Can coral reefs survive climate change?

When it became apparent in March that corals on the Great Barrier Reef had again been bleached on a large scale, it was a sobering realization, especially for environmentalists and researchers. Scientists are now not optimistic about the future of coral reefs. Even if humanity manages to limit warming to 1.5°C this century, scientists predict that up to 90 percent of tropical coral reefs will suffer severe damage.

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Read more after the announcement

However, many Australian researchers do not want to give up the fight for survival on the Great Barrier Reef. While everyone agrees that the most important action to take is to reduce global greenhouse gases, at least a scientific intervention can make a positive difference to coral reefs. In the meantime, these projects are no longer just planned on a small scale, but are designed to cover thousands of square kilometres.

heat tolerant corals

Promising projects include the cultivation of millions of heat-tolerant corals in aquaculture. A research team is working to further improve the natural adaptation of many coral species to warmer temperatures so that they can withstand additional heat stress of 1°C for up to four weeks. “We believe that a total of eight weeks of 1°C heat stress can be achieved,” the research team from the Australian Institute of Marine Science and the University of Melbourne wrote in an article published in the online journal The Conversation. “This extra level of heat tolerance can make a real difference to coral survival.”

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Read more after the announcement

At the same time, researchers have developed new devices that make it possible to “plant” young heat-resistant corals on corals. Currently, these projects are limited to a few thousand corals per year, but plans are in place to increase that number to several million per year using new methods. New models and improved data sets also make a positive difference. Because these make more targeted interventions possible. The lives of individual reefs can extend decades in this way.

Six mass bleaching operations since 1998

Although these projects offer hope, at least on a small scale, the reefs as a whole are not in good shape. The bad news came in March: Another heat wave in northern Queensland, the Australian state with a reef stretching 2,300 kilometers off the coast, caused severe coral bleaching. The Great Barrier Reef Marine Park Authority confirmed that bleaching can be seen in both the far north and central parts of the reef. In the central parts before Townsville it is likely to be particularly severe. Normally, corals should not bleach in the La Niña season, which brings cooler temperatures, clouds, and rain. “The year 2022 is a first thanks to anthropogenic warming,” wrote Terry Hughes of James Cook University, one of Australia’s leading researchers on coral. Twitter.

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Read more after the announcement

The Great Barrier Reef is suffering from climate change

Made up of 3,000 species of corals and home to 1,500 species of fish and 400 species of corals, the reef has been suffering from the effects of climate change for years. Rising sea temperatures, caused by man-made emissions, have already led to five mass-bleaching events of coral reefs in 1998, 2002, 2016, 2017, and 2020.

During the bleaching process, the symbiosis of the corals with a type of algae that provides energy to the hollows and gives them their bright colors is broken. Although animals can also recover from bleaching, if this continues for a long time or is repeated often, corals will often die completely. In addition to warmer water temperatures, storms, agricultural runoff, coal harbor expansion, and invasive species of crown-of-thorns starfish are also worrisome to coral reefs. But preserving coral reefs is not only of paramount importance to the diversity of Australia’s ecosystems, and the economic aspect of people should not be underestimated either: 60,000 people in Australia work in an occupation associated with the Great Barrier Reef.

World Heritage Committee visits coral reefs

It didn’t show up until November study, published in “Current Biology” has found that 98 percent of individual corals have already bleached since 1998. Only one group of corals has been rescued far south of the Great Barrier Reef, in a small area that has remained consistently cold during all bleaching events. Five group. In October 2020 was another study He also concluded that the number of small, medium and large corals on the Great Barrier Reef has declined by more than 50 percent since the 1990s.

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Read more after the announcement

The news of bleaching renewal comes at a critical time for coral reefs. Because the UNESCO delegation, which is set to decide again in June whether the reef should be included in the Red List, has been in Australia since last week for a visit to the reef. Last year, the reef narrowly avoided being included in the UNESCO Red List after a major marketing campaign by the Australian government.

Money alone cannot solve problems

Certainly in order to calm things down a bit in advance, the Australian government promised more money in January. Should the election be won, the current $2 billion rescue package would be increased by another A$1 billion – the equivalent of about €678 million. The money will flow to preserve the world heritage over the next nine years.

Scientists and ecologists welcomed this news, but at the same time they did not spare their criticism. This is how coral reef expert Terry Hughes commented on TwitterThat Australia, despite the infusion of cash, is still Coal and gas across the Great Barrier Reef are exported abroad every day. And the John ChurchA climate scientist at the University of New South Wales, in Sydney, complained that the investment was “minuscule” compared to the environmental and economic damage burning of fossil fuels and climate change would inflict on coral reefs.

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And also a coral reef expert at the World Wide Fund for Nature, Richard LakeHe stressed that cash alone will not solve coral reef problems. “We need to protect forests better and work harder on water quality,” he said. In addition, Australia must adhere to a climate policy consistent with limiting warming to 1.5 degrees. According to Leck, coral reefs have a chance of survival if Australia becomes the world’s largest source of renewable energy by 2030 while reducing both domestic and exported emissions.

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