A Nobel Prize-winning economic theory used by investors shows the first signs of helping save endangered coral reefs, scientists say.
Researchers at the Australian University of Queensland used modern portfolio theory (MPT), a mathematical framework developed by economist Harry Markowitz in the 1950s to help risk-averse investors maximize returns, identify the 50 reefs or coral sanctuaries around the world that are most likely to survive the climate crisis and to be able to repopulate other reefs, if other threats are absent.
The to study recommends targeting investments in conservation projects that have the “greatest potential for success” to protect priority reefs. The gains go beyond positive ecological outcomes and include crucial social, economic, health and nutritional benefits for communities, according to partners, organizations and funders interviewed by Blue Earth Consultants.
Professor Ove Hoegh-Guldberg, climatologist at the University of Queensland, who helped lead the ’50 Reefs’ project, said:’ It’s basically a strategy to help us make decisions on what to do with it. protect, if we want to have corals at the end of the century.
“This is our best chance to have a long term future for coral reefs,” he said.
Coral reefs face a grim future. Even if drastic reductions in emissions ensured that global heating was limited to 1.5 ° C above pre-industrial levels, which would require cutting global CO almost in half.2 emissions by 2030 compared to 2010 levels – 70% to 90% of current corals would disappear.
In October, a study on the health of coral reefs found that 14% had been lost globally in less than a decade, with bleaching events caused by rising sea surface temperatures being the main culprit.
“Modern portfolio theory is a framework that aims to reduce risk while maximizing returns,” Hoegh-Guldberg said. “It’s treating conservation like an investment opportunity. “
The strategy, resulting from a meeting of scientists at Hawaiian Institute of Marine Biology in 2017, drew on theory to help scientists choose a “balanced” portfolio of coral reefs.
“You have hundreds of these reefs across the planet,” Hoegh-Guldberg said. “Which one do you choose to focus your efforts on?” “
Dr Hawthorne Beyer, University of Queensland researcher on the use of quantitative modeling in environmental systems management, said: “Talk to business people and they will get it immediately. It’s a very logical idea and one that makes a lot of sense. Ours was the first to apply it globally.
Scientists have divided the world’s coral reefs into “bioclimatic units” (BCUs) of 500 km² (190 square miles). They used 174 measurements, in five categories, including temperature history and projections, ocean acidification, invasive species, cyclonic activity, and connectivity with other reefs, for each. Then, using a process called “scalarization,” they produced estimates for each BCU. This has captured the widest range of possibilities for the future. “We don’t know which metrics are best for predicting risk,” Beyer explained.
The team then used the MPT to quantify threats and identify reefs with the best conservation options, while accounting for uncertainty about future risks from climate change.
“You don’t want to put all your eggs in one basket, or bet on a measure of risk, when we have massive uncertainty as to what the risks will be,” he said.
The project identified reefs in the Middle East, North and East Africa, Australia, the Caribbean, the Pacific Islands, South America, South East and South Asia. They include parts of the Great Barrier Reef in Australia, Egypt and the southern Red Sea, and parts of the “Coral Triangle” around Indonesia, Malaysia, Papua New Guinea. Guinea and the Philippines. But, based on the criteria of climate and connectivity, the model excluded several ecologically important areas, such as Hawaii and the Central American Barrier Reef.
Almost $ 93million (£ 70million) has been invested in the project, funded by the Vibrant Oceans initiative of Bloomberg Philanthropies and others. The report found that the 50 reef-inspired approach has helped at least 26 organizations, and eight donors have now prioritized 60 coral reef ecosystems in more than 40 countries.
Coral reefs cover only 0.2% of the ocean floor, but are home to at least a quarter of all marine species and are home to hundreds of millions of people. Conservation efforts inspired by the study focused on five threats to coral: fishing; “Diffuse source pollution”, such as fertilizers, road runoff or sediment; pollution of sewage; coastal development; and the stress caused to reefs by climatic extremes.
Emily Darling, Director of coral reef conservation at the Wildlife Conservation Society (WCS), said part of the benefit was having a clear plan of where to best focus their efforts.
“One of the biggest benefits of the 50 reef approach has been this compelling message that climate change is the critical threat to coral reefs and it is an approach that can give reefs a fighting chance.”
WCS has $ 18 million in funding for work in 11 countries, including Fiji, Indonesia, Kenya and Tanzania, on 21 of the 50 reefs, to help communities reduce pressure on precious ecosystems.
“We are looking at non-climatic threats such as overexploitation, destructive fishing, unsustainable tourism, coastal development, water pollution. We then ask “well, what are the main local pressures? ”Said Darling. “And this is how we identify the intervention to be adapted to these different situations. “
A no-harvest protected marine area between Kenya and Tanzania – in which no fishing, mining, drilling or similar activities are permitted – has been supported by WSC to protect corals from these other pressures that accompany global warming.
“By doing this, we will not only protect the biodiversity of the coral reefs, but also the whales, the long-beaked dolphins, the dugong, the coelacanth fish, this whole ecosystem,” she said.
One of the 50 reefs identified is the ‘happy coral’ sanctuary discovered in Tanzania, reported by the Guardian last year, where coral species have thrived despite warming events that have killed neighboring reefs.