‘Limit overshoot, peak, decline’: A new global goal for climate change?

The signing of the Paris Agreement by 200 countries in 2015 was a rare moment of global unity, and the euphoria was real.

To cheers and tears, the international climate treaty was approved by nearly every country in the world. Fundamental to the agreement was a commitment to keeping temperatures from rising beyond 1.5C (2.7F) above the pre-industrial levels of the mid 19th-century.

But 11 years on, it is evident that the Earth is soon going to exceed that threshold because of the continued record burning of fossil fuels.

A report from the United Nations Environment Programme (UNEP) in Nairobi, Kenya – called Limiting Overshoot – has found that even under the most optimistic scenario, the Earth will heat up by 1.8C (3.2F) above pre-industrial levels. It adds that the best hope for the planet is an “overshoot, peak and decline” pathway.

That would mean it is still possible, and essential, to bring temperatures down and achieve the Paris goals, but a course correction is required to get there.

The UNEP report envisions that the global temperature rise will pass the 1.5C threshold “within the next few years”, continue to increase, then gradually cool to below the 1.5-mark, hopefully by the end of the century.

The report makes it clear that the impact of rising temperatures will intensify with every year spent above the 1.5C threshold. Extreme weather will get more extreme ; the danger of small island states and coastal cities being submerged will be more likely, while biodiversity loss will accelerate.

That means disasters such as the recent catastrophic Nepal flash floods – in which more than 1,300 people have died and thousands are still missing – which were caused by melting glaciers, could become more frequent.