Droughts have an immediate effect on plant growth. This in turn harms food chains; predators have a harder time finding prey animals and fresh water sources. People, too, suffer in drought conditions, especially those living by subsistence farming. In addition to crop losses, soil conditions decline, and winds blow away precious topsoil. Droughts often occur in marginal areas that have already been subjected to desertification. Crop failures in areas burdened with poverty can lead to famine, which may force people to migrate and encroach on wildlife habitat. At the same time, drought degrades habitat conditions by reducing vegetation and altering entire food webs.
Certain technologies lessen the effects of drought, such as the development of drought-resistant plants, drought-resistant soil blends, ground cover plants to reduce evaporation, and rain-fed irrigation and other water conservation techniques. In impoverished areas, however, even these actions have been difficult to establish. In China, for example, the Gobi Desert expanded 20,240 square miles (52,400 km2) during a five-year period in the 1990s; today it has crept to within 100 miles (161 km) of the Beijing metropolis. Japan and Korea now suffer springtime dust storms that originate in China’s desert, a distance of about 2,000 miles (3,200 km).
Pat Mulroy, head of the Southern Nevada Water Authority, spoke to the New York Times in 2007 about water conditions in Las Vegas: “This country is going to have 100 million additional people in it in the next twenty-five to thirty years,” she said. “Tell me where they’re supposed to go. . . . Every community says, ‘Not here,’ ‘No growth here,’ ‘There’s too many people already.’ We have an exploding human population, and we have a shrinking clean-water supply. Those are on colliding paths. This is not just a Las Vegas issue. This is a microcosm of a much larger issue.” As Mulroy suggests, this condition could describe almost any other place in the world today.
In the United States, the National Oceanic and Atmospheric Administration (NOAA) uses a calculation called the Palmer Index to put a value on the severity of droughts. A zero value indicates normal conditions; negative numbers indicate drought, and positive numbers indicate ample rainfall. The Palmer Index relates to the local climate so that it can be as useful in the Mojave Desert as it is in Maine. The crop moisture index provides similar information but calculates conditions during short-term periods—weekly, for instance, rather than seasonally as in the Palmer Index. Farmers use the crop moisture index to assess the best times for planting and harvesting crops.
Resource wars is a new term for the possibility of increased warfare throughout the world over natural resources that are necessary for civilization. Resource wars have taken place in human history over gold, salt, diamonds, and oil. Today society confronts increasing conflicts over food and water, and drought will intensify the problem. Increased irrigation works well during short-term dry periods, but a constant reliance on water reserves threatens groundwater storage and leads to salinization. Climatologist Roger Pulwarty of the NOAA told the New York Times in 2007, “You don’t need to know all the numbers of the future exactly. You just need to know that we’re drying. And so the argument over whether it’s 15 percent drier or 20 percent drier? It’s irrelevant. Because in the long run, that decrease, accumulated over time, is going to dry out the system.” Resource wars over water may dominate the future the way conflicts over oil have affected the present.
Source of Information : Green Technology Conservation Protecting Our Plant Resources
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