Tipping Points: Environmental Trends to Destroy or Save Civilization

With civilization standing at multiple self-generated tipping points, a renowned environmentalist outlines 10 environmental trends of grave concern and 10 trends that give us reason for hope.

Melting ice sheets
Every spring, water from melting glaciers in Asia feeds the continent’s rivers. Because of global warming, the glaciers are shrinking, threatening the region’s water supply.
ISTOCKPHOTO/GORFER