Since the 1960s each decade has been hotter than the last, exactly as predicted by many climate models. But there has been some debate in the science community about whether or not this rate of warming is accelerating, particularly in light of last year’s climate chaos.
A few months ago former NASA climatologist James Hansen, who published one of the main early papers warning the world about global warming, authored a study suggesting the rate of warming has jumped by 50 percent since 2010.
This was met with skepticism from colleagues, despite a degree of acceleration being predicted in some climate models.
“[Hansen’s study is] not implausible but not particularly well supported by the literature,” Berkeley climate scientist Zeke Hausfather told the Associated Press.
Now, a new study led by environmental scientist Audrey Minière from Paul Sabatier University in France has found signs of accelerating heating in ocean temperatures too.
“Detecting an acceleration of Earth heating has remained elusive to date, despite suggestive evidence of a potential increase in heating rates,” the researchers write in their paper.
Minière and team calculated the amount our oceans were warming was steadily at about 0.15 watts per meter squared (W/m2) each decade around the 1960s. But since then this has risen to a rate of 0.91 W/m2.
There is a large variability in their results and the data is less reliable for earlier years, the researchers caution, but their findings are consistent across several different datasets.
A recent literature review also suggests that between 1971 and 2020 the ocean’s heating rate was equivalent to 0.48 W/m2, whereas by 2006 to 2020 the rate had increased to 0.76 W/m2.
Here I’ve added the +0.5 W/m² average Earth’s Energy Imbalance from 1971-2020 from von Schuckmann et al. (2023) pic.twitter.com/8fnEuKcgf4
— Leon Simons (@LeonSimons8) September 4, 2023
“While there is increasing evidence of an acceleration of warming, it’s not necessarily ‘worse than we thought’ because scientists largely expected something like this,” Hausfather told The Washington Post.
There are several theories behind what could cause this potential acceleration, from changes in cloud cover and the staggering decrease in sea-ice creating a feedback system, to natural variability in combination with increasing contributions from human activities.
“The long-term acceleration of Earth warming aligns qualitatively with the rise in CO2 concentrations and the decline in aerosol concentration during the same period,” Minière and colleagues explain. “But further investigations are necessary to properly attribute these changes.”
Current data demonstrates we’ll soon smash beyond the global commitment of limiting warming to 1.5 °C, regardless of whether the heat increases are accelerating or not.
Here are monthly temperature anomalies for the year, showing how 2023 was far warmer than any prior year for each month of the year from June onward, with a particularly large record (0.5C!) set in September: pic.twitter.com/GejjTcDqng
— Zeke Hausfather (@hausfath) January 2, 2024
We’re already feeling, or at least witnessing, the consequences. All that extra energy in our atmosphere is jerking climate systems to one extreme or another like a wobbling spinning top just before it topples over, resulting in deadly floods, fires, and storms.
“There won’t be any argument [by] late next spring, we’ll be way off the trend line,” Hansen believes.
This research was published in Scientific Reports.
