96pc of world's coral reefs critically endangered, IUCN warns

Nearly all the world’s shallow-water coral reefs face an extremely high risk of collapse by 2075 because of climate change, the International Union for Conservation of Nature (IUCN) warned on Thursday, Dawn reported, citing AFP.

In the first global assessment of its kind, the world authority on threatened wildlife classified 96pc of the planet’s coral reef systems as “critically endangered”, its highest risk category.

“The future threat of climate change is looming and severe, and that poses a very high risk to the survival of these ecosystems,” said Mishal Gudka, scientific lead of the IUCN Red List of Coral Reef Ecosystems assessment.

The biggest reefs are at risk

The analysis examined 127 tropical and subtropical coral systems covering 188,362 square kilometres. The world’s largest and most biodiverse reefs are among those classified as critically endangered:

• Australia’s Great Barrier Reef
• the Coral Triangle in Southeast Asia and the western Pacific
• the Caribbean’s Mesoamerican Barrier Reef System
• the Red Sea coral reefs

A reef ecosystem collapses when hard corals, which build its living foundation, largely disappear and are replaced by algae, rubble and sponges, the IUCN said.

What is killing the reefs

“Heat stress from climate change is the single most consistent threat driving coral reef decline worldwide,” the IUCN said. Warming oceans make bleaching events more frequent and more intense.

Other threats include:

• Overfishing: the overexploitation of parrotfish and groupers, which help control algae, threatens 63pc of reef ecosystems.
• Coastal pressures: development, pollution and tourism.
• Storms: which are becoming more frequent.

Gudka said the emergence this year of a “super” El Nino also presents a risk to corals.

For its assessment, the IUCN used a “middle-of-the-road” UN climate scenario in which temperatures rise 2.7C above pre-industrial levels by 2100. The UN warned on Wednesday that the world is on track for 2.6C of warming this century under current pledges.

“Not yet lost”

The IUCN said reefs in most parts of the world “are not yet lost”. If scientists look only at what has happened over the past 50 years, without future climate projections, 24pc of reef ecosystems would be critically endangered instead of 96pc.

“This gives us a critical window for action for us to scale up conservation efforts and climate action to prevent the worst outcomes from occurring,” Gudka said.

IUCN Director General Grethel Aguilar said it was “not too late to give coral reefs a chance to recover”. “We know what is needed: ambitious emissions reductions, stronger protection and restoration efforts, and sustained investment in resilient coastal ecosystems and the communities that depend on them,” she said.

Presented at COP17

The IUCN presented its findings at the UN’s COP17 biodiversity summit in Yerevan, Armenia, where governments are under pressure to make progress on a pact to halt and reverse biodiversity loss by 2030. The summit has also heard that a fund meant to raise billions from companies using nature’s genetic data has collected just $7,085.

A study in the journal Nature last week found that by 2020 nearly half of coral species were at “elevated relative risk of extinction”, with climate change the main driver.