Earth warmed at a record rate in 2023 with scientists calculating 92% of last year’s surprising heat rise was caused by humans.
The group of 57 scientists from around the world used United Nations-approved methods to examine what was behind last year’s deadly burst of heat.
They said even with a faster warming rate they do not see evidence of significant acceleration in human-caused climate change beyond increased fossil fuel burning.
Last year’s record temperatures were so unusual, scientists have been debating what is behind the big jump and whether climate change is accelerating or if other factors are in play.
“If you look at this world accelerating or going through a big tipping point, things aren’t doing that,” said the study’s lead author Piers Forster, a Leeds University climate scientist. “Things are increasing in temperature and getting worse in sort of exactly the way we predicted.”
The report said the rise is largely explained by the build-up of carbon dioxide from rising fossil fuel use.
Last year the rate of warming hit 0.26C per decade — up from 0.25C the year before. That is not a significant difference, although it does make this year’s rate the highest on record, Mr Forster said.
The team of authors — formed to provide annual scientific updates between major UN scientific assessments every seven to eight years — determined last year was 1.43C warmer than the 1850 to 1900 average with 1.31 degrees of that coming from human activity.
The other 8% of the warming is due mostly to El Nino, the natural and temporary warming of the central Pacific that changes weather worldwide and also a freak warming along the Atlantic and just other weather randomness.
On a larger 10-year time frame, which scientists prefer to single years, the world has warmed about 1.19C since pre-industrial times, the report in the journal Earth System Science Data found.
The report also said that as the world keeps using coal, oil and natural gas, Earth is likely to reach the point in 4.5 years that it can no longer avoid crossing the internationally accepted threshold for warming: 1.5C.
Last year’s temperature rise was especially unusual in September, said study co-author Sonia Seneviratne, head of land-climate dynamics at ETH Zurich.
The year was within the range of what was predicted, albeit it was at the upper edge of the range, she said.
“Acceleration if it were to happen would be even worse, like hitting a global tipping point, it would be probably the worst scenario,” she said. “But what is happening is already extremely bad and it is having major impacts already now. We are in the middle of a crisis.”
