Carbon Dioxide

The government-owned Tennessee Valley Authority - and private producers of electricity in Georgia, Texas, Michigan, Pennsylvania, California, the Carolinas, Alabama and Ohio - are the top 10 utilities emitting carbon dioxide, a key pollutant linked to global warming. The list was compiled from Department of Energy statistics by Citizen Action, a major consumer organization, which said that the 10 producers accounted for 23 percent of all carbon dioxide released into the atmosphere by U.S. electric utilities.

Air Products & Chemicals Inc., Allentown, said it would receive $253 million in federal stimulus money to design, build and operate a system to capture carbon dioxide at a Valero Energy Corp. refinery in Port Arthur, Texas. The funds, from the Department of Energy, will pay for two-thirds of the $384 million project. The carbon dioxide is a by-product of methane reformers that produce hydrogen to help make cleaner-burning transportation fuels.    - Paul Schweizer

WHAT U.S. PRESSURE WON AT THE RIO CONFERENCE A principle of journalism holds that the more reporters on a story, the less gets covered. With several thousand correspondents at Rio, endless column-inches were devoted to the atmospherics and diplomatic sniping, both of which will be utterly forgotten. Little notice was accorded the actual contents of the treaties to be signed - though that's where the real story was. Consider the global-warming treaty, the primary achievement of the Earth Summit.

Trees are as important to today's Philadelphia cityscape, say the people who plant them, as they were on Sept. 30, 1681, the day William Penn announced plans for "a Greene Countrie Towne" to serve as the capital of his new colony of Pennsylvania. "Trees are every bit as important in a 20th-century urban environment due to the critical role they play in maintaining big-city quality of life," explained J. Blaine Bonham Jr., director of Philadelphia Green and Center City Green - two urban tree-planting programs sponsored by the Pennsylvania Horticultural Society.

Heard enough hot air from the Earth Summit about global warming? Here's a fresh blast that brings the issue closer to home. Pennsylvania sends up more of the greenhouse gas carbon dioxide in a single year than the nations of Belgium and Czechoslovakia combined, two Philadelphia-based environmental advocacy groups said yesterday. Citizen Action of Pennsylvania and the Delaware Valley Clean Air Council urged state lawmakers to tackle the problem. They called for tactics ranging from energy efficiency to alternative fuels to help trim the 247 million tons of carbon dioxide that gushed from Pennsylvania utilities, vehicles and other sources in 1990.

The disaster in Cameroon probably was the result of a freak natural occurrence in which a huge bubble of carbon dioxide rose to the surface of a volcanic lake and burst, emitting a cloud that suffocated nearby villagers, scientists in the United States and England said yesterday. "It's like a fantastic soda bottle blowing up," said Susan Russell- Robinson, a scientist with the U.S. Geological Survey in Reston, Va. Russell-Robinson and others said that reports from Cameroon were incomplete and that no one knew for certain what caused the release of gas. Scientists expect to learn more after international experts, including two teams of Americans, visit the mountainous and remote location in northwest Cameroon.

President Bush said yesterday that he was taking "important steps" to deal with climate change in his own way, as world leaders prepare next week to complete work on a treaty limiting the emissions that contribute to global warming, despite Bush's rejection of it. Bush's steps entail spending about $160 million on researching the causes of global warming, monitoring it better, and devising methods to keep carbon-dioxide emissions from escaping into...

Feeling as if the day is dragging? Blame global warming. Increased man-made carbon dioxide, a global-warming gas in the atmosphere, is slowing Earth's rotation, according to a study by Belgian scientists published last week in the journal Geophysical Research Letters. It's not much of a slowdown - about 1.7 microseconds, or 1.7 millionths of one second, a year, according to coauthor Michel Crucifix, a climate researcher at Catholic University of Louvain in Belgium. The slowdown occurs because extra carbon dioxide expands the mass of Earth's atmosphere from Earth's surface.

International leaders are not the only ones struggling to come up with a plan to curb carbon dioxide emissions as a way of combating global warming. As gusts of wind shook the branches of the majestic trees at Tyler Arboretum on Saturday, a small local group gathered inside Tyler's education center to learn what changes could be made to avert the potentially devastating effects of the warming trend. Arboretum volunteer Bob Maerten, who has worked in energy conservation, stressed that Americans must use less energy more efficiently.

LOS ANGELES - Think Mars today is a hostile place? It was worse 600,000 years ago, according to new research that suggests the planet had a dustier, stormier atmosphere. "It was an unpleasant place to hang out," said lead researcher Roger Phillips of the Southwest Research Institute. He said Mars' climate was probably a lot like the American Dust Bowl of the 1930s - but a lot worse. The evidence comes from the discovery of a huge underground reservoir of dry ice, or frozen carbon dioxide, at its south pole - much more than scientists had realized.