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Public Radio's Environmental News Magazine (follow us on Google News)

Thirsty Planet

Air Date: Week of

The Worldwatch Institute has just issued its State of the World Report 2000 and near the top of its list of worldwide environmental trends are dropping groundwater levels. Contributing author Sandra Postel (po-STELL) says that if we want to keep ourselves fed and watered, we're going to have to rethink the way we practice irrigated agriculture.


CURWOOD: It's Living on Earth. I'm Steve Curwood. In 1984, the folks at the Worldwatch Institute put out their first annual State of the World report. Looking ahead to the year 2000, they were hopeful that some of the disturbing environmental trends then occurring could be reversed. But this year's report is no less disturbing. Species extinction, ecosystem collapse, population growth, and climate change continue. And beneath the Earth's surface, another shift is occurring, a dramatic drop in water tables. Sandra Postel authored a chapter in the report titled, "Redesigning Irrigated Agriculture." In it, she tells us that historically, irrigation has proved environmentally unstable, and societies that have relied on it to feed their people have almost always failed. That age-old problem is still around, and, Sandra Postel says, there's some new ones, too.

POSTEL: The problem we're seeing now is that farmers are pumping more water out than nature is replenishing. And it's just like a bank account. If you withdraw more money than you're depositing, your account is going to get depleted. And so, the amount of water in storage is diminishing, which means that water tables are falling. Which means that wells will go dry. The water that they pump will be salty, or the wells just won't yield enough to be profitable to use. And we see this problem now, and it actually surprised me when I was doing the research for the book and for this chapter in State of the World, how extensive this problem is. That it's a very serious problem in most of the important grain baskets of the world. It's a problem in the Punjab of India, which is the principal bread basket for India. Water tables falling up to a meter a year. It's a serious problem in the North China plain, which produces 40 percent of China's food. Water tables there are dropping one to three meters a year. The central valley of California here in the United States, which produces about half of all the fruits and vegetables that we produce in the United States. In the Great Plains, the Great Ogallala aquifer is being depleted primarily to grow cotton and grain. So, added up, this is a very serious problem. I've made an estimate that as much as ten percent of the world's food supply today depends on the over-pumping of groundwater

CURWOOD: Give me a sense of the time scale of how soon we might be able to see a crunch in the global food supply because of the shortage of water.

POSTEL: It's difficult to know exactly when, but I think in countries like China and India, we will see over the next, probably within 10 years, the impacts of water scarcity beginning to be felt. These countries both have substantial population growth. They're trying to feed, in the case of China, an additional 15 million people a year, in the case of India an additional 18 million people a year. And their water budgets are badly out of balance. These are two of the biggest grain producers in the world, and I think we will see increased pressure internationally as they begin to experience the need to import more food to satisfy their own demands, in part because of water scarcity.

CURWOOD: If pressures increase, could the things blow? I mean, is this something that could lead to political instability, a shortage of water?

POSTEL: I think it very definitely could lead to political instability. At the moment the bulk of our societies are still, particularly in developing countries, are still rural. And if you begin to experience water scarcity in an agrarian, rural society, you can quickly move into a period of unemployment, of poverty, increased poverty, and a destabilization of communities within those rural societies, which of course has political ramifications. We're also going to see, for sure, increased competition for water internationally. If you look at all the major hot spots of water dispute today, these would include the Nile Basin, the Jordan Basin, the Tigris-Euphrates River Basins in the Middle East, the Ganges in South Asia, the Central Asian River Basins flowing into the Aral Sea, in each of these cases you see population projections of 30, 40, 50 percent increases, in one case 70 percent increase, between now and 2025. And in none of these river basins do we yet have a treaty that sets out how the river water should be shared among all the parties.

CURWOOD: So what direction should we be headed in here? Should we be improving irrigation efficiencies? Or should we be reducing dependence on irrigation?

POSTEL: I think at this point, with a population of six billion, and if the United Nations projections bear out we'll be heading toward nearly nine billion by 2050, I think we're going to need to remain dependent on irrigated agriculture. We've pretty much maxed-out on expanding rain-fed land. We've seen the best rain-fed land already come into production. So I think that the key, really, is going to be increasing productivity on the land that we've already brought in, and sustainably bringing some additional irrigation into production. We're also now in a world where the aquatic environment is under great stress, and so the demands for irrigation water are taking place within a context of needing to protect and restore the broader water environment. And this is the real challenge. I think it's going to take a closer marriage of ecosystem science, of what ecologists study, and what irrigation engineers study. A better understanding of the quality of water that's really required to grow crops. A better understanding of how we can satisfy certain ecosystem functions, at the same time using that water for agriculture. There's going to be a lot of multiple uses of water that we're going to need to orchestrate.

CURWOOD: Sandra Postel is director of the Global Water Policy Project and a senior fellow with Worldwatch, also co-author of The State of the World for the Year 2000 by Worldwatch, and also author of the book Pillar of Sand. Thank you so much for taking this time with us.

POSTEL: Thank you, Steve.



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