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From the Editors of E/The Environmental Magazine

Dear EarthTalk: Other than calculators, what are some other accessories and gadgets that are now available solar-powered? -- Frank Rogers, Concord, NH

While solar-powered calculators have been readily available and inexpensive for two decades, only recently has such technology been applied to other tools, accessories and small appliances.

Perhaps the most widespread use of energy from the sun today is for charging up small electronic devices like flashlights, watches, palm pilots and cell phones. Solar cells are also being put to use around the home increasingly to power garden, pool and security lighting as well as automatic watering and lawn-feeding devices. And as photovoltaic technology improves, people are using small solar cells to power up bigger devices like radios, cameras and even laptop computers. A good assortment of such items can be ordered from online stores such as Brunton, Sundance Solar, Real Goods, Global Merchants and Energy Federation (EFI).

Well beyond the realm of gadgetry, EFI sells a solar-powered oven, made by Sun Ovens International, which is working to protect the environment and raise the standard of living for the poor worldwide by developing solar cooking technologies that reduces the developing world's reliance on scarcer and scarcer wood products. The interior of the oven is heated by passive solar energy when the oven's reflectors are opened up and pointed toward the sun. According to the EFI website, "even though it is called an oven, food can be baked, boiled, and steamed at cooking temperatures of 360° F to 400° F." Here in the developed world, the Sun Oven can save resources and keep the air cleaner when used for backyard cooking or on camping outings.

According to Wired Magazine, climber Sean Burch used solar cells to charge his laptop and phone during his solo ascent of Mt. Everest in 2003. "The sun was so bright at 18,000 feet that it wasn't a problem at all," said Burch, who didn't have the manpower to bring along the hundred-pound batteries used by bigger climbing crews to power communications devices. "It was nice because I had my computer, solar panels and phone and I could communicate as well as anyone," he said. Indeed, by strapping small photovoltaic cells onto their backpacks, panniers and kayaks, adventurers heading out into the wilds can stay in touch with loved ones--and rescue crews if needed--more reliably and for less money than ever.

Despite the profusion of solar-powered devices, environmentally-conscious consumers know that it is greener not to buy something that they don't need. According to the website GreenChoices.org, people should only buy gadgets that are "genuinely useful additions to a green household, things that actually save energy or water, or make living green easier."

CONTACTS: Brunton, www.brunton.com; Sundance Solar, www.sundancesolar.com; Real Goods, www.realgoods.com; Global Merchants, www.global-merchants.com; Energy Federation (EFI), www.efi/org; Green Choices, www.greenchoices.org.

Dear EarthTalk: Where can I find green-friendly office products and back-to-school supplies?--Taylor Howe, San Francisco, CA

Environmentally-friendly school and office products have been available for decades from specialty suppliers, but in recent years many recycled kinds of papers, pens, pencils, ink toner cartridges, binders, folders and desk accessories have become ubiquitous in mainstream office supply stores.

Paper use continues to be the largest source of waste generated by office workers and students, and several paper manufacturers have risen to the challenge of providing recycled and even "tree-free" papers at competitive prices. New Leaf Everest, Badger Envirographic and Eureka! 100 are some of the leaders in recycled paper, while Dolphin Blue makes tree-free paper from recycled scraps of denim, old money, and the plants hemp and kenaf. Buyers can order these papers from online vendors including GreenLine Paper and Treecycle, although office supply retail stores also now carry a wide array of 100 percent post-consumer waste recycled papers.

Meanwhile, materials such as biodegradable cornstarch and recycled plastic and cardboard are starting to replace virgin plastic and vinyl in pens, binders, notebooks, and in desk accessories like rulers, pencil cases and staplers. Also, pencil manufacturers such as Pentel, Autopoint and ForestChoice have gotten serious about crafting their products from sustainably harvested timber and other green materials, including old currency. Online vendors like Green Earth Office Supply, the Recycled Office Products Company, Real Earth Environmental Company and Mama's Earth stock these products. Meanwhile, Discount Inkjet Printer Ink Cartridges sells a wide range of recycled inkjet toner cartridges and ink refills compatible with all major brands of copiers and computer printers.

Many of these companies offer special price breaks for non-profits, local government agencies, schools and universities and donate a portion of proceeds to environmental non-profits. Consumers shopping at these stores can rest assured that they are minimizing their impact on the Earth while supporting small, innovative companies. But those in need of a quick green fix might be surprised at how good the selection is these days at places like Office Depot, Staples and Office Max, too.

While individuals often feel powerless to help solve the world's environmental ills, they can make a difference through their consumer choices. And buying only environmentally friendly office and school supplies is a great place to start.

CONTACTS: Green Earth Office Supply, store.yahoo.com/greenearthofficesupply; Discount Inkjet Printer Ink Cartridges, www.discount-inks.com; GreenLine Paper, www.greenlinepaper.com; Treecycle, www.treecycle.com; Recycled Office Products Company, www.recycledofficeproducts.com; The Real Earth Inc., www.treeco.com; Mama's Earth, www.mamasearth.com.

Dear EarthTalk: What makes a city a "mega-city" and what are the environmental implications? --Eva Locke, Seattle, WA

Demographers define "mega-cities" as sprawling, crowded urban centers with populations topping 10 million. In 1995, 14 cities qualified as mega-cities; analysts predict that by 2015 there will be 21. The world's first mega-cities were in Latin America: Mexico City, Rio de Janeiro, São Paulo and Buenos Aires. But in recent years Asian countries--Japan, South Korea, China and India--have grown the fastest. Today the five largest cities are Tokyo, Mexico City, São Paulo, Mumbai (Bombay) and New York City.

The rapid population growth of these cities is due primarily to intra-country migrations as the rural poor move from the countryside to urban areas in search of better lives. The result, unfortunately, is often the proliferation of urban slums, increased crime, high rates of unemployment--and profound environmental degradation accompanied by serious health challenges for the majority of residents.

"By 2050, two-thirds of the world's population will live in urban areas, imposing even more pressure on the space infrastructure and resources of cities, leading to social disintegration and horrific urban poverty," says Werner Fornos, president of the Washington-based Population Institute. The rise of mega-cities, agrees The Washington Post, "poses formidable challenges in health care and the environment.the urban poor in developing countries live in squalor unlike anything they left behind."

According to the World Resources Institute, "Millions of children living in the world's largest cities.are exposed to life-threatening air pollution two to eight times above the maximum tolerable level [as established by World Health Organization guidelines]. Indeed, more than 80 percent of all deaths in developing countries attributable to air pollution-induced lung infections are among children under five."

Worldwide, over a billion people live without regular access to clean water. Mega-city residents, crowded into unsanitary slums, also fall victim to serious diseases. Lima, Peru (with population estimated at 9.4 million by 2015) suffered a cholera outbreak in the early 1990s partly because, as The New York Times reported, "Rural people new to Lima.live in houses without running water and use the outhouses that dot the hillsides above." Consumption of unsafe food and water subjects these people to regular and life-threatening diarrhea and dehydration. "All the demographic data point to the 21st century emerging as the urban century," says Deane Neubauer of the Yale Center for the Study of Globalization. "But evidence also indicates that a vast portion of the new 'megacities'.will be infested by 19th-century-style poverty."

One organization addressing the issue is the non-profit Mega-Cities Project, based at Trinity College in Hartford, Connecticut. The organization has brought together a diverse international group of community, government and business leaders to share ideas on ways to make mega-cities more ecologically sustainable and economically vital. Indeed, the fate of many of the world's poor rests with such efforts to smooth the transition to a planet where 60 percent of all people crowd into a few dozen sprawling metropolises.

CONTACTS: Yale Center for the Study of Globalization, www.ycsg.yale.edu; Mega-Cities Project, www.megacitiesproject.org.

Dear EarthTalk: What's the big environmental controversy over feral cats? -- Johanna Berg, Brooklyn, NY

According to the U.S. Census, Americans own more than 60 million domestic cats. But analysts estimate that another 40-60 million formerly pet cats and their offspring roam free. These so-called wild or "feral" cats are blamed for wreaking havoc on already stressed populations of songbirds and other small animals.

While roaming domestic cats also hunt birds and small mammals, their feral cousins--since they are beyond the control of human owners--take the brunt of the blame for the decimation of threatened species such as Least Terns, Piping Plovers and Loggerhead Shrikes.

Cat advocates, however, say the real problem is not feline but human. "Cats are not the primary culprit in dwindling bird populations," says Becky Robinson, co-founder of the Washington, DC-based Alley Cat Allies (ACA). "The Worldwatch Institute and other environmental research groups verify that the decline in bird and other wildlife populations is directly linked to the loss of natural habitat," she says. "Urban sprawl, deforestation, shopping malls, roads and golf courses, and increases in pesticide use and pollution are to blame. We need to put constraints on our own behavior, not the normal processes of nature."

ACA cites a number of scientific studies on feral cat diets which indicate that their impacts on bird populations are negligible. These studies conclude that cats are rodent specialists. Birds comprise only a small portion of their diets, and cats can prey on birds on large land masses without destroying their populations. Cats are opportunistic feeders, and live mainly by scavenging and on handouts from humans.

Feral cats are also blamed for transmitting new diseases to wild animals, and this is probably a legitimate charge. Cats have spread feline leukemia to mountain lions and may have recently infected the endangered Florida Panther with feline panleukopenia (feline distemper) as well as an immune deficiency disease. Some cats also carry diseases that can transmit to humans, including toxoplasmosis and rabies.

Despite these issues, ACA endorses sterilization and long-term management of feral cat colonies, as opposed to removal and extermination programs which they deem ineffective, costly to taxpayers and wasteful of scarce animal protection resources.

Regardless of one's personal beliefs about feral cats, individuals can play an important role in keeping cats off the "most-wanted" list. Most veterinarians recommend neutering pet cats, and keeping them well fed and indoors as much as possible to limit unwanted reproduction, predation and the spread of disease.

Perhaps most important, people shouldn't release unwanted cats into the wild. According to the Colorado-based Cat Care Society, this practice enlarges feral cat populations and is inhumane. Cats suffer in unfamiliar settings, even if they are good hunters. Contact local animal adoption organizations and agencies for help if you need to give up a pet cat.

CONTACTS: Alley Cat Allies, www.alleycat.org; Cat Care Society, www.catcaresociety.org.

Dear EarthTalk: I've been told that automobile air conditioners are bad for the environment. Exactly why and what part of the air conditioner is bad? --Susan Vogel, Somerville, NJ

The harmful effects of automobile air conditioners can be directly attributed to leaking of CFC R-12, one of a number of cooling ingredients patented by DuPont and popularly known as Freon. In December 1995, the U.S. banned the manufacture of this ozone-depleting chlorofluorocarbon (CFC) in order to adhere to standards set by the Montreal Protocol, an international treaty phasing out the production of such chemicals. But existing stockpiles of the gas--and pre-1994 autos that still use it--could keep its toxic legacy around for years.

The cooling ingredient HFC134A, also known as tetrafluoroethane, has since replaced CFC R-12 as the main cooling ingredient in car air conditioners. But while HFC134A does not contribute to ozone depletion and is a more eco-friendly choice than R-12, it is a gas that contributes to global warming. In fact, because of this, the European Union has slated a phase-out of HFC134A to begin in 2011 and be completed by 2017, despite the fact that alternatives are still only in experimental phases of development.

Owners of pre-1994 automobiles can spend a few hundred dollars to modify their air conditioners to use HFC134A, though the Environmental Protection Agency (EPA) cautions that not all systems designed for R-12 work as well using HFC134A and recommends such conversions only on cars made after 1980.

When air conditioners in cars that use CFC R-12 are being refilled or repaired, federal regulations require that the service shops recycle the refrigerant instead of releasing it into the air. Regulations also require that the refrigerant be removed from vehicles that are scrapped or have been abandoned. The refrigerant is then filtered so that it can be reused.

If the refrigerant in your vehicle's air conditioning system needs to be replenished, always have a professional do it. You can damage your system if you improperly change it yourself, and only certified mechanics can legally purchase refill cans of CFC R-12. Additionally, if your air conditioning system is leaking refrigerant, have it repaired--don't just refill it. This will both protect the environment and save you money in the long run.

There are other environmental considerations with auto air-conditioners, such as energy use. In an attempt to reduce the amount of energy car air conditioners use, Toyota has created a lightweight compressor--the heart of the air-conditioner--that consumes 60 percent less fuel.

Of course, the most environmentally sound and cheapest way to cool your car is to open your windows and let in the fresh air. According to the National Safety Council's Safety and Health Policy Center, driving without using the car's air conditioning increases fuel efficiency by about 2.5 miles per gallon.

CONTACTS: EPA Motor Vehicle Air Conditioning, www.epa.gov/ozone/title6/609/; Toyota Air Conditioning Compressor, www.toyota-industries.com/environment/product/compressor.html; National Safety Council's Safety and Health Policy Center, www.nsc.org/ehc.htm.

Dear EarthTalk: Are there environmentally friendly car waxes, washes and bug removers? -- Graham Berg, Portland, Oregon

Conventional car waxes, bug removers and other auto detailing formulas are good at their jobs because they contain strong chemicals. Unfortunately these synthetic substances--including glycol monobutyl ether, a registered pesticide, and the petroleum derivatives naptha and cosmoline--can irritate skin, cause other more serious health problems, and get into our groundwater once they are rinsed away.

Luckily consumers have many alternatives to choose from. A handful of forward-thinking companies have risen to the challenge of developing car care products that won't harm our bodies or the environment. Many car wax manufacturers have discovered that wax naturally-extracted from the Carnauba palm of Brazil does a great job of protecting auto paint and clear coat from bird poop, dead bugs and other nasties. Optimum Car Wax, for example, can protect your car's finish without abrasive chemicals and instead combines Carnauba wax with lanolins (obtained from sheep's wool) like those found in gentle hand lotions.

For washing your vehicle, Simple Green Car Wash Cleaner handles automotive dirt, grime, grease, bug stains and everything in-between without polluting. The concentrated formula contains none of the toxic volatile organic compounds (VOCs) found in most such cleaners. It can be used safely to clean paint, clear coat, windows, chrome, rubber, canvas and vinyl. Another environmentally sensitive way to clean off caked-on bug guts and other gooey debris without resorting to noxious chemicals is by dissolving baking soda in warm water, then gently rubbing the mixture into the car with a soft cloth.

Detailer's Pride Gel Wheel Cleaner, available online at driveit.com, among other retailers, is an environmentally sensitive choice for removing caked on brake dust on wheels and grime off trunk lids and engine compartments. It also gets stains off of vinyl and convertible tops, cleans greasy door jams, and is ideal for loosening and removing bug and white wax residues. It is water based, and contains no harmful solvents or chemicals.

For keeping your vehicle's moving parts at optimal performance, Balchip Corporation, based in Toronto, Ontario, offers a wide range of environmentally friendly engine treatments and fuel additives that serve to dissolve corrosive build-ups and keep parts working together smoothly. Based on the pioneering research of Canadian biochemist Paul Deogrades, all Balchip products are derived from plants and trees and as such are completely biodegradable and non-toxic.

CONTACTS: Simple Green, http://consumer.simplegreen.com; driveit.com/Detailer's Pride Gel Wheel Cleaner, www.driveit.com/tirewheelcare.html; Balchip Corporation, www.greencarcare.com; Optimum Car Wax, www.optimumcarcare.com

Dear EarthTalk: What are the health and environmental consequences of some of the methods used to control mosquitoes, ticks and other insects? -- Hunter White, Lafayette, IN

By far the most popular form of insect repellent available to consumers in the U.S. is diethyl-meta-toluamide, known popularly as "DEET." According to the U.S. Environmental Protection Agency (EPA), each year approximately one-third of the U.S. population uses insect repellents containing DEET, which is the active ingredient in more than 230 products, including sprays, lotions, liquids and wristbands.

But recent laboratory animal studies have found that frequent and prolonged exposure to DEET can cause neurons to die in regions of the brain that control muscle movement, learning, memory and concentration. Other studies using humans have found adverse effects ranging from skin irritation and blisters to memory loss, even seizures. Very high exposures, such as those that occur if the repellent is swallowed, have caused neurological damage in at least 18 children, three of whom died as a result. Yet despite these threats, the EPA insists that DEET products are safe as long as consumers follow the directions carefully.

Meanwhile, bug zappers--which emit ultraviolet light to draw pests--kill few if any mosquitoes, which are attracted not to light but to our body heat and the carbon dioxide we exhale. Some four million zappers are at work in the U.S., toasting nearly 71 billion insects--mostly non-target bugs--each month. The most common bugs killed are beetles, moths, flies, bees, ants and wasps, many that are themselves beneficial for insect control as well as pollination.

But while there are issues with many localized forms of pest control, most troublesome are the potential public health effects of the widespread application of "organophosphate" pesticides, such as Malathion, intended to wipe out large mosquito populations for miles around. In recent years, cities and states looking to stave off mosquito-borne maladies like West Nile Virus have undertaken large-scale mosquito control projects--often involving the use of Malathion. According to Pesticide Action Network, Malathion is chemically related to the nerve gases used in World War II. It kills by disrupting nervous system processes, and has been linked to cancer, nervous system disorders and a wide range of other maladies in humans.

One environmentally friendly alternative mosquito control method is Bacillus thuringiensis israelensis (BTI), a bacterium that can be applied to mosquito breeding grounds, usually in places where standing water collects. BTI is a naturally occurring organism that targets only the larvae of insects, and as a result poses no health threat to humans or wildlife. Some hardware stores stock BTI-infused mosquito "dunks" which are activated when wet. Another somewhat more costly option is the Mosquito Magnet, a trap that attracts mosquitoes by emitting an irresistible combination of carbon dioxide, heat and moisture. But perhaps the safest way to avoid bug bites is to don the always-dapper combination of a long-sleeved shirt, long pants, ankle socks and a wide-brimmed hat.

CONTACTS: U.S. EPA DEET Page, www.epa.gov/pesticides/factsheets/chemicals/deet.htm; Pesticide Action Network, (415) 981-1771, www.panna.org; Arbico Organics' Mosquito Control with BTI, http://store.arbico-organics.com/organic-pest-control-most-requested-mosquito-control.html.

Dear EarthTalk: What exactly are PZEV cars? Someone told me they were very clean, and on the market now. -- Thomas Lyons, Jamaica Plain, MA

Thanks to rigorous auto emissions standards in California--where regulators are trying to clean up the worst air in the country--no less than a dozen car companies now offer Partial Zero Emission Vehicle (PZEV) cars for sale in the U.S. While these cars run on gasoline and don't necessarily get better mileage than their traditional counterparts, they do produce much cleaner emissions by controlling exhaust gases with sophisticated engine controls and advanced catalytic converters.

Most auto pollution is released while a car is warming up and the catalytic converter is still cold. But PZEVs, through the use of lightweight steel and aluminum components, computerized valve timing and other advanced engineering technologies, heat the catalytic converter quickly, which reduces emissions significantly. These reduced emissions qualify the cars as "low-emission vehicles" (LEVs) in the "clean car states" of California, New York, Massachusetts, Vermont and Maine, each which requires automakers to sell a certain percentage of "green" cars.

Environmentalists are optimistic that the fast-growing fleet of PZEVs on America's roads will have a much larger and more positive impact on environmental quality than the even cleaner running gasoline-electric hybrids, which are still niche vehicles. In fact, already for every hybrid Prius sold by Toyota since it was introduced in 2000, Ford has sold three PZEV Focuses.

Indeed, what's perhaps most striking about the push by automakers to produce PZEVs is the lack of hype surrounding the vehicles, especially in light of all the attention being paid to the hybrids and to the coming hydrogen fuel cell cars. All new versions of Ford's popular Focus model, for example, meet PZEV standards, but consumers wouldn't know it unless they were to ask. Compared to a similar size traditional car, the PZEV Focus produces 97 percent fewer hydrocarbon and nitrogen oxide emissions, and 76 percent less carbon monoxide.

According to California's DriveClean website, car buyers looking to jump on the PZEV bandwagon will have to shell out a few hundred dollars extra for the greener technology, but have several models to choose from, including BMW's 325i, Dodge's Stratus and Sebring, Honda's Accord, Hyundai's Elantra, Mitsubishi's Galant, Nissan's Sentra, Subaru's Legacy, Toyota's Camry, Volkswagen's Jetta, Volvo's S60 sedan and V70 wagon, and of course, Ford's Focus. Consumers in the five "clean car states" should be able to order any of the PZEV models at local auto dealers. Only the Ford Focus is readily available in all 50 states but, according to the magazine Green Car Journal, "it's just a matter of time until the rest of the country catches up and we can all breathe a bit easier."

CONTACT: Ford Focus, www.fordvehicles.com/cars/focus; California's DriveClean Website, www.driveclean.ca.gov; Green Car Journal, www.greencar.com. Dear EarthTalk: The organization American Rivers names 10 "endangered rivers" every year. Which ones are they for 2005 -­ and are there any success stories pertaining to past nominees? -- Carolyn Cacciotti, Bridgeport, CT

For 20 years now, the organization American Rivers, in its annual "Most Endangered Rivers" report, has highlighted rivers around the U.S. that have the worst chronic problems in need of attention. This year the organization took a new approach and focused on those "facing the most uncertain futures."

American Rivers' "10 Most Endangered Rivers for 2005" are: the Susquehanna River flowing through New York, Pennsylvania and Maryland; McCrystal Creek in New Mexico; Colorado's Fraser River; the Skykomish in Washington state; Tennessee's Roan Creek; the Santee River in South Carolina; Ohio's Little Miami River; Utah's Price River; and the Tuolumne and Santa Clara rivers, both in California.

These rivers face a variety of threats, mostly involving pollution due to runaway real estate development and poor sewage treatment, and water diversions from dam projects and from excessive near-shore development. McCrystal Creek faces the possibility of methane drilling in its coal bed, which will pollute the creek. And in Tennessee, Roan Creek is neighbor to a large dairy farm that plans to build animal waste "lagoons" near its shores that could eventually send waves of liquid manure downriver.

The Susquehanna is the most endangered on the list. Throughout the river's watershed, aging sewer systems discharge enormous volumes of raw or poorly treated sewage that eventually flows into the Chesapeake Bay. "Unless lawmakers invest in prevention and cleanup, the Susquehanna will remain among the nation's dirtiest rivers," reports American Rivers. Happily, on the day American Rivers released its report, the state of Maryland backed away from plans to weaken water quality standards for the river.

Other success stories abound as well. Six months after the Tennessee River appeared on the 2004 list, the Knoxville Utility Board committed to eliminating sanitary sewer overflows into the Tennessee River within 10 years. After Massachusetts' Ipswich River appeared on the 2003 list, the Massachusetts Department of Environmental Protection issued new regulations to limit the amount of water that municipalities can draw out during low flow periods. And following American Rivers' inclusion of New York's Hudson River on its 2001 list, then-EPA Administrator Christine Todd Whitman ordered General Electric to foot the bill to clean up tons of PCBs that were contaminating the river bed.

Besides issuing its annual report and lobbying for better clean water legislation and enforcement, American Rivers works directly to remediate watershed problems across the country. Working with the National Oceanic and Atmospheric Administration (NOAA), for example, the group is removing barriers to salmon, striped bass and other species that migrate between fresh and salt water in the Northeast, Mid-Atlantic and California. So far, they've removed 13 unwanted dams, and created fish bypasses for six others.

CONTACTS: American Rivers, www.americanrivers.org; National Oceanic and Atmospheric Administration (NOAA), www.noaa.gov.

Dear EarthTalk: What exactly constitutes "Eco-Travel" or "Eco-Tourism"? -- Jeannette Peclet, Norwalk, CT

While tour operators and travel agents around the world may tout their trips as "eco-tours," environmentally conscious travelers take a variety of considerations into account when determining whether or not any given excursion qualifies as such. The International Ecotourism Society (TIES) defines eco-tourism as "travel to natural destinations that minimizes impact, builds environmental awareness, helps fund conservation, and respects and sustains local cultures while supporting human rights and democracy."

According to the United Nations Environment Programme (UNEP), eco-tourism is defined as travel focused on "the observation and appreciation of nature as well as the traditional cultures prevailing in natural areas." UNEP emphasizes that eco-tours must contain educational features, be organized for small groups by locally-owned businesses, minimize negative impacts "upon the natural and socio-cultural environment," and support the protection of natural areas by generating income for the host communities to use in conserving and sustaining their natural and cultural resources.

Recent studies indicate that as much as seven percent of all tourism worldwide operates under some sort of "eco" label. One recent survey concluded that eight million U.S. travelers have taken at least one "eco-tourist" holiday, while another concluded that three-quarters of all Americans have taken a trip involving nature and the outdoors. In the Asia-Pacific region, ecotourism accounts for 20 percent of all travel. Meanwhile, in Africa, where most visitors travel to nature reserves and game parks, the figures are even higher. The Kenya Wildlife Service, for instance, estimates that 80 percent of visitors come to see wildlife.

But the debate over what types of travel constitute eco-tourism has meant that a wide range of dining, lodging and transportation vendors advertise themselves as "green" regardless of whether their operations meet the criteria defined by TIES and other groups. As Jim Motavalli writes in E/The Environmental Magazine, "A beachfront hotel tower built of imported materials with absentee owners and no local employees is not an eco-resort, even if it does offer its guests the option of not washing their towels."

And travelers should keep in mind that "adventure" travel or "nature-based" tourism trips are not necessarily environmentally friendly. In fact, tour operators offering access to remote scenic and wild locations need to take extra care so that their trips do not endanger the very flora, fauna and geological features they are offering to showcase. Sad stories of so-called "ecotourism" run amok­where over-visitation has led to trampled landscapes and damaged wildlife habitat­abound from the Galapagos Islands and Mexico's Chiapas region to the coastal caves of Thailand, the reefs of Hawaii and beyond.

The moral of the story then, is buyer beware. Consumers should do their homework and ask travel vendors a lot of questions about how they operate in order to discern whether they are harming or helping local environments and cultures.

CONTACTS: The International Ecotourism Society, www.ecotourism.org; United Nations Environment Programme, www.unep.org.

Dear EarthTalk: How are coral reefs faring around the world? -- Debby Greco, Canton, CT

Not so well, unfortunately. Research experts from the World Resources Institute, a Washington, DC-based organization of scientists, economists and policy experts, report that coral reefs around the world are dying or disappearing at an alarming rate.

Lining 60,000 miles of shoreline along 109 countries, reefs and their related fisheries, marshlands and lagoons are home to more than a quarter of all fish species on Earth. An estimated 25 percent of coral reefs have already disappeared and an estimated 67 percent of all remaining coral reefs are endangered today. In Southeast Asia, 88 percent of the reefs are at risk. In the U.S. Florida Keys, more than 90 percent of the reefs have lost their living coral cover since 1975.

According to the Planetary Coral Reef Foundation, which monitors the health of coral reefs worldwide and coordinates an international "Save the Reefs Campaign," the greatest threat to coral reefs thus far has been the coastal development resulting from human population expansion. Over the last 30 years, this trend has profoundly increased the amount of freshwater "runoff" into costal areas. Known collectively as "non-point source pollution," this runoff has carried with it large amounts of sediment, sewage and chemicals from land-clearing areas, agricultural areas and septic systems into the reefs. The resulting pollution of the water thus decreases the amount of light reaching the corals, choking the life out of these fragile structures.

Meanwhile, increases in both commercial and sport fishing, enhanced by ever-improving technologies, have also taken a toll on reef health by removing so many of the large fish, which when healthy and plentiful keep fragile reef ecosystems in balance.

Moving forward, scientists studying coral health are most concerned about the impacts of a somewhat newer threat: climate change. Indeed, global warming is changing the surface temperatures of ocean waters faster than corals can adapt. "Coral reefs are so sensitive to temperature change that it seems inevitable that many will die as a result of global warming as well as all the other terrible things that are happening to them," says Rod Fujita, a marine biologist with Environmental Defense, a non-profit advocacy group. Furthermore, coral reefs' very sensitivity to environmental changes makes them a "canary in a coal mine" early warning system with regard to the overall declining health of the world's oceans.

Meanwhile, the non-profit Coral Reef Alliance is working toward the establishment of a comprehensive global map of living coral reefs to serve as a baseline for learning how fast we are losing them and how we can stem the decline. Also, a new program by the National Aeronautics and Space Administration (NASA) is monitoring coral reefs by satellite to try to put some of the puzzle pieces together.

CONTACTS: World Resources Institute, www.wri.org; Planetary Coral Reef Foundation, www.pcrf.org; Environmental Defense, www.environmentaldefense.org; Coral Reef Alliance, www.coralreefalliance.org; National Aeronautics and Space Administration (NASA), www.nasa.gov.

Dear EarthTalk: Which spray insulation products are safest to use? -- Malcolm Greeley, Evanston, IL

Spray insulation is commonly used to fill spaces in unfinished walls, attics and floors. Most of it is made from polyurethane and "closed foam cells," which means it forms a nearly impenetrable barrier. The material is widely recognized as a highly efficient insulator, effectively reducing heat transfer.

Despite the practical benefits, however, there are some environmental and health drawbacks. Although chlorofluorocarbons (CFCs) were phased out by the insulation industry because of the damage they were shown to inflict on the Earth's ozone layer, spray insulation is today typically blown into place with hydrochlorofluorocarbons (HCFCs), CFC alternatives that are still not completely ozone-friendly (they, too, are set to be phased out completely by 2030). Also, polyurethane can "off-gas" formaldehyde and other irritants once installed, potentially jeopardizing indoor air quality and causing discomfort to those with chemical sensitivities.

Meanwhile, open-cell insulation such as Icynene requires no ozone-depleting chemicals in its manufacture, and is usually blown into place with water. Also, it emits no harmful or irritating chemicals, yet provides a thermal barrier said to be more than 30 times as effective as traditional fiberglass insulation. In Canada, where the product originates, Icynene is endorsed by the Envirodesic Certification Program, which certifies eco-friendly construction materials and is endorsed by Canada's Lung Association. The downside of open-cell foam is that it is derived from petroleum products and, as such, requires the extraction of finite fossil fuels.

While newer and less well known, Air Krete is a thermally efficient and non-toxic spray insulation that is easily foamed into open or closed cavities in walls, roofs and ceilings. The product's basic raw material components are air, water and cement which, when combined, create a cost-effective, safe and high performance product. The National Audubon Society installed Air Krete in its New York City headquarters as part of an overhaul designed to "green up" that organization's entire operation.

Beyond sprays, there are many other forms of healthy and environmentally responsible insulation, such as cellulose, cotton, radiant metal barriers, and plastic PET batting. Some such products can be found on the shelves of local building supply stores, or at Home Depot. But for the widest selection, green building specialty stores such as the Environmental Home Center in Seattle, which sells online, are a good bet. Others can be found by searching for local retailers, by product desired, at greenerbuilding.org, a service of the non-profit Center for ReSource Conservation, based in Boulder, Colorado.

CONTACT: Icynene, www.icynene.com; Envirodesic Certification Program, www.envirodesic.com; Air Krete, www.airkrete.com; National Audubon Society, (212) 979-3000, www.audubon.org ; Environmental Home Center, (800) 281-9785, www.environmentalhomecenter.com. Greenerbuilding.org, (303) 441.3278, www.greenerbuilding.org.

Dear EarthTalk: What are the implications for Montana's Glacier National Park if the glaciers there keep melting? -- Oliver Ryan, New York, NY

Indeed, the glaciers for which Glacier National Park is named are melting away due to increasing global temperatures in recent decades, attributable most likely to global warming. A century ago, Grinnell Glacier, once the park's largest, covered almost 440 acres. Today it has shrunk to just a quarter of that size. Many of the glaciers are gone altogether: According to the Sierra Club, the number of glaciers in the park has dropped from around 150 in 1850 to approximately 35 today.

Most of the glacier loss in the park has occurred since the late 1960s when global warming trends began to intensify. Park scientists are now worried that, if nothing is done to curb global warming, by the year 2030 there may not be a single glacier left in Glacier National Park.

Glaciers form when huge ice sheets build up under snow that has slowly accumulated over time. As the snow cover mounts, the intense weight compresses the delicate snowflakes beneath the surface, gradually changing them into the ice grains that make up glaciers. During the last Ice Age some glaciers were a mile thick, covering huge swaths of the Earth, and carving out much of the topography we know today through their slow and grinding movements.

The warming of the Earth that occurred at the end of the last Ice Age--and which melted glacial ice from pole to pole--was a natural phenomenon, and took place over thousands of years. Today, the carbon dioxide emissions generated over just the last half-century from industrial and automotive sources could, say scientists, lead to an equivalent amount of glacial melting within just decades, not millennia.

This process could put plants and animals, which have adapted to certain living conditions over time, in deep trouble as their habitat characteristics shift right under their feet, fins and roots. And Glacier National Park will be no exception. For example, the lack of glaciers and snow pack there could eliminate avalanches, which perform a valuable ecosystem function by knocking down forested stands to make way for new growth in meadows. The berries that are prevalent in these meadows are a major nutrition source for the grizzly bears that call the park home. Without avalanches and the meadows they create, the park's already stressed grizzly population could suffer drastic declines.

Beyond such ecological implications, no one knows how a glacier-less Glacier National Park might play to tourists doing their grand western tours. If visitation to the park and therefore the region were to drop significantly, the local economy--now dependent upon tourism revenue--could suffer debilitating losses. After all, who would visit a place called Glacier if there were no glaciers to see?

CONTACTS: Sierra Club, www.sierraclub.org/globalwarming/articles/glacier.asp; Glacier National Park, www.nps.gov/glac/.

Dear EarthTalk: I've heard that aluminum is toxic. At the same time aluminum frames are said to be the healthiest choice for replacement windows, especially for those who are chemically sensitive. Are aluminum windows safe? -- F. Lane, San Diego, CA

Aluminum can be toxic if ingested in large amounts, but there is no evidence that it causes health problems through the kinds of minor skin or airborne exposure one might receive from a window frame. As such, aluminum window frames are certainly healthy alternatives to fiberglass or vinyl, each of which are problematic because they can "off-gas" chemicals like formaldehyde into the indoor environment of your home, which could in turn aggravate chemical sensitivities.

Homeowners should be sure that any aluminum windows they install feature "thermal breaks," a design that involves fusing two separate frames together so as not to conduct the heat that precipitates mold growth. Millions of people are allergic to mold, which can spread from window frames to the wood structure of a house and cause widespread rot.

On the downside, environmentally conscious consumers should know that the manufacture of aluminum is energy intensive and requires the burning of significant quantities of fossil fuels. Recycling your beer and soda cans can help reduce this problem because it takes far less energy to re-process aluminum than it does to produce it from scratch. Fortunately, a high percentage of aluminum is already being recycled today.

Also, John Bower, founder of the Healthy House Institute and author of several books on eco-friendly design and building, recommends putting triple glazed "low-emission" ("low-E") coated window glass in aluminum frames to preserve indoor air quality and maximize energy efficiency. "Over their lifetime, houses [with these windows] should save more energy than was consumed to process the aluminum frames in the first place," he says.

Wood window frames, as long as they are not "pressure-treated" with arsenic-laden pesticides or harvested from endangered "old-growth" forests, are also an attractive, healthy and green-friendly alternative to fiberglass or vinyl frames. But aluminum still provides more bang for the cost-conscious consumer's buck, often costing less than half of what wood frames would set you back.

CONTACTS: The Healthy House Institute, www.hhinst.com; Energy Star Anatomy of an Energy Efficient Window, www.energystar.gov/index.cfm?c=windows_doors.pr_anat_window.

Dear EarthTalk: What environmental and health issues, if any, are associated with cut flowers? -- Olivia Clark, Seattle, WA

More than half of all cut flowers sold in the United States at florists and supermarket chains are imported. Holland is the largest source and several Latin American countries, including Columbia and Ecuador, vie for second place. Because flowers are not food, the U.S. Department of Agriculture doesn't regulate them or inspect them for pesticide residues. Nonetheless, U.S. Customs will reject a whole shipment of flowers if they contain a single insect, and consumers for the most part will reject any bunch that is less than perfect.

It is no surprise, then, that cut flowers are one of the world's most pesticide-intensive crops. Flower workers, of which there are roughly 200,000 worldwide, pay the heaviest price. In Ecuador, the second-largest exporter to the U.S., 60 percent of workers suffer from headaches, nausea, blurred vision or fatigue, according to a 1999 study by the International Labor Organization. Doctors in Cayambe, the rose capital of Ecuador, confirm these findings and add birth defects, sterility and miscarriages to the list.

Flower exporters use a variety of fertilizers, insecticides and fumigants, including the highly toxic methyl bromide, which is also known to harm the Earth's protective ozone layer. Even in the U.S. flowers are grown with large amounts of pesticides in closed greenhouse environments, resulting in compromised worker health and flowers laden with pesticide residues. California roses, for example, in a 1997 Environmental Working Group study, were found to have 1,000 times the level of cancer-causing pesticides as comparable food products.

In 2001, Gerald Prolman, who founded Made in Nature, the first distributor of organic produce to supermarket chains, launched Organic Bouquet with the idea of selling organic flowers over the Internet. Now Organic Bouquet flowers are available at Whole Foods, Wild Oats, Trader Joe's and other natural foods chains, as well as on the company's website.

Organic Bouquet uses organic flower growers primarily in the western United States, but also in Ecuador and Colombia where Prolman discovered that, because of the prohibitive cost of pesticides and artificial fertilizers, a few growers had developed natural alternatives and were still producing perfect flowers. "They were using organic techniques without even knowing it," he recalls.

Two other online purveyors of organic flowers include Manic Organics of Lawrenceville, Georgia, which specializes in roses, and Seabreeze Organic Farm in San Diego. But one need not take to the Internet and wait for UPS to deliver in order to "say it with organic flowers." Organic, pesticide-free flowers can be bought in season from your local farmer's market. If you can't find one, the website of Local Harvest maintains a nationwide directory. You can buy from the company's online store, which helps small farms find markets for their products beyond their local areas, but their search engine can help you establish direct contact with small farms in your local area.

CONTACTS: Organic Bouquet, (877) 899-2468, www.organicbouquet.com; Manic Organics Flowers, (678) 377-8258, www.manicorganicsflowers.com; SeaBreeze Organic Farm, (858) 481-0209, www.seabreezed.com; Local Harvest, (831) 475-8150, www.localharvest.org/organic-flowers.jsp.

Dear EarthTalk: Nuclear power seems like such a clean and cost-effective alternative to burning fossil fuels. Why are so many environmentalists against it? -- Paul Franklin, Missoula, MT

Unlike fossil fuels, nuclear power spares us the carbon dioxide that promotes global warming and the airborne pollutants that cause respiratory harm. But the technology does have a serious downside: It generates radiation that can cause a host of genetic abnormalities, notably cancer. The lymphatic system, bone marrow, intestinal tract, thyroid and the female breast are most vulnerable to the effects of radiation, especially in children and adolescents.

When most people think of the dangers of nuclear energy they think of the highly publicized accidents that occurred at Three Mile Island in Pennsylvania in 1979 and Chernobyl in the Ukraine in 1986. Studies have turned up very little environmental damage from the Three Mile Island accident, which was quite minor, compared to Chernobyl. Although casualty figures are in dispute, Ukranian officials blame that accident for at least 4,300 deaths beyond the 30 that occurred during the meltdown and immediately afterwards. And there is little disagreement that the accident caused as much as a 100-fold increase in thyroid cancers among children in the Ukraine and in nearby Russia and Belarus. According to the Ukrainian Ministry of Health, in the Ukraine alone more than 2.32 million people, including 452,000 children, have been treated for radiation-linked illnesses, including thyroid cancers and blood cancers like leukemia.

A nuclear accident, however, does not have to occur for radiation to escape and pose a health threat. The waste from power plant operations is also radioactive, and already the U.S. nuclear industry has left behind a legacy of nearly 100,000 tons of it. Scientists have not yet found a way to store nuclear waste--which stays radioactive for thousands of years--such that they can guarantee it won't harm people, even when it is buried miles below ground. The nuclear industry and the Bush administration are proposing that Yucca Mountain in Nevada be a central repository for the nation's nuclear waste, but transporting the waste there from its widely dispersed locations poses even greater concerns for the health of citizens in the areas through which the transporting trucks and barges would pass.

Meanwhile, some environmentalists are advocating for more nuclear energy, but primarily as a stopgap measure to stave off global warming. Among them is noted scientist and author James Lovelock, considered by many to be one of the ideological leaders of the modern environmental movement. Lovelock argues that global warming is happening too fast and that renewable sources of energy like wind and solar are not developing fast enough to reverse that trend. "I don't see nuclear as the ultimate solution," he said. "I see it as a kind of medicine, which is an unpleasant medicine in some ways that we have to take while we're curing ourselves of fossil fuels."

CONTACTS: Nuclear Information and Resource Service, www.nirs.org. Environmentalists for Nuclear Energy, www.ecolo.org; International Chernobyl Research Information Network, www.chernobyl.info.

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