In 2023, global marine heatwaves were the biggest, most intense and most persistent on record, a new study reveals. The researchers suggest that these heat waves were driven by climate change and may signal a climate tipping point.
Global marine heatwaves (MHWs) are prolonged periods of unexpectedly warm ocean temperatures. These warm periods can critically threaten marine ecosystems, for instance by leading to coral bleaching and mass marine die offs, and can cause economic challenges by disrupting fisheries and aquaculture. While it’s widely accepted that human-driven climate change is making MHWs more destructive, little is known about the ocean dynamics behind the phenomenon.
“Marine heatwaves have emerged globally as one of the most severe threats to marine ecosystems,” Ryan Walter, a marine scientist at the California Polytechnic State University who was not involved in the study, told Live Science.
A climate tipping point?
In a study published Thursday (July 24) in the journal Science, the researchers used satellite observations and ocean circulation data to evaluate the MHWs of 2023. They found that the year set new records for MHW temperatures, duration and geographic range — some of which have been measured since the 1950s — with these events lasting four times longer than the historical average and covering 96% of oceans worldwide.
The most intense warming, which occurred in the North Atlantic, tropical Pacific, South Pacific and North Pacific, accounted for 90% of unexpected oceanic heating during 2023. The North Atlantic MHW lasted for 525 days, and the Southwest Pacific MHW broke records for geographic extent and duration.
Related: A Hot Blob in the Pacific Ocean Caused 1 Million Seabirds to Die
The scientists identified several drivers behind the extreme MHWs, including rising solar radiation due to reduced cloud cover, weakened winds and changes in ocean currents.
They suggest that the 2023 MHWs may indicate a fundamental shift in ocean dynamics — which could be early warnings of a climate tipping point. Though there’s not a singular definition of a tipping point, most researchers use it to mean the threshold at which certain effects of climate change are irreversible.
It’s still uncertain whether or not oceans have reached a crucial tipping point just yet. “Tipping points are difficult to quantify,” Walter said. Because the ocean and…
Click Here to Read the Full Original Article at Latest from Live Science…