Alarming new research shows global warming of 1.5\u00b0C relative to pre-industrial levels will be catastrophic for almost all coral reefs \u2013 including those once thought of as refuges.<\/p>\n
Associate Professor Scott Heron from James Cook University was part of the study. He said the team of scientists used the latest generation of climate model projections to predict future thermal exposure of shallow-water coral reefs around the globe.<\/p>\n
\u201cWe identified thermal refuges \u2013 places where it\u2019s thought coral reefs have a good chance of surviving warming oceans due to things like consistent upwelling of cool deep waters \u2013 at a resolution of only 1 km,\u201d said Dr Heron.<\/p>\n
He said the scientists found that the refuges will provide almost no escape \u2013 only 0.2%, or one fifth of one percent, of coral reefs globally are projected to avoid frequent bleaching-level heat stress under a 1.5\u00b0C climate warming scenario.<\/p>\n
\u201cThis means corals worldwide are at even greater risk from climate change than previously thought, especially as limiting warming to 1.5\u00b0C is looking increasingly unlikely,\u201d said Dr Heron.<\/p>\n
He said coral recovery following extensive thermal stress-induced mortality depends on local conditions, but science indicates it requires at least 10 years for coral communities to re-establish ecosystem functions.<\/p>\n
\u201cMost coral reefs won\u2019t have time to recover between bleaching events,\u201d said Dr Heron.<\/p>\n
Though small in number, there are some reef locations that may persist due to other factors.<\/p>\n
\u201cIn addition to locations where heat exposure events will be less frequent, like in French Polynesia and southern Indonesia, there are other \u2018hope sites\u2019 that have high variability in temperatures. Corals in these locations, such as the Eastern Pacific, may be better able to cope with temperature extremes,\u201d said Adele Dixon, lead author of the study from the University of Leeds in the UK.<\/p>\n
Dr Heron added that the scientists wanted to highlight that climate change effects are already impacting ecosystems in many areas of the world and will worsen, even at the 1.5\u00b0C of global warming set as a target in international agreements. This includes potential impacts of heat stress this year on the Great Barrier Reef and off Western Australia.<\/p>\n
\u201cThis analysis confirms that significant action on greenhouse gas emissions is urgent and needed this decade. We also need to ramp up local actions to help reefs survive through already predicted impacts. Promoting reef resilience, adaptation to higher temperatures and facilitating migration will be vital strategies to secure their survival,\u201d said Dr Heron.<\/p>\n
PAPER<\/strong><\/p>\n Dixon A.M., Forster P.M., Heron S.F., Stoner A.M.K., Beger M. 2022. \u2018Future loss of local-scale thermal\u00a0<\/b>refugia<\/span>\u00a0in coral reef ecosystems<\/b>\u2019. PLOS Climate<\/em>. DOI: https:\/\/doi.org\/10.1371\/journal.pclm.0000004<\/a><\/p>\n