The world will exceed 1.5°C. Here is what the new UN climate report says comes next

The world is now expected to exceed the Paris Agreement’s 1.5°C warming limit, probably within the next few years. The central question is no longer whether that threshold will be crossed, but how far temperatures rise above it and how quickly they can be brought back down. That is the main finding of Limiting Overshoot, a report released Tuesday by the United Nations Environment Programme.

The 1.5°C figure measures warming above the average temperature recorded between 1850 and 1900. It is not a point at which the climate suddenly collapses. It is a risk boundary: every additional fraction of a degree increases the frequency and severity of heat waves, droughts, floods and other disruptions.

Even under the report’s most optimistic scenario, warming would peak at about 1.8°C. Most other pathways produce peaks above 2°C. Current government policies put the world on course for at least 2.3°C of warming, according to research cited in the report.

UNEP now describes the best available strategy as “overshoot, peak and decline.” Under that pathway, temperatures temporarily rise above 1.5°C, reach the lowest achievable peak and then decline as greenhouse gas concentrations fall.

Reaching that outcome would require immediate, sustained reductions in carbon dioxide and methane emissions. Previous research cited by the authors indicates that keeping peak warming near 1.8°C would require global emissions to fall by roughly half by 2035.

It would also require removing carbon dioxide from the atmosphere through measures such as restoring forests and developing engineered removal systems. UNEP stresses that these methods must supplement emissions cuts rather than provide an excuse to continue burning fossil fuels.

Ice-sheet loss, ecosystem destruction and sea-level rise can continue for decades or centuries even if temperatures are pushed below 1.5°C, but the longer temperatures remain above the threshold, the greater the risk of triggering irreversible changes involving major ice sheets, the Amazon rainforest and Atlantic Ocean circulation.

 Governments must prepare water systems, farms, cities, hospitals and infrastructure for conditions that are already changing. For water-stressed countries such as Morocco, this means planning for more severe heat, unstable rainfall and higher pressure on agriculture and reservoirs.