Growing Pains, continued
While the Green Revolution averted crisis in the 20th century, researchers are far from sanguine about the prospects for the 21st.
For one thing, we are feeding vastly more people, so “the relative number of hungry people has been going down, but the absolute number hasn’t declined much,” explains Tom Tomich, director of the University of California Sustainable Agriculture Research and Education Program.
Moreover, says Tomich, the huge increases in food production have come with an environmental cost. “We have used more and more water for irrigation,” he says, “more and more fossil fuels”—which not only run tractors, but are used intensively to create fertilizer, of which we are also using more and more.
The Institute on the Environment’s Foley says one of the most worrying issues is growing water scarcity. “We have basically dried up most of the Aral Sea to irrigate what used to be the Soviet desert to grow cotton,” he says. “The Colorado River doesn’t flow into the ocean anymore,” because so much is diverted along the way for irrigation. Underwater aquifers are being used up. Ninety-five percent of Lake Chad has disappeared since the late 1960s.
“Agriculture already uses vastly more water and has changed the water cycle of the planet more than climate change ever will,” Foley says.
Big Question: Feast or Famine
The world population is growing by 75 million people each year. That's almost the size of Germany. Today, we're nearing 7 billion people. At this rate, we'll reach 9 billion people by 2040. And we all need to eat. But how? That's a critical issue the IonE tackles in our first Big Question video.
At the same time, agriculture is a major contributor to climate change and will suffer as an industry from the consequences.
Slash and burn agriculture, especially in the rainforest, emits a high level of carbon dioxide. Agriculture is also responsible for some of the highest human-caused emissions of methane and nitrous oxide, which are even more potent greenhouse gases than carbon dioxide.
As rice stalks decompose in the flooded conditions that allow many rice varieties to thrive, large amounts of methane get released into the atmosphere. Ruminant animals such as cows, which digest grains in a series of stages in several stomachs, also emit a significant quantity. Nitrous oxide, another powerful greenhouse gas, is released from over-fertilized fields.
When you weigh the amounts by the degree to which each gas warms the environment, Foley says, “agriculture is responsible for about 30 percent of greenhouse gasses, bigger than all other human activities, more than all the world’s transportation, or all the world’s electricity, or all the world’s manufacturing.”
Perhaps equally worrying are the trends in yield growth. After the dramatic increases of the late 20th century, some of the staple cereal crops seem to be reaching the limits of their potential.
Zeigler says, at least where rice is concerned, “we’re predicting about 20 years from now we’ll have squeezed about all we can out of our current technologies.”
All of this is true now, as we work to feed a global population of more than 6 billion. But estimates indicate the population will grow by another 50 percent by about 2060.
And if current consumption trends continue, says Wood, not only will every one of those people need to eat, but they will probably be eating a higher proportion of meat than today’s population. Raising equivalent amounts of food from livestock requires a higher degree of grain production than if humans were to eat the grain themselves.
“If you take into account both of those things,” Wood says, “maybe you need to grow 60 or 70 percent more food than we currently do.”
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Last modified on January 23, 2012