GLOBAL WARMING CAUSES INCREASING HUMIDITY ALONG WITH INCREASING TEMPERATURES:
It's not just the heat, it's the humidity that's likely to cause much of the pain of global warming, meteorologists are just now realizing.
Across a broad swath of America, the heat index -- a measure of discomfort that takes into account both heat and humidity -- is likely to soar over the next 50 to 60 years, forecasters predict in the federal government's first study to take increased humidity into account.
That could significantly increase the yearly average number of heat-related deaths in America -- from about 1,200 now to several thousand, one expert says.
Plugging humidity into their computer models of global warming, federal scientists determined that in the next half-century the average summer heat index will be near 100 degrees for much of the country.
What is now the occasional super hot-and-sticky day will probably become the average summer day in the South and East, explained three scientists at the National Oceanic Atmospheric Administration's Geophysical Fluid Dynamics Laboratory in Princeton, N.J.
"Things are going to be ... very hot and sticky and that's going to be a problem with global warming," said meteorologist Thomas Knutson.
For years, almost all scientists have agreed that an increase in man-made carbon dioxide is making the world hotter. Scientists are still squabbling about just how much hotter it will get, but the conventional wisdom is that average temperatures will rise between 3 and 8 degrees Fahrenheit as carbon dioxide levels double.
When humidity is factored in, that translates to a 7- to 10-degree increase in the heat index, Knutson and Delworth said.
(Knight Rider - November 1999)
NORTHWEST - INCREASING TEMPERATURES AND WATER SHORTAGES:
An Oregon with temperatures 5 degrees higher sounds almost balmy, especially on a wet, chilly November day. The rest of the forecast for the year 2050 sounds a little less appealing:
• More rain: Oregon and the rest of the Northwest could experience as much as 5 percent more rain and snow.
• More flooding: Higher temperatures will reduce the snowpack, raising the snow line in the Cascades by 1,000 feet. The snow would melt earlier, sending water gushing down streams and rivers while the ground still is soaked from spring rains.
• More forest fires. Summers will be hotter and drier, stressing trees and leaving them vulnerable to disease, pests and fire.
The forecast for 2050 was part of a study on the effects of climate change on the Northwest released Tuesday by the University of Washington's Climate Impacts Group.
"The consensus of climate scientists is that a warmer world in the next century is more than just a reasonable possibility," said Philip Mote, a UW research scientist who is the lead author of the new study.
Mote was among 19 regional scientists and policy analysts hired by the federal government to analyze Northwest weather trends. The group's report is part of a national assessment of climate change.
The scientists said that average temperatures in Oregon, Washington and Idaho have risen by 1.5 degrees Fahrenheit and that rainfall has increased by an average of 2.9 inches since 1900. Seven climate models suggest that the Northwest could warm by an average of 2 degrees in the next 20 years and by as much as 5 degrees by 2050, they said.
Mote and his colleagues are unwilling to draw a direct connection between violent storms or higher temperatures and the greenhouse-effect buildup in the atmosphere of gases such as carbon dioxide spewed from automobiles and coal-fired power plants. But they think there is some relationship between the buildup of gases and the global increase in average temperatures.
Some scientists say there's insufficient proof to link human activities with global temperature trends.
Oregon state climatologist George Taylor said he thinks the region's weather is determined by 20- to 25-year wet and dry cycles that have nothing to do with global warming. "I know the people at Washington," Taylor said. "I respect them. They trust the climate models, and, in general, I don't."
The Climate Impacts Group argues that there's enough evidence about climate change for government officials and natural resource managers to take it into account. The likelihood of warmer weather, wetter winters and drier summers should figure in planning for urban development, forest management and regional efforts to aid endangered salmon, the group said.
"At present the region is ill-prepared to tackle a changing climate," said Edward Miles, leader of the Climate Impacts Group and a University of Washington professor of marine affairs. The Northwest should be planning for water shortages, Miles said.
(November 1999)
LANDSLIDES:
Landslides affect all 50 states and the U.S. territories. At least half of the states, including Alaska and Hawaii, have significant problems. World-wide, landslides are responsible for at least 600 deaths annually, and in the 20th century catastrophic landslides have destroyed entire villages, killing upwards of 20,000 people at a time. Landslides, flows, collapses, and other forms of ground failure are a hazard that virtually all states have in common. Ohio, New York, Utah, Montana, and Kentucky have had numerous run-ins with landslides, as well as those states that have highly populated areas on high bluffs along the Mississippi and Missouri Rivers. The wildfire and rainfall cycle intensifies the hazards of landslides and debris flows in many western states, such as New Mexico, California, and Colorado. These geologic threats are not limited to the coastal and high mountain areas of the country. In June of 1995, a series of severe thunderstorms with heavy rainfall caused landslides, debris flows, and flooding in Madison County, Virginia, where an estimated 1,700-2,000 houses were badly damaged or destroyed. The geologic features that make Yosemite Valley such a special visual experience are the same that make it hazardous. The Village area in Yosemite Valley is built on the debris of prehistoric rockfalls. Employee housing located there continues to be threatened. According to Dr. Gerald Wieczorek, USGS geologist, "The natural cracking and shearing of the beautiful, but potentially deadly, granite bodes more rockfall events, probably in the near future."
The economic costs of landslides in the U.S. are conservatively estimated between $1 and $2 billion with 25 to 50 casualties per year. The 1997-98 El Niño-related landslide damage in the 10 San Francisco area counties was assessed at more than $140 million. Add the shaking from even a moderate earthquake to the equation and a double disaster could occur. Landslides wreak havoc along highway and railroad lifelines, disrupt utility lines, destroy animal habitat, and pollute rivers and streams. They are the bane of urban planners and building officials charged with designing future building sites, managing current urban growth, and providing for safer communities.
