A new "handbook" on global warming that looks at current warming trends from the perspective of past climatic changes is now available on the World Wide Web, the Commerce Department's National Oceanic and Atmospheric Administration announced today.

The Web site, called "A Paleo Perspective on Global Warming," explains global warming and the greenhouse effect, and describes how they relate to the issues of atmospheric ozone change. What makes this site stand out from other global warming Web sites is how it places current warming in the context of past temperature variations through the use of paleoclimatic data.

One chapter tells how scientists study global warming, including how they study variations in the Earth's temperature using satellite, instrumental and paleoclimatic data, or climate data extending as far back as millions of years. Paleoclimatic data can be found in the Earth's own archive of tree rings, corals, ice cores and sediments. They provide climate scientists with records of past climatic change extending back centuries and millennia. They are a valuable complement to the much shorter time series derived from instruments and satellites.

The site also contains references and displays from a number of climate articles that have appeared in peer-reviewed journals. It also includes links to a wealth of data on natural climate change over the past 120 million years.

"We wanted to give the interested general public and journalists a comprehensive understanding of global warming, and put today's temperatures into the context of those from Earth history," said Jonathan Overpeck, head of NOAA's Paleoclimatology Program at the National Geophysical Data Center in Boulder, Colo. "We plan to update the site regularly, as new information becomes available."

Visit the Web site at: http://www.ngdc.noaa.gov/paleo/perspectives.html