UN warns global warming likely to exceed 1.5C within next few years

Global warming is likely to exceed 1.5C (2.7F) above pre-industrial levels within the next few years, but temperatures could still be brought back down through rapid emissions cuts and sustained net-negative emissions, the UN Environment Programme (UNEP) said Wednesday.

"Global temperature rise is set to cross 1.5C, likely within the next few years, pushing climate risks and impacts to increasingly dangerous heights, but it is still possible to bring temperatures down and achieve global goals in the Paris Agreement," a new UNEP report said.

The report identified an "overshoot, peak and decline" pathway as the best option to minimize both the scale and duration of warming above 1.5C before eventually returning below that threshold.

The pathway seeks to limit peak warming through deep cuts in greenhouse gas emissions and subsequently lower temperatures through sustained net-negative emissions.

"There are no good outcomes if we remain above 1.5°C. Across the globe, extreme heatwaves are already proving that climate impacts will strike faster, hit harder, and last longer - costing more lives and causing deeper disruption," said UNEP Executive Director Inger Andersen.

The report said even the most optimistic scenario would see global temperatures peak at 1.8C above pre-industrial levels, exceeding the Paris Agreement goal of limiting warming to 1.5C.

Most other scenarios project even higher peaks.

Risks would intensify with every additional fraction of a degree of warming and every year temperatures remain above 1.5C, the report said, including through more severe extreme weather and ecosystem losses.

"Severe damage to human health, food security, water supplies, nature, cities, infrastructure, and economies is expected," it added.

The report also warned that the likelihood of crossing irreversible tipping points rises with both the magnitude and duration of higher temperatures.

"These include the destabilization of major ice sheets, degradation of the Amazon rainforest and disruption of the Atlantic Meridional Overturning Circulation (the system of currents that moves warm surface water north and cold deep water south, playing a key role in regulating the climate)," it added.

Some impacts are likely to emerge abruptly, while others will accumulate over time, the report said.