Thursday, August 21, 2008; A14

The Aug. 17 Metro story "Regardless of Size, Location, Species Share a Threat: Man" did a good job of bringing attention to the fact that many plants and animals are on the brink of being lost from our neighborhoods. Few people realize that worldwide we are experiencing the greatest species extinctions in human history, roughly one species every 20 minutes, according to mid-range estimates.

Typically, extinctions occur in faraway rain forests, where countless living organisms may not even have been discovered before being wiped out, primarily because of habitat loss. Other serious threats are overfishing, pollution and climate change.

We could lose more than one-third the species on Earth in less than 50 years because of climate change. What does this mean for people living in the D.C. area? It means we all lose sources of foods, medicines, raw materials and natural filters for our water and air, among other wonders of nature.

PETER A. SELIGMANN

Chairman and Chief Executive

Conservation International

Arlington