The world could soon temporarily overshoot the 1.5°C warming threshold – showing how close we are coming to missing the Paris Agreement’s target
10 May 2022
The UK Met Office has warned there is an almost 50-50 chance that the world will briefly overshoot its crucial 1.5°C climate change target within the next five years.
The Paris Agreement set an aim to limit global warming to 1.5°C above pre-industrial levels, a threshold seen as vital for limiting the worst impacts of global warming on people and ecosystems. That aim would only be missed if a temperature rise is sustained over a couple of decades.
The Met Office’s climate models estimate there is a 48 per cent chance that the average global temperature of any year between 2022 and 2026 will be more than 1.5°C above pre-industrial levels. For the previous five-year period, 2017 to 2021, the chance was less than 10 per cent.
The prediction shows how close the world is to failing on its climate goals. “It’s not a magic threshold, and things are not going to suddenly change,” says Leon Hermanson at the Met Office, part of the team behind the analysis produced for the UN’s World Meteorological Organization. “One year’s exceedance doesn’t mean anything; it just means that we’re getting closer and it’s a warning that we need to really double up on the efforts to cut carbon dioxide and reduce our use of fossil fuels.”
The reason the chance of temporarily hitting 1.5°C has increased is a combination of continued carbon emissions pushing Earth closer to the threshold, and new temperature data causing researchers to revise upwards their estimates of past warming since pre-industrial times.
As human-induced climate change has driven average temperatures up, the chance of natural cycles such as El Niño pushing us over 1.5°C have increased. El Niño can raise temperatures by 0.2 to 0.3°C, says Hermanson.
Last month, a major report from the Intergovernmental Panel on Climate Change said there are still pathways where emissions fall enough to stay under 1.5°C of warming. Whether that conclusion can be squared with the new study depends on the uncertainties in the models, including how sensitive the climate is to greenhouse gases, says Graham Madge, a spokesperson for the Met Office. However, the IPCC report did acknowledge that those pathways only give a 50 per cent chance of staying under 1.5°C.
Hermanson’s report, Global Annual to Decadal Climate Update, also finds there is a 93 per cent chance that one of the next five years will eclipse 2016 as the warmest on record. The analysis offers bad news for California, which is expected to continue the run of dry weather that has set the stage for forest fires in recent years. Hermanson says there is some good news for the Sahel region in North Africa, where rain-dependent subsistence farmers are expected to see wetter conditions than in the past 30 years.
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