What Would It Take to Come Back From 1.5C Overshoot?
United Nations climate policy now has a different problem to solve. The world will pass 1.5C, and the UN says that overshoot is unavoidable. Overshoot means temperatures climb past the target and have to be brought back down. The report maps a path back below the threshold.
What Happened to the 1.5C Goal
The Paris Agreement aimed to hold global heating to 1.5C above pre-industrial levels. That target is no longer within reach. According to The Guardian, the UN Environment Programme now says the world will cross the threshold in the next few years, and that global heating will reach at least 1.8C even in the most optimistic scenario. If every country pursued its most ambitious climate goals, warming would peak around mid-century at 1.8C. Under current government policies, the UN puts the trajectory at 2.6C by 2100, as NBC News reports.
The gap between those numbers is the space where policy still matters.
The UN's Three-Phase Route Back
The UN's strategy treats overshoot as a temporary condition, not a permanent one. The first phase is immediate emissions cuts. The second is a coping and containment phase during peak warming, when societies will have to live with higher temperatures and manage the damage. The third is a long-term resilience phase in which carbon dioxide removal actively cools the planet.
That last phase carries the heaviest load. The report says overshoot will likely last many decades, and NBC News notes that tree planting alone can shave only a tenth of a degree off global temperatures. Novel carbon dioxide removal approaches will therefore be needed.
The Cost of Overshoot
The UN does not sugarcoat what passing 1.5C means. The Guardian describes the report's warning that "there are no good outcomes above 1.5C." Under heating of up to 3C, glaciers could lose more than a quarter of their mass by 2100, raising sea levels by up to 13 centimeters. Global food production could fall by up to 14 percent by 2050 without effective adaptation.
What Would Change the Math
None of that is locked in as a single outcome. The UN's best-case path depends on countries adopting and enforcing their most ambitious targets rather than their current policies. The first phase of the plan starts with cuts made now; the rest of the route assumes those cuts actually happen. The difference between 1.8C and 2.6C is not a fixed prediction. It is the distance between the world's stated goals and its actual trajectory.