Amid ‘bad year’ for coral, UN launches tool and report outlining ways to protect threatened reefs

“Humans have left an indelible mark on the marine environment that has led to almost 20 per cent of coral reefs disappearing. But coral reefs are an invaluable natural asset we can’t afford to lose,” said UNEP Executive Director Achim Steiner in a press release.

“To give them a fighting chance, we need early and effective action on climate change,” he said.

UNEP noted that there has been unprecedented coral bleaching on the northern and central Great Barrier Reef, one of the world's most iconic reefs and a UNESCO World Heritage site. Bleaching in the central Indian Ocean is also severe, in the Maldives, Sri Lanka and in the Lakshadweep islands of India, where up to 100 per cent of corals are bleached in some locations. Many will not survive.

A dataset by UNEP, the National Oceanic and Atmospheric Administration (NOAA), the World Wildlife Fund (WWF) and the Pacific Islands Climate Science Center of the United States Geological Survey provides a new tool to prioritize reef management in the face of climate change.

By downscaling climate model projections for coral bleaching conditions, the time when severe bleaching conditions can be expected at a frequency of twice per decade, and when bleaching can be expected annually, has been identified, for all the world’s coral reefs, at a resolution of 4 kilometres, UNEP said.

The new report, Mesophotic Coral Ecosystems: A Lifeboat for Coral Reefs, examines what we know – and don’t know – about submerged reefs, and shows that coral ecosystems that live in low light conditions come to the rescue in some situations.

The report found that bleaching is chief among the threats of climate change to coral reefs. When bleaching occurs frequently, reefs become more vulnerable to erosion and lose their structure, which in turn means that their productivity and provision of ecosystems services diminish.

This will have wide-ranging impact on coastal dwellers in more than 100 countries, including most small island developing States, affecting in particular people who depend on reefs for income or food, as well as industry sectors developed around reefs, such as tourism, UNEP stressed.

As the global climate heats up, shallow coral reefs will experience increasing levels of catastrophic bleaching and mortality. Even if emission reduction committed to by countries in the Paris Agreement are achieved, more than three quarters of all the world’s reefs will experience bleaching conditions annually within this century, UNEP said.

The agency noted, however, there is a glimmer of hope in the great variation within and among countries.

“Many reefs are projected to experience annual bleaching conditions more than 10 years later than reefs within the same country or territory,” said Ruben van Hooidonk, NOAA Atlantic Oceanographic and Meteorological Laboratory.

These “relative refugia” are coral reef conservation priorities, and can be found within 16 of the 20 countries with the greatest reef area in the world, including, for example, Indonesia, the Philippines, Malaysia and Australia.

“Until now we have not been able to identify such refugia on reefs because the spatial scale of climate models is too coarse. This dataset provides an important resource in prioritizing reef management, including establishment of marine protected areas and reduction of direct human stresses to support ecosystem resilience,” said  van Hooidonk.

Available through a newly developed coral reef theme on UNEP Live, the data can be freely downloaded and used for management or adaptation planning as well as outreach.

UNEP said that in order to buy coral reefs more time and to support recovery of reefs that have bleached severely, some researchers are looking deeper for answers. They are studying submerged, light-dependent reefs to see if they may serve as lifeboats for nearby, connected shallow reefs that have been damaged by repeated bleaching. Mesophotic coral reefs are one of the few remaining ecosystems on earth to remain largely unexplored.

“While they are deeper and more remote than shallow coral ecosystems, mesophotic reefs are still subject to some of the same effects such as bleaching and habitat destruction,”  Steiner said. “We are just beginning to understand them, but in some locations they may resist the most immediate impacts of climate change, and may be able to help re-seed damaged or destroyed surface reefs and fish populations.”

The report’s main recommendations include to locate where mesophotic reefs exist, with a priority in the equatorial Indo-West Pacific and eastern Atlantic; to increase understanding of how they are connected to shallow reefs in order to understand the extent to which they can be used as a refuge for, or to reseed, shallow reefs; and to raise awareness among managers and policymakers of the importance of their ecosystem service values and encourage measures to protect them.

These tools may support implementation of the proposed UNEA-2 resolution on coral reefs, UNEP said.

“There is truly no time to waste, and UNEA-2 is an opportunity to accelerate action on safeguarding our planet,” said  Steiner.

Photo: UNEP GRID Arendal/Glenn Edney

Source: www.justearthnews.com