Week of 5/23/2004

Dear EarthTalk: What is the safest way to get a tan?

—Lauren Nivens, Cope, South Carolina

While dermatologists continue to remind us that long-term sun exposure can harm our skin, causing wrinkles, burns and age spots and, more seriously, malignant melanoma and other skin cancers, many people still yearn for that sun-worshipper look. "We encourage people to use self-tanning creams," says Dr. Robin Ashinoss from New York University"s Medical Center and the American Academy of Dermatology, which can help you find a dermatologist in your area. Creams use di-hydroxyacetone, a compound that binds to and stains dead skin cells, giving you a temporary tan. But beware, self-tanning creams will not protect you from the sun"s harmful ultra violet rays, which stimulate melanoma, change pigment color and damage skin cell DNA.

Using tanning beds is your worst option. People who use tanning beds or tanning lamps face a significantly higher risk of developing common types of skin cancer, according to a recent study published by the National Cancer Institute. Because artificial tanning devices use the same energy source as the sun"s rays—UV radiation—researchers suspect that tanning beds have the same damaging effects as overexposure to the sun. A recent study at Dartmouth College found that people who used a tanning device were 2.5 times more likely to develop basal cell carcinoma than those who avoided them. Basal cell carcinoma is the most common form of skin cancer, arising out of the bottom of the outer skin layer. They were also 1.5 times more susceptible to squamous cell carcinoma, the second most common form of skin cancer, involving tumors that arise in the outer layers of the skin.

Skin cancer is one of the most preventable cancers, yet it is also the most common cancer in the United States, accounting for almost half of all cancers, according to the Cancer Research and Prevention Foundation. "There is no need to be in the sun. The only benefit is that it helps the body to create vitamin D, for healthy bones," says Dr. Jim Baral of American Dermatology Center and Mount Sinai Medical Center in New York City.

CONTACT: American Academy of Dermatology, (888) 462-3376, www.aad.org Cancer Research and Prevention Foundation, (800) 227-2732, www.preventcancer.org.

EARTH TALKFrom the Editors of E/The Environmental Magazine

Dear EarthTalk: Is the world running out of oil?

—Allie Knopf, Kansas City, MO

Many experts say that evidence points to a declining world oil supply. According to renowned petroleum geologist Colin Campbell, who has worked for Texaco, BP, Shell and other major oil companies, world oil discovery peaked in the 1960s, while world production is set to peak about six years from now. Campbell predicts "the onset of a chronic long-term shortage" by 2010.

According to the Energy Information Administration (EIA), part of the U.S. Department of Energy (DOE), the U.S. has 22.7 billion barrels of "proven" oil reserves as of January 2004, about 20 percent less than we had in 1990. "Proven" refers to estimated amounts that can be recovered in upcoming years with reasonable certainty. Outside the U.S., nearly two-thirds of the world"s proven oil reserves exist in the 11 countries that make up the Organization of the Petroleum Export Countries (OPEC): Algeria, Indonesia, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, the United Arab Emirates and Venezuela.

The U.S. Geological Survey, which last conducted its World Petroleum Assessment in 2000, estimated that 649 billion barrels of undiscovered oil, and 612 billion barrels of "oil reserve growth," exist outside the U.S. "Undiscovered" refers to oil located in places that haven’t yet been drilled or explored; "oil reserve growth" refers to new discoveries near or in existing oil fields.

These estimates do not include oil sitting in storage facilities, such as the one billion barrel capacity U.S. Strategic Petroleum Reserve, located underground in salt caverns along the Gulf of Mexico coast. It is the world"s largest cache of emergency oil, with a provision of 53 days of import protection.

How much oil do we need anyway? According to the International Energy Outlook, released this year by the EIA, world demand is expected to increase by 1.9 percent annually, from 77 million barrels per day in 2001 to 121 million barrels per day in 2025, with much of the increase projected to occur in the U.S., China and other developing nations in Asia. Over 19 million barrels of oil were consumed per day in the U.S. alone in 2003.

Dr. Nancy Kete, director of the World Resources Institute"s Climate, Energy and Pollution Program, says: "We must face the inescapable fact that the nation"s environment, economy, national security and oil resource base all point to the need for vast investments in energy efficiency and the rapid introduction of new, non-oil energy sources."

+o<? lCT: United States Department of Energy"s Energy Information Administration, (202) 586-8800, http://eia.doe.gov; U.S. Geological Survey, (303) 236-5776, http://energy.cr.usgs.gov/oilgas/wep; World Resources Institute, (202) 729-7600, http://www.wri.org.