Environmental experts warned this week that war in Iraq will cause "massive and possibly irreversible" damage to the Persian Gulf region and significantly add to global warming. The environmental leaders said the ensuing damage to Iraq's ecosystem and food and water supplies may eclipse the destruction during the 1991 Persian Gulf War.

"I think it will be comprehensive damage, and I don't think it will be localized to the area of Iraq, regardless of how precise and surgical our bombing campaign will be," said Ross Mirkarimi, a San Francisco-based environmental analyst who made two trips to Iraq shortly after U.S.-led forces drove the Iraqis from Kuwait. "The pollution will travel in areas that will compound the damage that still remains from the 1991 military campaign."

During the Gulf War, retreating Iraqi forces set fire to more than 600 Kuwaiti oil wells, creating toxic smoke that choked the atmosphere and blocked the sun. The Iraqis dumped 4 million barrels of crude oil into the Persian Gulf, tarring beaches, killing more than 25,000 birds and driving millions more away, according to data compiled by the World Resources Institute and other organizations that monitor the environment. Spills of 60 million barrels of oil in the desert formed huge oil lakes and percolated into aquifers.

More than 80 percent of Kuwait's livestock perished during the war, and fisheries were heavily polluted, according to the monitoring groups. The burning oil fields released nearly a half-billion tons of carbon dioxide, an amount of greenhouse gas that many scientists say is the leading cause of the earth's rising temperature.

To date, a dozen nations affected by the Gulf War have submitted environmental damage claims to the United Nations totaling $79 billion. The U.N. has ruled so far on $1.9 billion of the claims, awarding about $1 billion, most of it to Kuwait and Saudi Arabia.

Environmental groups and experts said a new war in Iraq could do even more harm to the region's environment and water resources, and kill off dozens of endangered species of birds and animals.

"The first Gulf War was the biggest environmental disaster in recent history," said Gar Smith, former editor of Earth Island Journal and a spokesman for Environmentalists Against the War. "Unfortunately, with advances in military technology, a new Gulf War has the potential to be even worse."

Hans Blix, the chief U.N. weapons inspector in Iraq, said in a recent interview with MTV that, "To me the question of the environment is more ominous than that of peace and war."

Environmentalists say that U.S. fighter jets, tanks, armor-piercing shells and ground-shattering Massive Ordnance Air-Burst (MOAB) bombs likely will destroy or seriously damage Iraqi water and sewage treatment plants and dams; ruin ancient archaeological sites and harm what little remains of the Mesopotamian Marshlands, the primary source of fresh water in southern Iraq that was systematically destroyed by government engineers during the past 30 years.

Iraqi officials have said that they expect to maintain 10 percent of their water supply in a war. But aid agencies say taps could run dry within 12 hours of the first airstrikes on Baghdad, and they are stockpiling large quantities of drinking water for the capital's residents.

Environmentalists are particularly concerned about the use of armor-piercing munitions tipped with depleted uranium, a heavy metal that can penetrate tanks but also spreads radioactive dust to soil and water. During the 1991 conflict, U.S. forces fired 320 tons of depleted uranium, most of it from cannons mounted on Air Force A-10 Thunderbolt IIs, or "Warthogs." Radioactive material was spread across Kuwait, Iraq and Saudi Arabia, often in tiny fragments that some civilians picked up.

Defense Department officials last week said there is little evidence that depleted uranium poses a serious threat to public health or the environment, and they stressed the metal's ability to penetrate enemy armor. "Nobody goes into a war and wants to be even with the enemy," Col. James Naughton of the U.S. Army Materiel Command told reporters.

If oil wells are set ablaze again, they could do far more environmental damage than was inflicted in 1991, experts said. The Kuwaiti oil wells burned for as many as nine months, generating soot, sulfur and acid rain that covered croplands as many as 1,200 miles away.

"Over the last few decades, we've come to recognize that war has not only a tragic human cost, but a tragic environmental cost as well," said Carroll Muffett, a Washington environmental lawyer. "Fragile habitats are destroyed, wildlife lost and resources like fresh water are degraded beyond use."

Earlier this week, nearly 200 lawyers, scholars and environmentalists from 51 countries protested the looming war and urged leaders of the United States, Britain, Turkey and Iraq to pull back.

Their letter highlighted international rules of law for governments that impose a "solemn responsibility to avoid destruction of or serious or widespread damage to the natural environment and cultural heritage of Iraq and the Persian Gulf region."

An Iraqi tank destroyed in the 1991 Persian Gulf War sits amid oil well fires in northern Kuwait set by Iraqi forces. Experts fear worse environmental damage from the new conflict.