Scientists analyzed 300 years of ocean temperature records from sea sponges and found that global warming has increased 0.5 degrees more than previously estimated.
In the study… scientists mined ocean temperature records preserved in the calcium carbonate skeletons of long-lived sclerosponges.
Researchers from the University of Western Australia, Indiana State University and the University of Puerto Rico found that industrial-era warming began in the mid-1860s, consistent with what was expected from historical records, but more than 70 years earlier than suggested by records of measurements made from ships. of sea surface temperatures.
Lead author Emeritus Professor Malcolm McCulloch, from UWA’s Graduate School of Oceans and Oceans Institute, said the finding showed that global warming, the combined average of ocean and land surface warming, had been underestimated by around 0.5 degrees, mainly during the early part of the 19th century. the industrial era, when maritime transport coverage was still limited.
“So instead of the Intergovernmental Panel on Climate Change’s estimate that average global temperatures will have risen 1.2 degrees by 2020, temperatures were already 1.7 degrees above pre-industrial levels,” the professor said. McCulloch.
Last year was an extreme year in terms of weather events, with record global warming almost reaching the 2 degree limit or, before these new findings, what was previously the 1.5 degree limit.
The findings raise the question of whether global average surface temperatures have or will soon exceed the Paris Agreement, which aims to keep warming below 2 degrees.
“If current emissions rates continue, global average temperatures will likely exceed 2 degrees by the end of the 2020s and be more than 2.5 degrees above pre-industrial levels by 2050,” Professor McCulloch said.
“The now much faster rates of land warming also identified in the study are of additional concern, with average land temperatures expected to be around 4 degrees above pre-industrial levels by 2050.
“Keeping global warming to no more than 2 degrees is now the main challenge, making it even more urgent to halve emissions by the early 2030s, and certainly no later than 2040.”
Source: “Sea sponges reveal global warming has already exceeded 1.5 degrees”, University of Western Australia press release 6 February 2024.
Featured image from corresponding and connected home page: NOAA/Monterey Bay Aquarium Research Institute via Wikimedia Commons