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#Drought: America's new normal
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3142 Dead
Aug 12, 2012, 11:11:14 AM8/12/12
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http://www.readersupportednews.org/opinion2/271-38/12890-hundred-year-
forecast-drought
Hundred-Year Forecast: Drought
By Christopher R. Schwalm, Christopher A. Williams, Kevin Schaefer, The
New York Times
12 August 12
By many measurements, this summer's drought is one for the record books.
But so was last year's drought in the South Central states. And it has
been only a decade since an extreme five-year drought hit the American
West. Widespread annual droughts, once a rare calamity, have become more
frequent and are set to become the "new normal."
Until recently, many scientists spoke of climate change mainly as a
"threat," sometime in the future. But it is increasingly clear that we
already live in the era of human-induced climate change, with a growing
frequency of weather and climate extremes like heat waves, droughts,
floods and fires.
Future precipitation trends, based on climate model projections for the
coming fifth assessment from the Intergovernmental Panel on Climate
Change, indicate that droughts of this length and severity will be
commonplace through the end of the century unless human-induced carbon
emissions are significantly reduced. Indeed, assuming business as usual,
each of the next 80 years in the American West is expected to see less
rainfall than the average of the five years of the drought that hit the
region from 2000 to 2004.
That extreme drought (which we have analyzed in a new study in the
journal Nature-Geoscience) had profound consequences for carbon
sequestration, agricultural productivity and water resources: plants, for
example, took in only half the carbon dioxide they do normally, thanks to
a drought-induced drop in photosynthesis.
In the drought's worst year, Western crop yields were down by 13 percent,
with many local cases of complete crop failure. Major river basins showed
5 percent to 50 percent reductions in flow. These reductions persisted up
to three years after the drought ended, because the lakes and reservoirs
that feed them needed several years of average rainfall to return to
predrought levels.
In terms of severity and geographic extent, the 2000-4 drought in the
West exceeded such legendary events as the Dust Bowl of the 1930s. While
that drought saw intervening years of normal rainfall, the years of the
turn-of-the-century drought were consecutive. More seriously still, long-
term climate records from tree-ring chronologies show that this drought
was the most severe event of its kind in the western United States in the
past 800 years. Though there have been many extreme droughts over the
last 1,200 years, only three other events have been of similar magnitude,
all during periods of "megadroughts."
Most frightening is that this extreme event could become the new normal:
climate models point to a warmer planet, largely because of greenhouse
gas emissions. Planetary warming, in turn, is expected to create drier
conditions across western North America, because of the way global-wind
and atmospheric-pressure patterns shift in response.
Indeed, scientists see signs of the relationship between warming and
drought in western North America by analyzing trends over the last 100
years; evidence suggests that the more frequent drought and low
precipitation events observed for the West during the 20th century are
associated with increasing temperatures across the Northern Hemisphere.
These climate-model projections suggest that what we consider today to be
an episode of severe drought might even be classified as a period of
abnormal wetness by the end of the century and that a coming megadrought
- a prolonged, multidecade period of significantly below-average
precipitation - is possible and likely in the American West.
The current drought plaguing the country is worryingly consistent with
these expectations. Although we do not attribute any single event to
global warming, the severity of both the turn-of-the-century drought and
the current one is consistent with simulations accounting for warming
from increased greenhouse gases. The Northern Hemisphere has just
recorded its 327th consecutive month in which the temperature exceeded
the 20th-century average. This year had the fourth-warmest winter on
record, with record-shattering high temperatures in March. And 2012 has
already seen huge wildfires in Colorado and other Western states. More
than 3,200 heat records were broken in June alone.
And yet that may be only the beginning, a fact that should force us to
confront the likelihood of new and painful challenges. A megadrought
would present a major risk to water resources in the American West, which
are distributed through a complex series of local, state and regional
water-sharing agreements and laws. Virtually every drop of water flowing
in the American West is legally claimed, sometimes by several users, and
the demand is expected to increase as the population grows.
Many Western cities will have to fundamentally change how they acquire
and use water. The sort of temporary emergency steps that we grudgingly
adopt during periods of low rainfall - fewer showers, lawn-watering bans
- will become permanent. Some regions will become impossible to farm
because of lack of irrigation water. Thermoelectric energy production
will compete for limited water resources.
There is still time to prevent the worst; the risk of a multidecade
megadrought in the American West can be reduced if we reduce fossil-fuel
emissions. But there can be little doubt that what was once thought to be
a future threat is suddenly, catastrophically upon us.
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forecast-drought
Hundred-Year Forecast: Drought
By Christopher R. Schwalm, Christopher A. Williams, Kevin Schaefer, The
New York Times
12 August 12
By many measurements, this summer's drought is one for the record books.
But so was last year's drought in the South Central states. And it has
been only a decade since an extreme five-year drought hit the American
West. Widespread annual droughts, once a rare calamity, have become more
frequent and are set to become the "new normal."
Until recently, many scientists spoke of climate change mainly as a
"threat," sometime in the future. But it is increasingly clear that we
already live in the era of human-induced climate change, with a growing
frequency of weather and climate extremes like heat waves, droughts,
floods and fires.
Future precipitation trends, based on climate model projections for the
coming fifth assessment from the Intergovernmental Panel on Climate
Change, indicate that droughts of this length and severity will be
commonplace through the end of the century unless human-induced carbon
emissions are significantly reduced. Indeed, assuming business as usual,
each of the next 80 years in the American West is expected to see less
rainfall than the average of the five years of the drought that hit the
region from 2000 to 2004.
That extreme drought (which we have analyzed in a new study in the
journal Nature-Geoscience) had profound consequences for carbon
sequestration, agricultural productivity and water resources: plants, for
example, took in only half the carbon dioxide they do normally, thanks to
a drought-induced drop in photosynthesis.
In the drought's worst year, Western crop yields were down by 13 percent,
with many local cases of complete crop failure. Major river basins showed
5 percent to 50 percent reductions in flow. These reductions persisted up
to three years after the drought ended, because the lakes and reservoirs
that feed them needed several years of average rainfall to return to
predrought levels.
In terms of severity and geographic extent, the 2000-4 drought in the
West exceeded such legendary events as the Dust Bowl of the 1930s. While
that drought saw intervening years of normal rainfall, the years of the
turn-of-the-century drought were consecutive. More seriously still, long-
term climate records from tree-ring chronologies show that this drought
was the most severe event of its kind in the western United States in the
past 800 years. Though there have been many extreme droughts over the
last 1,200 years, only three other events have been of similar magnitude,
all during periods of "megadroughts."
Most frightening is that this extreme event could become the new normal:
climate models point to a warmer planet, largely because of greenhouse
gas emissions. Planetary warming, in turn, is expected to create drier
conditions across western North America, because of the way global-wind
and atmospheric-pressure patterns shift in response.
Indeed, scientists see signs of the relationship between warming and
drought in western North America by analyzing trends over the last 100
years; evidence suggests that the more frequent drought and low
precipitation events observed for the West during the 20th century are
associated with increasing temperatures across the Northern Hemisphere.
These climate-model projections suggest that what we consider today to be
an episode of severe drought might even be classified as a period of
abnormal wetness by the end of the century and that a coming megadrought
- a prolonged, multidecade period of significantly below-average
precipitation - is possible and likely in the American West.
The current drought plaguing the country is worryingly consistent with
these expectations. Although we do not attribute any single event to
global warming, the severity of both the turn-of-the-century drought and
the current one is consistent with simulations accounting for warming
from increased greenhouse gases. The Northern Hemisphere has just
recorded its 327th consecutive month in which the temperature exceeded
the 20th-century average. This year had the fourth-warmest winter on
record, with record-shattering high temperatures in March. And 2012 has
already seen huge wildfires in Colorado and other Western states. More
than 3,200 heat records were broken in June alone.
And yet that may be only the beginning, a fact that should force us to
confront the likelihood of new and painful challenges. A megadrought
would present a major risk to water resources in the American West, which
are distributed through a complex series of local, state and regional
water-sharing agreements and laws. Virtually every drop of water flowing
in the American West is legally claimed, sometimes by several users, and
the demand is expected to increase as the population grows.
Many Western cities will have to fundamentally change how they acquire
and use water. The sort of temporary emergency steps that we grudgingly
adopt during periods of low rainfall - fewer showers, lawn-watering bans
- will become permanent. Some regions will become impossible to farm
because of lack of irrigation water. Thermoelectric energy production
will compete for limited water resources.
There is still time to prevent the worst; the risk of a multidecade
megadrought in the American West can be reduced if we reduce fossil-fuel
emissions. But there can be little doubt that what was once thought to be
a future threat is suddenly, catastrophically upon us.
--
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Mr.B1ack
Aug 12, 2012, 5:35:46 PM8/12/12
to
On Sun, 12 Aug 2012 15:11:14 +0000, 3142 Dead wrote:
> http://www.readersupportednews.org/opinion2/271-38/12890-hundred-year-
> forecast-drought
>
> Hundred-Year Forecast: Drought
I don't put much stock in next WEEKS weather forecast,
> http://www.readersupportednews.org/opinion2/271-38/12890-hundred-year-
> forecast-drought
>
> Hundred-Year Forecast: Drought
much less in one for the next 100 years.
However, if a dry-out IS in progress, one that will
make the USA look kinda like Australia - with a big
desert in the middle - then now is the time to start
making some vital decisions and putting them into
action.
First off ... there isn't enough irrigation water on
the continent to grow corn in Kansas if Kansas is
gonna become a desert. They do that in parts of
California and that's part of the reason there isn't
enough water east of the Sierras (not to mention
salt accumulation in California soils).
This means we need a strategy to END farming in the
areas most likely to become deserts. No more federal
subsidies, no more federal crop insurance, no more
massive irrigation projects. The dry-out won't happen
overnight, so we can slowly expand the "Don't Bother"
zones over a period of decades.
Of course we STILL need the FOOD ... and that means
we'll need farmers to grow it. Therefore, if the
Fed is gonna do anything, it should look into MOVING
the farms AND farmers elsewhere - to wetter areas
where they CAN do well.
There's still a lot of undedicated private, state
and federal land out nearer the coasts. This is where
the new farms have to go. Better to spend money on THAT
than on trying to make a growing desert green.
Oh, and genetically-modified corn/wheat/whatever that
can tolerate harsher conditions are a must-have. The
time for the luxury of whining about frankencorn is
about over. We need stuff that can survive moderate
suprise dry spells and wet spells, stuff that can
thrive in saltier soils, stuff that needs less
expensive fertilizers and herbicides. Either be ready
to farm a rougher and less predicable land with
the best damned stuff you can plant or STARVE like
Ethiopian dirt farmers.
3142 Dead
Aug 12, 2012, 9:50:51 PM8/12/12
to
On Sun, 12 Aug 2012 16:35:46 -0500, Mr.B1ack wrote:
> On Sun, 12 Aug 2012 15:11:14 +0000, 3142 Dead wrote:
>
>> http://www.readersupportednews.org/opinion2/271-38/12890-hundred-year-
>> forecast-drought
>>
>> Hundred-Year Forecast: Drought
>
>
> I don't put much stock in next WEEKS weather forecast, much less in
> one for the next 100 years.
That's where ignorance comes in handy. It's so easy to make sweeping
> On Sun, 12 Aug 2012 15:11:14 +0000, 3142 Dead wrote:
>
>> http://www.readersupportednews.org/opinion2/271-38/12890-hundred-year-
>> forecast-drought
>>
>> Hundred-Year Forecast: Drought
>
>
> I don't put much stock in next WEEKS weather forecast, much less in
> one for the next 100 years.
dismissals based on an inability to distinguish between weather and
climate.
>
> However, if a dry-out IS in progress, one that will make the USA look
> kinda like Australia - with a big desert in the middle - then now is
> the time to start making some vital decisions and putting them into
> action.
>
> First off ... there isn't enough irrigation water on the continent to
> grow corn in Kansas if Kansas is gonna become a desert. They do that
> in parts of California and that's part of the reason there isn't
> enough water east of the Sierras (not to mention salt accumulation in
> California soils).
>
Actually, the Sierras are the reason there isn't much water to the east
> However, if a dry-out IS in progress, one that will make the USA look
> kinda like Australia - with a big desert in the middle - then now is
> the time to start making some vital decisions and putting them into
> action.
>
> First off ... there isn't enough irrigation water on the continent to
> grow corn in Kansas if Kansas is gonna become a desert. They do that
> in parts of California and that's part of the reason there isn't
> enough water east of the Sierras (not to mention salt accumulation in
> California soils).
>
of them. It was like that long before the first farmer showed up in the
Central Valley.
> This means we need a strategy to END farming in the areas most likely
> to become deserts. No more federal subsidies, no more federal crop
> insurance, no more massive irrigation projects. The dry-out won't
> happen overnight, so we can slowly expand the "Don't Bother" zones
> over a period of decades.
>
promoted.
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