ASHEVILLE, N.C. - It may be the summer's hottest news:
The first six months of 1998 were the warmest on record for planet Earth.
At its current pace, this year is likely to exceed 1997 as the warmest since reliable records began in 1880. Nine of the past 11 years have set such records.
Facts like these fuel debate over what could be the biggest environmental story, global climate change. They come from federal scientists who pore over mounds of data in this cool, green city.
The National Climatic Data Center is the world's largest trove of weather data. It stores the microfilmed jottings of Thomas Jefferson, upper-air observations of Thule, Greenland, and barometric-pressure readings from Plano, Texas. Weather never rests, and neither does information about it - the equivalent of 18 million pages pours into the center every day, regular as the tides.
That kind of statistical context gives researchers here the long view of the phenomenon once known as the greenhouse effect.
'Another piece of data'
The record heat of the 14 months through June is "just another piece of the data," said Robert Quayle, chief of the center's Global Climate Laboratory. (July's figures have not been calculated.)
Most scientists agree that the Earth is warming. Most also acknowledge that people play some role, mostly by burning fossil fuels that release carbon dioxide and other gases that blanket Earth's atmosphere.
"The balance of the evidence indicates that our activities are beginning to influence the climate," Quayle said. "That's a very shy statement, as befits the evidence."
The center is part of the National Oceanic and Atmospheric Administration. It came to this mountain city in 1952 simply because office space was available.
Its 179 employees spend much of their time storing land, ocean and atmospheric readings from a global network of human observers and automated stations, satellites, ships, radar and weather balloons. They write publications, update online information and answer 160,000 customer requests for detailed data a year.
Their mission is to place climate in historical perspective.
Climatologists once believed that was a rather straightforward task. A 30-year picture, they thought, could accurately describe weather patterns as they had been for thousands of years.
That assumption died in the 1970s, Quayle said, when "unprecedented things started happening" that suggested climate could change much more quickly.
As researchers pieced together historic records, they found unexplained leaps in recent decades from the globe's annual average temperature of about 59 degrees.
Global land and sea temperatures began steadily rising, the scientists found. The Earth has warmed about 1 degree this century.
The center developed two indexes in 1995 to measure changes in the U.S. climate. The indexes track the occurrence of extreme weather, such as floods and droughts, and trends that are expected to result from the greenhouse effect.
Since 1970, they've found, precipitation has increased about 5 percent above levels of the previous 70 years. Heavy downpours are increasing. Temperatures have also risen, mainly during winter and spring, and nights are warmer.
Climate extremes - including unusually heavy rain and high temperatures - have also occurred about 1.5 percent more zTC frequently since 1976 than in the previous 65 years. Computer models also predict an overall increase in severe droughts, but that hasn't happened yet.
There is a small chance the changes are a result of natural variations, the center says. Quayle says researchers need to know what percentage of climatic changes are due to greenhouse gas emissions.
But in this summer's onerous heat, which followed a U.S. commitment last year to rein in greenhouse gases, some politicians find all the evidence they need.
"How much more proof do we need that global warming is real?" Vice President Al Gore declared in July as he lobbied for reductions in greenhouse emissions.
Detractors say they take less issue with the center's work than with the spins put on it by politicians and advocates.
Differences between climate-change scientists are "a matter of degrees, literally," said John Christy, a University of Alabama-Huntsville atmospheric scientist.
Politics of research
Christy says the center has a "fixation" with extreme weather that magnifies events pointing toward global warming but ignores contrary ones. Where some researchers detect warning signs in severe droughts and heavy rainfall, Christy sees natural patterns that haven't changed in a century.
"Dallas is due," he said, referring to the record heat wave scorching Texas. Eight of the previous 10 years there, he said, and 20 of the past 30 were cooler than average.
Patrick Michaels, a University of Virginia professor and fellow of the libertarian Cato Institute, says the center has failed to correct clear misstatements about climate change.