Overshooting 1.5C risks ‘irreversible’ climate impact

Any breach of what climate scientists agree is the safer limit on global warming would result in "irreversible consequences" for the planet, said a major academic study published on Wednesday.

Even temporarily exceeding 1.5 degrees Celsius before bringing temperatures back down -- a scenario known as an "overshoot" -- could cause sea level rises and other disastrous repercussions that might last millenia.

This "does away with the notion that overshoot delivers a similar climate outcome" to a future where more was done earlier to curb global warming, said Carl-Friedrich Schleussner, who led the study co-authored by 30 scientists.

The findings, three years in the making, are urgent, as the goal of capping global temperature rises at 1.5C above pre-industrial levels is slipping out of reach.

Emissions of heat-trapping greenhouse gases must nearly halve by 2030 if the world is to reach 1.5C -- the more ambitious target enshrined in the 2015 Paris climate accord. Currently however, they are still rising.

Some kind of overshoot of 1.5C is increasingly being seen as inevitable by scientists and policymakers.

This new study, published in the peer-reviewed journal Nature, cautions against "overconfidence" in such a scenario when the dangers are not fully appreciated.