IRVINE — Methane, a major chemical linked to global warming, is leaking in massive amounts in several Eastern European cities, much of it thought to be from antiquated natural gas systems, according to researchers from UC Irvine.
Since methane accounts for up to 25% of the gases causing the so-called greenhouse effect, plugging leaky pipes in Eastern bloc nations could make an important dent in efforts to forestall global warming, the UCI scientists reported today in the scientific journal Nature.
"Methane is different," said research team director F. Sherwood Rowland, the UCI chemist who discovered in the mid-1970s that the Earth's protective ozone layer is being destroyed by chlorofluorocarbons, another variety of chemicals also implicated in global warming. "Because its lifetime is about 10 years, if we take away just 10% of (the world's methane) emissions, we can get methane in the atmosphere back in balance."
Eastern Europe would not account for all of that 10%, researchers say.
"We're not pointing a finger at any of the Eastern European cities," said atmospheric chemist Donald R. Blake, a member of Rowland's research team. "We're saying that here's an area, (given) the short lifetime of methane, where we could be seeing some results." Efforts to reduce methane in the rest of the industrialized world must also continue, he said.
The UCI data corresponds with previous findings of European scientists, said Kathleen Hogan, chief of the methane program for the U.S. Environmental Protection Agency's global resource division. Those scientists have estimated that as much as 10% of the natural gas supplies piped through the Soviet Union and Eastern Europe are leaking into the atmosphere, she said.
The high levels of methane were measured in air samples taken last May in the cities of Budapest, Hungary; Krakow, Poland; Prague, Czechoslovakia; and Berlin. Similar tests found far lower levels of methane gas--levels comparable to most U.S. cities--in the more modern cities of Vienna and Zagreb, Yugoslavia, Rowland, Blake and Neil Harris reported in the correspondence published in Nature.
Sampling in the Yerevan region of Soviet Armenia last January also turned up high emissions of methane, but because it is not an urban area, Rowland said they are uncertain of the source. Further studies throughout Eastern Europe are warranted, the researchers said.
Carbon dioxide, a byproduct of industrialization, is the chief gas responsible for the greenhouse effect, caused by a buildup of gases in the Earth's atmosphere that traps heat. Scientists believe an increase of only several degrees in the Earth's average temperature could result in rapid and dramatic changes in global weather patterns, rising ocean levels and possibly the extinction of many plant and animal species.
Carbon dioxide represents about half of the greenhouse gases, with methane and chlorofluorocarbons making up the remainder.
Methane is an odorless, flammable gas that is a chief component in the natural gas commonly used for household heating and cooking. It also is formed by decomposing vegetation and found in coal deposits. The bulk of the 550 megatons of methane spewed into the atmosphere each year is thought to come from such rural sources as swamps, marshes, tundra, coal mines, rice paddies, landfills and flatulent cows.
However, urban areas are increasingly being viewed as the easiest, quickest way to reduce methane concentrations. Because the Earth's atmosphere has the ability to cleanse about 500 megatons of methane per year, a 10% worldwide decrease in methane emissions would virtually eliminate the gas as part of the global warming problem, Rowland said.
Global warming experts called the UCI findings "very interesting."
"The sources of methane are not well understood," said Michael Oppenheimer, an atmospheric physicist with the Environmental Defense Fund and author of the book, "Dead Heat: The Race Against The Greenhouse Effect," which was published in April.
But Oppenheimer said the Rowland group's data "indicates that high levels of methane are being released in the (Eastern European) cities."
Reducing those releases by repairing leaky gas distribution systems, if indeed that is the source of the urban methane, "would be a cost-effective way to cut down on the growth of atmospheric gases," he said.
There are economic reasons, too, for Eastern European countries to consider repairing the pipelines that deliver most of their natural gas from the Soviet Union.
Hogan said that beginning Jan. 1, the Soviet Union will require hard cash in exchange for natural gas sold at market rates. That will be a heavy incentive to reduce waste through leaky systems, she said.
UNNATURAL GAS LEAKS--Here are methane levels measured in each city in parts per million by volume (ppmv). Methane concentrations found in the cities are believed to emanate from man made sources. For comparison, methane levels outside these cities averaged about 1.80 ppmv. Berlin, Germany: 1.96 Prague, Czechoslovakia: 2.30 Krakow, Poland: 2.15 Vienna, Austria: 1.86 Budapest, Hungary: 2.10 Zagreb, Yugoslavia: 1.85 Source: The Rowland Group at UC Irvine