The WMO’s secretary-general said the 1.5 degrees Celsius threshold indicates when climate impacts will become ‘increasingly harmful’ for people and the planet.
There is roughly a 50pc chance that the global average temperature will be 1.5 degrees Celsius higher than pre-industrial levels at some point in the next five years, according to the World Meteorological Organization (WMO).
The WMO’s latest climate update noted that the chance to temporarily exceed this temperature average has been increasing rapidly since 2015, when the odds were close to zero. Between 2017 and 2021 there was a 10pc chance that one of those years would reach the 1.5 degrees Celsius temperature increase.
The Paris Agreement in 2015 committed to keeping the rise in global temperatures well below two degrees Celsius, while working to keep them under 1.5 degrees.
“This study shows – with a high level of scientific skill – that we are getting measurably closer to temporarily reaching the lower target of the Paris Agreement on Climate Change,” WMO secretary-general Prof Petteri Taalas said yesterday (9 May).
“The 1.5 degrees Celsius figure is not some random statistic. It is rather an indicator of the point at which climate impacts will become increasingly harmful for people and indeed the entire planet.”
In February, a report by the UN’s Intergovernmental Panel on Climate Change (IPCC) warned that some effects of the climate crisis may be irreversible if human activity leads to global heating exceeding 1.5 degrees Celsius. It added that the people and ecosystems least able to cope are being hardest hit.
In another report last month, the IPCC said that halving global emissions by 2030 is achievable, but hard and fast cuts are needed across all sectors and nations to limit global heating.
“A single year of exceedance above 1.5 degrees Celsius does not mean we have breached the iconic threshold of the Paris Agreement, but it does reveal that we are edging ever closer to a situation where 1.5 degrees Celsius could be exceeded for an extended period,” said Dr Leon Hermanson from the Met Office, who led the WMO report.
The climate update said there is a 93pc chance that one of the years between 2022 and 2026 will become the hottest on record, a title currently held by 2016. There is also a 93pc chance that the five-year average temperature between 2022 and 2026 will be higher than the period between 2017 and 2021.
“For as long as we continue to emit greenhouse gases, temperatures will continue to rise,” Taalas said. “Alongside that, our oceans will continue to become warmer and more acidic, sea ice and glaciers will continue to melt, sea level will continue to rise and our weather will become more extreme.
“Arctic warming is disproportionately high and what happens in the Arctic affects all of us,” Taalas added.
In March, the Conger ice shelf – which was roughly the size of Rome – collapsed into the ocean. It was the third iceberg calving recorded that month as Antarctica experienced temperatures 40 degrees Celsius higher than normal.
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