Dear EarthTalk: Some say that polar bears are going to disappear in 50 years, but Alaskan officials insist their populations are recovering. What's the real story?
—Harper Howe, San Francisco, CA
There is no doubt that polar bears are in serious trouble. Already on the ropes due to other human threats, their numbers are falling faster than ever as a result of retreating ice due to global warming. The nonprofit International Union for the Conservation of Nature, which added the polar bear to its "Red List" of the world's most imperiled wildlife back in 2006, predicts a 30 percent decline in population for the great white rulers of the Arctic within three generations (about 45 years).
The nonprofit Center for Biological Diversity presents an even more pessimistic forecast. If current warming trends continue, they say, two-thirds of all polar bears—including all of Alaska's polar bears—will be extinct by 2050. Both organizations agree that the species as a whole will likely be wiped out completely within 100 years unless humans can get global warming in check.
The erroneous notion that Alaska wildlife officials don't believe the polar bear is in trouble was put forth by Alaska governor Sarah Palin when she initiated a suit against the federal government in hopes of overturning its decision to include the polar bear under the umbrella of endangered species protection. "I strongly believe that adding them to the list is the wrong move at this time," Palin wrote in a January 2008 New York Times Op Ed piece. "My decision is based on a comprehensive review by state wildlife officials of scientific information from a broad range of climate, ice and polar bear experts."
The real story is that affording the polar bear endangered species protection would bring further regulations capping greenhouse gas emissions, a threat to Alaska's main economic driver: oil revenues. Alaska professor Rick Steiner uncovered the misinformation in Palin's claims when he found evidence that the state's top wildlife officials agreed with federal findings that polar bears are headed toward extinction: "So, here you have the state's marine mammal experts, three or four of them, very reputable scientists, agreeing with the federal proposed rule to list polar bears and with the USGS [United States Geological Survey] studies showing that polar bears are in serious trouble," said Steiner.
A solid link between global warming and polar bear mortality emerged in 2004 when researchers were surprised to find four drowned bears in the Beaufort Sea off Alaska's North Slope. The meltdown of sea ice—the polar ice cap had retreated a record 160 miles to the north—forced the bears to swim unusually long distances to find solid ice, which they depend on as hunting and fishing platforms and for rest and recuperation. And more recently, USGS researcher Steven Amstrup published findings that polar bears are "stalking, killing and eating other polar bears" as competition for scarcer food heats up.
Beyond global warming, other risks to polar bear populations include toxic contaminants in the surrounding environment as well as in the fatty tissue of the prey they rely on, conflicts with shipping, stresses from recreational polar-bear watching, oil and gas exploration and development, and overharvesting through legal and illegal hunting.
Dear EarthTalk: There's a lot of talk today about solar and wind power, but what about biomass? How big a role might this renewable energy source play in our future? Couldn't everyday people burn their own lawn and leaf clippings to generate power?
—Deborah Welch, Niagara Falls, NY
The oldest and most prevalent source of renewable energy known to man, biomass is already a mainstay of energy production in the United States and elsewhere. Since such a wide variety of biomass resources is available—from trees and grasses to forestry, agricultural and urban wastes—biomass promises to play a continuing role in providing power and heat for millions of people around the world.
According to the non-profit Union of Concerned Scientists (UCS), biomass is not only a renewable energy source but a carbon neutral one as well, because the energy it contains comes from the sun. When plant matter is burned, it releases the sun's energy originally captured through photosynthesis. "In this way, biomass functions as a sort of natural battery for storing solar energy," reports UCS. As long as biomass is produced sustainably—with only as much grown as is used—the "battery" lasts indefinitely.
While biomass is most commonly used, especially in developing countries, as a source of heat so families can stay warm and cook meals, it can also be utilized as a source of electricity. Steam captured from huge biomass processing facilities is used to turn turbines to generate electricity. Of course, biomass is also a "feedstock" for several increasingly popular carbon-neutral fuels, including ethanol and biodiesel.
According to the federal Energy Information Administration, biomass has been the leading U.S. non-hydroelectric renewable energy source for several years running through 2007, accounting for between 0.5 and 0.9 percent of the nation's total electricity supply. In 2008—although the numbers aren't all in yet—wind power likely took over first place due to extensive development of wind farms across the country.
According to the USA Biomass Power Producers Alliance, generating power from biomass helps Americans avoid some 11 million tons of carbon dioxide emissions that burning the equivalent amount of fossil fuels would create each year. It also helps avoid annual emissions of some two million tons of methane—which is 20-plus times stronger a "greenhouse" gas than carbon dioxide—per year.
The largest biomass power plant in the country is South Bay, Florida's New Hope Power Partnership. The 140 megawatt facility generates electricity by burning sugar cane fiber (bagasse) and recycled urban wood, powering some 60,000 homes as well as the company's own extensive milling and refining operations. Besides preserving precious landfill space by recycling sugar cane and wood waste, the facility's electricity output obviates the need for about a million barrels of oil per year.
Some homeowners are making their own heat via biomass-fed backyard boiler systems, which burn yard waste and other debris, or sometimes prefabricated pellets, channeling the heat indoors to keep occupants warm. Such systems may save homeowners money, but they also generate a lot of local pollution. So, really, the way to get the most out of biomass is to encourage local utilities to use it—perhaps even from yard waste put out on the curb every week for pick-up—and sell it back to us as electricity.
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