Dear EarthTalk: Can you explain what "desertification" is and why it is an important environmental issue?

-- Jay Harris, Nashville, Tenn.

Desertification is the degradation of land in already dry parts of the globe that results from various factors, including natural climate changes as well as human activity. As the name connotes it is the expansion of desert-like conditions which render useless land that was once biologically and/or economically productive. According to the United Nations' Convention to Combat Desertification, the phenomenon occurs in "drylands" (arid, semi-arid and dry sub-humid areas) on all continents except Antarctica and affects the livelihoods of millions of people, including a large proportion of the world's poor.

Drylands constitute about 40 percent of the world's total land area, and are home to some two billion people--a third of human population. Water scarcity in existing drylands makes it difficult for plants, animals and humans to thrive there; desertification makes it impossible, forcing those affected to flee to more hospitable lands, whether they are welcome or not. The United Nations estimates that 10-20 percent of the world's drylands are already degraded to the point where desertification is an imminent threat.

While global warming -- and the resulting intensification of fresh water scarcity -- is the most serious factor in converting drylands into deserts, population pressure and lack of proper land use planning only serve to make matters worse. In Sub-Saharan Africa, one of the regions most vulnerable to desertification, severe droughts already lead to major food and health crises once every three decades or so on average; environmentalists and planners worry that human-induced warming and other factors will increase the frequency of such debilitating droughts and lead to even more problems with desertification there. The African Union is working to muster international support for the creation of a "Green Wall" -- a forested green belt -- to help hold back the Sahara desert.

Other governments are also taking steps to keep desertification in check. China is working to create a 2,800-mile forest belt that will not only block the fast advancing sands of the Gobi desert but serve as a "carbon sink," as well, to absorb greenhouse gas emissions. And Algerian leaders are optimistic that the recent creation of a 600,000 acre national park will head off a looming desertification crisis there.

Desertification is also a problem right here in the United States, mostly a result of overgrazing by farm animals and poorly designed irrigation schemes across especially vulnerable parts of Texas, New Mexico and Arizona. Some 40 percent of the continental U.S. is dry enough to be at risk for desertification.

Historians point to the Dust Bowl of the 1930s as proof positive of America's susceptibility to such problems. Lessons learned then led to the creation of the Soil Conservation Service--now called the Natural Resources Conservation Service--to teach farmers and other landowners agricultural practices that reduce soil loss and maintain biological diversity around agricultural operations. In spite of such efforts, desertification still plagues parts of the U.S. today. The hope today is that global warming won't tip us to the point where have to learn some hard lessons all over again.

CONTACTS: UN Convention to Combat Desertification,; African Union,; Natural Resources Conservation Service,

Dear EarthTalk: What's up with dishwasher detergents of late? They're clearly not working as well. I hope whatever was done is helping the environment because it's not helping my dishes.

-- Sally P.,

Everett, Wash.

What happened was that in July 2010 a significant reduction in the amount of phosphates allowed in automatic dishwasher detergent went into effect in Washington State. Similar regulations were implemented in 14 other states (Illinois, Indiana, Maryland, Massachusetts, Michigan, Minnesota, Montana, New Hampshire, Ohio, Pennsylvania, Utah, Vermont, Virginia, and Wisconsin) for 2009 before Oregon and Washington added their names to the list earlier this year. Previously phosphates could constitute up to 8.7 percent of dishwasher detergent; now the new regulations limit them to 0.5 percent.

The main problem with phosphates, which also come from agricultural and landscaping activities, is that they get into natural water bodies and act as fertilizer, accelerating plant and algae growth. When the plants and algae die, a feeding frenzy of bacteria consume all the oxygen dissolved in the water, creating an environment inhospitable to fish and other aquatic life. These oxygen-devoid "dead zones" can occur in freshwater or in the ocean. In fact, two of the world's largest dead zones are in the Baltic Sea and the Gulf of Mexico, the result of fertilizers running off of farmland. Besides phosphates' negative effect on water bodies, their presence in the environment can also be harmful to terrestrial wildlife and can trigger skin and eye irritation and allergies, among other ill effects, in humans.

Environmentalists and others supportive of the reduction in phosphates claim that the new regulations will spare wastewater treatment systems from dealing with 10-12 percent of the phosphates previously encountered. Wastewater treatment managers in Spokane, Washington, for example, found that a local year-old ban on phosphates in dishwashing detergent there saved them from dealing with upwards of 180 pounds of phosphates -- or about 10 percent of the total load -- each and every day at municipal wastewater treatment facilities -- saving not only money but also the other chemicals used to treat the water.

Given the shift in so many states, many manufacturers have reformulated their entire product lines for markets across the country, so even if you don't live in one of the affected states you might be getting dishwashing detergent with a lot less phosphorous as well. Consumer Reports tested 24 of the leading low-phosphate dishwasher detergents to see which ones got dishes cleanest. The top finishers were Cascade Complete All in 1 pacs (at a cost of 28 cents per load), Ecover tablets (27 cents), Finish Powerball Tabs tablets (22 cents), and Method Smarty Dish tablets (21 cents), but other brands and formulations also performed adequately if used properly.

Consumer Reports also provides tips on optimizing the performance of your dishwasher and dishwashing detergent no matter which brand you use. For starters, load large items at the sides and back of the dishwasher so they don't block water and detergent from reaching other dishes. And place the dirtier side of dishes towards the center of the machine to provide more exposure to the sprayer. Also, try to prevent dishes and utensils from nesting within one another so that the water can reach all surfaces.

CONTACT: Consumer Reports,

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