the upcoming U.N. climate summit in Glasgow, including a commitment to stop adding more greenhouse gas to the atmosphere by midcentury than can be removed.

Michael Mann, a prominent climate scientist at Pennsylvania State University, said he agreed with the report's message of urgency but questioned some of the starker warnings it contained. In particular, the 1.5C threshold agreed in Paris didn't apply to individual years, some of which can be unusually hot due to other factors, he said.

"This misleading framing unnecessarily feeds the fears that the public has that we've somehow already crossed that threshold and that it is too late now to prevent," said Mann. "We have not. And it is not."

He also noted that the drop in emissions seen during the pandemic could be viewed as a positive sign that significant cuts are possible if entire economies are weaned off fossil fuels.