Arctic Mayhem, Contrails and Climate, and Dirty Diesels

What threats would oil drilling in the Arctic National Wildlife Refuge pose to wildlife?

—Alexander Brower, Jefferson, WI

The U.S. Fish and Wildlife Service calls Alaska’s Arctic National Wildlife Refuge (ANWR) "among the most complete, pristine, and undisturbed ecosystems on Earth." ANWR’s Area 1002, the coastal plain where oil drilling is proposed, is home to a staggering array of native and migratory birds, ringed seals, beluga whales, musk oxen, polar bears, porcupine caribou, grizzly bears and wolves.

While it is impossible to determine exact consequences of proposed drilling, the Fish and Wildlife Service has cited numerous threats. The region’s fragile tundra is extremely sensitive to human exposure and still exhibits scars from seismic exploration vehicles that passed through almost 20 years ago. Defenders of Wildlife warns that drilling will likely disturb the historic birthing grounds of oxen and caribou, resulting in lower birthrates.

Drilling advocates claim that only 2,000 of ANWR’s 19 million acres would be subject to extractive operations. But the Arctic Protection Network argues that a much larger area is likely to be affected. The group cites the example of Prudhoe Bay, a neighboring oil-drilling site that had hundreds of square miles altered with roads, pipelines and power plants. In a single year, Prudhoe Bay experienced 293 oil spills.


Arctic Protection Network

Defenders of Wildlife
Tel: (202) 682-9400

—Laura Ruth Zandstra

Do jet contrails cause climate change?

—Isadore Klevitch, Palatine, IL

Condensation trails, which are also known as contrails, are formed when airplanes fly at high altitudes, where the air is extremely cold. The phenomenon is similar to exhaling in cold weather and "seeing your breath." Although contrails look harmless, they may actually affect the climate as they spread into high, thin cirrus clouds after they were formed. NASA researcher Patrick Minnis has found that this increased cloud coverage tends to warm the Earth because it traps the heat of incoming sunlight that cannot be reflected back into space. Some studies suggest that contrails may even trigger rainfall.

Contrails were difficult to study before September 11, 2001, because they normally cross each other by the hundreds. But with planes grounded for three days following the terrorist attacks, Minnis observed that six military aircraft caused about 7,700 square miles of cirrus clouds to form over Virginia and Pennsylvania in otherwise clear skies.

During that same time, David Travis, a University of Wisconsin atmospheric scientist, studied daily temperature ranges across the country and found that the average range increased, with the largest changes in the Northeast, the Midwest and the Pacific Northwest, where air traffic is usually heaviest. Although this complicates global warming arguments, it offers further evidence that contrails do affect climate in some way.

Contrails typically cover up to five percent of the sky over Europe and the U.S. But as air travel grows in popularity, Minnis warns they could increase by a factor of six by 2050.


NASA Research Center

—Phoebe Hall

Are there any environmental benefits of diesel-powered cars?

—Bill Darcy, Concord, NH

The high fuel economy of diesel-powered vehicles, such as the Volkswagen Golf GL TDI, may seem like a no-brainer for environmentalists looking for a new car. But don’t be fooled by the numbers. Though a four-cylinder, five-speed TDI gets 42 miles per gallon (mpg) in the city and 49 mpg on the highway, compared to 24 city/31 highway for a similar gasoline-powered Golf, that diesel engine emits a lot more harmful pollutants. Swedish and German studies have reported that diesel-powered cars have twice the cancer potency level of gasoline-powered vehicles. And the Union of Concerned Scientists reports that diesel exhaust accounts for 70 percent of the cancer risk from California’s polluted air.

The particulates, or soot, in diesel exhaust cause a host of health problems, from asthma to lung disease to premature death, according to the Environmental Protection Agency (EPA). Under current EPA regulations, diesel vehicles can emit 16 times more particulates into the air than gas vehicles can.

The EPA’s Green Vehicle Guide rates cars and trucks on a scale of zero to 10 (10 being the best) based on their emissions of smog-forming pollutants. While a gasoline-powered Golf received a rating of seven, the Golf TDI got a one. The gargantuan Ford Excursion and Hummer H2, SUVs with gas mileage in the single digits, both received twos.



Union of Concerned Scientists
Tel: (617) 547-5552