Dear EarthTalk: I've heard some environmental advocates claim that organic farming could produce enough food to feed the world. Is this true?
—Gabe Morello, Lynnwood, WA
Advocates of modern agriculture reliant on pesticides and widespread single crop plantings (known as "monoculture") have bragged for decades about the increased productivity their high-tech methods can yield. Indeed, several studies in the U.S., Britain and Australia have shown that such methods produce as much as 40 percent more than the more benign methods that served mankind well for thousands of years.
As a result, seed growers and pesticide makers are now working in poor countries to promote the same "green revolution" there, capable, they say, of growing enough food to feed the desperately hungry.
But a spate of new research has shown that organic farming actually yields better results than modern techniques when evaluated more holistically. A series of peer-reviewed papers published by the international journal, Nature, showed that organic methods for growing rice, corn and wheat all produced significantly higher yields—and at less the cost—than monoculture farms. And research at England's Essex University has shown that farmers in India, Kenya, Brazil, Guatemala and Honduras have doubled or tripled their yields by switching to organic agriculture. Cuban farmers, who cannot access fertilizers and pesticides due to the U.S. embargo, have also realized greater yields by taking up organic farming.
According to Dr. Christos Vasilikiotis of the University of California, Berkeley, a vocal advocate of organic farming, chemically intensive farming is highly undesirable due to the toll it takes on the land and the pollution it generates. "Organic
farming methods continually increase soil fertility and prevent loss of topsoil to erosion, while conventional methods have the opposite effect," he says. He further maintains that "only a conversion to organic farming will allow us to maintain and even increase current crop yields."
Dr. Liz Stockdale of Britain's Institute of Arable Crops Research agrees, and points out that even when organic yields are less than conventional ones, organic farmers make up the financial difference by not having to buy costly pesticides and fertilizers. She adds that improved growing techniques and new natural pest controls could eventually level the playing field, giving organic farmers the economic advantage.
According to the trade group, Organic Consumers Association, only slightly more than two percent of all farms in the U.S. are currently organic. But with sales of domestic organic food growing about 20 percent annually, the organization expects that figure to rise exponentially in years to come.
Still, though, feeding the world is a tall order, and everyone from organic farmers to environmental leaders to human rights workers agrees that ending hunger is dependent more upon political will than agricultural prowess. "Until governments tackle the social and political factors involved in poverty and food distribution, millions of people will continue to go hungry," concludes Stockdale.
Dear EarthTalk: How do solar swimming pool heaters work? Are they efficient? How do they compare in cost to conventional pool heaters?
—Bob Whelan, Providence, RI
While more efficient swimming pool heaters exist, solar heaters offer the most cost effective option, given that the fuel source, sunshine, is free. According to the U.S. Department of Energy's (DOE"s) Consumer's Guide to Energy Efficiency and Renewable Energy, solar pool heating systems cost more than other common options such as gas heaters or heat pumps, but will usually provide payback within two to seven years of purchase (depending upon local fuel costs) due to fuel savings.
Owners are guaranteed to make back their initial outlay, too, as solar heaters are not dependent upon motorized moving parts, and thus last twice as long as other types of heaters and don't rack-up significant maintenance costs. Of course, solar pool heaters are also the most environmentally benign option, as no fossil fuels need to be burned to maintain the right amount of warmth.
Most solar pool heating systems come with four key interacting components: a flow control valve takes pool water and sends it through a collector; a filter removes debris before the water reaches the collector; the collector itself heats the water that passes through it; and a pump sends that water back into the pool. In warmer climates, the system can be used to cool the pool in summer months by operating only at night.
But such solar technology need not be restricted to warm climates. As long as the sun is shining, it can provide solar energy—not to be confused with the sun's heat—even when it is cold outside. Indeed, the DOE reports that solar pool heaters are sold in every climatic region of the continental U.S., meaning that solar is a smart choice even for pools in more northern latitudes like Maine or Minnesota.
While solar pool heaters excel at maintaining steady water temperatures over long time periods, they are not nearly as fast as gas heaters for quick last-minute heat-ups. As such, many pool owners install hybrid systems combining the best elements of gas and solar systems. Also, using a pool cover will reduce heat, water and chlorine loss while maintaining efficiency and preventing debris from sullying the water, regardless of which type of heater system is in place. Even better, "solar blankets" are high-tech covers that use thousands of sealed air pouches to facilitate heat transfer from the sun's ray to the pool water below.
If you are thinking of installing a solar pool heating system, the online version of the DOE's Consumer's Guide provides tips on determining if your pool's location is adequate enough (i.e. does it get enough sunlight?) and on how to choose the system that best suits your needs. The handy website will also show you how to compare competing systems and investigate relevant local pertinent regulations.
Some of the leading manufacturers of solar pool heating system include EZ Heat, Hi-Deluxe, Sungrabber and Suntrek. As always, unless you're familiar with the intricacies of your pool's inner workings, it's best to get a certified installer to work with you to make sure installation goes swimmingly.
CONTACT: Consumer's Guide to Energy Efficiency and Renewable Energy, www.eere.energy.gov/consumer; EZ Heat, www.harterindustries.com/ezheat.htm; Hi-Deluxe, www.cetsolar.com/hideluxe.htm; Sungrabber, www.sungrabber.net; Suntrek, www.suntreksolar.com .