"The world has quietly entered a new era, one where there is no national security without global security. We need to recognize this and to restructure and refocus our efforts to respond to this new reality." –Lester R. Brown, Plan B 4.0: Mobilizing to Save Civilization.
Now in its 43rd year, Earth Day has become an international day dedicated to promoting environmental awareness and action. Lester Brown explains what's changed, as concern about climate change and green energy have come to the forefront of the movement.