The unexpected jump in global temperatures since 2023 has helped fuel a relentless assault of associated disasters around the world, including the still-burning LA fires and the deadly Valencia floods, leaving researchers scrambling for explanations.
Data from the world's oceans now reveal that an alarming acceleration in sea surface warming likely contributed. A new study from the University of Reading in the UK finds the tops of our oceans are warming more than four times faster than in the late 1980s.
Sea surface temperatures were the highest on record (again) for the month of December across the northern half of the Atlantic Ocean.
Data available from NOAA ERSSTv5: www.ncei.noaa.gov/products/ext… 🌊
— Zack Labe (@zacklabe.com) Jan 27, 2025 at 11:48 PM
Several theories have been suggested for the excess heat beyond what was expected from the El Niño and known rates of increasing CO2. Theories include an increase in heat-trapping water vapor from the 2022 eruption of Hunga Tonga-Hunga Ha'apai, a decrease in surface-cooling aerosols from shipping regulation changes in 2020, and peak activity in the current solar cycle sending more heat our way.
But even combined, these couldn't fully account for observed temperatures.
So meteorologist Chris Merchant and colleagues used satellite data records since 1985 to calculate the change in the rate of sea surface warming.
They found the underlying rate of warming was about 0.06 °C back in the 80s, but that's now increased to 0.27 °C per decade. The team notes this is not a linear increase but an accelerating one.
While some of the excess heat was indeed driven by the recent El Niño, the researchers calculate that about 44 percent of it was due to the oceans absorbing heat much faster than anticipated over the last decade.
"If the oceans were a bathtub of water, then in the 1980s, the hot tap was running slowly, warming up the water by just a fraction of a degree each decade," explains Merchant. "But now the hot tap is running much faster, and the warming has picked up speed."
The team warns that if this trend continues, in only the next 20 years, we will exceed the sea surface temperature rise we've experienced in the last 40 years.
"This leaves unanswered the important question of what has caused the Earth energy imbalance trend," they write.
With all that excess energy already decimating wildlife en masse, leaving millions hungry from destroyed crops, and exacerbating diseases and other health conditions, it's hard to fathom how much worse this will rapidly get.
"Policy makers and wider society should be aware that the rate of global warming over recent decades is a poor guide to the faster change that is likely over the decades to come, underscoring the urgency of deep reductions in fossil-fuel burning," Merchant and colleagues write.
Concerned scientists have been laying out plan after plan to try and steer our sinking living biosphere back towards safety. We've known for decades what needs to be done, yet subsidized fossil fuel industries continue to exacerbate the situation.
Every little thing we can do to reduce our fossil fuel emissions now will save future lives, regardless of what point we're at along this dark timeline.
This study was published in Environmental Research Letters.