April 22nd 2010 is the 40th anniversary of Earth Day, an occasion for people to celebrate and raise awareness of the natural world.

Today with news of melting glaciers, increasingly severe droughts, floods, and storms and rising ocean levels, Earth Day celebrants around the world are marking the anniversary with new calls to combat global warming and to protect our threatened environment.

In the years leading up to that first Earth Day in 1970, many Americans felt growing concerns about unchecked air and water pollution and the destruction of forests and other important ecosystems around the planet.

Read more here.