Global Warming Puts Half of All Reefs at Risk

GEELONG, Australia, October 25, 2005 (ENS) - Half of the world’s coral reefs may die within the next 40 years unless urgent measures are taken to protect them from climate change, the World Conservation Union (IUCN) warns in a new report released today. Warming ocean temperatures are causing reefs to bleach and die, but Marine Protected Areas can help.

The report, “Coral Reef Resilience and Resistance to Bleaching” was presented at the First International Marine Protected Areas Congress (IMPAC1) taking place in Geelong through Friday.

Some 520 delegates from 64 countries are attending the global conference organized by the IUCN and its World Commission on Protected Areas together with Australian governmental and institutional partners.

“Twenty percent of the Earth’s coral reefs, arguably the richest of all marine ecosystems, have been effectively destroyed today," says Carl Gustaf Lundin, head of IUCN's Marine Programme. "Another 30 percent will become seriously depleted if no action is taken within the next 20-40 years, with climate change being a major factor for their loss.”

Marine protected areas are key to preventing further degradation of these “underwater rainforests” by making corals more robust and helping them resist bleaching, advise the report's authors, Rod Salm and Gabriel Grimsditch.

“Destructive fishing practices such as blast or poison fishing can make coral reef more vulnerable to bleaching - it can decrease coral cover or deplete fish populations that are important for the coral reef ecosystem,” says Salm, who serves as cirector of the Nature Conservancy's Coastal Marine Program.

Corals are animals that are usually coloured tan, green or blue due to the presence of millions of microscopic plant cells within their tissues. These tiny plants use sunlight and the coral animal's respired CO2 to produce energy rich compounds that feed the coral host and release oxygen.

When seas get too warm, the relationship collapses, the brown plant cells are ejected, the white coral skeleton becomes visible through the now transparent animal tissues, and the coral slowly starves.


Bleached coral on the Great Barrier Reef (Photo courtesy Australian Institute of Marine Science)
Bleaching conditions that last longer than 10 weeks can lead to the death of the coral. In the worst ever recorded coral bleaching event in 1998, up to 90 percent of coral reefs died in some areas of the Indian Ocean.

"Current predictions are that massive coral bleaching will become a regular event over the next 50 years," warns Lundin.

He calls Marine Protected Areas a key tool, relieving coral reef ecosystems from other stress factors that also cause bleaching – sediment run-off, pollution, overfishing and invasive species.

Australia’s Great Barrier Reef Marine Park Authority has received international acclaim for efforts to extend protection to cover one-third of the world’s largest coral reef, which the IUCN says should help the area better cope with water pollution and sudden outbreaks of the invasive and voracious crown-of-thorn starfish.

The Great Barrier Reef Marine Park Authority says that under zero-stress conditions, reefs affected by the crown-of-thorns starfish can recover within seven to 15 years. But recovery can take much longer if the resilience of the ecosystem has been eroded by other stresses such as water pollution or bleaching.

The report recommends a strategy for the establishment of a global Marine Protected Areas network in the face of climate change, covering all important marine ecosystems including coral reefs.

"For a global MPA network, we need to take climate change into consideration. Some marine ecosystems become more valuable, others less so, which influences our decisions on which site should be included in the global network," says Lundin.

Sustainable fisheries management and integrated coastal management are seen as additional valuable strategies that enable coral reefs to be more resilient to bleaching.

IMPAC1 aims to advance Marine Protected Areas as a key tool for marine conservation, carrying forward the implementation of resolutions on these areas from the 2003 IUCN World Parks Congress. This gathering was the first to recognize that Marine Protected Areas are under-represented at the global level.

Only one percent of the world’s oceans are under protection today.

In addressing marine issues, the conference is designed to embrace the entire global range of marine protected areas in-shore, reef, deep water, high seas and remote locations.

The delegates will aim to develop a blueprint for partnerships between Marine Protected Area managers, fisheries managers, management agencies, indigenous peoples, local communities and industries reliant on marine resources.

Presenters will provide examples or models of best practice approaches for biodiversity and ecological processes through the management of Marine Protected Areas, address emerging issues, and explore innovative approaches and possible solutions to enable effective management of these issues.

"Coral Reef Resilience and Resistance to Bleaching" is available at: