Yesterday’s scorching ocean extremes are as we speak’s new regular. A brand new evaluation of floor ocean temperatures over the previous 150 years reveals that in 2019, 57 % of the ocean’s floor skilled temperatures hardly ever seen a century in the past, researchers report February 1 in PLOS Climate.
To present context for the frequency and length of contemporary excessive warmth occasions, marine ecologists Kisei Tanaka, now on the National Oceanographic and Atmospheric Administration in Honolulu, and Kyle Van Houtan, now on the Loggerhead Marinelife Center in Juno Beach, Fla., analyzed month-to-month sea-surface temperatures from 1870 by 2019, mapping the place and when excessive warmth occasions occurred decade to decade.
Looking at month-to-month extremes reasonably than annual averages revealed new benchmarks in how the ocean is altering. More and extra patches of water hit excessive temperatures over time, the workforce discovered. Then, in 2014, the whole ocean hit the “point of no return,” Van Houtan says. Beginning that yr, a minimum of half of the ocean’s floor waters noticed temperatures hotter than essentially the most excessive occasions from 1870 to 1919.
Marine warmth waves are outlined as a minimum of 5 days of unusually excessive temperatures for a patch of ocean. Heat waves wreak havoc on ocean ecosystems, resulting in seabird hunger, coral bleaching, dying kelp forests, and migration of fish, whales and turtles in quest of cooler waters (SN: 1/15/20; SN: 8/10/20).
In May 2020, NOAA introduced that it was updating its “climate normals” — what the company makes use of to place every day climate occasions in historic context — from the common 1981–2010 values to the upper 1991–2020 averages (SN: 5/26/21).
This examine emphasizes that ocean warmth extremes are additionally now the norm, Van Houtan says. “Much of the public discussion now on climate change is about future events, and whether or not they might happen,” he says. “Extreme heat became common in our ocean in 2014. It’s a documented historical fact, not a future possibility.”
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