Is Global Warming Shrinking Harvests?

Europe’s summer heat wave left elderly city dwellers struggling to survive in their ovenlike apartments—and farmers desperate to save their wilting fields. Day after day for weeks on end, temperatures in France, England, and Spain soared more than 20 Fahrenheit degrees above average, creating severe drought conditions that devastated crops. World grain harvests plummeted by 32 million tons, with the worst shortfalls concentrated in a region stretching from the United Kingdom to Ukraine. The heat wave is over, but it left researchers wondering whether the searing summer was an anomaly or an indication that global warming has started to wreak economic havoc.