Want to Eat? Then pay up.

• Author: Brown, Lester R.
• Position: EYE ON ECOLOGY - Droughts and rising grain prices

OVER THE SUMMER, the price of corn skyrocketed, taking the world into new terrain. This is not the way it was supposed to be, according to the Department of Agriculture, which, on June 12, projected that the U.S. harvest would hit a record 376,000,000 tons. However, the drought conditions that initially had been confined to the Southwest began to spread and intensify. In its next monthly report (July 11), the USDA reduced its projection to 329,000,000 tons, down by 12%. In the end, the actual decline was closer to 30%, or roughly 100,000,000 tons. Because the USDA overestimated the harvest, it underestimated the subsequent rise in food prices. Even as com prices set all-time highs, so too did soybean prices, putting still more upward pressure on food costs for consumers.

There were several reasons for the large reduction in the harvest. One was extremely high temperatures. Nationwide, the first half of this year was the hottest on record. Thousands of daily temperature highs were set locally. For instance, in St. Louis, Mo.--in the southern part of the Com Belt--there were 10 consecutive days with temperatures of 100[degrees] to 108[degrees] in late June and early July.

Timing and distribution of rainfall also helped determine the corn crop's destiny. The summer of 2012 was one of below-normal rainfall in the Corn Belt, especially the central and eastern parts. The combination of high temperatures and low rainfall led to the rapid spread of drought. During May and early June, the drought was concentrated in the Southwest, but the dryness kept expanding into the Midwest and the Upper Great Plains until, by the end of July, drought covered 63% of the country--the most extensive in half a century.

When the thermometer rises well above the norm, plants suffer. As a rule, as the temperature goes to 68[degrees]E photosynthesis increases. From 68[degrees] to 95[degrees], it remains steady. Beyond this, it declines fast. At 104[degrees], photosynthesis ceases entirely. At such elevated temperatures, plants go into thermal shock.

Intense heat also disrupts pollination. Corn particularly is vulnerable because of its complex pollination system. The tassel at the top of a corn plant releases pollen, which must fall on each strand of silk coming out of the ear of corn and travel to the kernel site, where fertilization occurs. If it is too hot, the silk will turn brown and dry out, leaving the pollen with no chance of reaching its destination.

This...