"We’re going to be living in a climate that's unlike anything we’ve seen in modern history," predicted Thomas R. Karl on May 8 at the National Summit on Coping with Climate Change, a historic gathering of the world’s leading scientists, scholars and policy makers.

Karl should know about such things. As director of the U.S. Department of Commerce’s National Climatic Data Center, he sits atop a virtual mountain of scientific information, which overwhelmingly supports the contention that global climate change, driven largely by the combustion of fossil fuels and by deforestation, is already occurring.

And, what’s more, no nation in the world is exempt from the damage climate change is causing, or will cause in the future, as atmospheric concentrations of carbon dioxide, methane and other greenhouse gasses increase.

To hear Karl tell it, we’re all on a speeding freight train, heading full-tilt toward the edge of a cliff.

Over the past 100 years, global temperatures have risen 1.3 degrees Fahrenheit. Since 1970, late summer Arctic Sea ice has retreated 15% to 20% and snow cover has decreased 10%. Sea levels have increased 4 to 8 inches since the 19th century.

With carbon-dioxide concentrations expected to double by 2100, scientific number crunchers project global temperature could rise between 2 and 12.5 degrees Fahrenheit by 2100, and sea levels could rise between 7 and 23 inches.

"Clearly, we could be witnessing changes that are by all counts spectacular," Karl remarked.

Scientists also have noted a 20% increase, between 1908 and 2002, in the amount of precipitation falling in very heavy daily events. Since 1995, there have been more Atlantic hurricanes, many of far greater intensity, than there were over the previous two decades. These trends will only continue, Karl said, as sea temperatures increase.

U.S. residents living in northern states have not been spared either. Nor’easters, as non-tropical cold-season storms are commonly called, have become much stronger in New England. One late-winter storm in February dumped more than 100 inches of snow on upstate New York, cutting off power and stranding thousands.

The consequences of climate change will affect life-style patterns, landscapes and commercial business. For example, increases in temperature and water-vapor content in the atmosphere will impact aviation, making it necessary for airports at higher elevations to construct longer runways for takeoffs.

By 2030, Karl predicted, a 747 jet aircraft will lose 17% of its cargo-transport capability at Denver’s airport and 9% at Phoenix’s airport.

What really has scientists worried, however, is the possibility that climate changes will occur much more rapidly when critical “tipping points” and thresholds are reached. "One of the things we should keep in mind is potential surprises," Karl concluded. "Clearly we’re on our way to higher levels of greenhouse-gas concentrations."

The National Summit on Coping with Climate Change, May 8-10, was hosted by the School of Natural Resources and Environment on behalf of the University of Michigan. The summit is part of the Clinton Global Initiative, a non-partisan catalyst for action, established by former President Bill Clinton and the William J. Clinton Foundation for the purpose of bringing together global leaders to devise and implement innovative solutions to pressing world challenges.

By Claudia Capos

For more information, contact Cynthia Shaw at

cshaw@umich.edu, or call 734-763-6605.