World must navigate 'reality' of 1.5C overshoot, says UN

The United Nations' Environment Programme has reported that global temperatures will exceed the critical 1.5 degrees Celsius threshold, marking a shift from the previous focus on avoiding overshoot to now navigating through it. This assessment, the first of its kind, was commissioned following the 2015 Paris Agreement's commitment to limit global warming to 1.5C above pre-industrial levels, with many nations aiming to achieve this more ambitious goal.

UN Secretary-General Antonio Guterres acknowledged the inevitability of overshooting 1.5C, but this dedicated report marks a significant milestone in addressing the issue head-on, drawing both criticism and support from various stakeholders.

Scientists emphasize that warming above 1.5C poses grave risks, and nearly 200 nations have committed to trying to keep global temperature rises within this safer threshold. However, with the world expected to surpass the 1.5C target in a matter of years, the focus has now shifted to making any overshoot as brief and contained as possible.

In its report, the UNEP underscored that 1.5C will indeed be surpassed, signaling a reality check and urging policymakers to reconfigure climate governance around dealing with an overshoot pathway. Report co-author Richard Betts from the University of Exeter stressed the need to live with a warmer world while still taking action to limit warming.

Fellow author Debra Roberts highlighted the importance of recognizing that the rules of the game have changed, emphasizing the urgency for a new approach to climate governance. The report's stark language has alarmed climate campaigners, who have long advocated for the 1.5C target, but it also serves as a clarion call for reconfiguring climate strategies in light of the new reality.

Small island nations, particularly threatened by rising seas, have been vocal defenders of the 1.5C target, urging wealthier countries not to abandon this milestone even as it becomes increasingly difficult to reach. The world has already warmed roughly 1.4C since 1850-1900, primarily due to the burning of fossil fuels, and the last three years have been the hottest on record.

Scientists warn that any overshoot of 1.5C could trigger more extreme weather and push the planet closer to tipping points, such as the collapse of ice sheets and loss of coral reefs. UNEP executive director Inger Andersen stressed that there are no good outcomes if we remain above 1.5C, emphasizing the need to approach this target differently from above.

To minimize harm, the report advocates for cutting emissions now and considering carbon removal alongside deep and rapid cuts to greenhouse gas emissions.