Newsgroup: it.politica.internazionale
Titolo: C'è il cambiamento climatico dietro ai disastrosi incendi in sud California?

CLIMATE CHANGE-US:  Wildfires Rekindle Global Warming Debate
By Adrianne Appel*
BOSTON, Dec 21 (IPS/IFEJ) - The massive wildfires that roared and twisted their 
way through southern California in 2007 are a glimpse of what a future of global 
warming may hold, scientists say.
The western U.S. can expect to see more "mega forest fires" of over 100,000 
acres due to an increase in greenhouse gases, says Thomas Swetnam, director of 
the Laboratory of Tree-Ring Research at The University of Arizona in Tucson.
"Lots of people think climate change and the ecological responses are 50 to 100 
years away. But it's not 50 to 100 years away -- it's happening now in forest 
ecosystems through fire," Swetnam said.
Since the mid-1980s -- as spring temperatures increased, mountain snows melted 
earlier and summers grew hotter -- the number of forest fires in the Western 
U.S. and acreage burned have increased, Swetnam said.
"I see this as one of the first big indicators of climate change impacts in the 
continental United States," said Swetnam. More research is needed on the 
Southern California ecosystem, with its chaparral and forests, and climate 
change, he said.
About 500,000 acres of chaparral, forests, and residential neighbourhoods 
outside of Los Angeles and San Diego are now nothing more than empty tracts of 
charcoal remains as a result of 16 fires that began Oct. 21 and ended Nov. 9.
A 20-acre fire destroyed five homes in the ultra-wealthy Malibu, outside Los 
Angeles in January and then another very large fire burned in the same area from 
Nov. 24 to Nov. 27 destroying over 50 homes. In May, more than 800 acres burned 
in Los Angeles’ Griffith Park and more than 4,700 acres burned on Santa Catalina 
Island. In June, hundreds of homes were destroyed or damaged in wildfire at Lake 
Tahoe.
In total, tens of thousands of people were evacuated and upwards of 9,000 
firefighters were summoned to battle the flames.
Lately, some rain has been falling in Southern California and flash flood 
warnings have been in effect. Authorities fear mudslides may occur because of 
the loss of vegetation.
The Southern California region is naturally prone to fires but unlike centuries 
past, it is now heavily populated with millions of homes.
The climate in Southern California this year was different than normal, and 
created ideal conditions for fires, experts say.
This year’s conditions mirrored those of 2003, when drought conditions and Santa 
Ana winds helped fuel fires that burned 750,000 acres in Southern California.
It is impossible to draw sound conclusions about climate change from one or two 
events, like the California wildfires, said Ronald Neilson, a professor at 
Oregon State University and a contributor to publications of the 
Intergovernmental Panel on Climate Change. But the fires and recent weather 
patterns match Nielson’s predictions that Southern California will heat up over 
the next century, provoking periods of unbroken drought and stretches of heavy rain.
"This is exactly what we’ve been projecting to happen, both in short-term fire 
forecasts for this year and the longer term patterns that can be linked to 
global climate change," said Neilson, who also serves as a bioclimatologist with 
the U.S. Department of Agriculture’s Forest Service.
Southern California has been in the midst of a harsh drought. Just 3.21 inches 
of rain fell in the year ending Jun. 30, 2007, the lowest level since 1877. The 
average annual rainfall is 15.14 inches, according to information from the 
University of California at Los Angeles Meteorology Department.
The hot, dry Santa Ana winds blow on and off each year from about October to 
February but this year the winds were unusually strong and blew for days on end. 
The winds started fires by bringing down electrical lines and then fanned the 
flames into towering infernos, according to the U.S. Forest Service.
"These fires are among the worst disasters in California history," said 
California Governor Arnold Schwarzenegger after viewing the area in October.
Santa Ana winds usually last just a day or two at a time -- blowing at 20 mph 
from the Great Basin of Nevada, Utah and Southern Idaho -- but this year the 
winds clocked 30 to 40 mph with gusts of 85 to 105 mph. They blew for 78 days, 
three times as many days as their average, according to NASA.
"In the future, catastrophic fires such as those going on now in California may 
simply be a normal part of the landscape," said Neilson. The fires "may be 
another piece of evidence that climate change is a reality, one with serious 
effects."
"I think we can demonstrate higher severity, larger fires and certainly over the 
last seven to eight years, more frequent fires and a longer fire season," said 
Abigail Kimbell, chief of the U.S. Forest Service, who recently testified to a 
committee of the U.S. Congress, about climate change and forest fires.
Kimbell, an appointee of U.S. President George W. Bush, said the fires may be 
due to factors related to global warming but said more research is needed before 
a definitive relationship can be made between global warming and the large 
forest fires.
The small, frequent fires that are a natural part of the California ecosystem 
have not been allowed to burn. This has led to the accumulation of large amounts 
of dead and dry timber, and it helped fuel the recent, large fires, Kimbell said.
The fires themselves may be adding to global warming, by releasing huge amounts 
of carbon dioxide (CO2) into the atmosphere.
Christine Wiedinmyer, of the National Centre for Atmospheric Research in 
Boulder, Colorado, estimates that between Oct. 19 and 26, the Southern 
California fires emitted 7.9 million metric tons of CO2, the equivalent of 25 
percent of the average monthly emissions from all fossil fuel burning throughout 
California.
"Enormous fires like this pump a large amount of CO2 quickly into the 
atmosphere," Wiedinmyer says.
Wiedinmyer’s colleague, Jason Neff, an assistant professor of geosciences at the 
University of Colorado in Boulder, studies CO2 across the continental U.S. In 
the undisturbed, natural climate and ecosystem of the U.S. continent, CO2 was 
kept in balance, with excess CO2 taken up by forests and oceans, he says.
The forests of the western U.S. and the oceans are unable to absorb all of the 
excess CO2 emissions, Neff told IPS.
The problem is muted in the eastern U.S., where large amounts of farmland have 
been allowed to grow into woodlands during the past century. The woodlands use 
the CO2 to grow. In the West, there is no massive new growth of forest and 
excessive amounts of CO2 are causing trouble.
"It starts a feedback process. The western U.S. starts to get warm and dry. As 
this happens, it increases the likelihood of greater frequency and severity of 
forest fires," Neff said. "The fires release CO2, which causes more warming and 
drying, and this causes more fires… In a natural situation the CO2 is balanced. 
But we’re not in a natural climate anymore."
(*This story is part of a series of features on sustainable development by IPS- 
Inter Press Service and IFEJ-International Federation of Environmental Journalists.)
(END/2007)
http://www.ipsnews.net/news.asp?idnews=40577

Persio wrote:
[cut]
Ti consiglierei di focalizzarti di più sulle scie chimiche.
Persio, sei un pirla.
Tb
-- 
Libertà per i comunisti siriani in carcere: Fateh Jamus, 'Isam Dimashqi,
Basel Hurani, 'Abd al-Halim Rumieh, Ratib Sha'bu, and Doha 'Ashur
al-'Askari 
http://snipurl.com/1oqtm

 Persio, sei un pirla.
http://www.ansa.it/site/notizie/awnplus/mondo/news/2008-01-02_102155587.html

Persio wrote:

Hanno ragione. Embé?
Mi indichi, per favore, dove gli incendi dolosi sono attribuiti al "cambiamento 
climatico"?
Persio...


 Persio...
Capita a molti di pestare una merda; ad alcuni succede di pestarla e di 
scivolarci sopra; credo invece che siano molto rari quelli che pestano una 
merda, ci scivolano sopra e poi ci si rotolano con voluttà.
Sei un caso molto raro.

 una merda, ci scivolano sopra e poi ci si rotolano con voluttà.
Insomma, nessuna relazione tra le tesi ufologiche e la notizia.
Persio, sei un pirla.
