Special Section: WEATHER CHANGE: POORER HARVESTS

In rich fields of India's Rejasthan state, where the monsoon rains usually sweep in faithfully each summer, the rice crop has been devastated by the first drought in years. Eastward on the Indian subcontinent, great floods have ruined the Bangladesh harvest. Far off in Africa's Sahel region, six years of drought have only recently been interrupted by rain. In the U.S., both the corn and soybean crops will fall far below expectations this year because of a freakish succession of excess spring rains, summer drought and early fall frost.

Is this roster of natural disasters an omen of worse weather to...