When ocean waters become too warm, causing coral reefs to bleach and die, that imperils the entire marine food web — and ultimately a food chain that helps to feed eight billion people.
🚨 We are in a planetary climate emergency. 🚨
Global heating has pushed the world’s coral reefs to a fourth planet-wide mass bleaching event that is on track to be the most extensive on record, US government scientists have confirmed.
Some 54% of ocean waters containing coral reefs have experienced heat stress high enough to cause bleaching, the National Oceanic and Atmospheric Administration’s Coral Reef Watch said.
The first global bleaching event happened in 1998 with 20% of the ocean’s reef corals exposed to a level of heat stress high enough to cause bleaching. The second event, in 2010, saw 35% reaching that threshold, and the third from 2014 to 2017 peaked at 56%.
Dr Derek Manzello, the Coral Reef Watch director, told the Guardian the current bleaching was likely to surpass the previous most widespread event soon “because the percentage of reef areas experiencing bleaching-level heat stress has been increasing by roughly 1% per week”.
Manzello said global heating had combined with a global El Niño to push up sea surface temperatures. He said predictions made by scientists decades ago about the fate of corals in a warming world were now coming to pass.
“The bottom line is that as coral reefs experience more frequent and severe bleaching events, the time they have to recover is becoming shorter and shorter. Current climate models suggest that every reef on planet Earth will experience severe, annual bleaching sometime between 2040 and 2050.”
Prof Ove Hoegh-Guldberg, a pioneer of coral research who was among the first to link bleaching to global heating, said: “It’s a shock. We clearly have to prevent governments from investing in fossil fuels, or we won’t have a chance in hell to save reefs.”
@breadandcircuses I appreciate it’s not a solution and agree we’re in a crisis, but I’m curious: are corals setting up new homes in parts of the ocean that used to be too cold for them?