Polar Amplification
Guest commentary by Cecilia Bitz, University of Washington
"Polar amplification" usually refers to greater climate change near the pole compared to the rest of the hemisphere or globe in response to a change in global climate forcing, such as the concentration of greenhouse gases (GHGs) or solar output (see e.g. Moritz et al 2002). Polar amplification is thought to result primarily from positive feedbacks from the retreat of ice and snow. There are a host of other lesser reasons that are associated with the atmospheric temperature profile at the poles, temperature dependence of global feedbacks, moisture transport, etc. Observations and models indicate that the equilibrium temperature change poleward of 70N or 70S can be a factor of two or more greater than the global average.
The Arctic Climate Impacts Assessment (ACIA) summarized the evidence for amplification in Arctic surface warming with the statement, "Over the past 100 years, it is possible [33-66% confidence] that there has been polar amplification, however, over the past 50 years it is probable [66-90% confidence]" (ACIA, 2005, p 22). This uncertainty in the evidence of polar amplification should not be confused with the evidence for significant warming in the Arctic. Arctic warming is both highly significant and substantial — it is just not possible to say with very high confidence yet that the Arctic has warmed more than the rest of the hemisphere or globe. The purpose of this posting is to explain why there is sometimes an absence of evidence for polar amplification.
Dramatic changes in ice at the poles are often cited as evidence of recent climate change — changes such as thinning and retreat of the sea ice, collapse of ice shelves along the Antarctic Peninsula and on the north coast of Greenland, melting permafrost, etc. Are these changes evidence of polar amplification? Not really. Because ice is mostly confined to the high latitudes, it is impossible to compare the magnitude of changes in ice across many latitudes. Therefore it seems a mistake to consider changes in ice as prima facie evidence of polar amplification. Instead, I would argue that changes in ice are a consequence of warming, though they may play a role in causing polar amplification. The term "polar amplification" should therefore be reserved to describe the amplification of surface temperature changes.
Fig 1. Latitude-height distribution of the zonal mean difference in annual mean temperature (K) in response to the quadrupling of CO2. [From Manabe and Stouffer (1980)] (click to enlarge)
Manabe and Stouffer (1980) first popularized the phrase "polar amplification" to describe the amplified rate of surface warming at the poles compared to the rest of the globe in their climate model's response to increasing GHG levels. Their early climate model had a simple ocean component that only represented the mixed layer of the water. Their model had roughly symmetric poleward amplification in the two hemispheres, except over the Antarctic continent, where they argued the ice is too thick and cold to melt back (see Fig 1). Both poles warmed more at the surface than the midlatitudes or equatorial regions. Figure 1 also shows that polar amplification only occurs below about 300mb (ie, only in the troposphere). The vertical profile of warming in the lower atmosphere and cooling in the stratosphere from GHGs is well understood as a function of increased absorbtion and re-radiation.
Fig 2. Linear surface warming trend in °C per century from NCAR CCSM3 averaged from 9 ensemble members using the SRES A1B scenario. (click to enlarge)
Observed polar climate change from the instrumental record is not symmetric. Except along the Antarctic Peninsula (Vaughan et al., 2003), most evidence of significant warming is from the Arctic. In addition, total sea ice extent in the Southern Ocean has had no significant trend since satellites began taking data in 1979 (Cavalieri et al 2003). Newer climate models generally also have very modest or no polar amplification over the Southern Ocean and Antarctica in hindcasts of the last century. The presence of a deep and circulating ocean component is key because ocean heat uptake increases most in the Southern Ocean as the climate warms (see Gregory 2000). The asymmetry at the poles does not however result from a difference in feedback strength associated with the ice or atmosphere. In fact, when these same climate models are run to equilibrium (in the same way that Manabe and Stouffer ran their model so that ocean heat uptake is not a factor) the hemispheres have nearly equal polar amplification.
Fig 3. Zonal mean surface temperature change at 2080-2099 relative to 1980-1999 for models archived at PCMDI for the IPCC AR4. The temperatures are normalized by the global mean to emphasize the relative polar amplification across models. (click to enlarge)
In addition to the asymmetry from ocean heat uptake, models have been used to attribute a considerable fraction of the warming on the Antarctic Peninsula and the lack of warming elsewhere on Antarctica to a decreasing trend in stratospheric ozone levels in the past few decades (Shindell and Schmidt, 2004). Due to the successful treaty to reduce ozone-depleting chlorofluorocarbons (CFCs) emissions, ozone levels in the stratosphere are expected to recover over Antarctica by about 2040, so eventually Antarctica begins to warm somewhat in climate model predictions of the 21st century (see Fig 2) (WMO, 2002).
It is well established that climate models exhibit Arctic amplification of future climate change (see Fig 3). In addition, averaging over numerous hindcasts from a single model started with differing initial conditions (known as an ensemble average) yields significant Arctic amplification in simulations of the last century. However, single realizations with a climate model do not universally show Arctic amplification in the past [Bitz and Goosse, in prep]. Thus models and observations alike show uncertainty in Arctic amplification in the last century. Nonetheless Arctic amplification in models (and most likely in nature too) is a robust result of forced climate change, provided the forcing is sufficiently large to overcome internal climate variability. Antarctic amplification only occurs if a model is run long enough so ocean heat uptake in the Southern Ocean does not damp the positive feedbacks and if trends in stratospheric ozone do not cause compensatory cooling. Predictions with climate models indicate that Arctic amplification will be significant (above the 95% confidence level) in one to two decades, while significant Antarctic polar amplification will take much longer. A lack of polar amplification over relatively short periods of time is therefore understandable and does not undermine the credibility of climate models or climate theory in any way.
References:
ACIA, 2005. Arctic Climate Impacts Assessment, Cambridge University Press, New York, U.S., 1042pp.
Cavalieri, D. J., C. L. Parkinson, and K.Y. Vinnikov, 30-Year satellite record reveals contrasting Arctic and Antarctic decadal sea ice variability. Geophys. Res. Lett., doi:10.1029/2003GL018031, 2003.
Gregory, J.M., Vertical heat transport in the ocean and their effect on time-dependent climate change, Clim. Dyn., 16, 501-515, 2000.
Holland, M.M., and C.M. Bitz, Polar amplification of climate change in the Coupled Model Intercomparison Project, Clim. Dyn., 21, 221–232,2003.
Manabe, S. and R.J. Stouffer, Sensitivity of a global climate model to an increase of CO2 concentration in the atmosphere, J. Geophys. Res., 85, 5529–5554, 1980.
Moritz R.E., C.M. Bitz, and E.J. Steig, Dynamics of recent climate change in the Arctic, Science, 297, 2002.
Shindell, D.T. and G.A. Schmidt, Southern Hemisphere climate response to ozone changes and greenhouse gas increases, Geophys. Res. Lett. doi:10.1029/2004GL020724, 2004.
Vaughan, D. G. et al. Recent rapid regional climate warming on the Antarctic Peninsula. Climatic Change, 60, 243-274 2003.
2 January 2006 at 7:42 PM
The text around the figures are mixed up with the rest of the text for me… on IE
[Response: Should be better now… - gavin]
2 January 2006 at 10:18 PM
From the guest commentary article above: [… The term “polar amplification” should therefore be reserved to describe the amplification of surface temperature changes.]
It is interesting to see this article. I’m updating my Excel spread sheet data plots which show annual air temperature at Alaska climate stations (1950-2005 for most stations). I began this effort in 2000-2001 for posts I made regarding articles in 2000 and 2001 by Willie Soon and Sally B. on climate change in Alaska. My posts were at ClimateChangeDebate (David Wojick group). I made a couple recent (Dec 2005) posts to RC on the thread called Naturally trendy regarding an article on temperatures in Alaska by the Alaska Research Climate Center. I’m not sure what to do with the spread sheet data plots I’m finishing up this week. I would like to share them if others at RC, but I would need advise in where and how to put them at a place that others might access.
3 January 2006 at 2:34 AM
With regard to the Antarctic, although I can understand the idea that the ozone hole strengthens the circumpolar westerly. I presume that the extra UV reaching the surface through the hole adds to the overall warming as it’s absorbed and reflected back. How significant a contribution is this?
Also as the Arctic warms and the thermohaline circulation drops off presumably there will be an increase in the flow of water into the southern Atlantic and hence to the Southern Ocean. If that’s the case then presumably this additional flow will inhibit the formation of El Nino’s and perhaps is already doing so, contrary to most expectations?
Lastly, an imbalance in global heating between south and north that’s exacerbated by the ozone hole (I’m not optimistic about this disappearing anytime soon - treaties notwithstanding - consider the impact of PFOA(perfluoro-octanoic acid which is AFAIK not in the treaty) does not seem to be conducive to stable circulation. Consider the unequal impact on the position and activity of the ITCZ(Intertropiocal Convergence Zone).
3 January 2006 at 2:34 AM
Just noting an apparent typo: in the sentence “Due to the successful treaty to reduce ozone-depleting chlorofluorocarbons (CFCs) emissions, ozone levels in the stratosphere are expected to peak in about 2040 and decline thereafter,…”, I presume that it should be “CFC levels”, not “ozone levels”, peaking in about 2040.
[Response: Thanks. I’ve adjusted the text to read “ozone levels in the stratosphere are expected to recover over Antarctica by about 2040″. Sorry for the confusion. - Cecilia]
3 January 2006 at 4:37 AM
I notice that the model output puts the greatest warming in the arctic ocean, probably related to the shrinking summer ice.
The greatest observed warming so far is occurring over Siberia in winter. When will summer warming overtake winter warming?
Average temperature has little meaning in the arctic, given the annual amplitude of 60 K. Are seasonal maps available?
3 January 2006 at 11:50 AM
The early GCM’s which showed amplified warming in the polar regions did so because the models used very crude ocean and sea-ice components. This was true thru the 1980’s, as the models exhibited too much sea-ice with the ice edge located much closer to the equator than actually happens. Since the ice was located where it would intercept more solar energy, this sea-ice was easily melted in the 2xCO2 experiments, producing greater input into the slab oceans used at the time. The effect of high zenith angle on the ocean’s albedo was also left out, thus the difference in albedo produced an amplification which was much greater than that seen in the real world.
The apparent cooling trend over the Antarctic is deduced from MSU data analyzed by UAH. There are severe problems with the UAH TLT over the Antarctic, as I pointed out in a GRL report in 2003. The impact of the relatively high surface elevation and sea-ice on the UAH TLT product may be producing a trend with stronger cooling than that which is actually happening. Furthermore, the influence of the lower tropopause (about 300 mb) over the Antarctic on the UAH TLT may also produce an additional cooling trend in the data. Carl Mears at RSS has produced a TLT product and pointedly leave out data poleward of 70S. My personal opinion is that I don’t trust the TLT data poleward of 60S. This question was not considered as part of the new Climate Change Science Program draft report on the MSU lapse rate issue, which I find most distressing.
3 January 2006 at 1:10 PM
A useful paper on what causes polar amplification in the models is Winton 2005. Amplified Arctic climate change: What does surface albedo feedback have to do with it? Geophys Res Lett. In press. In those models where it occurs (and in some it’s rather small), it’s not principally ice-albedo feedback. Rather, it’s due to non-surface short-wave feedback (i.e. clouds, as I understand it).
3 January 2006 at 9:15 PM
Recheck that ozone/CFC peak date, against late 2005 news please?
I recall NASA announced at the Dec. 2005 AGU meeting a delay in recovery. They put the recovery date off to maybe 2065, because CFCs keep showing up unexpectedly — either more leaks, or more production, than hoped.
There’s still a lot being produced, e.g.
http://www.japantimes.co.jp/cgi-bin/getarticle.pl5?nb20051021a3.htm
3 January 2006 at 9:33 PM
NASA on ozone, delays/doubts about recovery here:
http://www.nasa.gov/centers/goddard/news/topstory/2005/ozone_recovery.html
4 January 2006 at 4:11 AM
There is also at least another way of determining Polar amplification, which is by optical atmospheric refraction, measurable all over the world, by mainly using the sun as a baseline sphere.
Some above the horizon high Arctic sun disks were measured to have an average increase as much as 1% in vertical diameter in one year, this is a huge number, and may be due optical amplification not totally dissimilar to temperature.
Current GT anomaly maps, the latest NH monthly ones, are truly giving the impression that SAT amplification is a done deal,. it is kind of hard to understand why current GT anomaly maps are not good examples of amplification since they resemble the display above.
5 January 2006 at 3:13 PM
The refraction photos are a new approach? How much of, or how longterm a collection, do you need to get a statistical basis for those measurements’ confidence, and to compare them to other data? (Which statistical test do you plan to use, how many measurements will you need to collect, or over how long a period, to run it?)
5 January 2006 at 9:19 PM
Ozone hole recovery model runs here:
http://www.nasa.gov/centers/goddard/images/content/139176main_ozone_recover_figure2.jpg
Google for “always been an ozone hole” to see the baloney as served to the blind who don’t look up references (sigh). Mythinformation prevails throughout.
6 January 2006 at 3:34 AM
#11, Hank , it is a totally novel approach, based on data spanning back to 2000. a study of upwards of 14 tropospheres in one shot. I find statistical analyses not as good as theoretical applications from comprehensions. Breaking ground in this science is a whole lot of fun though, as I test my concepts by making projections paired with past NH GT’s. So far it works quite well. Confidence is partly taken from judging accuracy of my projections, although statistical information is equally interesting. . Namely 5 seasons of data collection suffices more or less to see a trend, but a particularly striking one between 2004 and 2005, When there was a marked increase in sun disk sizes of something like 80% of the levels (between 0 and 10 degrees elevation, there are up to 100 deci levels), Some expansions were truly epic, but that is not new, what was strange was a noticeable consistency found from one comparison to another. This reminded me of an amplified signal, a meaning above statistical variances, which eventually prompted to call 2005 the warmest ever for the NH in early April of 2005.
6 January 2006 at 4:31 PM
This is an informative post, helpful to those of us curious but lacking in the requisite knowledge about the polar amplification concept. I wonder if a little more might be said about Fig. 2, which, I assume, represents some of the most recent projections along with earlier ones (is this correct?). This figure suggests a rather extraordinary amount of warming of the Arctic oceans, but also a distinct “boundary zone” between moderate and extreme domains of warming (i.e. a steep “warming gradient,” so to speak). Has this been discussed in the relevant literature? Thanks very much for any relevant response.
7 January 2006 at 10:59 PM
Fresh off the credibility-boosting exercise of the UAH satellite data revisions of earlier this year (yes, that’s sarcasm), John Christy weighs in on Arctic warming: http://www.upi.com/NewsTrack/view.php?StoryID=20060105-114143-6931r . His thesis seems to be that so much of the warming is concentrated in the Arctic that the warming in the rest of the northern hemisphere must have some other explanation. He then trots out the good old natural cycle argument (for which he has no evidence whatsoever, at least as indicated in this story). Also interesting is that he seems to have gotten into the global temp business. If his temp figures are based on his satellite data, I wonder if he’s still including the bad data from 70oS to the South Pole.
7 January 2006 at 11:29 PM
Clarification: I meant surface temp business, but as far as I can tell from the MSU web site they still have nothing on surface temps. It’s not clear which temperature data set was being discussed in the article, nor does Christy appear to have really started promoting annual temp data in an active way (since I couldn’t find a press release or other indication of such an effort). So presumably the reporter initiated things, although if those were indeed just off-the-cuff comments from Christy I have a feeling he’ll end up being sorry about them. OTOH, maybe it’s just a matter of him believing there’s no longer a professional cost to letting his true views be known.
8 January 2006 at 6:10 AM
16 Steve, astounding article, as outrageous as it gets in this domain. A cycle as suggested by Christy, the only logical claim asserted, needs some evidence, anything, a story even a memory would help, but there is none to be found in the Arctic. The closest thing I can gather is the mythical open Arctic ocean as conjured up by some tale or theory which got a lot of 19th Century sailors in frozen trouble. The rest of the claims, shall I dare say, are childish in reasoning.
8 January 2006 at 12:28 PM
I don’t know much about the various (decadal) oscillations & how they do/don’t relate to GW or Arctic warming, but I just read off of ClimateArk (from LA Times) that the ocean temp off Santa Barbara is highest in 1,400 years, indicating it goes beyond the Pacific Decadal Oscillation, or that oscillation is acting weird, with shortening cycles.
See: http://www.climateark.org/articles/reader.asp?linkid=50379
Would shortening oscillations (perhaps also in the arctic) be related to GW? I was thinking 10-15 years ago, when people were blaming weird weather on el ninos, that GW might be impacting el ninos (making them appear more frequently and/or severely). Methinks skeptics & denialists are hiding behind “natural” oscillations & el ninos, etc, without considering how these themselves might be impacted by GW. I know it would be difficult to tease out the GW effect from the natural oscillation, but wouldn’t one expect in a GW world for GW to impact & amplify these?
8 January 2006 at 5:29 PM
John Christy has not “done the homework”. *
* See … How to be a real skeptic at:
http://www.realclimate.org/index.php?p=210
According to the NewsTrack link below, the director of UAH’s Earth System Science Center, Mr. John Christy said:
“It just doesn’t look like global warming is very global,” … “The carbon dioxide from fossil fuels is distributed pretty evenly around the globe and not concentrated in the Arctic, so it doesn’t look like we can blame greenhouse gases for the overwhelming bulk of the Northern Hemisphere warming over the past 27 years” he said. “The most likely suspect for that is a natural climate change or cycle that we didn’t expect or just don’t understand.”
http://www.upi.com/NewsTrack/view.php?StoryID=20060105-114143-6931r
Until Mr. Christy has “done the homework”, any media people or others who allow his statements to be heard or read by the public are behaving as irresponsible human beings.
John Christy is hereby given an assignment to complete before he does any more interviews. He is to write a thorough report on the presentation given by Hansen, J. 2005 (link below). His report will be graded (pass/fail) by knowledgeable and responsible scientists who have been participated in RC discussions during the last 12 months.
Presentation by Hansen, J. 2005. Is There Still Time to Avoid “Dangerous Anthropogenic
Interference” with Global Climate? A Tribute to Charles David Keeling (5.5 MB PDF).
Presented Dec. 6, 2005, at the American Geophysical Union, San Francisco. 50 p
http://www.giss.nasa.gov/~jhansen/keeling/keeling_talk_and_slides.pdf
Additional reading:
http://groups.yahoo.com/group/ClimateArchiveDiscussion/
8 January 2006 at 10:09 PM
RE #15 - Here’s another commentary with Christy’s comments. This appears to be the source of the UPI story.
http://www.livescience.com/environment/060106_2005_heat.html
It is rather strange that Christy appears to be unaware of the model results which project that the greatest warming will be seen at polar latitudes. Now that his TLT results have been changed to show warming in the tropical troposphere, one wonders why he is still downplaying the warming trend. One might think that he has an agenda.
8 January 2006 at 10:52 PM
#20, a key clue which shows some bias would be articles, like the one you linked, which claim 2005 as #2 warmest (true for some organizations) globally, but fail to mention that 2005 was #1 for the Northern Hemisphere, with 6 months having anomalies greater than +1 C (Nasa Giss). Another clue, is Christy’s baseline GT temperature period, 1979 to 1998, giving an impression that current temperature anomalies are weak. I would expect a great deal of opposition from what ever else like minded experts are conjuring up.
9 January 2006 at 10:40 AM
Christy has a point(ish). A portion of the polar warming is due to a shift in the Arctic Oscillation. Now this shift might be triggered in some way by global warming. Then again, it might be natural - the jury is currently out on that one. What’s clear is that trends in sea level pressure differentials (arctic-tropical) over the past century are not recreated by the models at all well (Gillett et al, 2005)
9 January 2006 at 12:28 PM
#22, If Arctic Oscillations have any effect on Arctic Ocean sea ice similar to what is going on right now, it would be hard to prove,. Case in point, the quest for the Northwest passage and Bowhead whaling, historically documented events backed by Inuit oral history. If AO’s repeat themselves a couple of times within 100 years , they didn’t clear the ice as much as with fall of 2005. The Norse couldn’t go further West then Devon Island ( about 800-1000) , from Martin Frobisher (1576-1578) , amongst many others following (Davis, Bylot etc). , would have had this passage named after them . Aso whalers ( late 1700t o 1910) would have easily made it down to Alaska from Baffin Bay, invited by an AO triggered occasion of wide open water, and so, some multiple attempts to crack open the Northwest Passage route should have been successful. The passage was said to be impossible, until Amudsen used a small ship, it took all his formidable skills to make it through between 1903-06. Right after this accomplishment Captaine Bernier (1906-1925) didn’t find the ice packs any easier Not until the advent of modern Ice breakers was this passage used on more or less an irregular basis. From documented history, late 16th century until recently, there was no period of an open sea route, or depleated ice conditions, which would justify AO cycles causing similar recent ice conditions, nothing in history is confirming this newly theorized strictly Polar warm up concoction.
9 January 2006 at 12:58 PM
The warming of the Arctic in the early 20th century was probably a result of the influx of warmer water into the Barents Sea, resulting from a short-lived change in wind patterns (although probably not AO/NAO) - Bengtsson et al (2004). So substantial Arctic warming can occur naturally. The pattern of modern warming is different, however, suggesting a different mechanism is afoot.
9 January 2006 at 1:34 PM
With my limited knowledge, I’m trying to think about various GW factors together. There is the fast(er) warming of the Arctic (for whatever reasons, AGW and/or natural oscillations), which would melt permafrost & send up CH4 & CO2, causing greater GW, not to mention the positive feedback of reducing albedo, and these perhaps eventually leading to the melting ocean clathrates & releasing even vaster amounts of CH4 & causing a lot more warming.
(I think there’s also the physics of ice melting — the melting process requires (absorbs) a lot of energy, but once ice is melted water warming happens very rapidly, along with air warming — since the refrigerator effect is no longer in play. OK, go ahead & laugh at my kitchen physics.)
I’ve also been reading news reports about the slowdown in the Atlantic ocean conveyor, which if greatly slowed or halted would make the Arctic colder, and would perhaps reduce this thawing, as apparently has happened in the past.
But could the rate of these processes have a bearing on the ultimate configuration - whether we trigger enough negative feedbacks (e.g., ocean conveyor halting) to stave off (limited) runaway GW, or whether the negative feedbacks don’t quite make it in time to thwart the positive feedbacks (e.g., thawing permafrost & clathrates), and we enter catastrophic (but limited) runaway GW? (For another instance, I think the rapidity of our GHG emissions seem possibly to be compromising nature’s ability to reaborbs these; plants like CO2, but if they’re dead due to heat or other GW-related factors, they can’t do much absorbing.)
In the past I think the warming & GHG release was slower, & once it triggered the ocean conveyor slowdown or halt, this greatly reduced natural GHG emissions. The natural GHG release & warming was slow enough for the ocean conveyor halt to gradual reverse the warming (except in the few cases of limited runaway warming & mass extinction).
But now we are emitting GHGs lickity split (in geological terms), and the warming (though it seems slow & sluggish on a human scale) is really quite fast, geologically speaking. And perhaps this speed will make the positive feedbacks superseded the negative ones, throwing us into limited runaway GW. And maybe we won’t get such a severe ice age in Europe & North America, even if the conveyor halts.
But even if it did get colder in the north, then people would be forced to burn more fossil fuels to stay warm. And, of course, here in the south, we’d be running our ACs full blast nearly year around.
So might the rapidity (as well as the dose) make the poison?
There you have it, how science gets translated into the mind of a semi-well informed layperson with an active imagination!
9 January 2006 at 6:24 PM
What I missed in this discussion until now, is the role of the increase in solar strength (another natural cause) of the last century in the increase of the Arctic temperatures. There is a comprehensive summary of the influence of the solar cycle (and ozone depletion) on global/polar climate by Baldwin and Dunkerton. The role of the longer term solar strength increase is not mentioned, but may be deduced from the results of the change from minimum to maximum within one cycle.
Further, what wonders me is the difference in trends in the Arctic seasons: warming in spring to autumn, but cooling in winter, strong enough to refreeze near all ice that was melted in the other seasons. The role of clouds (and their influence on the heat balance) in this is enormous (and not captured by any model)…
9 January 2006 at 9:38 PM
In mid-high latitude (lat) regions, cold seasons have become warmer and more humid and with shorter durations, than years ago, while warm seasons have become warmer and more humid and with longer durations than years ago.
Very cold and dry air masses in mid-high lat regions are less frequent now than years ago. Annual humidity in mid-high lat regions has increased compared to years ago, as shown in my studies on increasing annual average dewpoints in the Upper Midwest and other mid-high lat regions.
Increased humidity, cloud cover and greenhouse effect in mid-high lat regions are allowing the regions to warm more rapidly than in low lat regions. Shorter duration snow cover, shown in my studies on earlier season snowmelt runoff for rivers in the Upper Midwest, indicates a shorter duration of albedo-cooling effect than took place years ago.
Increases in humidity and cloud cover, and the greenhouse effect, particularly in mid-high lat regions in winter with longer nights and short days. Overnight loss of heat has been greatly reduced in mid-high lat regions in winter and other seasons as well.
Growing season duration has increased in the mid-high lat regions compared to what it was years ago, which has allowed increases in yearly evaporation and puts higher amounts of water into the air… leading to increases in humidity in the lower atmosphere. The higher amount of moisture in the lower atmosphere, particularly in mid-high lat regions is warming soils to great depths, as studies have shown. Cold loving native plants have been inhibited while warm loving invasive plant species are taking over undisturbed or lightly disturbed sections in mid-high lat regions at alarming rates, studies have shown.
Large increases in annual humidity and more frequent extended cloudy periods during the longer winter nights are most significant in the mid-high lat regions, compared to low lat regions. Mid-high lat regions will continue to experience higher rates of annual warming than low lat regions, mainly a result of large accumulations of of greenhouse gases in the atmospheric, a result of fossil fuel emissions and global warming feedbacks.
9 January 2006 at 11:11 PM
RE 26 & 27, I’m also thinking of the longer summer days & longer winter nights in the high latitudes. I read somewhere, I think in relation to the 2003 European heat deaths, that the nights do not cool down as much as they used to. I’m thinking there is not only a greenhouse effect during the day, but a GHG blanket-effect at night (& during the day), which would apply to the very long winter nights in the Arctic & keep us toastier than we would be without our additional GHG emissions, even in periods without much sunshine.
Of course, if the sun should become brighter, that would only amplify the warming all the more. Since we can’t control the sun, then we should be even more earnest in doing what we can do in reducing our GHGs. The more nature starts making things warmer, the more we will have to reduce. Luckily the scientists haven’t found any increased solar brightness at this point (and I believe them), but we should keep vigilant, ready to super-reduce if such should start happening.
10 January 2006 at 12:41 AM
Re: No. 26, 27, 28 - Someone (the U.S. Senate?) needs to investigate the National Weather Service. They are letting us all down. The National Weather Service should be using it’s staff of more than 100 offices 1-2 in nearly every state with ties to local and state gov and media, to help educate the public on climate change. Instead, they ignore the whole concept of global warming by saying the problem is minor or by saying it’s too controversial or uncertain or outside their area to say anything about it publicly. It the meantime, the situation gets worse while the public is kept in the dark.
My concern for a long time has been that the National Weather Service is doing a disservice to all of us by not doing what it is required by Congress to do - predict the weather, including flooding forcasts which threatens life and limb, based on the latest scientific knowledge, which includes knowledge of global warming. I have written my U.S. Senators about this in the past but didn’t have the studies to back up my concerns. Now I do.
Because of the increased temperatures and humidity, global warming increases the amount of water that major storms produce and discharge over land, thus increasing the potential severity of flash floods in places where it does rain (or snow). This was the finding of the study which is summarized below.
Therefore, the U.S. National Weather Service is remiss in avoiding
the reality of global warming in its flood prediction and public
warming notification programs.
The National Weather Service ought be investigated for being
negligent in its duties of accurately forecasting floods as they
are ignoring the whole subject of global warming which, according to the NCAR study, underestimates the severity of flooding and the threat to human lives and property (because more water is discharged).
——————————————-
Fri Oct 14 13:36:00 PDT 2005
“Warmer Seas, Wetter Air Make Harder Rains as Greenhouse Gases Build”
October 13, 2005
BOULDERâ??Storms will dump heavier rain and snow around the world as
Earth’s climate warms over the coming century, according to several
leading computer models. Now a study by scientists at the National
Center for Atmospheric Research (NCAR) explains how and where warmer
oceans and atmosphere will produce more intense precipitation. The
findings recently appeared in Geophysical Research Letters, a
publication of the American Geophysical Union.
The greatest increases will occur over land in the tropics, according
to the study. Heavier rain or snow will also fall in northwestern and
northeastern North America, northern Europe, northern Asia, the east
coast of Asia, southwestern Australia, and parts of south-central
South America during the 21st century.
“The models show most areas around the world will experience more
intense precipitation for a given storm during this century,” says
lead author Gerald Meehl. “Information on which areas will be most
affected could help communities to better manage water resources and
anticipate possible flooding.”
NCAR authors Meehl, Julie Arblaster, and Claudia Tebaldi analyzed the
results of nine atmosphere-ocean global climate models to explain the
physical mechanisms involved as intensity increased. Precipitation
intensity refers to the amount of rain or snow that falls on a single
stormy day.
Both the oceans and the atmosphere are warming as greenhouse gases
build in the atmosphere. Warmer sea surfaces boost evaporation, while
warmer air holds more moisture. As this soggy air moves from the
oceans to the land, it dumps extra rain per storm.
Though water vapor increases the most in the tropics, it also plays a
role in the midlatitudes, according to the study. Combined with
changes in sea-level pressure and winds, the extra moisture produces
heavier rain or snow in areas where moist air converges.
In the Mediterranean and the U.S. Southwest, even though intensity
increases, average precipitation decreases. The authors attribute the
decrease to longer periods of dry days between wet ones. The heavier
rain and snow will most likely fall in late autumn, winter, and early
spring, while warmer months may still bring a greater risk of drought.
http://www.ucar.edu/news/releases/2005/hardrain.shtml
10 January 2006 at 12:45 PM
My comment 2. in another thread says:
… I’m updating my Excel spread sheet data plots which show annual air temperature at Alaska climate stations (1950-2005 for most stations).
I’m more than half way done with the work now. I created two albums for Excel generated plots of annual temperature data (1950-2005) for groups of inland and near coast stations. The plots are available for public access for 7 inland stations now. Anyone can access the plots by going to:
http://login.yahoo.com/config/login?.src=ph&.done=http%3a//photos.yahoo.com/ph//my_photos&.intl=us
If you don’t have a member yahoo ID and password, it’s pretty easy to subscribe (for free).
Please let me know if you can get to them and what you think.
10 January 2006 at 12:58 PM
re 30.
I meant to post the text in 30. to the Naturally trendy thread, but since it’s already here at Polar Amplification I’ll keep it here only.
There is an easier way to access and view the Alaska temperature plots (inland and coast stations) … by going to and joining at:
http://groups.yahoo.com/group/ClimateArchiveDiscussion/
10 January 2006 at 5:56 PM
ClimateArchiveDiscussion(CAD) yahoogroup Photos now contains annual temperature plots for 13 stations in Alaska (7 more for coast group expected this evening or tomorrow am).
The 13 stations in CAD now include:
Inland area
———-
Northway
Talkeetna
Big Delta
Bettles
Fairbanks
Gulkana
McGrath
Coast area
———–
Homer
Anchorage
Annette
Barrow
Bethal
Cold Bay
http://groups.yahoo.com/group/ClimateArchiveDiscussion/
10 January 2006 at 11:55 PM
[NOTE: ALL MY TEMPS ARE IN FAHRENHEIT.] I don’t see how anyone can say that there is no evidence that establishes that the Arctic (and northern areas not as far north as the Arctic Circle) are warming faster than the rest of the globe. Yes they are. That is an absolute fact, not a claim.
I lived in Alaska for 17 years and, unlike many people who lived there, I ACTUALLY PAID ATTENTION. Juneau Alaska was founded in 1880, so we have 125 years of weather records. It was a much colder and snowier place until the 1970s. In 1986 the high was 92 degrees, never did it ever break 86 before. In the 1920s people sometimes had to walk through snow tunnels downtown taller than 7 feet. This never happens now. Snow 2 to 3 feet deep is a big deal now. Sometimes in mid-Winter in Juneau it now gets to 55 degrees. This never happened until the 1970s.
Almost all Alaskan glaciers are melting - more than 90% of them. The ice over the Arctic Ocean is smaller (in sq miles) every year, and thinner. I’ve stood on that ice at Prudhoe Bay — trust me, its changed dramatically. Many villages in Alaska are 8 or 9 degrees warmer than fifty years ago. Not the 1 to 2 degrees that climate scientists say the Earth as a whole has warmed in 100 years. ( I believe the Earth as a whole has warmed more than this, but that is less clear cut.) Tens of thousands of square miles of permafrost lands in interior Alaska are now melting, and are impenetrable bogs now.
There are HUNDREDS of pieces of evidence from all over Alaska which show a dramatic warming since the 1950s. The U.S. non-Alaskan media rarely report any of them. You will be shocked when you do some research and find out I am right.
11 January 2006 at 12:14 AM
Here’s an article stating that Northern Alaska and Central Alaska are now warmer than in the last 1,000 years. And that this region of Alaska warmed 1.0 degree Centigrade/ 1.8 degrees Fahrenheit PER DECADE between the mid-1970s and the mid-1990s.
11 January 2006 at 12:19 AM
The URL didn’t post . Here it is:
http://www.usgcrp.gov/usgcrp/seminars/971202DD.html
11 January 2006 at 12:57 AM
It is good to have this article on Polar amplification, very fortunate, especially when, by coincidence a newish theory (#15-16) clearly pushes it aside and almost claims amplification must not exist. Adding to #23, an important detail, would much like to read comments from evolution biologists, about their views on Bowhead whales, which are very regional, the Eastern Arctic Bowhead, does not migrate to Alaska, kept a peculiar counterclockwise migrating track around Baffin Island for millenia, Sir John Ross found a complete skeleton NE Baffin about 150 meters above sea level. Could it be that the Bowhead, nearly hunted to extinction by Eastern Arctic whalers (who never sailed to Alaska), have something to add to this debate? It is more like a final confirmation, there was no time like our days unless you go back, way back when the Pacific Bowhead was the same as the Atlantic one.
#26 Ferdinand , not so for clouds, go to any Arctic IR satellite picture , now is good , but better in a few weeks, and you will find that clouds are scarcer than at warmer latitudes, at certain times of the Arctic year, cloudless models should be quite accurate. In the context of the solar cycle, it may be easier to look back not so far in the past, 2004 with more sun spot activity was cooler than 2005, this in itself shows something else than solar activity at play.
11 January 2006 at 8:43 AM
Re #36: Waine, the suncycle-cloud connection is rather general. Measured by satellites, there is some 2% global (low) cloud cover change over a sun cycle (see Kristjansson ea. Fig. 1). This is measurable as a global temperature cycle of some 0.1 K (~ in phase for the 11 year cycle, with an average 2.2 years lag, for the 22 year cycle, see Scafetta and West) superposed over a longer term warming trend. The change in cloud cover and temperature is even more visible in the tropics, where the sea surface temperature can increase several tenths K in a few years towards a solar maximum.
The sun cycle is only vaguely visible in Arctic cloud cover changes, probably together with ENSO cycles (which have a lower frequency). Of more importance is the long-term solar trend: solar activity now is higher than in the past 8,000 years. There is measured evidence that changes in solar strength are coupled with climate for the short (11-22 yr) solar cycles and there is empirical evidence that longer term solar changes have their influence on longer term climate (LIA-current).
In addition, the Science article by Wang and Key points to the influence of the AO (Arctic Oscillation) for the advection of warmer air into the Arctic and a probable influence on cloud cover. The increase in solar strength may have an influence on this too, as changes in tropical stratospheric temperature are forwarded towards the poles and have an influence on the AO…
About the trends that current models project for the future Arctic warming: Even those submitted for the now pending AR4 have the wrong sign for cloud cover changes in the Arctic. From Winton, NOAA, page 3:
For cloud cover, this simply is the opposite of what is seen in reality. The increase of clouds in summer and the decrease of clouds in winter both reduce the warming, thus effectively counteract the amplification of the Arctic vs. the rest of the globe…
See further the graphs of the Science article at the UKww discussion list…
11 January 2006 at 9:37 AM
Re #34/35:
Robert, one need to be careful with articles which only give linear trends, as linear trends in cyclic events are highly vulnerable to start and endpoint choice. In the case of Alaska, there is a sudden rise in 1976, due to a change in PDO, but after that there is no trend at all (or even a slight cooling) for Anchorage, Fairbanks and Nome. Only Barrow, at the Arctic Ocean (probably more influenced by ice melting), shows a positive trend of some 2 degr.C in the period 1977-2005, be it that this is from -12.4 to -10.4.
Tom Rees has made a comparison of Alaskan temperatures with the PDO, where you can see that most of the temperature trend is related to the PDO, with a residual increase of 0.28 K/decade, which still is some 50% larger than of the global GISS trend. I suppose that most of the residual increase here too is due to the Barrow trend…
11 January 2006 at 12:53 PM
I’ve been sidetracked from completing my annual temperature plots at Alaska COOP stations. I took time instead to create a ten year moving average figure showing annual temperatures from 1820 through 2005 at Minneapolis. To my knowledge, there are no other stations in the U.S. that have a temperature record that goes back that far (1819). The figure can be viewed at:
http://madison.indymedia.org/newswire/display/28356/index.php
After using the ten year moving average, I’m planning to convert my figures for the annual temperatures at Alaska stations. Most of the stations in Alaska have 1950-2005 data, except Homer and Anchorage go back to the 1930s). The plots which I posted yesterday have five year trend lines, at:
http://ph.groups.yahoo.com/group/ClimateArchiveDiscussion/photos
11 January 2006 at 4:54 PM
In an early post (#6) it was mentioned that the data indicating a cooling trend in Antarctica has seriously problems. Are there external sources (preferably on the web) which go into this in more detail?
Thanks in advance.
11 January 2006 at 5:24 PM
I remember an RC contribution of Markus Rex from PKI/Potsdam in Dec04/Jan05 predicting an extreme decrease in Arctic ozone cover due to more numerous PSC’s, and as a consequence a falling total ozone column. So this would rather play against a warming, if I understand correctly (or do increasing clouds and falling O3 levels cancel out?) . Have Markus’s predictions been fullfilled? Can we estimate the cooling ( or better the not realized warming) caused by this thinning, if it happened. Have ground UVB levels reached exceptional high values in the Arctic this spring?
11 January 2006 at 6:46 PM
Most of Antarctic is warming, so there are no legitimate reports on cooling trends there. Articles below indicate Antarctica and ocean waters near Antarctic have been warming more rapidly than anticipated earlier.
Excerpts … The ocean west of the Antarctic Peninsula has warmed by more than a degree since the 1960s - contradicting the results of computer models. … Geophysical Research Letters, Michael Meredith and John King of the British Antarctic Survey write: “Marine species in this region have extreme sensitivities to their environment.” … A study published last year showed krill numbers had fallen by 80% since the 1970s and experts linked the collapse to shrinking sea ice (the crustacean feeds on algae under the ice). … Professor Lloyd Peck, a polar expert also at Bas, commented: “It is the first paper to show a temperature change in the Southern Ocean that could have ecological significance and possibly global importance.” … “Air temperatures on the Antarctic Peninsula have gone up by three degrees in the last 50 years or so and none of the computer models show that either,” Professor Peck told the BBC News website.
… 19 October 2005 Antarctic species feel the warmth
http://news.bbc.co.uk/1/hi/sci/tech/4356422.stm
Also see:
Antarctic glaciers calving faster into the ocean
18 October 2005 NewScientist.com news service
Fred Pearce http://www.newscientist.com/article.ns?id=dn8173
11 January 2006 at 6:57 PM
(I recognize I am going off topic here to engage a comment)
#29:
Michael, a call to investigate the NWS could end up crippling it. It has been downsized numerous times already.
I should mention that the local offices of the NWS are only pieces of NOAA. Are you talking about NOAA?…because you said National Weather Service, and they are different. NOAA also includes a many many “national centers,” some of which engage in short-term and longer-term climate projections. I suspect your beef is really with the National Center for Environmental Prediction (NCEP), or more specifically the Climate Prediction Center (CPC).
The local offices of the weather service mostly make daily and multi-day forecasts. They are also responsible for issuing Watches, Warnings and Advisories, with the exception of severe weather watches, which are issued by the Storm Prediction Center. I can’t imagine how working GW wording into their forecasts would go, especially because it is nearly impossible to demonstrate the effect of GW on an *event level.* Maybe something like this:
“Partly cloudy with a 30% chance of thunderstorms, the precipitation from which may have been enhanced by global warming. High of 84 (83 without global warming). Winds out of the south at 10- 15 mph, indicating a persistent, global warming-induced poleward transport of sensible heat.”
I agree that NOAA should have a better outreach program for public information. But unless we are going to start populating NWS offices with outreach climatologists (rather than operational meteorologists), I think we should leave the local weather forecast offices alone.
I should also point out that NOAA has always done a poor job of reaching out to the public. Just look at NOAA weather radio (which transmits local weather forecasts; you have to have a special receiver (shortwave or something in the 162.55 mHz range) to hear its transmissions. Most folks have to shell out extra money just to get this “publicly-available” information.
So I guess all this was to say, I think the problem you identified was with NOAA.
11 January 2006 at 8:18 PM
Thank you for your response. My understanding is also that the Peninsula has been cooling, but that it only makes up about 10% of the total area of Antarctica. Per comment #6, it sounds as though current data shows that on average, the Antarctic climate is cooling. The studies I have seen referenced on this point make the same claim.
http://www.sciam.com/article.cfm?articleID=000671C5-3A33-1CDF-B4A8809EC588EEDF&sc=I100322
http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v415/n6871/abs/nature710_fs.html
http://www.gsfc.nasa.gov/topstory/20020820southseaice.html
I am interested in finding and reading the sources that show that this data is incorrect.
11 January 2006 at 8:50 PM
I think I’ve read the articles sited 44, 3-4 years ago. The data used in the articles to claim a cooling trend anywhere in Antarctic was outdated even then. It is badly misleading to make general statements about a cooling trend or absence of warming using outdated regional climate warming data without clearly showing the dates associated with the data and reports.
Samples:
According to a new study, air temperature on the southernmost continent fell by 0.7 degree Celsius per decade between 1986 and 2000
http://www.sciam.com/article.cfm?articleID=000671C5-3A33-1CDF-B4A8809EC588EEDF&sc=I100322
… net cooling on the Antarctic continent between 1966 and 2000,
The McMurdo Dry Valleys have cooled by 0.7 °C per decade between 1986 and 2000,
http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v415/n6871/abs/nature710_fs.html
21 years (1979-1999) of Antarctic sea ice satellite records and discovered that, on average, the area where southern sea ice seasons have lengthened
http://www.gsfc.nasa.gov/topstory/20020820southseaice.html
11 January 2006 at 10:55 PM
Sorry, I should have included the dates - because they were available in the articles and I provided the links, I assumed I didn’t need to include them, though this was a mistake.
Is the 2000 data really outdated? In the initial post, a paper with 2003 data about the Artic is sited as a source, as is data from papers from 1997 (Minobe 1997) and 2002 (Beltaos 2002). Without going into details (though I am happy to, if needed) much of the studies re: climate use data that only goes up to 2000 or so.
Of course, if there is a newer study on Antarctica average temperatures, then the data I site would be outdated. Is there such a study, and if so, would you provide the name / source so that I may read it?
I would also be happy to receive a source for the claim made in #6, if someone would provide it.
Thanks.
12 January 2006 at 12:08 AM
RE #40 and 44:
The temperature trends deduced from the MSU instruments on satellites shows a cooling trend at high southern latitudes. This data is not the same as surface temperature, as the MSU channel 2 measures a weighted sum of microwave emissions in a narrow frequency band, which it is claimed, represents “temperature”. However, there is still some questions regarding the validity of this data and there have now been several approaches used to analyze this information.
The two most often referenced results are those from Spencer and Christy at UAH and Mears and Wentz at RSS. Both have now produced a so-called “lower troposphere” analysis. Mears has a presentation available which includes a plot of the trends of these two products vs. latitude from computed zonal averages. In Figure 4, both approaches show cooling at high latitudes in the SH. Here’s the URL link:
http://ams.confex.com/ams/Annual2006/techprogram/paper_104116.htm
This is a follow on to the paper Mears and Wentz published in SCIENCE last year. Notice that Mears and Wentz have chosen to exclude the data poleward of 70S, which includes almost all the Antarctic. Christy and Spencer still include the highest SH latitudes, AIUI. There is a known problem of surface influence due to high mountains, such as those of the Antarctic. There may also be another problem due to the large annual cycle in sea-ice extent, as I suggested in a GRL report in 2003. Take a look back at the earlier RealClimate comments regarding the continuing MSU controversy, especially the new CCSP report on some of the issues.
http://www.realclimate.org/index.php?p=170
http://www.realclimate.org/index.php?p=217
12 January 2006 at 1:49 AM
Thank you - looks like some good bed time reading!
12 January 2006 at 5:13 AM
Eric, thanks for the link to the new paper. Could you point to where it says that S+C continue to include latitudes south of 70S? Figure 4 seems to show them all stopping there.
12 January 2006 at 10:55 AM
re Justin Rietz in 46. Is the 2000 data really outdated?
I think 2000 is out dated, especially as the endpoint in a range of years, suggesting to the RC viewer that it may pertain to recent years.
Trends for these ranges in years (below) have nothing to do with what’s happening now.
As in this excerpt:
“Although previous reports suggest slight recent continental warming, our spatial analysis of Antarctic meteorological data demonstrates a net cooling on the Antarctic continent between 1966 and 2000″,
Antarctic climate cooling and terrestrial ecosystem response
PETER T. DORAN*, JOHN C. PRISCUâ? , W. BERRY LYONSâ?¡, JOHN E. WALSH§, ANDREW G. FOUNTAIN, DIANE M. MCKNIGHT¶, DARYL L. MOORHEAD#, ROSS A. VIRGINIA, DIANA H. WALL**, GARY D. CLOWâ? â? , CHRISTIAN H. FRITSENâ?¡â?¡, CHRISTOPHER P. MCKAY§§ & ANDREW N. PARSONS**
* Department of Earth and Environmental Sciences, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607, USA
â? Land Resources and Environmental Sciences, 334 Leon Johnson Hall, Montana State University, Bozeman, Montana 59717, USA
â?¡ Byrd Polar Research Center, Ohio State University, 1090 Carmack Road, Scott Hall, Columbus, Ohio 43210, USA
§ Department of Atmospheric Sciences, University of Illinois, 105 South Gregory Street, Urbana, Illinois 61801, USA
Department of Geology, Portland State University, Portland, Oregon 97207, USA
¶ Institute of Arctic and Alpine Research, 1560 30th Street, Campus Box 450, Boulder, Colorado 80309, USA
# Department of Earth, Ecological and Environmental Sciences, 2801 W. Bancroft Street, University of Toledo, Toledo, Ohio 43606, USA
Environmental Studies Program, Dartmouth College, 6182 Steele Hall, Hanover, New Hampshire 03755, USA
** Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, Colorado 80523, USA
â? â? USGSâ??Climate Program, Box 25046, MS 980, Denver Federal Center, Denver, Colorado 80225, USA
â?¡â?¡ Division of Earth and Ecosystem Sciences, Desert Research Institute, 2215 Raggio Parkway, Reno, Nevada 89512, USA
§§ Space Science Division, NASA Ames Research Center, Moffet Field, California 94035, USA
Correspondence and requests for materials should be addressed to P.T.D. (e-mail: pdoran@uic.edu).
http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v415/n6871/abs/nature710_fs.html
12 January 2006 at 11:47 AM
I’m not commenting re 49. 23. directly, just some general comments I’d like to make, below.
It is clear that many contributors to RC do not understand the links between NOAA and NWS and how those links have changed over time. For example, the Weather Bureau was operational for 3/4 of a century before NOAA was created. NOAA came about round 30 years ago, starting out with little or no direct influence on how NWS functioned.
In Jan 2000, Dr. James Baker head of NOAA, made powerful statements while a guest for 5 straight nights on the CBS Evening News with Dan Rather … about the very serious threat of global warming 5 days in a row in Jan. of 2000
Seeing that convinced me that global warming was serious. At that time, the director of NWS was Gen Jack Kelly, now a NOAA administrator. While Gen Kelly was NWS director there was little or no concern given to global warming.
In 2001, there was a policy change of some kind that resulted in the Bush Administration forcing a change in the leadership at EPA, due to statements made by then EPA director (name slips me), which statements were made publicly about a flipflop in the Bush Administration position on CO2 related to global warming. A new EPA leader was chosen, then the Bush Administration called for more science research and technology as his way of dealing with global warming. Directors of the major departments and agencies (the permanent civil service career positions) are now (since 2001) operatiing under the direction of the Bush Administration agency administrators. For example the current director of NWS may be under heavy influence of the current NOAA Administrators (6-7?) and the Department of Commerce (DOC). I think Mr. Mahoney may be both a NOAA Administration and an Assistant Secretary of DOC, but I may be in error on that… hard to determine. Anyway, it never used to be that NWS directors were influenced much in terms of how their programs were operated (except for money). Now it seems like the Bush Administration has heavy influence on operations withing the agencies, especially regarding global warming. In years before 2001, permanent employee directors were pretty much free to run the agency programs the way they felt the agencies would be most responsible to the public. Now the operations of federal agencies seem to be influenced heavily by whoever has the power of the President and Congress. Thus, there is potential for agencies to have more numerous and larger flip flops in the way programs are run for the public service.
I got a bit more lengthy than I planned. Now little time left to proof read, so if other’s at RC see these things a bit differently than described above please comment.
12 January 2006 at 12:53 PM
RE melting glaciers (e.g. in Greenland), scientists sometimes state that the sea would rise by such & such (say, 20 feet) if such & such glaciers melt. Now is this 20 feet projected rise taking into account that the land ususally slopes gently away from the shore. I mean, does this indicate that if we live 19 feet above sea level we can expect the sea to come into our homes, or are they basing their calculations on an image of a huge 90 degree cliff along all shores?
12 January 2006 at 2:30 PM
Re: 51:
Pat, you’ve done your homework…more than I am willing to do anyway. My whole point is from an operational perspective, the NWS, with its regional centers and local forecast offices has focused expertise in short-to-medium-range weather forecasting…with some hydrology thrown in there. Go in to a local NWS WFO and you will not find global warming experts there. Not now anyway. So why go after the NWS?
On the other hand, go to the big AMS meeting in Atlanta, and go to the 18th Conference on Climate Change (or whatever it’s called), and among the presenters you will see a number of the heavy hitters; many of their affiliations are with the big (NOAA-related) National Centers.
12 January 2006 at 2:35 PM
#47. I do understand that some AGW models call for a warming in the troposphere, especially in the tropics, but perhaps the upper air should be cooler over Antarctica, with most of its surface topography well above sea level, this should not come as a surprise at certain times of the year.
Some basic Upper Air analysis calls for the following examples: If the above surface lapse rate is “warmish” lets say a cooling of 8 C/km over an Antarctic station with a surface temperature to be -20 C, at 1 km ASL, 5 kilometers higher, the temperature would be -60 C. But if you take a “normal” Polar lapse rate of
5 C/km the temperature at this 5 kilometers the temperature would be -45 C, warmer!
The just of this story, is that warming of the Upper Atmosphere (by description many places in Antarctica) may be not found if the lapse rate is of a temperate nature . One must look at lapse rates rather than temperatures in the upper air to find any sign of significant warming. This obsession over Upper Air temperatures should be presented with lapse rate analysis otherwise it may be confusing. Then again most contrarian skeptics adore this ambiguity.
12 January 2006 at 3:09 PM
Re #52 (LV): 20 feet (or so) is 20 feet, whether across a slope or up a cliff. If you mean did they take into account the fact that there’s a little extra volume involved with the slopes (as opposed to cliffs), I suspect the volume difference is so small as to not make much difference (maybe an inch or two). If you’re really curious, the calculation would be pretty easy to do to a first approximation. All you would need is the number on total ocean shoreline (inc. bays etc.), assume a number for average slope, say 5 degrees, work out the volume involved up to 20 feet, then see how that stacks up against the 20 feet applied to the existing ocean area.
12 January 2006 at 4:29 PM
Your “big (NOAA-related) National Centers” don’t have any local or state contacts in government or media centers. There has been no way for not so “big (NOAA-related) National Centers” people in NASA, NOAA CMDL, NCDC and other not so big agencies to get the word out locally on global warming. The really big agency is NWS (more than 5000 government employees and managers with ties to local and state governments through their “outreach”, but nobody is reaching out to inform the people about the change in climate that happening. It’s obvious that rapid global warming is already upon us and that most of it is due to our emissions from burning fossil fuels, but no one is willing to talk about it or try to explain it to the public at the local level.
The attitude to not take any economic risks toward reducing greenhouse gas emissions has been sickening me for six years already, since Jan. of 2000. I have two young adult daughters who would like to have families. Do you think this world will offer the babies born this year a good chance for a happy life? I don’t. Young people need to think about this now, as part of their decision making process on starting or building on a family. They’re not. They should think about how their babies will feel about all this after they mature.
12 January 2006 at 4:49 PM
RE #49
Steve, the reference I gave is written by Carl Mears. Christy and Spencer (UAH) appear to still include the highest latitudes of the SH in their analysis. If you will look at the CCSP Draft SAP 1.1, Chapters 3 and 4, figures 3.5c and 4.3a and 4.3b, you will notice the different coverage. It should be noted that RSS also excludes other mountain areas and maybe Greenland as well (Fig 4.3). You may download the individual chapters as Acrobat files or just the figures from each chapter.
http://www.climatescience.gov/Library/sap/sap1-1/public-review-draft/default.htm
Of course, C & S may be doing something different now, for all I know.
12 January 2006 at 4:56 PM
Re: #43 #56
The Arctic’s temperatures exert a major influence on local weather conditions, including weather predictions. Therefore, global warming - and polar amplification in particular - ought be very much of concern to an agency like the NWS, who’s duties include weather prediction and the issuance of storm warmings, flooding alerts and heat wave advisories to the public.
Regarding getting the information out before the public, pat’s right. The NWS has a powerful means of communications with the public through its contacts with local TV, radio and newspaper media meteorologists. It uses them when it issue advisories and warmings, it should have been alerting them about greenhouse gas warming as well. Political interference by the Bush administration prevented that.
The TV and radio personalities who carry the message about “weird” weather, flash flooding and storms, etc., cite the NWS as the source of the predictions in much of what they present over the air. It’s not NOAA who gets the credit for issuing the warnings and alerts - itâ??s the NWS.
The fact that the NWS ignores global warming has a direct bearing on the accuracy of its predictions. The Arctic air that moves into Wisconsin nowadays is not as cold as it once was. The warming has already measurably influenced the timing of snowmelt, when the ground frost can be expected to leave, when ice goes out on its rivers and streams, and even what kind of plants are prevalent.
The seasonal weather we have experienced in the past in Wisconsin is no longer a good indicator of what kind of weather we can anticipate in the future. For example, the cold, numbing weather conditions during the Ice Bowl football game in Green Bay when the Packers beat the Dallas Cowboys in the NFL Championship Game doesn’t visit anymore. It had been the kind of winter weather Wisconsin was once known for. During the 50s and 60s, we annually had several days of 20 below zero (sometimes lower) temperatures. Not anymore.
NWS managers have been given orders not to reality of global warming into public conversations, reports and public presentations. I’ve heard it said on a Wisconsin public radio program that I listened to last fall. A member of the public called in and said they walked into a federal agency staff meeting in Manitowoc Co., WI, and heard the NWS staffers say they had orders not to talk to the public about global warming. They were forced to choose between disciplinary action and the possible loss of job and retirement pay, or being silent about global warming. The public has been deceived by our government into believing global warming is not a problem. This problem needs to be corrected because there are a lot of people in the U.S. who believe global warming is still not really happening (nor is polar amplification), because neither the National Weather Service, their president nor their local TV meteorologist have said it is. That needs to be corrected, now!.
Congress needs to act on this, now! What is needed are Congressional hearing. The issue should also be extensively addressed in the State of the Union speech. It probably won’t be if people who know it should be remain silent though.
http://www.beyondearthday.com
12 January 2006 at 5:37 PM
Mike, Pat,
I yield that you are paying more attention to NOAA/NWS than I am, at least administratively. I stress that issuing a severe thunderstorm warning for Taylor county is very different–and requires a different kind of expertise–from informing the public about global warming. Do I think local offices *should* have the capacity to do better AGW outreach? Yes. Do I think they *do* have that capacity currently? No I do not.
I agree with you: throughout the Upper Midwest, winters are not what they used to be; that stopped in 1986. We may indeed have seen an obvious impact up here before much of the rest of the country, where the jury still appears to be out. But for people who are from this region and can make even mediocre observations, it’s a no-brainer. Substantial regional climate change is well underway.
A minor correction. You said that: “The fact that the NWS ignores global warming has a direct bearing on the accuracy of its predictions. The Arctic air that moves into Wisconsin nowadays is not as cold as it once was.”
The second part of the statement is accurate; the first is fallacious. NWS forecast verification scores are not suffering from the effects of GW. The initial conditions on which numerical forecast models are based are already present…so modified conditions are built into the forecasts.
12 January 2006 at 6:40 PM
RE: #52. Taken as a whole, the ice sheet in Greenland is not melting, but growing. While receding has occured near the Greenland coast, significant increases have been measured in the interior of
Greenland, resulting in a net total gain of 5.4 ± 0.2 cm/year.
Johannessen et. al. 2005. SCIENCE: http://www.sciencemag.org/cgi/content/abstract/310/5750/1013
[Response: It is not as clear as that. The remote sensing does not give the answer right to the edge, and there is significant melting at lower elevations. See Alley et al 2005 http://www.sciencemag.org/cgi/content/abstract/310/5747/456 from the a few issues before. -gavin]
12 January 2006 at 6:51 PM
re 59.
Ken,
In our posts earlier this month at RC (Naturally trendy) we discussed the NWS hydrologic probabilistic products, which are based on the NWS Advanced Hydrologic Prediction Service, AHPS. http://www.crh.noaa.gov/ahps2/index.php?wfo=mpx
In 93. you said that you “believe large short-term hydrologic events do make it into the probabilistic outlooks also. It’s not perfect, but I do think it is a reasonable product”.
In 94 I replied that although I understand that things can’t be perfect, I believe that professional hydrologists should try to adjust for inadequacies in modeling procedures and forecasts, which currently do not take account of the large amount of evidence showing that hydrologic climate warming has been happening in the Upper Midwest.
A took quite a bit of my time in posting additional links in 94. and 96. on AHPS hydrologic operational products in effect now for many river stations in Minnesota, Wisconsin and Michigan. I’d like it if you could review some of the information at those links and post any comments you may have on that to this thread instead. Although the Upper Midwest isn’t in a polar region, like Mike said, we did used to feel the effects of bitter arctic air much more frequently years ago than in recent decades. After your review (hopefully you can squeeze in some of your time), I’d like to know if you still think it’s OK for NWS to ignore regional hydrologic climate change trends in issuing their 90 day probabilistic guidance for spring flood potential, and at other times of the year for floods and droughts?
Naturally trendy?
http://www.realclimate.org/index.php?p=228
12 January 2006 at 10:48 PM
Re: 59:
Long ago, I used to be able to eat and pay bills because of the NWS. Administrative stuff aside, the folk working there do way more with their salary than 99% of professions [data point possibly biased :o) ]. I used to plot Skew-Ts by hand, and the technological revolution should have freed up time spent plotting etc. to think about stuff and to acquire more data - but instead budget cutcutcuts haven’t alleviated stress and there still aren’t enough data in the GulfAK and WPac to do the job the way it should be done.
Just a different perspective.
Best,
D
13 January 2006 at 12:37 AM
re 62.
NWS would be serving in the best public interest by helping to educate the public about global warming. Why aren’t they?
13 January 2006 at 2:35 AM
Dano,
Thanks for the perspective. I still teach hand-plotted stuves, because, you know, we all had to go through it! (For those of you wondering what Skew-Ts and Stuves are, they are “psuedoadiabatic” diagrams on which weather balloon or “sounding” data are plotted. They have numerous axes: temperature, pressure (height), mixing ratio, dry and wet adiabatic lapse rates. I think they are fun, but most would disagree).
D, I think you were referring to the unusually low pay NWS employees receive, especially if they don’t make their careers there. Or were you saying they engage in an abnormal amount of “extracurricular” activies?
Pat, in answer to your question, I spent a decent amount of time looking at and studying the links you provided. I must admit that I generally am on the other side of hydrology (precipitation production), so I had to stretch my brain a bit.
If the probabilistic forecasts *are* being informed by the traces you showed–which do indicate a one-month shift towards earlier peak flows in recent years–then I think that information should indeed be available to the public, even if burried somewhere in a technical discussion.
I am not sure on which level you mean “…ignore regional hydrologic climate change trends…” If you mean that they don’t even take it into account when making their probabilistics, then I think that is patently dumb, because we have a bonafide trend that I personally feel I can hang my hat on with very good success. If you mean that they aren’t mentioning it as a basis for their reasoning, then, no, I do not think that is okay. I should stress that if it did seem like I disagreed with your position, it was because we were talking about two different things.
13 January 2006 at 12:29 PM
RE 58, Here is an example of perverse TV weather reporting. NBC News yesterday (1/12/06) had a segment on really abnormal weather events around the world — way too warm where it’s usually cold, extreme rainfall, etc, including 60 degrees (I assume F) below the norm in Delhi this week, where many many people have died from the cold. They seemed to be leading up to, “Could this be due to GW?” They didn’t even mention GW (if I recall), but came to the conclusion that these events were all quite normal. Typical January weather.
Well, if it’s abnormal, how can it be normal, esp. worldwide? I thought the least they could have done is say, “We can’t attribute any single weather event to GW, since GW is about overall statistics, but these weird events are what we might expect in a global warming world. So let’s do what we can to reduce our GHGs.”
At the very least they should have remained mum about it being normal & typical & usual. We’ll have a new generation who think GW & its effects are typical & normal, so don’t fight them, just live (& die) with them.
13 January 2006 at 1:34 PM
Ken (#64), it was the pay even then, how hard you scramble, and the distractions to continuous thought during the time you’re in the office (I wasn’t eating prime rib, for sure). Conditions then (and data paucity) made wx forecasting more difficult than it needed to be. This was before the internets and Wx Channel-type operations, so it was tough to strike out on your own. We sometimes had to plot sfc obs too, and I still have ICAO station identifiers crowding out important information in my head [it’s fun when you don’t have to do it]. BTW, I think if you plot by hand, LIs are much easier to comprehend and appreciate - I suspect some of these young guys in PacNW don’t recognize this…
Say, what was the topic again?
Best,
D
13 January 2006 at 4:41 PM
re: 24. Tom Rees wrote … “The pattern of modern warming is
different, however, suggesting a different mechanism is afoot”.
My recently completed plots of annual temperature for 19 climate stations in Alaska (most 1950-2005) are now at:
http://ph.groups.yahoo.com/group/ClimateArchiveDiscussion/photos
Do you see PDO and global warming signatures?
13 January 2006 at 5:33 PM
Ken said: …” If you mean that they don’t even take it [G. warming] into account when making their probabilistics, then I think that is patently dumb …”.
I agree. But I’d go a lot further than just saying “it’s dumb”. I’d also say it’s neglectful and potentially injurious to the public. Look at it this way, the National Weather Service, an agency that most people in the U.S. (and outside the U.S.) have come to trust and rely on, has been knowingly making errorenous predicitons by ignoring regional hydrologic climate change trends in issuing their 90 day probabilistic guidance for spring flood potential, for floods and for droughts. Especially now in light of the polar amplification (which suggests the warming rate is speeding up), this is very serious matter that demands to be exposed. Spring is in fact almost already here in Wisconsin. January temperatures in Madison have been way, way above normal for this time of year. Madison’s lakes and rivers are already beginning to open up (I ride right by two three of them on my way to work everyday). Yet the NWS continues to make its predictions based on political directives from the White House, rather than on well-established scientific principles and facts.
Let’s face it, the only way to right this wrong is for the Congress to conduct hearing, exposes the guilty parties, and correct the policies and procedures as soon as possible before spring flooding begins throughout the Midwest.
15 January 2006 at 5:50 PM
I am 56 years of age with 5 grandchildren and I would like to support the views of Pat Neumann in 56..
I feel myself a bit like Lynn Vincentnathan, who with a name like that ought to be three people (sorry), as almost understanding what the major issues are.
From a risk point of view I have always been impressed by the impact of ice sheet melting on the way we live (or die). I have read two articles by Mr Hansen on ice sheet melting and in particular how the process could be catastrophic : it has a certain “feel” about it - sorry not to use scientific terms in a science blog but there it is. I remember Aberfan in Wales way back and the usual avalanches and landslides which are a feature of winter sports and adventure holidays. It is easy to believe that the process of cold to warm has a much shorter cycle than warm to cold.
I would like to disbelieve it please!
Can anyone recommend any good science on ice sheet melting?
16 January 2006 at 6:18 AM
Re #67,
Pat, one need to take into account the fact that solar cycles have a huge influence on Alaskan temperatures. From Sheng Hu ea. in Science, 2003 (for the abstract of the article see here):
They used sediments of Arolik lake (SW Alaska) to look for temperature proxies. Several cycles (135, 170, 195, 435, 590, and 950 years) were identified, of which the ~200, 400-500 and 950 year cycles are also identified in solar activity connected 14C and 10Be data. To be sure what part of the current Alaskan warming is due to GHGs and what part is solar related, one need to have more accurate estimates of the influence of current solar activity (which currently is very high, compared to the previous 8,000 years).
16 January 2006 at 9:57 AM
re 69.
Eachran, I too “would like to disbelieve it please!” I think you may be interested in the referenced material dealing with ice sheet melting, below.
Bowen’s “Thin Ice” is wonderful clear writing. … The author’s website has many photographs that didn’t fit the book:
http://www.mark-bowen.com/
His collection of links to the labs and publications is here:
http://www.mark-bowen.com/links.html
Excerpt from comment 38. at: http://www.realclimate.org/index.php?p=219
More technical, from Science magazine:
Miller, K.G. et. al (Science, 2005) said: “We propose that the early Eocene peak in global warmth and sea level (Fig. 3) was due not only to slightly higher ocean-crust production but also to a late Paleocene-early Eocene tectonic reorganization. The largest change in ridge length of the past 100 My occurred ~60 to 50 Ma (57), associated with the opening of the Norwegian-Greenland Sea, a significant global reorganization of spreading ridges, and extrusion of 1 to 2 x 10^6 km^3 of basalts or the Brito-Arctic province(58). A late Paleocene to early Eocene sea level rise coincides with this ridge-length increase, suggesting a causal relation. We suggest that this reorganization also increased CO2 outgassing and caused global warming to an early Eocene maximum”. The Phanerozoic Record of Global Sea-Level Change (Miller, K.G. et. al.): 25 Nov 2005 Science.
Excerpts from comment 20. at:
http://www.realclimate.org/index.php?p=236
16 January 2006 at 12:41 PM
Re #69 “The Two-Mile Time Machine” by Richard Alley is another book about the last ice collapse, when the temperature in Greenland rose by twenty degrees F within three years! They rose another 15F in the following 1000 years as the remaining northern ice sheets (except Greenland) melted. The initial rapid rise in temperature was almost certainly caused caused by the sudden disappearance of the sea ice in the north Atlantic. This would have altered the albedo and also converted the climate from cold continental type to warm oceanic type. The same rapid warming is likely to occur when the Arctic sea ice goes!
You can see how rapidly the Arctic ice is thinning on my webpage at
http://www.abmcdonald.freeserve.co.uk/north.htm
Each year the winter extent remains high but the concentration decreases because the ice is thinning.
This sudden warming cause by the Arctic sea ice is included in James Lovelocks’s new book ‘The Revenge of Gaia’. He says “To give just a single example out of very many: the ice of the Arctic Ocean is now melting so fast it is likely to be gone in a few decades at most. Concerns are already acute about, for example, what that will mean for polar bears, who need the ice to live and hunt.
But there is more. For when the ice has vanished, there will be a dark ocean that absorbs the sun’s heat, instead of an icy surface that reflects 90 per cent of it back into space; and so the planet will get even hotter still.”
See ‘Why Gaia is wreaking revenge on our abuse of the environment’ By Michael McCarthy
Published: 16 January 2006 © 2006 Independent News and Media Limited
http://news.independent.co.uk/environment/article338879.ece
16 January 2006 at 1:00 PM
Thanks for 71 Pat, a bit of light bedtime reading I suspect.
16 January 2006 at 2:39 PM
re 70.
Ferdinand,
It is wrong to say that the influence of current solar activity … “currently is very high, compared to the previous 8,000 years”.
See p. 19 in Hansen, J. 2005. Is There Still Time to Avoid “Dangerous Anthropogenic Interference” with Global Climate? A Tribute to Charles David Keeling (5.5 MB PDF). Presentation given Dec. 6, 2005, at the American Geophysical Union, San Francisco.
http://www.giss.nasa.gov/~jhansen/keeling/keeling_talk_and_slides.pdf
16 January 2006 at 3:40 PM
#74 how does page 19 of Hansen’s paper show solar activity is not at an 8,000 year high?
Of course the answer is it doesn’t. One on the aspects of climate science that I can’t seem to reconcile is that regardless of what solar scientists discover about how active the Sun is currently climate scientists still attribute very little forcing to the Sun. This hasn’t changed in the last several years. Hansen’s page 19 is basically the same forcings as shown in the 2001 IPCC TAR, which came out before the discovery that the Sun is at an 8,000 year high.
From 1640 to 1710 there were almost no sunspots recorded and the Sun was very inactive. Recent research has shown that the Sun is now at an 8,000 year high for activity. Does it really make sense that from 1750 to 2000 that solar forcing was only .3 W/m2?
[Response: There is no contradiction between a long term trend and it’s magnitude. However, how one scales the sunspot record to forcing is still uncertain on long time scales, though recent analyses have been arguing for a lower effect than previously suggested (Foukal et al, Lean’s latest papers). The key thing for recent decades is that there is no evidence of any increase since the 1950’s , and so solar is very unlikely to be a factor in the recent accelaration of the warming since the 1970’s - regardless of the scaling. - gavin]
16 January 2006 at 5:05 PM
Re #74,
Pat, for current solar activity, see Usoskin ea. for the last millennium, and for the past 11,000 years, see the abstract and the article by Solanki ea.
The presentation of Hansen has a lot of good information, but some of the assumptions are disputable. To name a few:
- Slide 12: Changes during ice ages / deglaciations are calculated as 0.75 K/W/m2. This includes the change in ice sheet albedo, aerosols and GHG changes (no changes in insolation?). But the ratio between those three is not true for the onset of the last glaciation, where ice sheets were again at their maximum, before CO2 started to decline, without much influence on temperature. See here for the temperature/CO2/CH4 graphs of the Eemian. This points to a lower sensitivity for CO2 and a higher sensitivity for ice sheet albedo.
- Slide 19&20: all the aerosol forcings here are assumptions, which are very uncertain and probably overestimated (huge changes in aerosol precursor emissions in Europe and South Asia are not measurable in regional temperatures). GHGs and solar only include direct forcing, but differ in feedbacks, like pole ward propagation of the jet stream, influences on cloud cover, precipitation,…
- Slide 21: The model follows the 1993-2003 ocean heat content change closely. But I don’t believe that the same model with the same parameters can follow the 1980-1990 ocean heat content trends (decreasing with increasing GHG levels…). See Levitus Fig.S2
- Slides 32&33: While I am jealous about the nice picture of the Illulisat/Jacobshavn ice fjord (mine is in cloudy, foggy conditions…), the retreat of the break-up point of the glacier started already before 1850 and was fastest in the period 1929-1953, before GHGs had much of their influence. Moreover, Greenland temperatures after 2000 just reach the temperatures seen in the 1930-1940’s, with a cooler climate in between…
16 January 2006 at 5:48 PM
re 70.
For periods when GHGs are at low atmospheric concentrations, slight variations in parameters other than GHGs may result in climate changes - possibly even cyclic.
However, when the concentrations of GHGs are high (like now), effects of slight variations in other parameters (like solar radiation) are washed out - for having a noticeable effect on climate.
16 January 2006 at 10:35 PM
re: #75 gavin
Foukal or Lean argue for a lower effect than the IPCC figure that Hansen used of .3 Wm2 for the last 250 years??
Also there are studies showing an increase in tsi since the 1980s. Scafetta and West show an increase as measured by ACRIM. While this is fairly new work and is still being discussed I think it’s a bit strong to say there is no evidence of increased solar forcing.
17 January 2006 at 1:26 AM
Re #75: Jim, you array climate scientistis against solar scientists, but I think it’s fair to say that most solar scientists (including one of the RC co-authors) disagree with your cites.
17 January 2006 at 3:48 AM
Re #77:
Pat, I think that you underestimate the strength of natural variations. A small (1%) decrease in cloud cover in the (sub)tropics (30S-30N) for the period 1985-1994 results in some 3 W/m2 more loss to space. That is as high as the combined forcing of all GHGs together since the start of the industrial revolution (but with opposite sign!)… The same for the Arctic, where cloud forcing trends actually exceed GHG forcing trends with an order of magnitude (again with opposite sign…)…
17 January 2006 at 5:00 AM
Re #75 (Gavin):
Gavin, as already mentioned by JimR, although there is still controversy between the MODIS and ACRIM calculation of TSI, if ACRIM is right, there is a short-term (11-year) increase of TSI of some 0.45 W/m2 TOA between the last two cycles. Based on different methods to deduct the short-term cyclic sensitivity (~0.10 K/Wm-2) for solar forcing (Douglass & Clader, Lean ea., White ea., Scafetta & West) the increase would be responsible for some 7-20% of the recent warming. Based on the 22 year cyclic sensitivity (0.14 or 0.17 K/Wm-2, according to White ea., resp. Scafetta & West), this may increase to 10-30% of the recent warming.
Moreover, even if the TSI plateaued in recent decades, it is higher today than in the 1930-1940’s (based on solar reconstructions). That means that the longer-term sensitivity via ocean heating and ice albedo still is at work. If one should stop GHG emissions today, all models still expect an increase of 0.6 K (and more) in the following century, due to similar feedbacks. Why shouldn’t that be true for solar influences?
I don’t think that one need to exaggerate the controversy between solar scientists and climate modellers, but I have the impression that climate modellers need to listen more carefully to what solar scientists have found (like the correlation between TSI and low cloud cover) and implement that in their models…
17 January 2006 at 7:33 AM
re 78.
There is little or no evidence for increased solar forcing but there is overwhelming evidence for increased greenhouse gas accumulation forcing. Trends at NWS cooperative climate stations show warmer overnight lows in January and February in higher latitude regions of the US. Temperature plots for stations with 100 years of record are at: http://groups.yahoo.com/group/ClimateArchiveDiscussion/
17 January 2006 at 3:52 PM
Ferdinand, as you are well aware, here’s what the solar scientists have found: http://ams.confex.com/ams/pdfpapers/74103.pdf . Accurate observations of the last quarter century show about .1oC insolation forcing. Also, regarding your proposal for insolation to have effects into the future similar to the GHG warming lag, what mechanism do you propose for this? Are you saying that insolation-driven heating has inertia?
17 January 2006 at 6:20 PM
This is not a polar story, but I thought it may be useful information, which really corresponds with what the IPCC is saying:
“‘Balmy’ Winnipeg weather breaks 134-year record”:
http://www.cbc.ca/story/canada/national/2006/01/17/winnipeg-weather060117.html
18 January 2006 at 9:13 AM
Re #83:
Steve, the 0.1 K you mention is about 25% of the recent warming, and is identical for what was deduced from empirical evidence, based on the 11/22-year cycle (thus not including longer-term responses). That is twice as high as what the direct change in radiance should have induced theoretically in the same period, which points to amplification mechanisms (where several are described in the article). About the past century, the article mentions: