To enlarge a photo,
click on it. Airborne smoke particles tend to reduce the frequency and quantity of rainfall from clouds below 16,000 feet, according to data collected by NASA.
To enlarge a photo,
click on it.
Smoke particles decrease the odds for rainfall near sources of smoke and increase the odds of severe storms far away from sources of smoke.
In recent years, an increasing percentage of the rainfall has been occurring in storms that have enough vertical development to move smoky moist air above 16,000 feet. Storms with clouds reaching above 16,000 feet tend to produce locally heavy rains, large hail, damaging winds, and tornados.
|
"We all know what to do when it rains.
But nobody knows how to farm when it doesn't." |
Cursed with a drought worse than the Dust Bowl of the 1930s, farmers like Bob Roberts, 67, of Scottsbluff, Neb., watched their dreams of a green harvest dry up and blow away. Says Roberts: "You're looking at a sad man" |
The U.S. Drought Monitor provides current information about drought conditions in the U.S.A.
The following Internet sites contain evidence that mankind's use of coal is increasing the frequency and severity of droughts.
Federal subsidies continue to increase the use of coal in electric power plants that emit huge quantities of particles that absorb more solar energy than they reflect.
Global warming has resulted in drought in many regions. Droughts reduce the accumulation of plant biomass, which sequesters a large portion of the earth's store of labile carbon. The loss of vegetation caused by drought thus results in a net release of carbon from the biosphere into the atmosphere. Droughts also lead to an increase in the amount of atmospheric dust. Scientists say that dust from China and Africa has been blown all the way to the USA.
The American Lung Association estimates that 64,000 premature deaths occur annually in the USA are due to inhalation of toxic particles, about 20 times more each year than the deaths on 9/11. About 30,000 of those premature deaths result from the particles and gasses emitted by coal-fired power plants.
Now, Congress is debating whether to allow coal-burning power plants to emit even more pollution. (Reference: Environmentalists Sound a Battle Cry Over Clear Skies )
Perhaps you will agree that we would be foolish to base electrical power supply decisions solely on achieving the lowest cost per kilowatt hour, if the consequences include:
Where There's Smoke, There's Climate Change
Source:
Scientific
American
March 5, 2004
To anyone who has ever seen a forest fire in action or the eerie, charred landscape left in its wake, the ground-level damage is devastatingly clear. More difficult to assess has been what transpires in the atmosphere as a result of biomass burning. New research suggests that the atmospheric effects of these blazes are profound, and may significantly impact climate on regional and continental scales.
Findings from two studies of smoke pollution from forest burning in the Amazon are detailed in the current issue of the journal Science. In the first paper, Meinrat O. Andreae of the Max Planck Institute for Chemistry in Mainz, Germany, and his colleagues report that in cases of heavy pollution, smoke suppresses rainfall, allowing the aerosols to penetrate the upper levels of the atmosphere. As a result, the clouds appear to smoke. Ultimately, the smoke aerosols can alter the amount of radiation reaching the earth and encourage long-distance transportation of the smoke. And when the aerosol- and water-laden clouds eventually release their precipitation, they generate intense thunderstorms and large hail instead of the usual moderate rainfall. "The invigorated storms release the latent heat higher in the atmosphere," the authors write. "This should substantially affect the regional and global circulation systems."
In the second study, a team led by Ilan Koren of the NASA Goddard Space Flight Center analyzed satellite data from the Amazon during the dry season and found that scattered cumulus-cloud coverage fell from 38 percent when the air was clean to zero in heavy smoke conditions. The incoming heat resulting from this reduction in cloud cover, they say, can swamp the cooling effects of the scattering of solar radiation by the smoke particles. This, the researchers conclude, may help explain "why Earth warmed substantially in the last century despite the expected aerosol cooling effect." --Kate Wong
By Angie Wagner
Friday 18 June 2004
To
enlarge the image, click on it.
Las Vegas - The drought gripping the West could be the biggest in 500 years, with effects in the Colorado River basin considerably worse than during the Dust Bowl years, scientists at the U.S. Geological Survey said Thursday.
"That we can now say with confidence," said Robert Webb, lead author of the new fact sheet. "Now I'm completely convinced."
The Colorado River has been in a drought for the entire decade, cutting an important source of water for millions of people across the West, including Southern California.
Environmental groups said the report reinforces the need to figure out a better way to manage the Colorado River before reservoirs run dry.
"The water managers, they just continue to pray for rain," said Owen Lammers, director of Living Rivers and Colorado Riverkeeper. "They just say, well, we hope that things change and we see rain."
The report said the drought has produced the lowest flow in the Colorado River on record, with an adjusted annual average flow of only 5.4 million acre-feet at Lees Ferry, Arizona, during the period 2001-2003. By comparison, during the Dust Bowl years, between 1930 and 1937, the annual flow averaged about 10.2 million acre-feet, the report said.
Scientists use tree-ring reconstructions of Colorado River flows to estimate what conditions were like before record-keeping began in 1895. Using that method, the lowest five-year average of water flow was 8.84 million acre-feet in the years 1590-1594. >From 1999 through last year, water flow has been 7.11 million acre-feet.
"These comparisons suggest that the current drought may be comparable to or more severe than the largest known drought in 500 years," the report said.
The report said the river had its highest flow of the 20th century from 1905 to 1922, the years used to estimate how much water Western states would receive under the Colorado River Compact. The 1922 compact should now be reconsidered because of the uncertain water flow, said Steve Smith, a regional director for the Wilderness Society.
The report did not surprise water managers.
Adan Ortega, spokesman for the Metropolitan Water District of Southern California, said the water district has been increasing water storage, buying water from farmers, and investing in alternatives to the Colorado River.
"The big lesson is communities cannot afford to put all their eggs in the proverbial basket. You need ... a diverse portfolio of resources," Ortega said.
Herb Guenther, director of the Arizona Department of Water Resources, said the agency continues to plan for a lingering drought.
"It's serious, but the sky is not falling. Of course, we wish it would in the form of rain," he said.
Droughts seldom persist for longer than a decade, the report noted. But that could mean the current drought is only half over.
"If you're a betting person, you will bet that we will come out of this drought next year," Webb said. "It's a very severe event, and these things tend to end fast. There are other indications, though, that suggest that this drought could persist for as long as 30 years. "We don't really know."
You can help by improving energy efficiency and by working to protect the Clean Air Act.
