Coral reefs under threat.

• Author: McKeown, Alice
• Position: VITAL SIGNS

About one-fifth of the world's coral reefs have already been lost or severely damaged, while another 35 percent could be lost within 10-40 years, according to the latest review by the Global Coral Reef Monitoring Network. The number of coral reefs considered at low risk stood at 46 percent, up from' 30 percent only four years ago, but the number of effectively lost reefs remained constant during the period--although this figure was double the 10 percent lost or severely damaged in the first global estimate in 1992. However, the recent estimates do not take into account risks from climate change; when these are included, all coral reefs are in danger and widespread mortality is predicted.

Coral reefs in Asia and the Indian Ocean are most at risk, with 54 percent either lost or critically threatened and another 25 percent moderately threatened. Southeast Asia, which contains the highest biodiversity of all coral reefs as well some of the...