The United Nations has issued a stark report acknowledging that the world will miss its goal of preventing the most severe impacts of global warming. Instead of solely focusing on preventing warming, the strategy now involves managing an "overshoot" period of higher temperatures before working to bring them back down.
Earth is projected to exceed the 1.5 degrees Celsius (2.7 degrees Fahrenheit) warming limit agreed upon in the 2015 Paris climate accord within the next few years due to continued fossil fuel use, according to the report released by the United Nations Environment Programme (UNEP).
"Humanity is speeding past the limit to avoid climate catastrophe," United Nations Secretary-General António Guterres stated. The report emphasizes that even with this acknowledgment, the 1.5 degrees Celsius target remains the ultimate goal, but the approach must shift.
"Let’s be very clear, 1.5 target is still the goal. But now we need to approach it differently from above," said UNEP Executive Director Inger Andersen. The report envisions a scenario where global temperatures surpass the 1.5-degree threshold, peak, and then gradually cool back down below that mark, ideally by the end of the century.
This "overshoot" period, however, is expected to last for "many, many decades" and will result in increased weather-related disasters, rising sea levels, species extinctions, and melting ice and glaciers. "Every tenth of a degree we avoid still means less damage," noted climate scientist Andrew Weaver, who was not part of the study.
Scientists involved in the report suggest that limiting the peak temperature reached during the overshoot phase and reducing the duration above 1.5 degrees Celsius are crucial. "If we act now we can limit overshoot," the report states. "Not a safe world, but safer than remaining above" 1.5 degrees for the long term.
The report warns that current government policies are on track to push global temperatures to 2.6 degrees Celsius (4.7 degrees Fahrenheit) above pre-industrial levels by 2100. Under the most optimistic scenario, where countries pursue ambitious climate goals, warming could peak at 1.8 degrees Celsius (3.2 degrees Fahrenheit) around mid-century.
During the overshoot period, the UNEP report anticipates increased mortality and illness due to climate change impacts and extreme weather. Food production may decline, water shortages could worsen, economies could suffer, and species such as coral are at risk of extinction. The report also highlights the danger of "tipping points," such as the irreversible loss of major ice sheets or the Amazon rainforest, and potential disruptions to ocean circulation systems.
To eventually cool the planet, the report proposes carbon dioxide removal from the atmosphere. While traditional methods like planting trees are mentioned, they are estimated to have a limited impact. The report suggests that more novel approaches to carbon removal will be necessary, though some scientists express skepticism about their reliability and cost-effectiveness.
Richard Betts, a climate scientist at the University of Exeter and co-author of the report, described the situation as a "reality check," emphasizing that "there's still a lot we can do to limit warming."