LINK TO SOURCE: https://www.theguardian.com/environment/2022/feb/01/all-coral-will-suffer-severe-bleaching-when-global-heating-hits-15c-study-finds

PART-1: WHAT THE SOURCE DOCUMENT SAYS

All coral will suffer severe bleaching when global heating hits 1.5C. Scientists used the latest climate projections to confirm that 1.5C heating would be ‘catastrophic’ for coral reefs. Almost no corals on the planet will escape severe bleaching once global heating reaches 1.5C, according to a new study of the world’s reefs. Reefs in areas currently regarded as cooler refuges will be overwhelmed at 1.5C of heating, and just 0.2% of reefs will escape at least one bleaching outbreak every decade, according to the research. The team of scientists from the University of Leeds, Texas Tech University and James Cook University used the latest climate model projections to confirm that 1.5C of global heating will be catastrophic for coral reefs. The Great Barrier Reef on verge of another mass bleaching after highest temperatures on record. Corals bleach when ocean temperatures are too high for too long. Algae that provide corals with much of their food and colour separate from the coral during heat stress. Severe bleaching can kill corals, but they can recover from milder outbreaks if there are several years with no further heatwaves. The world’s oceans are heating due mostly to the burning of fossil fuels. The study comes as the world’s biggest coral reef system, the Great Barrier Reef off Australia’s Queensland coast, is on the verge of another mass coral bleaching event. In the study, the team analysed climate projections across all of the world’s shallow-water coral reefs, which constitute the vast majority of reefs and provide habitat, tourism revenue and coastal protection. About 84% of the world’s corals exist in areas that are expected to bleach less than once a decade and are regarded as “thermal refugia, the study said. But the analysis suggests at 1.5C of global heating, only 0.2% of the area covered by reefs is in water cool enough to avoid bleaching at least once every five years – a frequency considered too short to allow corals to recover. The only area to escape, the study claims, would be in a region of the east Indian Ocean in an area of natural upwelling of cooler water. Even areas with strong currents that can protect corals from heat, such as those in Panama, Florida and the Lesser Sunda Islands in Indonesia, would be overwhelmed by the heat. Associate Prof Scott Heron, a marine scientist at James Cook University and a co-author of the study, said coral reefs sustained a billion people around the world. He said the study, published in the journal PLOS Climate, showed corals worldwide were at even greater risk from climate change than previously thought. That meant it was crucial that conservation work continued on reefs to give corals a fighting chance of survival, he said. “Until we reach the point where I can’t see a single coral, it isn’t too late. We have to keep pursuing our best practices to protect coral reefs. Real people rely on these reefs and that is a driver to keep gathering the best knowledge possible. Adele Dixon, lead author of the study and a PhD student at the University of Leeds, said corals in French Polynesia and southern Indonesia may be exposed to heat stress less frequently, and the study did identify a small number of “hope sites”. Corals in these locations, such as the eastern Pacific, may be better able to cope with temperature extremes,” she said. But one prominent coral reef expert challenged the findings, and doubted the real world outcomes would be as catastrophic as the research suggests. Prof Peter Mumby, a reef expert at the University of Queensland studying the effects of climate change on corals, agreed that at 1.5C corals worldwide would be under greater stress than they are today. But I don’t agree that this research provides evidence that corals are untenable under 1.5C of warming,” he said. Mumby said the levels of heat stress used in the study to identify severe bleaching were arguably too low, and the method was unlikely to capture local conditions that could protect some reefs. Even reefs that are hit by bleaching every five years could include areas of coral that would survive, he said.

PART-2: CRITICAL COMMENTARY

CORALS WILL NOT SURVIVE 1.5C: IN THIS STATEMENT REPEATED MANY TIMES IN THE SOURCE DOCUMENT THE “1.5C” IS A REFERENCE TO 1.5C OF WARMING SINCE PRE-INDUSTRIAL. THE PROBLEM WITH THE CLIMATE SCIENCE POSITION OF KNOWING HOW MUCH WARMING SINCE PRE-INDUSTRIAL THE PLANET CAN STAND BEFORE IT ALL GOES TO HELL IS THAT CLIMATE SCIENCE DOES NOT KNOW WHEN PRE-INDUSTRIAL WAS AND WHAT THE TEMPERATURE WAS BACK THEN. IT WAS INITIALLY PROPOSED BY THE IPCC IN 2001 THAT PRE-INDUSTRIAL WAS THE YEAR 1750. IN THE IPCC REPORT OF 2015, THEY CHANGED THEIR MIND ABOUT WHEN THE PRE-INDUSTRIAL YEAR WAS AND WROTE THAT IT WAS THE YEAR 1850. IN THE WORLD’S FIRST CLIMATE CHANGE RESEARCH PAPER PUBLISHED BY CALLENDAR IN 1938, HE WROTE THAT THE PRE-INDUSTRIAL YEAR WAS 1900 WHEN THE BURNING OF COAL REALLY TOOK OFF AND THAT ALL THAT FOSSIL FUEL EMISSIONS CAUSED A STEADY WARMING RATE FROM 1900 TO 1930. IN 2015, CLIMATE SCIENTIST JAMES HANSEN, KNOWN AS “THE FATHER OF CLIMATE CHANGE” WROTE THAT GLOBAL WARMING STARTED IN 1950 AND LATER NASA ADOPTED THE JAMES HANSEN PRE-INDUSTRIAL YEAR AND DECLARED THAT GLOBAL WARMING STARTED IN 1950. IN 2020, CLIMATE SCIENTIST PETER COX WROTE THAT GLOBAL WARMING HAD STARTED IN “THE 1970S”.

WHAT WE SEE HERE IS THAT CLIMATE SCIENCE KNOWS EXACTLY WHAT KIND OF HORROR 1.5C OF WARMING SINCE PRE-INDUSTRIAL WILL DO TO THE PLANET BUT THEY DON’T KNOW WHEN PRE-INDUSTRIAL WAS AND SO THEREFORE THEY ALSO DO NOT KNOW WHAT THE PRE-INDUSTRIAL REFERENCE TEMPERATURE IS. UNDER THESE CONDITIONS THE EXTREME CERTAINTY OF WHAT 1.5C OF WARMING SINCE PRE-INDUSTRIAL WILL DO TO THE CORAL IS NOT CREDIBLE.

YET ANOTHER ISSUE IS THAT IN THE CLIMATE SCIENCE POSITION THAT THE AMOUNT OF WARMING SINCE PRE-INDUSTRIAL MUST NOT BE ALLOWED TO GO BEYOND 1.5C OR ALL HELL WILL BREAK LOOSE AND WE WILL NO LONGER BE ABLE TO TAKE CLIMATE ACTION TO CALM THE CLIMATE DOWN, THE 1.5C FIGURE IS ITSELF SUBMERGED IN AN EXTREME FORM OF UNCERTANTY.

IN THE IPCC 2001 REPORT, CLIMATE SCIENCE STATED THAT THE AMOUNT OF WARMING SINCE PRE-INDUSTRIAL MUST NOT BE ALLOWED TO EXCEED 5C OR NATURAL FEEDBACKS WILL TAKE OVER AND ALL HELL WILL BREAK LOOSE BECAUSE OUR CLIMATE ACTION WILL NO LONGER WORK. HOWEVER, IN THE 2007 IPCC REPORT THIS CRITICAL AMOUNT OF WARMING SINCE PRE-INDUSTRIAL WAS LOWERED FROM 5C TO 4C. MUCH LATER IN THE 2013 IPCC REPORT THE CRITICAL FIGURE FOR THE AMOUNT OF WARMING SINCE PRE-INDUSTRIAL WAS LOWERED AGAIN TO 3C AND IN THE 2015 IPCC REPORT IT WAS LOWERED AGAIN TO 2C AND LATER IN THE 2018 IPCC REPORT IT WAS LOWERED AGAIN TO 1,5C WHERE IT HAS NOW BEEN FOR THE LAST 4 YEARS.

IN VIEW OF THE UNCERTAINTIES IN WHEN THE PRE-INDUSTRIAL YEAR WAS, WHAT THE TEMPERATURE WAS BACK THEN, AND HOW MUCH WARMING SINCE PRE-INDUSTRIAL IT WILL TAKE TO SET THE WORLD AND THE CORAL REEFS ON FIRE AND BEYOND CLIMATE ACTION TO MODERATE, THE EXTREME CERTAINTY IN THE ARTICLE ON WHAT 1.5C SINCE PRE-INDUSTRIAL WILL DO TO CORAL IS NOT CREDIBLE.

EVEN MORE IMPORTANT, THE CURRENT PERIOD OF GLOBAL WARMING IS NOT THE FIRST EXPERIENCED BY THE CORAL BECAUSE INTERGLACIALS BY NATURE ARE NOT AT A STEADY TEMPERATURE BUT GO THROUGH VIOLENT CYCLES OF WARMING AND COOLING A CENTENNIAL AND MILLENNIAL TIME SCALES. IN THE PREVIOUS INTERGLACIAL, THE EEMIAN, A GLOBAL WARMING CYCLE HAD CAUSED THE WEST ANTARCTIC ICE SHEET TO DISINTEGRATE AND RAISE SEA LEVELS BY SEVERAL METERS. AND IN THE NEXT INTERGLACIAL, THE HOLOCENE, {WHERE WE ARE NOW}, THERE HAVE BEEN SEVERAL STRONG GLOBAL WARMING CYCLES OVER THE LAST 11,000 YEARS THAT AMONG OTHER THINGS CREATED HUMAN CIVILIZATION, AND CAUSED CATASTROPHIC HARM TO THE ROMAN EMPIRE AND THE LATE BRONZE AGE CIVILIZATION. AND YET, THE CORAL ARE STILL HERE. BASED ON THESE LESSONS FROM HISTORY WE CONCLUDE THAT NEITHER THE CERTAINTY OF THE IMPACT OF 1.5C SINCE PRE-INDUSTRIAL NOR THE ASSUMED FRAGILITY OF THE CORAL TO GLOBAL WARMING CYCLES IS CREDIBLE AND THAT THEREFORE, THE CLAIMS MADE IN THE SOURCE TEXT ABOVE ARE NOT CREDIBLE.