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Has Pacific Northwest snowpack declined? Yes.

Filed under: — eric @ 20 March 2007

There has been a bit of a flap here at the University of Washington over the state of the snowpack in United States Pacific Northwest region. The Seattle city mayor, Greg Nickels (a well known advocate for city-based CO2 reduction initiatives) wrote in an Op-Ed piece in the Seattle Times that

The average snowpack in the Cascades has declined 50 percent since 1950 and will be cut in half again in 30 years if we don’t start addressing the problems of climate change now. That snow not only provides our drinking water, it powers the hydroelectric dams that keep our lights on.

The number “50 percent decline” apparently comes from a statement in an Oregon State University report in 2004 signed by many Northwest Scientists. This is not actually the best estimate for average snowpack decline, according to published work by Phil Mote, of Climate Impacts Group at the University of Washington. Mote reviewed the Oregon report back in 2004 and pointed out that the 50% figure was erroneous. Mote’s 2003 paper in Geophysical Research Letters, highlighted in Science a few years ago, cited losses “as great as 60%” in some locations. Subsequent work (Mote et al., 2005) attempted to quantify change in total snowpack for the Cascades, and arrived at 15-30% for the period 1950-1997. This remains the best estimate, even when including the time period up to the present. Furthermore, this number represents measurements at many different elevations. If high elevation stations are excluded, the declines are generally larger, as would be expected if the chief culprit is increasing temperature, rather than declining snowfall.

So why the fuss? Well, the media can’t seem to get enough when there is apparent controversy over something. Both the local and national media were thus quick to jump on the “story” when another UW staff member, Mark Albright, sought to correct the 50% number in a series of emails to the Mayor’s office, among other places. Unfortunately, Albright didn’t simply provide the corrected information, but set up a web site entitled “The Myth of the Vanishing Cascade Mountain Snowpack”, with the very clear message that snowpack has not declined at all. Beyond the appearance of a controversy, this makes for a good newspaper story because it appears to cast doubt on Mote’s credibility. This is rather important given that Mote is Washington’s “State Climatologist” and is also the lead author on the chapter on the cryosphere in the upcoming IPCC Fourth Assessment report.

So has Pacific Northwest snowpack declined? Emphatically yes. I say “emphatically yes” for three reasons. First, because Albright illustrates the supposed lack of a trend by comparing specific periods (e.g. 1940-1949 vs. 1997-2006), in which snowpack has increased in some locations. This is not very informative, because both the spatial and temporal variability is large, and any question of decline can only be correctly addressed using all the data together, and over a statistically significant time period (30 years or more would be preferred). According to a summary statement prepared by Dennis Hartman to try to clarify the situation for the media and government, the decline is quite evident when the analysis is done correctly. (Hartmann is currently Chair of the Atmospheric Sciences Department at the University of Washington).

Second, “yes”, because lost in the media focus on controversy over the exact number is the fact that even a 15% decline would be huge. You can get this smaller number by starting in 1940 rather than 1950. This isn’t really justified because low elevations are substantially undersampled before 1945. Using a starting point of 1950 gives you about 30%. Either way, these are big numbers, and represent anything but a trivial change for water resource planners, backcountry skiers, and fisherman (not to mention fish). (For those readers that might wish to look at the data themselves, the State Climatologist’s Office has a rather nifty mapping and trend-analysis tool, here: http://www.climate.washington.edu/trendanalysis).

Third, “emphatically” because the snowpack will very likely continue to decline in the future. In his summary statement, Hartmann notes that “temperatures in the … Cascades will increase in the future as a result of global warming … and it is expected that this, by itself, should result in further decreases of snow … particularly at lower elevations.” Hartmann points out that it is less certain how precipitation will change in the future, and this could conceivably balance some or all of the increased spring time snow melt due to increasing temperatures. However, this is a pretty weak statement. It generally takes a very large increase in snowfall to offset small changes in temperature. Furthermore, precipitation is highly seasonal in this region, and an overall increase in temperature will, at a minimum, cause earlier snowmelt, even in the unlikely event that annually averaged total snowpack remains the same. This means less available water in summer, when fish, farmers, and hydroelectric dams most need it.


173 Responses to “Has Pacific Northwest snowpack declined? Yes.”

  1. 1

    You do not state whether this retreating snow matches the models, but I suspect not. Moreover, you seem to see the main danger of a melting snowpack as the lack of river water, but surely that will remain the same provided that the annual precipitation does not change. All that needs to be done is to build additional resevoirs to contain the same amount of water as that which was produced by the annual snow melt.

    What you do not seem to be considering is that when the snow line rises the albedo will change, and since this ice retreat is global then the global albedo will be reduced leading to an increase in global mean temperature. This is what is causing global warming, and not the change in the radiating temperature of the tropopause, which satellites measurements have failed to find.

    Most of the increased absorption and consequent warming of the air due to the increase in CO2 is happening close to the surface of the earth. Think of Beer’s Law. This is what causes the snow to melt. Lindzen is correct in that CO2 has little direct effect of global temperatures, but its indirect effect can cause and end ice ages.

    Cheers, Alastair.

    [Most of the increased absorption and consequent warming of the air due to the increase in CO2 is happening close to the surface of the earth. Think of Beer's Law. This is what causes the snow to melt. Lindzen is correct in that CO2 has little direct effect of global temperatures, but its indirect effect can cause and end ice ages.

    Cheers, Alastair.

    [Response: Reservoirs! Why didn't I think of that. Let's see, the total land area we are talking about is, umm,,, wait a minute, how many $billions? Wait, I've got another idea! Let' all just limit bathing to Tuesdays, and car washing to the 4th Tuesday of each month. What? That'll damage the economy. Well then lets ship in snow from Switzerland? Oh, they don't have any this year? Umm...

    Look, I'm sorry for the sarcasm, but your explanation of global warming is ridiculous, which you can easily prove to yourself with the simplest energy balance model. I have zero doubt that Lindzen would agree with me. And your suggested solution to declining snowpack really is quite laughable. --eric ]

  2. 2
    Johnno says:

    That’s not a problem if the hydro dams dry up; just burn more coal.

  3. 3
    Fernando Magyar says:

    “Moreover, you seem to see the main danger of a melting snowpack as the lack of river water, but surely that will remain the same provided that the annual precipitation does not change. All that needs to be done is to build additional resevoirs to contain the same amount of water as that which was produced by the annual snow melt.”

    It is exactly this don’t worry be happy there is no problem we can’t fix with technology, attitude that makes me really worry about those that advocate geo engineered solutions to problems that supposedly don’t even exist. “All that needs to be done…” I’m afraid that the mediators here might not allow my posting to be seen if I actually said what *I* think needs to be done and used the words I’d like to use, argh @#%&!!!!

  4. 4
    Juola (Joe) A. Haga says:

    What’s all the hoo-ha? At AAAS Convention in February ’05 Tim Barnett, on the basis of his paper presenting his models,–which batted .950–predicted dry summers in twenty years for all the major highlands and mountain chains across the planet. Later,–I think the summer of ’05 –he said the rivers of the western U.S. wouldn’t be at risk because of the reservoirs, just as Alastair has it in Comment (1). As I understand it not one of the reservoirs has recovered much from the growing drought across the west. I know the Oglalla aquifer ain’t. What does puzzle me about my fellow members of “man wising-up”(homo sapiens) is their understanding of compound interest. When they invest in alternative heating supplies to transport heat out of a room to the outside of a house (air “conditioning”) they don’t consider the processes and their consequences. With Business As Usual for at least another five to ten years, here is a real good verifiable prediction: Despite the panic among Swiss Re actuaries, BUA insures that we seven billions will be halved by 2037. And I really, really, REELY hope I live to 105 to find my prediction falsified. Seeing as how we’re all of us embarked on the greatest uncontrolled experiment since we dropped from the tree, that”s the best I could come up with that’s in screaming distance of scienterrific method.

  5. 5
    Phil says:

    Alastair.

    Please forgive my very simple questions, I’m just trying to get this straight in my mind.

    If this change in global albedo is what is causing global warming, how did the process get started? I understand that the ongoing process feeds itself but if the result is the cause, surely the result cannot start the cause in the first place?

  6. 6
    Edo River says:

    Can you give me an example of what around 30% reduction would mean on the ground for the flora/fauna or the average homeowner over time?

  7. 7
    Phillip Shaw says:

    Re #1:

    Alastair,

    Your logical reasoning is circular and, well, simply wrong. You said that the diminishing snowpack is due to global warming, and that global warming is due to diminishing snowpack (due to reduced albedo). What do you believe started this cycle? And, if your hypothesis were true, what would keep the melting/warming from continuing until the very last flake of snow is gone from every mountain?

  8. 8
    Don Thieme says:

    I would be interested to learn what the causes for this change are in atmospheric circulation that can be modeled. Certainly there is going to be more water circulating to land in a warmer atmosphere, but apparently less as snow in the Cascade region. Discussions that I have read for the eastern United States mention not necessarily less total snowfall but a shorter season so that early rains cause the snow to melt.

  9. 9
    Ray Ladbury says:

    OK, while we’re at it, I’ll jump on the “Pick on Alastair bandwagon, too. Think for a moment about the differences in runoff for snowpack and rain. Snowpack usually melts gradually over a period of month, whereas rainfall tends to saturate the ground and then run off all at once. Not only is rainfall more likely to cause erosion, followed by dry riverbeds, it is more likely to run off without recharging groundwater.
    When one seeks to base an argument on ceteris paribus (all things being equal), it’s a good idea to think it through and make sure the ceteris are in fact paribus.

    [Response: I don't usually resort to sarcasm in my original response, above, but Alastair McDonald's comment must surely rank as one of the most impressive displays of know-it-all-ness I've seen yet on RealClimate. He not only knows the cause, but he knows the solution to all our global warming concerns. Still, let's make this the last "Pick on Alastair" comment. The thread is already hopelessly off topic already. -eric]

  10. 10
    Ken Winters says:

    Re #1
    Rain run-off is very different from snow run-off. In my NW community, a heavy rain will produce a rapidly flowing turbulent creek or river, often too dirty for the filtration systems and often it requires water rationing. Snow melts at a more consistent rate and keeps the water running clean. Trying to replicate the snow melt run-off for all the rivers and creeks in the NW area currently supplying water to various communities would be a massive project. We’re not talking about a few big reservoirs located in easily accessible areas, but 100′s (often located in very difficult to access areas).

  11. 11
    matt bullard says:

    To follow up on #9 – higher snow levels presumably mean more rain events for areas formerly covered in snow throughout the winter, resulting in saturated ground. Add to that an earlier melt of the snowpack that remains, and I believe that leads to an increases probability for floods. This is a concern where I live in SW Idaho (which, while not part of the Cascades, obviously, is still considered the Pac NW if you use the Egan definition of “anywhere a salmon swims” (or swam as the case may be). I am not sure about the dam issue – could dam operators adjust their operations to capture the earlier runoff? I suppose not, if that water is falling as rain and saturating the ground and not running off, as snowpack tends to do. Any clarification on this point would be appreciated…

    [Response: Yes, all of this is correct. Obviously one could in principle try to capture more of the early season runoff, but existing reservoirs tend to get overfilled in spring around here. So we'd have to increase the size of existing reservoirs. -- eric]

  12. 12
    matt bullard says:

    I wasn’t necessarily talking about new reservoirs – I agree that would be silly, though our Governor thinks we should be building more of them to keep more of our water “in state.” What I hear out this way is that we could simply adjust the operations of existing dams to catch the earlier runoff, but that point is moot if the runoff does not happen or comes all at once. My point was there are no simple solutions…

    [Response:Matt, my apologies; I edited my response to your last comment and we crossed in cyberspace. In any case, I agree with you.--eric]

  13. 13

    Re Philip’s #7

    What I am saying is that man made CO2 is causing the snow to melt and that is causing global warming. In other words, global warming is an indirect consequence of anthropogenic greenhouse gases. They are not the direct cause, in the way they are modeled by scientists. The models are wrong, and the effects of the increase carbon dioxide over the last century will be much more severe than is currently imagined/modelled.

    Of course the full story is much more complicated than that. But keeping it simple, the models are based on the idea that when the surface temperature increases, then more infrared radiation is emitted to space, but that is not how the global temperature is regulated. When the surface temperature rises, eventually more clouds form that block solar radiation. This has been the case ever since the time of the faint young sun. In other words the surface temperture has been held at a level suitable for life for over three billion years by changes to the incoming solar radiation, not by changes to the outgoing infrared radiation.

  14. 14
    Karen Kohfeld says:

    Hi Eric, The decreasing trend in snowpack is on the order of 15-30% from 1940/50 to 2004. Are there estimates of snowpack *variability* in addition to the trend, for the Cascades or parts of the Cascades? For example, I would think the most worrisome time periods for water management would be during extreme warm vs cold phases of the Pacific Decadal Oscillation, especially when reinforced by El Nino/La Nina years. Can you elaborate on how much snowpack variability you see, on top of the observed trends? Thanks — Karen

    [Response: These are excellent questions. I refrained from addressing them because I felt it was important to first clarify that there is an observed trend. The question of variability vs. trend is a bit more complex, and the question of attribution (e.g. "global warming" vs. "natural variability") is not trivial. In particular see Mote, 2006. The Climate Impacts group has a good discussion of this on their website.--eric]

  15. 15

    Re Eric’s response to #1

    My first point is that we don’t have to build resevoirs to hold all the ice that is covering the mountains. It does not all melt each year. We only need enough storage during the winter to provide a supply during the summer, to augment that which is not provided by the summer rain. Of course there is a problem finding space for all those resevoirs, but when the glaciers retreat there will be a lot of unowned empty U-shaped valleys which should do very nicely :-)

    I agree that I can expect little support from Lindzen, since he believes that increased CO2 is not a danger, and I am arguing the complete opposite. But he is saying that the models should not be trusted, with which I am in agreement. Moreover, in my reply to Philip #13, I pointed out that it is clouds which keep the planet cool, and that idea is not too far off Lindzen’s Iris.

  16. 16
    El Cid says:

    I wish that newspapers had a real science section every single day, and many more nit-picking yet important scientific debates would pop into the national conscience.

  17. 17
    Mark A. York says:

    Yeah the salmon can’t get to the headwaters to spawn as it is for all the reservoirs. Looks like a lot of fish rescue efforts in the future when they get stranded in isolated pools.

  18. 18
    James says:

    Re #13: [What I am saying is that man made CO2 is causing the snow to melt and that is causing global warming.]

    OK, I’ll bite on this one. CO2 is causing the snow to melt, but not by causing global warming? Then how? I’m at a loss.

    [In other words, global warming is an indirect consequence of anthropogenic greenhouse gases.]

    No, what you have is the initial CO2-caused warming being amplified by the reduction in albedo that it causes.

    [Response: Correct. But in any case the snowpack loss we are talking about in the Pacific Northwest is trivial from a snow-albedo feedback point of view (except very very locally of course). --eric]

  19. 19
    Ray Ladbury says:

    Alastair, this makes zero sense. Presence or absence of CO2 does not affect the melting point of ice. And clouds form when 1)the relative humidity reaches 100% and 2)there are sufficient nucleation sites. None of these has anything to do with CO2, or indeed with surface temperature. Dry air will not saturate no matter how much you chill it.
    Maybe for teh sake of clarity, you need to go into a little more detail so that we can judge whether you have the foggiest idea of what you are talking about.

  20. 20
    egbooth says:

    Hi Eric,
    Great post! Just a few comments:

    On dams: Yes, theoretically, we could build more artificial reservoirs to offset the “snowpack reservoir” that is declining but you have to realize that pretty much all of the potential sites for dams in the west are taken up already. Also, it is nearly impossible (politically) to build a dam right now because of the enormous constituency in the NW to protect anadromous salmonids (fish that need to migrate up rivers from the ocean as part of their life cycle but have a hard time jumping over large dams). There are many examples, throughout the west (and the rest of the country) of dams being removed for fish passage.

    Secondly, people should realize that this snowpack decline is not just isolated to the Pacific NW. The “snowpack reservoir” is absolutely essential to nearly all of western North America. For example, California’s economy would be enormously affected by even a modest decline in snowpack. I recommend the work by Dettinger, Cayan, and Stewart at Scripps who have shown a clear trend toward earlier streamflow timing in snowmelt-dominated watersheds across western North America (J. of Climate, 18(8): 1136-1155).

    Finally, I have a quick question that I’ve thought a little bit about. As far as the network of snow sensors across the Cascade Range, what does their topographic distribution look like? Are the majority in fairly high elevation locations or are there are a fair amount within the snow-line transition zone? I ask because I would think that the most dramatic declines in snowpack would occur closer to that snow-line transition. Any thoughts would be great. Thanks.

    [Response:Thanks for your thoughtful comments. Regarding the last question, you can examine the distribution of stations readily on the web site I noted above -- http://www.climate.washington.edu/trendanalysis/. The original data are largely here: http://www.wcc.nrcs.usda.gov/snow/ The published work does show greater changes at lower elevations, as I noted in my post.--eric]

  21. 21
    Joe says:

    One item that you didn’t mention in your summary of the UW dispute is that (at least according to the Seattle Times article) Phil Mote apparently tried to squelch debate by insisting on reviewing all e-mails issued by Albright on the snowpack issue. When Albright refused, Mote banned him from associating with the state climatologist’s office. Given that RealClimate has justifiably criticized the Bush administration for similar tactics in trying to suppress debate on climate issues in Federal agencies, I’m surprised that this didn’t merit some attention here.

    Regardless of where you come down on the snowpack issue, this kind of heavy handed suppression of opposing views certainly plays into the hands of some critics of the climate science community.

    [Response: Some of my RealClimate colleagues felt I should comment on this too, but I declined to comment on this because I am at UW and felt that it was not appropriate to insert myself into a personnel dispute that should be handled between the individual parties, or if necessary by the directors/chairs of the respective departments. It might be worth pointing out that Phil Mote is not in a position to threaten anyone with a loss of income. The State Climatologist's office is purely titular.--eric]

  22. 22
  23. 23
    Karen Kohfeld says:

    Thanks for the link, Eric. Just to clarify: I wasn’t questioning the presence of a trend, but was considering the increased vulnerability of a watershed when additional, extreme variability is imposed on the trend. But I’ll check out the resources you’ve mentioned. Cheers.

  24. 24
    Harold Ford says:

    Reducing Albedo? Do you mean the reduction of the Earth’s ability to handle incomming energy from the sun? Sort of like using ice cubes to cool off a drink where the heat circulates within the drink until the ice is gone and we have a drink of equalized yet increasing temperature? In the case of the Earth, the ice cubes would be located at the poles and the drink would be the oceans and atmosphere. One more “quick” question, is the increase of CO2 homogeneous or does it hang about in certain areas on the face of the Earth or is this largely unknown.

  25. 25
    cbone says:

    Are there any assessments of the snowpack for the first half of the century? It seems rather ‘convenient’ to pick as your starting date for the assessment a point which coincides with the beginning of the mid-century cooling period associated with the 50′s-70′s. Wouldn’t a more accurate assesment be to compare today’s snowpack to that of the 20′s and 30′s during the peak of the early century warming?

  26. 26

    [[the models are based on the idea that when the surface temperature increases, then more infrared radiation is emitted to space, ]]

    Not quite. The same amount is emitted to space. But in order to keep this in/out equilibrium, the surface temperature has to change when the atmosphere changes.

  27. 27
    Hank Roberts says:

    Harold Ford, no, that’s not what albedo means. You can look it up:
    http://www.google.com/search?q=define%3Aalbedo&start=0

  28. 28
    Matt says:

    In central California the snow pack is already melting and winter is still here. Weather reporters no longer give the cheery “what a great sunny winter”, they now show far more frowns and concerns when reporting warm winter trends.

  29. 29
    James says:

    Re #18 comment: [But in any case the snowpack loss we are talking about in the Pacific Northwest is trivial from a snow-albedo feedback point of view (except very very locally of course).]

    If we’re just considering the PNW snowpack, of course, but it seems reasonable to suppose that the same reasoning would apply to all mountain ranges, and indeed, to any place with snow. So I did a bit of looking, and it seems the Sierra Nevada snowpack is melting earlier:

    http://sfbay.wr.usgs.gov/hydroclimate/pulse.html

    The total snowpack seems to have declined as well, though there seems to be more snowfall at higher elevations.

    Another consequence would seem to be increased risk of severe floods such as happen here (northern Nevada) when a warm winter storm dumps heavy rain on a snowpack that’s already near melting.

  30. 30

    [[One more "quick" question, is the increase of CO2 homogeneous or does it hang about in certain areas on the face of the Earth or is this largely unknown. ]]

    It’s well mixed in the troposphere. The only major gases that isn’t true for are water vapor and ozone.

  31. 31
    W F Lenihan says:

    Based upon empirical knowledge the alleged declining snow pack is is not abnormal. We skiers know.

    For example, photos taken during construction of the Timberline Lodge at Mt Hood show that the permanent snowfield above 7000′ and the glacier near the peak on the south facing slopes were missing. This year the snow pack is sufficient to permit summer skiers to ski down to the Lodge at 6000′ in August. The permanent snow field and glacier are alive and well. Natural variation of the snow pack in the Cascade Range is significant.

    The Columbia River system starts in the Columbia Ice Field in Alberta. Are there any studies showing that critical ice field is shrinking? Is there any peer reviewed research indicating that precipitation will decrease in the Pacific Northwest due to increased anthropogenic gas emissions?

    The form of precipitation, whether rain or snow, only determines the time of year that river flows increase from runoff. Intuition and historical records indicate that precipitation will remain constant (or perhaps increase) during warmer periods.

    The gloom and doom is not justified.

  32. 32
    Phillip Shaw says:

    Re #21:

    Thank you for your response, but I think you took my questions too seriously. I was somewhat faceously trying to point out the logical fallacy in Alistair’s first post. Other commenters did a better job of that than I did.

    I have already read the links you posted and have been a committed believer in the evidence for AGW for several years. I just worry about the vast amounts of debate going on and the microscopic amount of real progress. Hopefully that will change.

  33. 33
    cat black says:

    Much of the period ’45-’90 is somewhat influenced by “global dimming” caused by late-industrial era pollutants, which have now largely been checked. The most recent rapid and catastrophic warming records perhaps foreshadow an inflection point in snow melt. As such, the interesting trends in snow packs might not have even started yet, or barely begun.

    There is a tendency to assume that trends are linear, and curves are normally distributed. It is prudent when feedbacks are in play to look for inflection points and non-normal curves. We won’t know for a few more years, of course, but I have the increasing sense that we have entered a warming acceleration phase unseen before and entirely unanticipated. The trend might still be linear (we pray it is so!) but I sense the slope of the line is moving and not in our favor.

  34. 34
    Hank Roberts says:

    Mr. Lenihan, you can look this stuff up. Intuition and historical records don’t include the current science.

    Try these to start with:
    http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla%3Aen-US%3Aofficial&hs=sBO&q=%2Bprecipitation+%2Bdecrease+%2B%22Pacific+Northwest%22+due+to+increased+anthropogenic%22&btnG=Search

  35. 35
    Aaron Lewis says:

    In some ways this is an engineering issue, i.e. “Are the dams still suitable for the current climate?” Many dams in the PNW were designed using snowpack/stream flow data from the period 1920 to 1950. So the real question is: “Is snowpack/stream flow data in the period 1976 – 2006 similar to the 1920 to 1950 data?

    This would be comparing apples to apples.

  36. 36
    egbooth says:

    Re#29: Yes, if precipitation does not change, the annual water balance will not be largely affected (there may be increased evapotranspiration). But the timing of streamflow is a lot more critical than you think. With a diminishing snowpack, this means more of the streamflow will be shifted earlier in the year because you no longer have as much snowmelt. Thus, to maintain the water balance, more streamflow is expected in the winter and less in the summer. And then you can ask yourself, when do humans consume the most amount of water? Answer: during the hot summer when agricultural irrigation takes place. So unless you plan on building more and more reservoirs (which is just infeasible at some point), we have a major issue to deal with. Many researchers have been looking at this issue for a long time (check out work done by Dennis Lettenmaier at U. of WA or Jay Lund at UC-Davis for instance). People are working on solutions but it will by no means be easy and a lot of sacrifices will need to be made. It is definitely something to be concerned about.

  37. 37
    michael sweney says:

    The snowmelt is going on in the Rockies as well:

    “Vanishing Glaciers in the Wind River Range” on the Wyoming Outdoor Council website.

  38. 38
    egbooth says:

    Re#33: This is another important issue that has been getting a lot of attention in the hydrology community over the last decade or more. Our flood control infrastructure is designed under the assumption that the flood record is consistent with a stationary time-series. In other words, climate does not change.

    But as we now are aware, this is not a very good assumption. Many flood records have indeed seen increases in the frequency of large floods. Rivers draining the western Sierra Nevada show an increasing trend (see the 1999 NRC report on Improving American River Flood Frequency Analyses, http://books.nap.edu/openbook.php?record_id=6483, also see: http://repositories.cdlib.org/jmie/sfews/vol4/iss2/art2/)

    There have also been trend analysis studies for the Mississippi River, Yangtze River, and I think several others. See Milly et al. (2006, Nature (415): 514-517) for a look at this issue on a global scale.

  39. 39
    egbooth says:

    Sorry. Comment 36 should be in reference to #31.

  40. 40
    Chuck Booth says:

    Re # 31 “The Columbia River system starts in the Columbia Ice Field in Alberta. Are there any studies showing that critical ice field is shrinking? ”
    From the Parks Canada Jasper National Park website:

    Because of a warming climate, the Athabasca Glacier has been receding or melting for the last 125 years. Losing half its volume and retreating more than 1.5 kms, the shrinking glacier has left a moonscape of rocky moraines in its wake.

    http://www.pc.gc.ca/pn-np/ab/jasper/visit/visit32_e.asp

  41. 41
    Lynn Vincentnathan says:

    It needs to be clarified here, that it is hypothetically possible to get more snowfall and snowpack in a globally warming world (at least for a while), due to increased precipitation (which is predicted in a warming world, esp for the higher latitudes) coming down as snow. Also not all places are warming in lock-step; it’s the average temp that going up, and (I think) it’s even possible there could be greater variance or extremes (hotter hots, colder colds), as the average continues to go up (but I’m no scientist, and I don’t really know).

    So, an increased snowpack would not disprove global warming.

    OTOH, these decreasing snowpacks and decreasing glaciers around the world, it seems, is one of the most serious harms from AGW, since, for instance, 40% of India and 40% of China (& and many, many others) depend on the yearly glacial cycle of summer meltwater supplying their waterways during their growing seasons, and snows replenishing the glaciers during winter. If the precip comes as rain or fast-melting snow during the winter, causing flooding, and the glaciers are all melted, with no water for agriculture or drinking, that’s a recipe for big disaster.

    Now, I think the debate should shift to which harm from AGW will be greater. Let’s get to it & make such a ruckus no one can even hear the contrarians anymore.

  42. 42
    Richard Ordway says:

    Re. 31 Mr. Lenihan,

    [[Based upon empirical knowledge the alleged declining snow pack is is not abnormal. We skiers know.]]

    Ok, I’ll bite.

    Your comments are blatently not scientific and demonstrate common red herrings often used by people with a political agenda.

    Firstly, Results need to be openly analyzed for truthfulness in the world-wide journal process.

    Second, Results need to be analyzed from many different locations to rule out natural local variability. Ie. Perhaps the local winds changed the precipitaion in your local location temporarily, but not other places but are not representative of the long term average which is being influenced by larger forces.

    Non-scientific global warming charlatons for instance, have a website (co2science.org- largely energy funded) that denies GW and “shows” how the GW is not happening because temperature has INCREASED in one city every month.

    Scientifically, this is lieing for the two above reasons. One, is it is not necessarily true (sometimes it is blatently against the scientific records that I checked).

    Two, you need many different readings from many different locations to determine long-term trends (like AGW [warming]). The Eath cannot heat or cool evenly, which I remember learning as a child.

    Many people who use these ridiculous arguments, are either liars or totally ignorant of the scientific process.

  43. 43
    Eli Rabett says:

    In an important way this is like the issue of sea level rise. We know what the endpoint will be, but not how long it will take to get there. The longest time estimate is big trouble. The shortest time estimate is a full blown disaster.

  44. 44
    David says:

    Our wise President Vaclav Klaus has spoken:
    “The â�� so called â�� climate change and especially man-made climate change has become one of the most dangerous arguments aimed at distorting human efforts and public policies in the whole world. …”
    “… I feel obliged to say that the biggest threat to freedom, democracy, the market economy and prosperity at the beginning of the 21st century is not communism or its various softer variants. Communism was replaced by the threat of ambitious environmentalism. This ideology preaches earth and nature and under the slogans of their protection â�� similarly to the old Marxists â�� wants to replace the free and spontaneous evolution of mankind by a sort of central (now global) planning of the whole world. …”
    More of his worldshaking wisdom is to be found in his “Answers to questions from the House of Representatives of the U.S. Congress, Committee on Energy and Commerce, on the issue of mankindâ��s contribution to global warming and climate change” – here:
    http://data.zpravy.cz/soubory/ln_domov/A070320_HLM_3.19.07_VACLAV_KLAUS_RESPONSE.PDF
    You got your bush, we got our klaus…
    Greetings from Prague.
    David

  45. 45
    James Annan says:

    The average snowpack in the Cascades has declined 50 percent since 1950 and will be cut in half again in 30 years if we don’t start addressing the problems of climate change now.

    Unfortunately you fail to correct the most obvious howler in this quote: regardless of the numerical details that you discuss at some length, whatever future changes are in store over the next 30 years will happen irrespective of what we do with emissions.

  46. 46
    Hank Roberts says:

    Yep. And watch for surprises.

    “With global climate change, temperatures in the Arctic stratosphere are expected to continue to decrease …. For every degree of stratospheric cooling, a reduction in ozone of 15 Dobson units can be expected. This sensitivity is three times larger than had been extimated previously from model calculations …..”

    http://www.rsc.org/pps Photochemical and Photobiological Sciences 2006, 5, 13-24
    DOI: 10:1039/b515670j

  47. 47
    Hank Roberts says:

    Here that is as a link — the older journals appear free; the current year requires payment. So if yo want to know what’s happening with ozone and climate change for 2007, go to http://www.rsc.org/pps — there’s a whole issue of newer info than what I can read here: http://www.rsc.org/Publishing/Journals/PP/article.asp?doi=b515670j

    but it is interesting the sensitivity calculation turns out to be 3x what the modelers thought. I haven’t seen that in the news anywhere.

  48. 48
    dhogaza says:

    This year the snow pack is sufficient to permit summer skiers to ski down to the Lodge at 6000′ in August.

    Is there any particular reason Mr. Lenihan failed to mention that the Timberline Ski Area collects and packs down as much snow as they can in spring in order to extend the snowpack below the Palmer Glacier down to the Lodge as long as they possibly can during the summer skiing season?

    It’s odd, from his post you’d swear the snowfield he claims disproves the snowpack claim is entirely natural, not manipulated by the ski area …

    I work part of each september banding hawks on Bonney Butte, where we have a fine view of the ski area. The snowfield is a rectangle, hmmmm … I wonder why?

  49. 49
    Ken Winters says:

    Re: 31 Mr. Lenihan

    A much broader perspective is needed than your memory and a few pictures during one lodge construction period. According to:
    Lillquist K, Walker K (2006) Historical Glacier and Climate Fluctuations at Mount Hood, Oregon. Arctic, Antarctic, and Alpine Research: Vol. 38, No. 3 pp. 399â��412 between 1901 and 2001 the 5 studied glaciers on Mount Hood are in a clear overall retreat. They have gone through 2 cycles of retreat and advance: retreating during 1901 – 1946 warming, advancing during wet cooling period mid-century, continued retreating during late 1970′s to mid-1990′s warming period, and a slight advance due to high precipitation in late 90′s.

  50. 50
    Philippe Chantreau says:

    #45, you need to clarify. Are you hence suggesting that we should not do anything? How about the following 30 years? And the 30 years after that?


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