I spent an evening with Lester Brown, president of the Earth Policy Institute and a winner of the coveted MacArthur Prize, for some long term thinking about the environment and its investment implications. 

Global warming is causing the melting of ice sheets in Greenland and Antarctica, glaciers in the Himalayas, and the Sierra snowpack. Water tables are falling and fossil aquifers are depleting.

In the coming decades this will cause severe shortages of fresh water that could