From San Francisco, the Latest News of the World
In mid-December 2001, more than 8,500 scientists gathered in San Francisco for the annual meeting of the American Geophysical Union. I wandered amid the mass of humanity in the Moscone Convention Center—equal to the population of Ketchikan—and heard some of the latest news in Earth and space sciences. Here's some scribblings from my notebook:
• Melting Alaska glaciers are adding more to global sea level than any other glacial source yet measured, including the Greenland ice cap and Antarctica, according to Keith Echelmeyer of the University of Alaska's Geophysical Institute.
• Columbia Glacier in Prince William Sound is receding by more than 80 feet each day, and Mark Meier of the University of Colorado at Boulder estimates it could retreat as much as 10 miles in the next decade.
• Alaska glaciers have disappeared rapidly at elevations below about 4,500 feet in the last 30 years, according to Bruce Molnia of the U.S. Geological Survey. At elevations above about 4,500 feet, Alaska glaciers have changed very little.
• Changing wind patterns in the Arctic have caused a rapid thinning of western Arctic Ocean sea ice, according to Walter Tucker of the U.S. Army Cold Regions Research and Engineering Laboratory. Data collected from U.S. Navy submarines shows a thinning of sea ice by more than three feet in the late 1980s.
• Three of Antarctica's largest glaciers have lost up to 150 feet of thickness in the last 10 years, according to a panel of scientists that spoke of global warming's effects on cold regions.
• Forest fires in the North American boreal forest have doubled in the last 30 years, according to Eric Kasischke of the University of Maryland.
• Alaskans and northern Europeans might see more rain in the near future because of a process called the arctic oscillation. The arctic oscillation is a flip-flop of atmospheric pressures at polar and mid latitudes. When the oscillation is positive, it brings high pressure to the mid-latitudes and low pressure—which can cause more precipitation—to the poles. Nathan Gillet of the University of Oxford in England said the present positive phase, which has lasted since then 1980s, is possibly due to an increase of greenhouse gases.
• Human beings and their automobiles and power plants emit seven billion tons of carbon each year. Two billion tons of that carbon goes into Earth's oceans, according to a panel of climate change specialists.
• To eliminate emissions of the greenhouse gas carbon dioxide from power sources, David Criswell of the University of Houston's Institute for Space Systems proposes power plants on the moon that would capture the sun's rays and send them to Earth as microwave beams. Antenna fields on Earth covering 100,000 square kilometers would convert the microwaves to usable energy in a program that would cost as much as the first Apollo moon launch.
• A high-speed camera developed by Hans Stenbaek-Nielsen at the Geophysical Institute captured images of the Leonid meteor shower at 1,000 frames per second. The images show for the first time how a shock wave forms in front of a meteor and then expands into a ball of hot gas as the meteor blazes into Earth's atmosphere.
• NASA's Odyssey spacecraft detected large hydrogen deposits on Mars that may be water in the form of ice.
• The population density of wooly mammoths in the lowlands of northern Siberia during their peak was one mammoth per square kilometer, which is more than the concentration of elephants on the Africa savanna, according to researchers including Terry Chapin of the University of Alaska.
