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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. 101
    Dan says:

    re: 99. “Use our brain power and technology to create new forms of energy…”

    Which of course defies the fundamental “Energy can not be created or destroyed”.

    [Response: I've turned off comments for the moment so I can have a chance to respond to some of the above. I'll turn them back on soon, with the hope that the coments can get back on topic! --eric]

  2. 102
    eric says:

    OK, comments are back on, but please

    a) be civil

    b) TRY to stick to the topic at hand!

    Eric

  3. 103
    J. Althauser says:

    re: 99 [[I know, I have to suspend common sense and historical perspective and embrace the conclusions of modeling done by the IPCC.]]

    Ken, those two views depend critically on what things one is aware of. Here is the unappreciated recent history of abrupt climate change.

    While the whole article is useful, the paragraphs next to and after fig. 5 are essential to understand what constitutes ‘common sense’ to those who work in climate science.

  4. 104
    Len Conly says:

    Eric has written that

    “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.’”

    Greg Nickels recently proposed replacing the Alaska Way Viaduct in Seattle with an underground freeway. It is inconsistent to advocate for measures to reduce greenhouse gas emissions and at the same time promote projects that will not mitigate these emissions, but most certainly increase them – in this case a proposal to replace the Alaskan Way Viaduct with a tunnel.

    Voters in Seattle recently rejected his proposal, as well as one to build an elevated freeway.

    Read “Removing Urban Freeways” at http://www.planetizen.com/node/23300

    “Likewise, Seattle is debating what to do about the earthquake-damaged Alaska Way Viaduct on its waterfront. An active citizen’s movement and one of the local newspapers says that the Alaska Way should not be rebuilt; it should be replaced by surface streets and transit. But Washington’s governor has run a referendum that just lets voters choose between an elevated freeway and an underground freeway, and Seattle’s Mayor, Greg Nickels, supports the underground freeway.

    Nickels has taken many minor steps to reduce greenhouse gas emissions in Seattle. If he would back freeway removal and more balanced transportation, he could make Seattle into a leader in fighting global warming – an example for the rest of the country and the world to imitate.

    Instead, Nickels has backed an alternative that hides the traffic but does nothing to reduce the region’s auto dependency and carbon dioxide emissions. He has not learned anything from the huge cost overruns of Boston’s Big Dig. And he does not realize that, as global warming causes sea levels to rise, his underground waterfront freeway could turn into the world’s largest underground swimming pool.”

    [Response: In fairness to Nickel's the State put him in something of a bind by saying that any plan that didn't move 100,000 cars a day was a non-starter. Happily, the voters said NO to both the Big Dig and the Viaduct rebuild option, and now Nickels and Governer Gregoire are starting to talk seriously about public transit. If the people lead the leaders will follow, goes the saying.--eric]

  5. 105
    Lynn Vincentnathan says:

    I hope the RC folks discuss Mark Lynas’s new book, SIX DEGREES (National Geographic, 2007). He doesn’t have ice melting from both poles until a 5 degree increase in warming; but he does mention a big portion of fresh water loss (incl glacial water) with only a 1C increase, which apparently is already in the pipes as James Annan alludes to(#45), even if we halt all our GHG emissions immediately (which is impossible).

    Here is a brief summary of what happens at each of the 6 Degrees (I think the worst case projected upper warming limit (re both highest emissions & highest sensitivity) for 2100 is now 6.4C):

    1C INCREASE: Ice-free sea absorbs ?more heat and accelerates global warming; fresh water lost from a third of the worldâ??s surface; low-lying coastlines flooded.

    2C INCREASE: Europeans dying of heatstroke; forests ravaged by fire; stressed plants beginning to emit carbon rather than absorbing it; a third of all species face extinction.

    3C INCREASE: Carbon release from vegetation and soils ?speeds global warming; death of the Amazon rainforest; super-hurricanes hit coastal cities; starvation in Africa.

    4C INCREASE: Runaway thaw of permafrost makes global warming unstoppable; much of Britain made uninhabitable by severe flooding; Mediterranean region abandoned.

    5C INCREASE: Methane from ocean floor accelerates global warming; ice gone from both poles; humans migrate in search of food and try vainly to live like animals off the land.

    6C INCREASE: Life on Earth ends with apocalyptic storms, flash floods, hydrogen sulphide gas and methane fireballs racing across the globe with the power of atomic bombs; only fungi survive.

    Chance of avoiding six degrees of global warming: zero if the rise passes five degrees, by which time all feedbacks will be running out of control.

    [Response: Now THIS is alarmism and it is not supported by science! The Earth has been much warmer than 6 degrees above its present value in the past. I haven't seen Lynas's book, but if this is really a quote from it I don't have any plans to read it, and even less to recommend it to anyone else!--eric]

  6. 106
    George K says:

    I guess you can just pick a date to start with and get a different result.

    Here is the snowpack charts from 1879 to 2005 and from 1915 to 2005 for two Washington state locations from the University of Washington.

    http://www.atmos.washington.edu/marka/snowpack.html

  7. 107
    Jim Crabtree says:

    I would think that Nickels should check out the active earthquake faults in the area (the Seattle Fault for example). Puget Sound has had tsunamis in the past. The underground waterfront freeway could become a swimming pool very fast.

  8. 108
    Lynn Vincentnathan says:

    Re #106 & http://www.atmos.washington.edu/marka/snowpack.html

    Is the Donner Summit from the Donner Party fame (that had to resort to cannibalism to survive)?

  9. 109
    Ike Solem says:

    Having data on the European Alps, the Andes, the Himalayas, Kilimanjaro as well as the Pacific Northwest matters when discussing global warming – for example, the press release could have pointed out that this is a global trend in many different parts of the world, not just in the Pacific Northwest.

    Having such data would allow comparisons to be made to model output, like this study: http://www.sciencedaily.com/releases/2006/05/060519102250.htm : “New Century Of Thirst For World’s Mountains”

    Alaska in 2100 will maintain but 64 percent of its year 2000 snowpack. In Europe, the Alps will be at 61 percent and Scandinavia 56 percent. The Sierras, Cascades and southern Rockies will be at 57 percent of current levels. The Andes will drop to 45. And Mt. Cook and its snowcapped neighbors in New Zealand will be much less scenic at 16 percent of current.

    (So if the prediction for 2100 is for 57% reduction, and currently there is a 15-30% reduction, it seems that model behavior still generally agrees with observations)

    However, the model seems to be missing other trends:

    Ghan cautioned about “significant limitations” to the model. For example, field observations in Africa suggest the famous snows of Mt. Kilimanjaro will be gone within decades, and on Greenland signs point to accelerated snow and ice melt.

    “This climate model doesn’t show that,” Ghan said. “That doesn’t mean Kilimanjaro and Greenland aren’t in trouble. But our model doesn’t account for all of the snow loss that is possible. Our model neglects downward flow of snow by avalanches and snow slides, glacial creep in places where snowfall is heavy and the snow doesn’t have time to melt.”

    Speaking of Kilimanjaro, see: http://www.sciencemag.org/cgi/content/abstract/298/5593/589 (Kilimanjaro Ice Core Records: Evidence of Holocene Climate Change in Tropical Africa, Thompson et al 2002). There’s also this realclimate article on tropical glacier retreat: http://www.realclimate.org/index.php/archives/2005/05/tropical-glacier-retreat/

  10. 110
    dhogaza says:

    Is the Donner Summit from the Donner Party fame (that had to resort to cannibalism to survive)?

    Yes.

  11. 111
    Zen says:

    Re #108: Yes. Donner Lake, Pass, and Summit are all in the vicinity of Truckee, CA, and named for the ill-fated party.

  12. 112
    Blair Dowden says:

    Re #105: Well, Lynn, you said earlier that it was OK to lie to exaggerate global warming (except for scientists). Now you found someone who did it. That “Six Degrees” stuff is complete and utter rubbish, and certainly does not represent even the most extreme end of the IPCC consensus.

    The earth was 10 degrees warmer during the Cretaceous and had much higher levels of carbon dioxide, and life did not end in “apocalyptic storms, flash floods, hydrogen sulphide gas and methane fireballs racing across the globe with the power of atomic bombs”, and more than fungi survived.

    This kind of apocalyptic fantasy only damages serious efforts to get people to take global warming seriously. Denialists love this sort of thing, it makes their opponents look like idiots.

    [Response: Thanks! Yes, you are right on the makr. -eric]

  13. 113
    Jeffrey Davis says:

    Re: 112

    Straw man. We have a vast, complex, world-wide civilization with nearly 6.5 billion of us depending upon that civilization functioning smoothly. How many deaths from hunger is an acceptable price to pay for Hummers and chilled air in the summer time?

  14. 114
    Ray Ladbury says:

    Re 112: While I agree alarmism is not productive, the fact remains that nobody can predict the outcome of the current warming epoch, precisely because climate is a chaotic system. This lends itself to projection by everybody of either their fondest hopes (a greener world crap) or their worst fears (the day after tomorrow crap). By looking at paleoclimatic reconstructions, we can glean some possible outcomes, but this still leaves a broad range of possibilities. I do agree that life on Earth will persist, but given that the infrastructure of civilization has never experienced an epoch of change like the present, we have to be concerned with its resilience in the face of such unpredictable change.

  15. 115
    matt says:

    Eric wrote-

    2) Your comments on the PDO will also be misleading to many of our readers, because you are implying that there is some predictability in the PDO. But the power spectrum doesn’t show periodicity, and one cannot use it to make any sort of predictions. We might get a “run” of 10 years in the positive phase, but then again we might not. I think that Don Percival (also here at UW) has shown this quite clearly.

    This comment is itself misleading, unfortunately. There is little predictability (beyond about a year) for the PDO, but whatever part of the snowpack change is “due” (really correlated with) the PDO is likely a natural swing. This was the point Cliff was getting at. Yes, it doesn’t have to swing back the other ways necessarily, because the PDO is neither truly decadal nor an oscillation. But to the extent it represents decadal ENSO variability, and to the extent that neither the PDO nor ENSO regions have experienced any significant trend over the last 100 years (whereas virtually the entire remainder of the Pacific basin has), you can’t brush off Cliff’s comment so easily.

    [Response: I was by no means brushing off Cliff's comment. He brings up the importance of the large variabilty that has nothing to do with "global warming" and he is right. In my view, the extent to which the average decline in snowpack is attributable to such variability is unclear but it is certainly a significant fraction -- very likely more than 50%. However, a big difference between the "natural varibilty" and the forced (anthropogenic change) is that the first is not very predictable. So the best prediction will be a snowpack decline, +/- some big number due to that natural variabilty. The further out we go, the less important it becomes that the +/- is a big number. That is essentially what Cliff said, and I agree. Now, what Cliff specifically said was this: "Furthermore, the PDO may switch to a snowier regime as would be expected from its typical periodicity. Thus, we may well see the Cascade snowpack being maintained for the next decade or so, until the global warming signal is overwhelming." I agree with this entirely with the caveat that there is not enough data to say anyting meaningful about the "typical periodicity" of the PDO. It is reasonable of course to say that we may have "more snow" due to a shift in the mean PDO state, but it is equally true that the PDO may "switch to a less snowy regime". --eric]

  16. 116
    James says:

    Re $112: [The earth was 10 degrees warmer during the Cretaceous and had much higher levels of carbon dioxide...]

    Those conditions developed over many millions of years. Rates of change are important too: if you don’t think so, consider the difference between stopping your car by gently applying the brakes, and crashing it into a concrete wall :-)

    For a possible example, consider methane hydrates. If they had existed prior to the Cretaceous, a gradual warming would have released them slowly, the CH4 would have oxidized, and so there would have been only trace amounts of CH4 at any time. In a rapidly warming world, they might be released quickly enough to allow much higher atmospheric concentrations to accumulate.

  17. 117
    Hank Roberts says:

    Yep. Fill the bathtub with a slow trickle while the drain’s leaking a bit —- get a steady state where what’s added matches what’s subtracted. That’s the natural state, where CO2 and methane and other organic material are cycling.

    Turn up the tap to add water faster to that bathtub, and it’s going to overflow.

    The rate of change from burning fossil fuels is faster than natural recycling —CO2 has gone up in the atmosphere by 30 percent in the last couple of centuries since we started burning coal and oil at a great rate, and into the oceans fast enough to change the pH. Simple chemistry, nothing complex about this.

    You’ve read it here repeatedly. Why act like it’s unfamiliar?

  18. 118
    Lynn Vincentnathan says:

    RE #105 (Eric’s response), the quote was from the Sunday Times summarizing some of Mark’s points ( http://www.timesonline.co.uk/tol/news/uk/science/article1480669.ece ), so they may have exaggerated (I’ve ordered SIX DEGREES, but haven’t read it yet). Perhaps it was just a suggestion of the worst of all possible scenarios, and not something very likely.

    However, I did read some science articles (not sure where) about toxic hydrogen sulfide releases during some past warming, and also vast methane releases, so I do think that is possible, at least at some level of warming. I also read several months ago that scientists had found that some clathrates are not as deep in the ocean as previously thought. Whether these releases, even on a massive scale, could cause fire balls or mass extinction, might be hard to say (though I understand that there were past periods of mass extinctions, likely associated with GW). I’ve also read about how superanoxia (caused by some warming processes in the past) killed off a lot of sea life. Maybe that applied to the end-Permian 251 mya, so maybe it’s all very speculative.

    Nevertheless, I can’t see how scientists can dismiss it out-of-hand as totally impossible, especially given the rapidity of the warming now, with no indication people (on the whole) are going to reduce emissions, but rather just keep increasing them.

    [Response: We’re certainly not dismissing it out of hand as impossible. Just not likely. At all! (Note, I’m not saying 6 degrees is that unlikely, just that the extreme consequences of such a rise are unlikely.). One way to tell whether people really have any idea what they’re talking about is looking at whether they say what “will happen” with certainy (e.g. the way Don Easterbrook on Fox News talked about how we are going to soon be on a cooling trend) vs. what “will likely happen” with stated uncertainties (like the IPCC). If Six Degrees reads like it sounds it does, then it sounds rather like the former style … –eric

  19. 119
    Lynn Vincentnathan says:

    RE #105 (Eric’s comment), another thing that puzzles me is that a couple of years ago when I speculated on RC that perhaps the warming might go above 6C, say, in future centuries, Andrew Dodds (I believe) corrected me and said that maximum the earth has ever warmed is 6C (above today’s level), and that seems to be it’s natural limit (until the sun gets really hot, I guess).

    So how hot has it gotten in the past? And was there a high rate of extinction going on then? Or is it that a 6C increase may cause some harm, but not too much?

    [Response: There is nothing to this "natural limit" stuff. There's no magical number. Certainly it has not been 6 degrees warmer than today for millions of years, but I've no doubt it has happened. --eric ]

  20. 120
    Jim Crabtree says:

    (119) Lynn:

    You might want to check out the following link to answer your questions.

    http://www.ucar.edu/news/releases/2005/permian.shtml

    Grain production would be knocked way back by a 6C increase. For every one degree increase over optimal day time growing temperature, wheat production drops by about 10%. Researchers at Lawrence Livermore and Stanford U estimate that GW is cutting grain production by about 40 million metric tons a year currently and that is even wtih more acreage being planted. I haven’t seen the latest numbers, but as of about 3 years ago, the world’s grain supply was near a 30 year low.

  21. 121
    Lynn Vincentnathan says:

    RE #118, Eric’s response.

    I’m familiar with Mark Lynas’s writings & (if I recall) it’s not so much that he says those catastrophic things will happen at 6C warming, but that if we reach 6C warming (by 2100 or 2200 or whenever), then that may set in motion positive feedbacks that will cause even greater warming and worse harms (without even one additional ounce of human GHG emissions). So (I think) he, in consultation with top scientists (and he reads every sci article on GW there is, it seems), considers 6C warming to be sort of a threshhold point at which positive feedbacks become dominant & warming and/or harms increase greatly.

    And that there is some threshhold point for positive feedbacks becoming dominant (& irreversible until it stabilizes at a much hotter temp) and that the threshhod might be 6C warming makes sense to me…sort of based on the principle that heat melts ice & there’s ice that has many gigatons of GHGs locked in right now.

    But I’d be happy to know this is pretty much well off the plate for the next three centuries. Then all we’d have to worry about is a few degrees of warming, which we supposedly could reduce eventually by reducing our GHG emissions. Of course, it would still be a serious problem requiring much effort to mitigate (that part won’t change).

    [Response: Let's just say I don' t lose sleep over this kind of thing.--eric]

  22. 122
    Blair Dowden says:

    Re #113:

    Straw man. We have a vast, complex, world-wide civilization with nearly 6.5 billion of us depending upon that civilization functioning smoothly. How many deaths from hunger is an acceptable price to pay for Hummers and chilled air in the summer time?

    Straw man sets up the false dichotomy: the “Six Degrees” statement is wrong therefore global warming is an illusion. I am trying to establish the reality of what climate change means, however inconvenient the truth may be.

    Three degress of warming takes us back a few million years, while (an unlikely) six degrees takes us back to the Eocene fifty million years ago. The world seemed healthy enough in those times, however it has been correctly pointed out that now we are trying to support a fragile civilization of 6.5 billion people, and the change will occur much more quickly than in the past. There is no question that this will be disruptive, and the faster greenhouse gas emissions rise the worse it will be. But I think any disaster will be more of a social disaster than a natural disaster with fireballs, hypercanes and whatnot. In other words the problem is more the fragility of our civilization than that of nature.

  23. 123
    Blair Dowden says:

    Re #120: “For every one degree increase over optimal day time growing temperature, wheat production drops by about 10%.” So how much does wheat production increase for one degree of warming over a sub-optimal growing temperature? And what is the net balance? It obviously depends on the rate of change, as faster change is harder to adapt to.

    All I am asking for is a complete and balanced picture.

  24. 124
    Steve Reynolds says:

    From the Mark Lynas website link from the RC ‘Other Opinions’ bar:

    “Buried within the newly released IPCC report is an apocalyptic warning: if greenhouse gas emissions continue to rise at current rates, global warming by the end of the century could total 6.4C. The scientists donâ��t say so explicitly, but a rise in temperatures of this magnitude would catapult the planet into an extreme greenhouse state not seen for nearly 100 million years, when dinosaurs grazed on polar rainforests and deserts reached into the heart of Europe. It would cause a mass extinction of almost all life and probably reduce humanity to a few struggling groups of embattled survivors clinging to life near the poles.”

    Since RC apparently agrees [edited]

  25. 125
    Hank Roberts says:

    Eric, I just read New Scientist’s review of the Lynas book — which identifies his sources (as extensive, academic, peer reviewed scientific work) and speak well of his work as an attempt to present the current science and talk about what might be expected — as eventual consequences — over the range of possible temperature changes.

    From that review, it might be worth looking at the book before judging it by those covering it in the press. It sounds at least worthy of comment on the specifics the author chose to discuss. Pierce does point out that the book misses the recent suggestions that the big ice caps may go not by slow melting but by more rapid disintegration, so understates the possibility researchers have suggested of more and faster problems in that particular regard.

    None of us past our teens likely need lose any sleep over any of this, for our own sakes, of course.

    The NS review is behind their pay wall, I read the library copy.

    The teaser is here (and the title sucks, it’s not descriptive of the review, let alone of the books reviewed).
    http://www.newscientist.com/channel/life/mg19325952.500-mathematical-models-are-no-way-to-save-the-planet.html

    The same review also talks about the recent Pilkey book on failures of large scale models — the reviewer presents that too in a very different light than the remarks I’ve read in blogs and US publications — the bad models discussed are things like the cod fishery model (which predicts a continuing harvest, though the fishery has collapsed and isn’t recovering). The flaws are those of political optimism, not bad science.

    I don’t know if it’s mentioned, but it reminds me of the US Ag Dep’t's Forest Service model for success in longterm sustainable management through clearcutting, bulldozing and burning everything left, and then planting Ponderosa pines in the dust and gravel. Worked fine in the short term, for corn and wheat.

  26. 126
    Pierre Gosselin says:

    Again, why has the discussion gone from the scientific cause of global warming to its EFFECTS? We all know that climate has never been constant and that snowpacks etc. have receded and advanced over the last couple of million years. Either snowpacks grow, or shrink. They never stay constant. No one ought be shocked by this.
    Melting snowpacks may provide dramatics, but this is not what science is about. Attempts to dramatise, emotionalise or tabloidise the subject only acts as a disservice to science, and thus should be refrained from.
    So why is the temperature of the planet going up? If this has already been settled, then what is the point of continuing this blog?
    The objective of this blog is to support the thesis of man-made global warming, is it not? Melting snowpacks indicate warming, but do not lend any evidence to their causes.
    The focus must remain on what share do man-made greenhouse gases have on climate change when compared to the entire portfolio of factors that influence climate.

    [Response: RealClimate is certainly not designed "to support the thesis of man-made global warming". From our "about" page: "RealClimate is a commentary site on climate science by working climate scientists for the interested public and journalists. We aim to provide a quick response to developing stories and provide the context sometimes missing in mainstream commentary." The discussion of snowpack decline would seem to fit that bill rather well. The impacts of climate change are of broad interest for obvious reasons and I think we'd be remiss to restrict the blog entirely to the underlying theory of the causes of climate change.--eric]

  27. 127
    Pierre Gosselin says:

    @105
    Eric is right.
    I think this has more to do with dramatics, magazine sales and fanning panic then it does with real science.
    I could also speculate on what happens if a 200m, 500m, 1000m, 2000m etc. diameter meteor strikes the earth. As you know, we’ve been hit before!
    Indeed this topic, and snowpacks too, don’t belong in this blog. It’s stuff you sell tabloids with. Let’s focus on the causes, and not the effects.

  28. 128
    mauri pelto says:

    One key aspect of changing Pacific NW snowpack this thread has missed is the changing ratio between April 1 snowpack and precipitation. If this ratio rises than more total precipitation is captured as snowpack. If this ratio declines than more rainfall or melting is occuring during the winter season. A comparison of April 1 SWE at five sites in the North Cascades since 1946 Fish Lake, Stevens Pass, Rainy Pass, Lyman Lake and Miners Ridge indicates that mean April 1 SWE has declined 26% during this interval. At both Diablo Dam and Concrete (reliable long term low elevation weather stations) winter precipitation has risen 1% and 3% respectively thus, the cause is not less precipitation. Instead we are seeing more winter rain and melting events. This is evident in the graph linked which compares the ratio of precipitation at Diablo Dam to SWE at the higher altitude stations. The higher the ratio the greater the percentage of precipitation that is retained as snowpack as of April 1. Snowmelt or rain are the only two events that can reduce the ratio. Since most significant melt events accompany rain, this ratio is a good indicator of the increasing amount of rain events at high altitudes during the winter. North Cascade snowpack-ppt ratio North Cascade Snowpack

  29. 129
    George K says:

    Here is the table for the latest north cascade snowpacks.

    Right now, (March 15, 2007 data) the snowpack appears to about average – some locations higher, some lower.

    The 2005 snowpack at this time of year, however, was about 30% HIGHER than normal.

    http://www.localsnow.com/avaltot.php

    So, I really have to question this line of evidence which is clearly using data selection timelines, rather than the whole record.

  30. 130
    Lynn Vincentnathan says:

    RE #122, you’ve hit a very important point, Blair. It’s the fragility of civilization. I think of the stock market near “crash” in the 80s caused by a computer glitch, and imagine what if there were some real problems. Okay, if we have a Katrina once in 100 years, we can handle it (though not very well, apparently). But if many of the effects of even 1C or 2C of GW were to occur within a much shorter time frame (& considering that we are currently living off mortgaging the future, as it is), eventually we won’t be able to pay the bills AND maintain our current living standard. Even without GW, considering all sorts of other environmental & non-environmental problems, we’re heading for rough time. Add in some harms from 1C or 2C, it could mean devolving into civil strife even. (How that works, is that people find scapegoats for their misery, then lash out in all directions.)

    I was talking with a biologist last night and we discussed how the geologists are so focused on the level of warming, but don’t have a lot of understanding that even small amounts of warming can really disrupt various species, esp the small, but rapid change we are witnessing today.

    So small inconsequential changes in one system (air can’t die, anyway), can have enormous impacts as they get translated into other systems. And I think our modern high lifestyle might be as vulnerable (maybe more so) than those baby birds who can’t get worms to eat, because they’re hatching a few weeks too early or something.

    Who needs a Cat 6 hurricane, when a Cat 3 will totally flatten the house?

    So, Pierre (#126), yes, scientists of all types are quite interested in results, effects. What’s the point of the experiment, if we don’t want to look at the effects? I hope that’s not the next contrarian argument, that we should only look at the warming as the final effect of the GHGs, and not how the warming might impact life on earth.

  31. 131
    Stephen Pranulis says:

    Has anyone mentioned the density of the snowpack in this thread? Didn’t see any mention of it. Does all snowpack typically assume some constant density? Doesn’t seem likely. Does anyone measure the mass of the snowpack per unit area? If not, why not?

    [Response: Much of the data (most, I believe) is based on snow pillows, which depend on mass (it is essentially a pressure transducer), not area. Note though, that if you want the details to read the original research cited in the post.--eric]

  32. 132
    Stephen Pranulis says:

    Re #130. As has probably been said earlier somewhere in RC, those people who are most aware of global warming will hopefully be in a better position to deal with its consequences. I posit a human survival trait that brings both sides to this blog to try and predict and influence and sometimes to ignore our collective future. A little like the scientists and the imperial government in Asimov’s Foundation series (the famous science fiction trilogy about scientist-mathematicians foreseeing an approaching and inevitable breakdown of civilization, and taking steps to mitigate the disaster).
    Cheers.

  33. 133
    Steve Reynolds says:

    Re editing of my comment #124:

    I recognize that RC has the right to edit or censor comments, but I don’t think it is right to edit in a way that could imply a meaning opposite of what I wrote.

  34. 134
    Mark A. York says:

    I used that Lynas quote pushing my novel Warm Front in the contest at Gather.com not because I believe it, or did anything similar in mine, but to draw attention to the problem. Many readers said they didn’t feel any sense of impending doom. In a novel one starts with a terrible trouble, but my rendition is more about trying to figure out what the problem is; how bad it will get, and some harrowing escapades with what is already happening. Naturally the extensive sceptic community and politicians are involved in trying paper over the whole thing.

    Lynas has gone for full blown sci-fi disaster. Like Crichton’s novel it’s the least likely scenario.

  35. 135
    Clifford Mass says:

    I just wanted to respond to Eric’ comments. His point about not being able to predict the PDO is exactly right..in fact, we don’t even know if the PDO is a real oscillation or a residual of other influences. So where are we? It appears that the global change signal in the NW is to increase precipitation (which could increase snowpack), there has not been much warming at all in the region over the past 20-30 years when the global warming signal has become much more evident, and we can’t predict the PDO signal. Essentially we have no idea what the snowpack will do over the next decade or so. Society needs to know this. There are too many implications otherwise by certain politicians and climate impacts groups. Now most of us believe, based on model simulations…including the high resolution model simulations of the joint effort between my group and CIG..that the warming will eventually win. But of course there are manifest uncertainties there.
    Regarding the validity of looking at the last 20-30 years, this is not as far fetched as some suggest. At the recent climate workshop at UW, a leading climate researcher at the Climate Analysis Center told me that no one should look at trends of more than 30 years because of the PDO issue and the fact the global warming signal should be very small then. A number of people criticized the use of linear trend analysis, particularly when there is large interdecadal variability.
    In short, the whole business needs a careful reexamination and that is exactly what will happen now.

    [Response: Cliff. Fair enough. I don't find anything in your comment to disagree with (though I doubt any of us would actually want to "not look at" trends of more than 30 years). Re-examnation is always healthy. Very nice to have you part of this forum. --eric]

  36. 136
    James says:

    Re #131: [Has anyone mentioned the density of the snowpack in this thread? Didn't see any mention of it. Does all snowpack typically assume some constant density?]

    Snowpack (at least the Sierra one, with which I’m familiar) is generally measured as snow water equivalent (SWE), the depth of water you’d have if the snow were melted, so as to eliminate concerns about density.

    [Response: Same in our area.-eric]

  37. 137

    Re: [I haven't seen Lynas's book, but if this is really a quote from it I don't have any plans to read it, and even less to recommend it to anyone else!--eric]

    I have read Mark Lynas’s previous book. He is a serious person. He might make mistakes, but I would like to hear what they are and I may not notice them myself. There will be lots of people like me. The book will most certaily be very popular. I was quite surprised with your remark. I do not believe in “science” that says offhand what is impossible if the deductions and evidence is available and has not been read. I do admit that Mark Lynas’s book is not peer reviewed science but still it does refer to serious science.

    What does it prove that our globe has been warmer? Nothing at least to me as I am not a scientist in this field. As an perhaps analogous example; it has also been colder with more CO2 than now. You have explained here that situations were different then and we must accept that when situations differ, effects may differ. Why can’t that deduction apply in this case. Mark Lynas certainly may have scientific articles and sound deduction to back his claim. Perhaps Mark Lynas is talking about a longer time frame and runaway effects and the shorthand makes it easy to misinterpret. It may be that he refers to worst case probabilities or partial geographical events. Whatever the case, I surely wish that Mark Lynas is wrong. I will read the book and hope that someone points out where he has made his mistake if this is the case.

    Please also understand how it looks if you seem to take joy in reading all sorts of intentional bullshit from the denialist camp and you attack seriously again and again the faulty presentations by people whose claims clearly have no merit. Then you offhand label as an alarmist someone from the other side from one or two lines of text that does not please you. Why not give a review on a sincere and thorough popular attempt by a person who might fault to the other side and give it similar respect. Is it not the attempt here to have an objective handling of all issues. That can only be achieved when treating both sides similarly. Clearly there has been enough talk on the possibility that IPCC has made a mistake to the side of exaggerating the risk. It is strange that it is almost a tabu to talk about the possibility of grave mistake to the other side. Perhaps we think that the risk is already grave enough. And it should, but where is the action. Anyhow – the book will be popular, people will talk about it regardless if it is recommended by Realclimate or not. Hopefully it is analysed here.

  38. 138
    Dave Rado says:

    Sorry if this is off-topic but there’s a very interesting speech by Paul Wolfowitz (who could hardly be accused of being a left-wing liberal environmentalist!) here.

    “Financing Clean Energy: A Framework for Public Private Partnerships to Address Climate Change”.

  39. 139
    Jim Crabtree says:

    123:

    Blair:

    Here is a link that ties together a lot about wheat (grain) production and global warming.

    http://www.theglobeandmail.com/servlet/story/RTGAM.20070223.wclimatestarve0224/BNStory/ClimateChange/home

    I had seen the same thing from individual reports that came from different research groups. Hope this helps to answer your question.

    By the way, the USDA last fall put the world grain supply at a 25 year low because of the droughts in Australia, China and the Ukraine.

  40. 140
    Richard Ordway says:

    #122 [[But I think any disaster will be more of a social disaster than a natural disaster with fireballs, hypercanes and whatnot. In other words the problem is more the fragility of our civilization than that of nature.]]

    The sustained peer-reviewed literature would mostly disagree with you about “what you think”.

    CURRENT documented changes most likely due to AGW (Human-warming) are literally legion.

    Many current biological and other changes are happening now most likely due to AGW- as recorded in a body of evidence in Nature and Science journals at least. (Go to your library to read them.

    The oceans are becoming much more acidic due to increases in CO2. This causes shelled animals to have weaker shells.

    Corals are massively being destroyed partly due to warming ocean temperatures (More co2 makes weaker coral skeletons as well). They are one of the primary fishing grounds for developing countries.

    Animal, fish, bird and plant range/ migration patterns are changing most likely due to warmer temperatures.

    On average, they are changing by 600 meters (6 US football fields) poleward yearly. Every ten years, these species are migrating an average upward by about 6 meters (18 feet) in elevation.

    Genetic changes are being observed due most likely to the warming in at least certain mosquitos (Wyeomyia smithii).

    Whole toad and frog species have disappeared from ranges (and at least one just disappeared completely) in central America due most likely to precipitation and temperature changes due to AGW (human-warming).

    In the Arctic, where much of the strongest warming is being observed, due to “polar amplication effects” such as- melting “reflective” ice exposes more light-absorbing dark land/ocean, species are overlapping each other so that one species is being reduced…such as the red fox taking over the habit of the arctic fox.

    Mosqitoes are taking over northern habitats such that certain nesting birds are being hurt by them as they try to nest for long periods of times.

    Plankton species have been changing their ranges in the Antarctic most likely due to AGW. This is the basic building block for oceanic life of the food chain.

    Breeding seasons are changing for certain birds but not as rapidly for their insect food sources, so this delicate counterbalance is being destroyed.

    Pinebark beetles are held in check in many places around the world largely by low temperatures. They increase their number of eggs in warmer temperatures.

    They are expanding their ranges into whole new areas and whole new tree species most likely due to AGW.

    A forest in Alaska the size of New Jersey has been destroyed partly due to the pine bark beetles’ expansion largely due to AGW.

    Mosquitoes with Dengue fever at least have climbed elevations most likely due to AGW.

    Certain crop species make less protein due to increased carbon dioxide amounts.

    I have only listed a few of the observed changes that have stood up under scientific scrutiny in the journals- most likely largely due to AGW.

    This isn’t something projected for the future…this is happening NOW after only an average warming of .6 degrees celsius (about 1 degree F.) over the Earth over 100 years measured over thousands of points on Earth…some points cooler…lots of points massively more warmer than this up to 6 degrees F.

    “Big balls of fire”…no…but to say “oh, who cares about those animals, fish, birds and plants…it’s not us…”

    Well, crops, human health, coral fishing areas, water supplies, human wars, human mass migration all are affected if you experience AGW.

  41. 141
    Blair Dowden says:

    Re #139: Thanks, Jim. The point made by the article is that the large wheat growing area in India is at the southern limit for that crop, and further warming will reduce yields. The compensating gains will be in cooler areas elsewhere. To adapt, they will have to change the strains of wheat, or switch to something else, eg. rice. Not so easy in a relatively poor area. And as always, the faster the change the harder it will be to adapt.

    As for drought in the future, I am looking at the chart at the end of the 2007 Summary for Policymakers. The first observation is the large amount of uncertainty. Beyond that, I see a general increase in precipitation with the exception of a band of the sub-tropics. I can see why Europeans in particular are worried about global warming.

    I think we should do our best to slow this change down by reducing fossil fuel emissions. But while some areas will suffer, others may come out ahead, and it is not a worldwide disaster. It will be unfortunate if the poorest areas (that did not cause the problem) get hit the hardest.

  42. 142
    Richard Ordway says:

    Re. 141 Blair wrote: “wheat growing area in India is at the southern limit for that crop, and further warming will reduce yields… compensating gains will be in cooler areas elsewhere.

    Please be careful with this comment.

    Although, this is true …to an extent (most likely for the near-term future of decades), it can be unconsciously misleading to a point of potential severe danger…

    Much of the potential “arable” soils of the north start to become very different in composition to the rich soils of the south the further north you go. The soils start to become thinner and less than ideal for crops.

    So for a while, northern crops can probably compensate for the loss of crops in the south.

    However, lots of projected crop range shifts into Canada and Siberia and other northern areas becomes an exercise in futility as they become potentially less and less productive the farther north you go…even possibly resistant to genetic engineering.

    It does not nesessarily mean that these obstacles are insurmountable…but it might become very difficult and time-consuming to achieve if a rapid climate shift occurs…which almost all available robust peer-reviewed evidence shows has happened multiple times- even about 11,000 years ago off the area of the current east coast of the United States at least…

    This also applies for tree species’ shifts.

    Now let’s get into what some crops do when they are hit with higher co2 levels. Evidence show that some lose some of their protein content and become weaker to pests.

    Again genetic engineering can possibly compensate a lot for this…but that takes time that we might not have if a sudden climate shift happens.

    So for policy planners to plan policy on this assunption… could literally have fatal consequences in certain potential possible scenarios.

    So people have to be careful when they make an assumption that, “Oh, we can replace lost GW crops in the south, with ones to the north.”. It is not potentially a linear replacement.

  43. 143
    Jim Crabtree says:

    re #141:

    Blair:

    You might want to check out rice. It’s productivity drops as night time optimal growing temperatures increase (again – 1 degree increase is a 10% decline). Rice production in Japan and rest of SE Asia is down because of that.

    Australia was a major wheat exporter. Not this year. Overall, their crop production is down 60% this year and researchers at CSIRO says this is global warming and a sampling of things to come. On top of that, some of the researchers are predicting that the Great Barrier Reef will be dead in about 20 years. The Outer Reef (not affected by pollution) is already 50% dead or dying. The Murray-Darling River system is drying up. Several of their major cities are down to less than a 18 month water supply. So this is a rich country that is going to suffer a large impact.

    Most people don’t realize that our central plains (much of our bread basket) could become more desert-like if the rainfall decreased just by a few inches and temperatures warmed by just a few degrees.

    We are doing one heck of an uncontrolled experiment and we are the lab rats!

  44. 144
    Ike Solem says:

    Snowpack relates to precipitation, warm winters, high early runoff followed by late severe drought, soil moisture balance, increased wildfires due to drought, secondary effects of drought on a regional level, etc. The problem seems to be in estimates of how the hydrologic cycle will respond to warming; will you see increased precipitation or not? No increase in precipitation plus warmer temperatures seems to indicate a decrease in the snowpack. For example, a characteristic of El Nino years is the ‘pineapple express’; warm winter storms originating in the subtropical regions dumping more rain than snow, correlated with changing atmospheric circulation. Thus, the record 1997-1998 El Nino was accompanied by a 25% reduction in snowpack across the Northern Rockies and massive rain in the Southwest. Meanwhile, the Sierra snowpack was at 150% of average. What does that mean for predictions of snowpack in a warming world?

    If we can’t predict the response of El Nino to global warming, it seems that it’ll be hard to predict the regional effects in the Pacific Northwest, the Southwest and the Rockies – but the trend of increasingly drier conditions across most of the region seems robust; there’s more wildfires, changing patterns of stream runoff and hydrology, and a diminishing snowpack across the Rockies. The PDO signal seems of secondary important to the El Nino signal, and predictions of the how El ino will change in a warming world are still speculative. It’s also worth noting that these cycles have been abused as explanations of warming phenomena – the increase in hurricane intensity and the AMO, the Pacific snowpack changes and the PDO, the warming Alps and the NAO, and claims that the record winter warmth in the US was simply El Nino – these arguments have been publicly used over and over again as explanations for observed global warming trends – a curious coinicidence that they all seem to be in simultaneously ‘increasing modes’.

    However, one robust prediction seems to be for for hotter summers all across the west, which will reduce runoff and impact agriculture and ecosystems: for example see http://www.sciencedaily.com/releases/2004/08/040824014711.htm:

    Under the study’s lower emissions scenario, summer temperatures in California will rise 4 to 5 degrees Fahrenheit by the end of the century. If nothing is done to curb our use of fossil fuels, summer temperatures rise a dramatic 7.5 to 15 degrees Fahrenheit, according to the study…

    …The researchers also find that hotter weather triggers reductions in the Sierra Nevada Mountains snowpack, which feeds into California’s streams and reservoirs. By mid-century, the snowpack decline translates into a loss of 2.6 to 4 million acre-feet of water storage. By the end of the century, the snowpack could decline by as much as 30 to 90 percent, depending upon whether emissions are controlled, the study finds.

  45. 145
    Hank Roberts says:

    Lynn, would you say specifically if what you posted is a direct quote from Lynas’s book, or someone’s paraphrase? If anything was left out, there should be an ellipsis — regular academic quotation style.

    I’m just puzzled to see the review in New Scientist, by someone who says he read the book, differ so hugely from the comments by people here who say they haven’t read it and don’t want to — based on the material you posted.

    Maybe it’s a true and fair quote; maybe it’s accurate but out of context; maybe it’s a paraphrase. I can’t tell. I don’t have the book yet.

  46. 146
    Hank Roberts says:

    Okay, digging a bit. The six-degrees list quote appears to come from a Times article he wrote (or his corrected version on his web page — I’m not sure which).

    From National Geographic, the book’s temp. range is from the 2001 IPCC, not the current release — I believe the range has been narrowed, which may be reassuring to those relying on it.

    http://www.nationalgeographic.com/emerging/mlynas.html

    “In 2001, the Intergovernmental Panel on Climate Change (IPCC) released a landmark report projecting average global surface temperatures to rise between 1° and 6°C (2° to 10°F) by the end of this century.” (From a baseline in the recent past, right?)

    From the intro at marklynas.org:

    “… the end of the Permian period, 251 million years ago. For reasons that are still not properly understood, temperatures rose by 6C over just a few thousand years ….”

    That appears the worst case; I hope there’s a probability/error range attached to it. And I hope there’s an interpolation to follow based on the 2007 IPCC update.

    Moreso, I hope there is a good list of footnotes and sources available or to become available with the book.

    Eric’s right, nothing to lose sleep over personally; as far as I know, every “worst case” scenario would occur after everyone alive on Earth now is dead (of old age, more than a century from now).

  47. 147
    David B. Benson says:

    Re #146: Hank Roberts — Thanks. I sugggest that Jared Diamond’s book Collapse is also most relevant for the twenty-first century…

  48. 148
    Hank Roberts says:

    Maybe, tho’ I think one of its scenarios has already been outrun by the science, on this lap at least.

  49. 149
    Philippe Chantreau says:

    So, Hank, just to clarify, I understand that you don’t care at all about what happens after you and a few people you know are gone, is that right?

    You also seem to imply that a 6 degree change is the highest known and whatever existing IPCC forecast is nothing to be excited about, considering the margin of error; my notion of what happened at the end of the Permian suggests we should not be anywhere close to (or just not far enough from) the changes that took place then.

    Seriously, would you wish even those generations coming after “everybody living now is dead” the task to live through an event just comparable to the end-Permian?

    I wonder why it is acceptable to consider a comparison between the result of human activity and some of the most severe extinctions this planet has experienced.

  50. 150
    Blair Dowden says:

    Re #140, 142, 143: That is a lot of information directed my way. I will pick a few points that I have a problem with.

    I was not aware that any land plants actually suffered with increased carbon dioxide levels. That surprises me, as these plants evolved under higher CO2 levels than today. Do you have a reference for this? I am not pushing “greening earth” utopia nonsense, but I thought most plants grew somewhat better under higher CO2 levels. This benefit may be offset by other conditions such as warmer temperatures or less rainfall.

    I read about the rice story here earlier, but it does not make sense to me. The temperature range for rice growing areas (eg. between Japan and Vietnam) is much greater than recent changes due to warming. Is rice growing in southern regions less productive than in the north? Or are different strains of rice adapted for different temperatures? Can it get too warm to grow rice?

    The pine bark beetle is a classic global warming situation. Forests grow very well in the warmer conditions in which northern forests are now suffering, because they have different trees. Ultimately the northern trees will be replaced, but that does not happen instantly, so we are losing vast areas of forest. So this is a problem of transition. But as long as we keep increasing greenhouse gas emissions, we will continue to be in a condition of transition, and losses will continue.

    I am more concerned about the oceans than land. It seems that a climate that is good for land is bad for the oceans. Generally (and not in transition) warmer climate and higher CO2 (unless I am wrong about this) are more productive on land. But warmer water holds less oxygen, and ocean acidification by CO2 removes an important base of the food chain. One other factor is the ocean depends on dust from land for nutrients. Increased desert area leads to increased fertilization of the ocean. I don’t know which way global warming will push this, as a warmer world is generally wetter, but it seems sub-tropical deserts may increase in size. Or they may just shift away from the equator.

    I don’t think the uncontrolled experiment we are engaging in is a very good idea, and we would be wise to slow this down as much as possible. The point of science is to understand what is going on as accurately as possible, so we can make the best decisions on how to act.


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