While fellow scientists have focused with increasing urgency on the problems of global warming, one expert argues that an equally notable threat lurks underfoot, and there’s something that we can do about it. That was the message delivered at the annual Charles Zabriskie, Jr. Lecture by David Montgomery, a professor of Earth and Space Sciences at the University of Washington in Seattle and a 2008 recipient of the MacArthur “genius award” for his work in the field of geomorphology, which studies the evolution of the landscape.
“The global problem of soil degradation is one of the underestimated environmental crises of the 21st century,” warned Montgomery, who spoke to a group of students and faculty in Davis Hall on Thursday night, February 16th. “Most people don’t tend to think of soil as a strategic resource, but it’s just one that doesn’t tend to be in view.”
Montgomery has taken aim at the world’s dwindling supply of arable land in his recent book, “Dirt: The Erosion of Civilizations.” He noted in his Nichols presentation that the loss of soil is nothing new, from cultures in the ancient world and Europe to American farmers fleeing the Dust Bowl of the 1930’s, all of whom migrated to new land or even other continents.
The difference this time around, Montgomery stressed, is that little new land remains to cultivate, the world has come to depend on agriculture for 97% of its food supply, and over the past 40 years, farmers have abandoned almost one third of the cropland on the planet because of either erosion or the degradation of the soil left behind.
Montgomery noted that the loss of farmable soil worldwide amounts to 23 billion tons a year, just under one percent of the entire quantity on Earth. The means to stem that loss lie in making extensive changes in agricultural methods, he continued. Among the most promising alternatives are increased organic farming, which replenishes soil in ways that it would take the earth decades and even centuries to restore on its own, and no-till farming, for which crops are planted without turning over the soil.
“The message doesn’t seem to have gotten out that organic agriculture, which conserves soil fertility, can feed the world. In many cases, the crop yields from no-till and organic agriculture appear able to match those from conventional agriculture,” Montgomery concluded.
“It’s the way to feed a 10-billion person planet. Any approach based on the ongoing loss of soil, even small percentages a year, is going to catch up with us.”