Decline in Snowpack Is Blamed On Warming

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BSquared
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Decline in Snowpack Is Blamed On Warming

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By Marc Kaufman
Washington Post Staff Writer
Friday, February 1, 2008; Page A01

The persistent and dramatic decline in the snowpack of many mountains in the West is caused primarily by human-induced global warming and is not the result of natural variability in weather patterns, researchers reported yesterday.

Using data collected over the past 50 years, the scientists confirmed that the mountains are getting more rain and less snow, that the snowpack is breaking up faster and that more rivers are running dry by summer.

The study, published online yesterday by the journal Science, looked at possible causes of the changes -- including natural variability in temperatures and precipitation, volcanic activity around the globe and climate change driven by the release of greenhouse gases. The researchers' computer models showed that climate change is clearly the explanation that best fits the data.

"We've known for decades that the hydrology of the West is changing, but for much of that time people said it was because of Mother Nature and that she would return to the old patterns in the future," said lead author Tim Barnett of the Scripps Institution of Oceanography at the University of California at San Diego. "But we have found very clearly that global warming has done it, that it is the mechanism that explains the change and that things will be getting worse."

Many in the West and the Southwest depend on the snowpack's springtime melt for power, irrigation and drinking water. When the snow fields melt earlier and more suddenly, dams are able to capture less of the water and must release more of it to flow on to the ocean.

"Our results are not good news for those living in the western United States," the researchers wrote, adding that the changes may make "modifications to the water infrastructure of the western U.S. a virtual necessity."

Although parts of the West have been hit by record snowfalls this winter, the data collected by the team showed that since 1950, the water content of the snowpack as of April 1 each year has decreased in eight of the nine mountain regions studied, by amounts ranging from 10 percent in the Colorado Rockies to 40 percent in the Oregon Cascades. Only the southern Sierra Nevada range did not show a drop.

The study is part of what has become a drumbeat of dire assessments based on reports of quickening climate change caused by the buildup of carbon dioxide from vehicles, power plants, industry and deforestation. Last week, the American Geophysical Union, a leading scientific group in the field, issued a warning that "Earth's climate is now clearly out of balance and is warming."

"Many components of the climate system -- including the temperatures of the atmosphere, land and ocean, the extent of sea ice and mountain glaciers, the sea level, the distribution of precipitation and the length of seasons -- are now changing at rates and in patterns that are not natural and are best explained by the increased atmospheric abundances of greenhouse gases and aerosols generated by human activity during the 20th century," the organization said, in its strongest statement to date on the subject.

Although the decline of the Western snowpack over the past few decades has been documented before, yesterday's study is the most definitive in assigning the blame to human-induced climate change.

Barnett said his team used computer models to assess what natural climate variability, sun spots, volcanoes and climate change could do to the snowpack. The climate-change model best matched the actual trends of the period from 1950 to 1999.

The chance that the model is incorrect, he said, is somewhere between 1 in 100 and 1 in 1,000.

"Given the amount of carbon in the air and the trends for future releases, we have to expect that conditions will get progressively worse for some time, no matter what we do now," he said. His team included researchers from the Lawrence Livermore National Laboratory, the University of Washington and the National Institute for Environmental Studies in Japan.

Researchers have also predicted that the Southwest is likely to get less winter rainfall as a result of the buildup of greenhouse gases. Because the region gets much of its water from the Colorado River -- one of the rivers affected by the reduced snowpack -- the already-dry area could be losing water from both of its main sources, Barnett said.

Jonathan Overpeck, a climate scientist at the University of Arizona in Tucson, said the new study "closes the circle" in terms of understanding what is happening to the climate of the West.

"Almost all of the models we've seen in recent years show the area becoming warmer and more arid due to climate change, but the question was always whether we could believe them," he said. "Now someone has done the statistical analysis to connect the dots so they can say with real confidence that this is happening because of greenhouse gases."
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Re: Decline in Snowpack Is Blamed On Warming

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Well,It would seem that the snowpack is pretty good this year. It NEVER fails to amaze me how we moderns continually live in the present moment only .With little sense of history , for perspective on the future.The very definition of the word "climate" is a pattern gathered over years.One volcanic eruption ,or the cycles of sun spot activity have more effect on climate than all the crap we spew into the atmosphere in a year. Anyone thinking otherwise has alterior motives, or is not very studious ,or is just plain stupid.Have these "scientists" heard of the Maunder minimum?[possible bad spelling] What was the cause of the "little ice age" in the 1700's I believe? We have been warming for at least 10,000 years. How did we cause that? What caused the extreme rainfall that resulted in devastating erosion in the southwest in the late 1800's that changed the face of that land? This world continouslly experiances drought somewhere. It has been ever and forever thus. I have talked to a well driller in the valley [San Joaquin] who routinely drills through redwood hundreds off feet down. What was the climate like in their time? Warmer, or cooler? jls ;)
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Re: Decline in Snowpack Is Blamed On Warming

Post by BSquared »

G'day, Alde, how're things up Alaska way?

Excellent point that one or two good snow years, like this year, don't mean the "climate" has changed. It's dismaying how people get excited about global warming during one or two hot summers and then seem to forget about it the next year—of course "we moderns" [I like that!] need to pay more continuous attention than that if we're to understand long-term changes.

Your questions about the Maunder minima, the relative contributions of natural CO2 sources like volcanoes, and the Little Ice Age are all questions that lots of people ask about climate research. A good website for answers to these points is http://environment.newscientist.com/cha ... th/dn11462, from "New Scientist," a good, readable, reasonably authoritative magazine, although a couple of the links were broken when I last looked there. UCAR also has a good website with lots of the same material http://www.ucar.edu/news/features/clima ... e/faqs.jsp, and the National Academies have a good brochure available as a pdf, http://dels.nas.edu/basc/Climate-LOW.pdf.

Briefly, here's what these sources say:
-Humans put roughly 150 times the amount of CO2 into the atmosphere as all natural sources combined, including volcanoes. (There's a hilarious history story about getting volcano output wrong in connection with the ozone hole that involves personalities as diverse as Dixie Lee Ray, Rush Limbaugh, and Lyndon LaRouche at http://www.sustainer.org/dhm_archive/in ... 504ozoneed.)
-Scientists do know about the sunspot cycles, orbital variations of the Earth, and so on, and they take all that into account.
-The Little Ice Age and the Medieval Warm Period before it are now thought to be relatively local events (Northern Europe and eastern North America), and I don't think anybody's sure about the causes.
-The Earth is certainly warmer now than it was 10,000 years ago (during the last glacial maximum), but it hasn't been warming continuously for the past 10,000 years. In fact, the climate has been extremely stable for the last 1000 years, until the last 60 years or so when the current rapid warming began.
-I didn't know about the fossil redwoods in the San Joaquin Valley—cool! I do know that the genus is extremely ancient, going back at least 30 million years, so it could have been warmer, cooler or the same, when these things grew there.

-B2
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Re: Decline in Snowpack Is Blamed On Warming

Post by AldeFarte »

Hey B2. It's a bit chilly around here right now. Kinda neat, but tiring to work in. Did you hear about wolves picking off dogs around these parts? Not enough snow makes it hard to tackle moose ,because they are not floundering. Loose dogs can become the easier meal. Regarding your post, You make rational points. It's all about what one reads and the credence we give same, isn't it? A point I try to reiterate is that history and climate both go back many years before we were born and we should take both in context when evaluating the present. I have seen it warmer and I have seen it cooler, but personally, I would rather it got warmer. I don't fear a warmer planet. Diversity likes heat. New plants and animals will colonise previously uninhabitable areas due to a simple warming of the climate. The garden gets better in warm years. Etc. jls :)
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Re: Decline in Snowpack Is Blamed On Warming

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Spoken like one from the cold north! I have a friend who's a real expert on this stuff, and he recently gave a talk at his old hometown in Maine. After the talk a native Maine guy came up and said, "Wait. You said it's going to get warmer, mostly at night, and mostly in the winter. And this is a bad thing?!?!" It all depends on who you are and where you live, I suppose. You note that "diversity likes heat." True: most of the world's species are in the tropics. However, since the tropics are already quite warm, most scientists are predicting a substantial loss in biodiversity if the warming goes much beyond 2 °C. That New Scientist reference has a good summary.

It seems to me that the overall results of global warming will be somewhere between mildly unpleasant and disastrous, impacting my grandchildren's generation much more than mine. It's therefore worth it to take prudent steps: work hard on sustainable energy (wind, solar, maybe nuclear but...), build much more efficient cars, export clean technology to India and China, and so on.

Stay warm.

-B2
Last edited by BSquared on Sun Feb 10, 2008 7:19 am, edited 2 times in total.
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Re: Decline in Snowpack Is Blamed On Warming

Post by Rosabella »

B2 - thanks for the link to the article! Really interesting. Our weather's been a little crazy up here this year with all the severe flooding and more snow than "usual", but it's always been cyclic... 100-year floods, etc. I'm certainly not claiming that this year's weather is proof of climate change, but there is certainly growing evidence that does support it.

I've always told my sons not to believe everything they hear (from the media, polititians, as well as their teachers)... we can find "studies" that will support just about anything...and that support any opinion, but as one of the links in the article pointed out regarding the myth "Many Leading Scientists Question Climate Change" ....it all depends on what you mean by "many" and "leading". The information has to be considered, as well as where the information came from, and who supports it. I would be a little skeptical about a "study" that was funded by the very Company or Organization than would benefit by the results of that study.

Yeah, I would like it if Washington has the same climate as California, but it doesn't... and shouldn't. I am hoping that this world (including the wolves and polar bears) will still be arround and as beautiful for my grandchildren. I think we're going to have to make some changes so that it will be.
Last edited by Rosabella on Sun Feb 10, 2008 7:31 pm, edited 1 time in total.
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Re: Decline in Snowpack Is Blamed On Warming

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It NEVER fails to amaze me how we moderns continually live in the present moment only .With little sense of history , for perspective on the future.
Great observation AF. And memory doesn't even have to go far back in time. All you have to do is watch the news after a big storm for the "whoa, I've lived here 2 years and never seen a storm this big" reactions. My neighbor (here 20 years) even said this last series we got in California was the biggest he's seen. Yet I remember skiing off our deck several times in the 80s -- several El Nino years. It also helps that I do snow surveys, so can actually remember some measurements for the really big years.

I mean, the Pleistocene, now THAT was a big year!

Great references B2 -- I'd not come across that. Pretty much covers all the arguments brought up against Global Climate Change (though I have to say, opposition now seems mostly faith based and that's not likely to change too many opinions...).

g.
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Re: Decline in Snowpack Is Blamed On Warming

Post by oldranger »

Here is another article about global warming and its relationship with fire and the nature of fire in much of the west.

mike
Mike

Who can't do everything he used to and what he can do takes a hell of a lot longer!
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gdurkee
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Re: Decline in Snowpack Is Blamed On Warming

Post by gdurkee »

And this too:
Lake Mead Water Could Dry Up by 2021

SAN DIEGO, California, February 12, 2008 (ENS) - There is a 50 percent chance Lake Mead, a key source of water for millions of people in the southwestern United States, will be dry by 2021 if the climate changes as expected and future water use is not limited, warn researchers at Scripps Institution of Oceanography at the University of California-San Diego.

Without Lake Mead and neighboring Lake Powell, the Colorado River system has no buffer to sustain the population of the Southwest through an unusually dry year, or worse, a sustained drought.

In such an event, water deliveries to cities such as Las Vegas, Los Angeles and San Diego would become unstable and variable, say research marine physicist Tim Barnett and climate scientist David Pierce.

The researchers say that even if water agencies follow their current drought contingency plans, it might not be enough to counter natural forces, especially if the region enters a period of sustained drought or human-induced climate changes occur as currently predicted.

"We were stunned at the magnitude of the problem and how fast it was coming at us," said Barnett. "Make no mistake, this water problem is not a scientific abstraction, but rather one that will impact each and every one of us that live in the Southwest."
Rest of article:
http://www.ens-newswire.com/ens/feb2008 ... 12-095.asp

I'm often suspicious of models greater than 20 years, but this one is well under that.

g.
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Re: Decline in Snowpack Is Blamed On Warming

Post by oldranger »

Well I guess I ought to past in the link for the article I thought was interesting.

http://www.onearth.org/article/our-tria ... e?page=all

Sent the link to my son, a Fire Ecology and Management major at the University of Idaho and he responded "thanks dad, can't use it. Its not a refereed article." Interesting none the less.

mike
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