Yesterday’s scorching ocean extremes are at the moment’s new normal. A new evaluation of floor ocean temperatures over the previous 150 years reveals that in 2019, 57 p.c of the ocean’s floor skilled temperatures not often seen a century in the past, researchers report February 1 in PLOS Local weather.
To offer context for the frequency and length of contemporary extreme heat occasions, marine ecologists Kisei Tanaka, now at the Nationwide Oceanic and Atmospheric Administration in Honolulu, and Kyle Van Houtan, now at the Loggerhead Marinelife Heart in Juno Seaside, Fla., analyzed month-to-month sea-surface temperatures from 1870 by 2019, mapping the place and when extreme heat occasions occurred decade to decade.
month-to-month extremes quite than annual averages revealed new benchmarks in how the ocean is altering. Increasingly patches of water hit extreme temperatures over time, the workforce discovered. Then, in 2014, the whole ocean hit the “point of no return,” Van Houtan says. Starting that yr, at the very least half of the ocean’s floor waters noticed temperatures hotter than the most extreme occasions from 1870 to 1919.
Marine heat waves are outlined as at the very least 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 looking for cooler waters (SN: 1/15/20; SN: 8/10/20).
In Might 2021, NOAA introduced that it was updating its “climate normals” — what the company makes use of to place each day climate occasions in historic context — from the common 1981–2010 values to the larger 1991–2020 averages (SN: 5/26/21).
This research emphasizes that ocean heat 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.”