The Right Amount of Water

Dec. 5, 2018

We often report on the problems major storms and excess rain bring: flooding, washed-out culverts, combined sewer overflows. The recently released National Climate Assessment, in fact, contains some dire predictions about what’s going to happen as larger and more frequent storms occur in the Midwest, including erosion in agricultural fields and larger algae blooms and dead zones in the Great Lakes.

More rain isn’t always a bad thing, though, especially if the crop you’re buying benefits from it. White truffles—the elusive, expensive fungi prized by chefs and by diners willing to pay for them—are abundant this year because there has been lots of rain in northern Italy. That’s good for restaurants and consumers, because it means the price of truffles is dropping; a pound of them now costs only about $1,100, about half as much as last year when the region experienced drought, as this article explains. (Exceptionally large individual truffles bring a higher price; a nearly 2-pound one recently sold for $96,000 in Alba, Italy. The average size is less than an ounce.)

Relatively few of us, I’m guessing, are regular truffle consumers, but changing rainfall patterns are affecting agriculture in much larger ways. Numerous studies are underway tracking the relationship between rainfall, average temperatures, and food production all over the world. Although many areas use irrigation systems to deliver water to their crops, about 60% of the world—and as much as 90% of sub-Saharan Africa—relies on direct rainfall.

As this report explains, current climate trends indicate that wet regions will get even more rain and drier ones will get less. Although the consequences of less rain seem obvious, more carries risks as well: wetter conditions can hamper storage of grains after harvest, for example, and make timely planting of the next crop more difficult.

Some studies, like this one from 2014, have even indicated that land-use changes can affect the amount of precipitation in a particular region. Converting large areas of forested land to agricultural use apparently resulted in a 10% rainfall reduction during the monsoon season in Africa’s Sahel region.

About the Author

Janice Kaspersen

Janice Kaspersen is the former editor of Erosion Control and Stormwater magazines.