As a record heat wave baked the earth across the Midwestern United States this month, farmers in America’s bread basket looked on their bone dry fields and wilting crops with growing dread. This past June was the tenth driest on record in the U.S., creating severe drought conditions across several states, and the 10-day spell of unusual, unrelenting heat from the end of June through the first week of July significantly increased the stress on food crops already damaged by drought, including much of the nation’s corn and soy supply.
The United States is the world’s foremost producer of corn, one of the world’s most important food crops. Originally domesticated in Mexico, corn thrives in ordinary summer heat, and it can withstand occasional high daytime temperatures. But the temperatures during this heat wave were anything but ordinary for North America at this time of the year. With temperatures 10-20 degrees above average, the heat wave toppled more than 3,800 all-time records nationwide. Many areas experienced more than a week straight of daytime temperatures above 100 degrees Fahrenheit (38 degrees Celsius) and nighttime temperatures that failed to fall below the 80s.
To grow well and produce a strong harvest, corn depends on daytime temperatures in the 80 – 90 degree range, and nighttime temperatures that fall below 80 degrees. Under such persistent heat conditions as the U.S. has experienced this summer, corn plants become stunted by heat stress, failing to grow to their usual height and producing fewer ears. If such heat hits a corn field during its crucial early summer crucial pollination period, the plants often also fail to release pollen at the appropriate time, which prevents ears from forming at all, entirely ruining the crop.
As a consequence of weeks of serious drought followed by severe high temperatures, U.S. corn farmers may be facing one of the worst crop losses in history. Monday, the U.S. Department of Agriculture reported that heat and drought have significantly damaged the corn crop in 18 states, and nearly a third of the corn in those states is now rated in poor or very poor condition. Nationwide, only 40 percent of the corn crop is considered by the USDA to be in good condition.
Soybeans, too, have suffered during this season’s prolonged high temperatures. Monday fears of a significantly damaged 2012 crop pushed soy prices to an all-time record high.
Because the U.S. exports staple food crops to many other countries, the consequences of this year’s record-breaking hot dry summer will almost certainly push food prices higher not just within the country, but worldwide, for the rest of the year.
Massive crop losses due to natural disasters seem to be on the rise, and so too do related spikes in global food prices. Last year, a global wheat shortage drove a 36 percent increase in staple food prices worldwide. The cause? A severe drought and high heat in Texas led to wildfires that damaged two thirds of the state’s wheat crop. In 2010, drought and wildfires in Russia destroyed half that nation’s wheat fields, while epic flooding in Pakistan ruined not only food growing in the fields but also tons of stored grain.
In the continental U.S., the first six months of 2012 have been the warmest of any year since record-keeping began in 1895. Though scientists are usually hesitant to link any specific weather event to climate change, recent studies show that severe weather events across the globe are on the rise right along with the average global temperature.
Fighting climate change means much more than protecting coastal cities from flooding, or saving arctic species from extinction. A changing climate threatens the stability the whole world’s food supply. As the Earth continues to warm, we can expect severe weather risks — and food prices — to rise in tandem. The cost of our unsustainable addiction to carbon fuels is already coming due — and this year, Americans will be paying part of it at the grocery store.
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Drought photo by Tomas Castelazo, from Wikimedia Commons. Used under Creative Commons license.