[Vision2020] Western U.S. Forest Wildfire Activity

[pkraut at moscow.com]

Its all built in a desert and they cannot steal enough water to save 
themselves! This is not news!



> All-
> 
> Regarding the ongoing Southern California fires, and the very important
> issue of Western US fire potential (especially in Idaho) and causes in
> general, the following fact and science based sources are critical.
> 
> Read about the record drought and heat waves for Southern California 
(both
> this year), coupled with the findings from the research on Western USA
> fires, in the Science magazine article below, co-authored by the 
scientist,
> Thomas Swetnam (University of Arizona), who I referenced at the start of
> this thread, who was interviewed on CBS 60 Minutes last weekend on the
> subject of wild land fire, with astonishing timing, given the explosion 
in
> the Southern California fires that occurred immediately after:
> 
> 
http://www.terradaily.com/reports/Western_US_States_Swelter_Under_Record_He
> atwave_999.html
> 
> *Parched California has driest 'rainy season' on record*
> 
> Los Angeles (AFP) July 1 - Los Angeles suffered through the driest rainy
> season on record in 2007, marking the least amount of precipitation here 
in
> the 130 years
> 
> http://www.noaanews.noaa.gov/stories2007/s2838.htm
> 
> In Los Angeles, the lack of rainfall led to the driest water-year to date
> for the city since records began in 1877. From July 1, 2006, through the
en> d
> of March, downtown Los Angeles had received only 2.47 inches of rain,
almos> t
> one foot below the normal amount of rainfall for the period.
> 
> In the West, where mountain snowpack is relied upon to supply water needs
> throughout the region, below-average rain and snowfall have become
> increasingly common. In only two of the past nine years has snowpack on
> April 1 been at or above the long-term average in at least half the 
region.
> --------------
> 
> For those who wish to skip most of the Science magazine article, here is 
a
> critical finding of their research, indicating human land use is not the
> cause of the documented increase (note not the cause of the "increase," 
not
> that humans do not start fires) in Western USA fires in recent decades:
> 
> http://www.sciencemag.org/cgi/content/full/313/5789/940
> 
> We compiled a comprehensive database of large wildfires in western United
> States forests since 1970 and compared it with hydroclimatic and
> land-surface data. Here, we show that large wildfire activity increased
> suddenly and markedly in the mid-1980s, with higher large-wildfire
> frequency, longer wildfire durations, and longer wildfire seasons. The
grea> test
> increases occurred in mid-elevation, Northern Rockies forests, where
> land-use histories have relatively little effect on fire risks and are
> strongly associated with increased spring and summer temperatures and an
> earlier spring snowmelt.
> --------------------
> 
> I will excerpt a few more paragraphs from this article:
> 
> 
> *Science* 18 August 2006:
> Vol. 313. no. 5789, pp. 940 - 943
> DOI: 10.1126/science.1128834
>  Prev <http://www.sciencemag.org/cgi/content/short/313/5789/936> | Table 
of
> Contents <http://www.sciencemag.org/content/vol313/issue5789/index.dtl> |
> Next <http://www.sciencemag.org/cgi/content/short/313/5789/944>
> Research Articles Warming and Earlier Spring Increase Western U.S. Forest
> Wildfire Activity *A. L.
> 
Westerling,1,2*<http://www.sciencemag.org/cgi/content/full/313/5789/940#COR
> 1>
> H.
> G. Hidalgo,1 D. R. Cayan,1,3 T. W. Swetnam4 *
> 
> http://www.sciencemag.org/cgi/content/full/313/5789/940
> 
> We compiled a comprehensive database of large wildfires in western United
> States forests since 1970 and compared it with hydroclimatic and
> land-surface data. Here, we show that large wildfire activity increased
> suddenly and markedly in the mid-1980s, with higher large-wildfire
> frequency, longer wildfire durations, and longer wildfire seasons. The
grea> test
> increases occurred in mid-elevation, Northern Rockies forests, where
> land-use histories have relatively little effect on fire risks and are
> strongly associated with increased spring and summer temperatures and an
> earlier spring snowmelt.
> ------
> 
> Snow carries over a substantial portion of the winter precipitation that
> falls in western mountains, releasing it more gradually in late spring 
and
> early summer, providing an important contribution to spring and summer 
soil
> moisture
(*35*<http://www.sciencemag.org/cgi/content/full/313/5789/940#REF3> 5>).
> An earlier snowmelt can lead to an earlier, longer dry season, providing
> greater opportunities for large fires due both to the longer period in
whic> h
> ignitions could potentially occur and to the greater drying of soils and
> vegetation. Consequently, it is not surprising that the incidence of
> wildfires is strongly associated with snowmelt timing.
> 
> Changes in spring and summer temperatures associated with an early spring
> snowmelt come in the context of a marked trend over the period of 
analysis.
> Regionally averaged spring and summer temperatures for 1987 to 2003 were
> 0.87°C higher than those for 1970 to 1986. Spring and summer
temperatures>  for
> 1987 to 2003 were the warmest since the start of the record in 1895, 
with 6
> years in the 90th percentile—the most for any 17-year period since the
st> art
> of the record in 1895 through 2003—whereas only 1 year in the preceding
1> 7
> years ranked in the 90th percentile. Likewise, 73% of early years since
197> 0
> occurred in 1987 to 2003 (Fig.
> 1<http://www.sciencemag.org/cgi/content/full/313/5789/940#FIG1>
> ).
> 
> --------
> 
> If the average length and intensity of summer drought increases in the
> Northern Rockies and mountains elsewhere in the western United States, an
> increased frequency of large wildfires will lead to changes in forest
> composition and reduced tree densities, thus affecting carbon pools.
Curren> t
> estimates indicate that western U.S. forests are responsible for 20 to 
40%
> of total U.S. carbon sequestration
> (*38*<http://www.sciencemag.org/cgi/content/full/313/5789/940#REF38>,
> *39* <http://www.sciencemag.org/cgi/content/full/313/5789/940#REF39>). If
> wildfire trends continue, at least initially, this biomass burning will
> result in carbon release, suggesting that the forests of the western 
United
> States may become a source of increased atmospheric carbon dioxide rather
> than a sink, even under a relatively modest temperature-increase scenario
(> *
> 38* <http://www.sciencemag.org/cgi/content/full/313/5789/940#REF38>,
> *39*<http://www.sciencemag.org/cgi/content/full/313/5789/940#REF39>).
> Moreover, a recent study has shown that warmer, longer growing seasons 
lead
> to reduced CO2 uptake in high-elevation forests, particularly during
> droughts
(*40*<http://www.sciencemag.org/cgi/content/full/313/5789/940#REF4> 0>).
> Hence, the projected regional warming and consequent increase in wildfire
> activity in the western United States is likely to magnify the threats to
> human communities and ecosystems, and substantially increase the 
management
> challenges in restoring forests and reducing greenhouse gas emissions.
> 
> ------
> 
> Vision2020 Post: Ted Moffett
> 





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