Ocean sponges suggest Earth has warmed longer, more than thought; some scientists dubious
A handful of centuries-old sponges from deep in the Caribbean are causing some scientists to think human-caused climate change began sooner and has heated the world more than they thought.
They calculate that the world has already gone past the internationally approved target of limiting global warming to 1.5 degrees Celsius (2.7 degrees Fahrenheit) since pre-industrial times, hitting 1.7 degrees (3.1 degrees Fahrenheit) as of 2020. They analyzed six of the long-lived sponges—simple animals that filter water—for growth records that document changes in water temperature, acidity and carbon dioxide levels in the air, according to a study in Monday's journal Nature Climate Change.
Other scientists were skeptical of the study's claim that the world has warmed that much more than thought. But if the sponge calculations are right, there are big repercussions, the study authors said.
"The big picture is that the global warming clock for emissions reductions to minimize the risk of dangerous climate changes is being brought forward by at least a decade," study lead author Malcolm McCulloch, a marine geochemist at the University of Western Australia. "Basically, time's running out."
"We have a decade less than we thought," McCulloch told The Associated Press. "It's really a diary of—what's the word?—impending disaster."
This undated image provided by Amos Winter shows a sponge from the Caribbean. This sponge, a simple animal that filters water, and a handful of other centuries-old sponges are causing some scientists to think human-caused climate change began sooner and has heated the world more than they thought. Many sponge species live long, and as they grow they record the conditions of the environment around them in their skeletons. Credit: Courtesy of Amos Winter via AP
This undated image provided by Amos Winter shows a sponge from the Caribbean that has been cut. This sponge, a simple animal that filters water, and a handful of other centuries-old sponges are causing some scientists to think human-caused climate change began sooner and has heated the world more than they thought. Many sponge species live long, and as they grow they record the conditions of the environment around them in their skeletons. Credit: Courtesy of Amos Winter via AP
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