Polar Ice: Crushed or Cubed

[don]

great shots: http://www.guardian.co.uk/environmen...udio-slideshow


keeping it between the poles . . .

[springbok]

Re: Polar Ice: Crushed or Cubed

Don,
This is my first post. I have been lurking around the iTulip blogs for about a month now. Great site. There are a lot of black belts on this site. As my knowledge grows perhaps I will become bolder.

I watched the video and gather that NPR believes that global warming is man made.

Scientists in general will champion the view point that their financial sponsor determines -the golden rule.

I would very much like to see an honest fact driven debate to discuss what is really going on with the climate.

I do know that in winter we have global cooling and in summer global warming.

[don]

Re: Polar Ice: Crushed or Cubed

This is a very touchy subject here on the 'tulip. An ongoing FIRE critique is a free pass in comparison. Why I don't know. I supposed there's no one answer. Some members have personal agendas they prefer not to reveal. Others simply have a measured difference of opinion.

[santafe2]

Re: Polar Ice: Crushed or Cubed

Don,
This is my first post. I have been lurking around the iTulip blogs for about a month now. Great site. There are a lot of black belts on this site. As my knowledge grows perhaps I will become bolder.

I watched the video and gather that NPR believes that global warming is man made.

Scientists in general will champion the view point that their financial sponsor determines -the golden rule.

I would very much like to see an honest fact driven debate to discuss what is really going on with the climate.

I do know that in winter we have global cooling and in summer global warming.

This was a greenman3610 blog post. The "honest fact driven debate" has already happened in the science community. This is a good place for economic discussions but don't expect much in the way of understanding climate change. As don said, there are agendas. It's not worth discussing on this site.

[Diarmuid]

Re: Polar Ice: Crushed or Cubed

Hi Don

You might find this new site interesting sponsored by the Dutch envirnomental ministry, it at least purports to do what you ask for - below some excerpts from its first article with opinions from three atmospheric science professors.

http://www.climatedialogue.org/

Melting of the Arctic
What are the causes of the decline in Arctic sea ice? Is it dominated by global warming or can it be explained by natural variability?
Introduction
Over the period 1979–2012, the Northern Hemisphere minimum sea ice extent for September—the end of the summer melt season— has declined by more than 11% per decade and the trend appears to be steeper for the last decade with record lows in 2007 and 2012. The decrease in winter sea ice extent is less strong, but the amount of thicker, older ice has decreased as well and therefore the decrease in total sea ice volume is even stronger than sea ice extent, both in summer and winter.
What is the cause?
Several studies have suggested that the decline in arctic sea ice is at least partly caused by global warming. An oft cited paper by Stroeve (2007)[1] and also more recent studies (i.e. Rampal 2011)[2] show that greenhouse forced climate models greatly underestimate the observed trend in arctic sea ice. A more recent study by Stroeve (2012)[3] shows that progress has been made in this area, but the climate models still cannot account for the full extent of the Arctic sea ice decline.
This could be explained as “it’s worse than we thought.” However it could also be interpreted as “models are yet unable to realistically simulate the sea ice behavior” and thus unable to conclude on the dominant role of global warming in the decline of Arctic sea ice. The low performance of climate models may be due to the difficulty in accounting for natural variations, or the physics associated with positive feedbacks. For example, it is not fully clear yet what role different oscillations have played like the Arctic Oscillation, the North Atlantic Oscillation and the Pacific Decadal Oscillation. Also, other anthropogenic forcings like black carbon could be important.
Discussion
A central question for the discussion is what is causing the recent decline in arctic sea ice. And can these processes be related to the emission of anthropogenic greenhouse gases?
Questions that are relevant for the discussion:
1) What are the main processes causing the decline in Arctic sea ice?
2) How unusual is the current decline in historical perspective?
3) What is the evidence for a substantial role of “global warming” in the current Arctic sea ice decline?
4) What is the evidence for a substantial role of natural variability (AO, AMO, NAO, PDO)?
5) What percentage of the recent decline would you attribute to anthropogenic greenhouse gases?
6) Do you think the Arctic could be ice free in the (near) future and when do you think this could happen?

Walt Meier

Over the last 30+ years, Arctic sea ice has declined precipitously, particularly during summer. Summerextent has decreased by ~50%, including most of the older, thicker ice [1, 2]. Globally warming temperatures have been the primary cause of the long-term decline in Arctic sea ice [3]. Many processes effect the sea ice on several temporal spatial scales – e.g., winds, ocean currents, clouds – but the multi-decadal decline in all seasons, and in virtually all regions (Bering Sea in winter being an exception) cannot be explained without the long-term warming trend that has been attributed to anthropogenic greenhouse gas (GHG) emissions.

Unique
The current decline appears to be unique in at least the last 5000 years. While the consistent satellite record began only in 1979, earlier partial records indicate decreased extent in the Russian Arctic and the Greenland and Barents seas during the 1930s [4]. However, these reductions were regionally and temporally variable, unlike the pan-Arctic decline seen in recent decades. There are also indications that the North American side of the Arctic did not experience warm temperatures and thus low sea ice conditions during those years [5]. Thus, the 1930s period appears to be more of a regional event, as opposed to the pan-Arctic warming and sea ice decline we’re seeing now.

Earlier than the 1930s, proxy records from paleographic data (e.g., sediment cores) are essential to understand Arctic-wide sea ice conditions. The indicate reduced sea ice extent at levels near or possibly below current conditions during the Holocene Maximum, a period between 5000 and 10,000 years ago [6], though these are far from comprehensive. The next earliest potential period when ice conditions might have been low as now was during the Eemian period, the previous interglacial, about 130,000 years ago when temperatures were quite warm.
Global warming
The evidence for a substantial role of “global warming” in the current sea ice decline comes from the fact that the decline (1) correlates with the global warming temperatures over the past several decades, (2) is outside the range of normal variability over the past several decades and likely over the past several centuries, (3) the decline is pan-Arctic, with all regions experiencing declines throughout all or most of the year. Also, model simulations of sea ice cover consistently show a response of declining sea ice to increasing GHGs (albeit slower than the observed decline); conversely, model runs over the last 30 years without GHG forcing do not show a decline [7, 8]. Finally, there does not appear to be a mechanism to sufficiently explain the long-term decline without including the effect of GHGs [9].

Attribution
It is difficult to put a precise number on how much of the decline is due to GHGs. There is strong natural variability, which is seen in observations and in model simulations. It is likely that at least some of the acceleration of the loss of sea ice in the past ~10 years is due to natural variability. A modeling study [14] suggested that about half of the observed September sea ice trend from 1979-2005 could be explained by natural variability, with the rest attributable to GHGs. There may also be some influence of black carbon, though how much is unclear.

Judith Curry

On the decline of Arctic sea ice
Judith Curry
I applaud the Dutch Ministry for establishing Climate Dialogue, and I am very pleased to participate in this inaugural dialogue on the decline of Arctic sea ice.
At my blog Climate Etc. http://judithcurry.com , I’ve written four lengthy articles on Arctic sea ice over the past 18 months:
Pondering the Arctic Ocean. Part I: Climate Dynamics
Likely causes of recent changes in Arctic sea ice
Reflections on the Arctic sea ice minimum: Part I
Reflections on the Arctic sea ice minimum: Part II
This essay presents an overview of my perspective on this topic; see the original articles for more details and references to scientific publications.
Observations
The conventional understanding of Arctic sea ice extent shows a general retreat of seasonal ice since about 1900, and accelerated retreat of both seasonal and annual ice during the latter half of the 20^th century. Hints that this understanding may be overly simplistic in view of the uncertainties and ambiguities in the period prior to satellites are described in this presentation by John Walsh about plans for a gridded sea ice product back to 1870. Further, I’ve recently had some discussions about this with a historian that is investigating historical reports of sea ice extend during the period 1920-1950. He has found reports of reduced wintertime extent during this period, and a general lack of data from the Russian sector. While this material is not yet published, it reminds us that prior to 1979, we do not have a reliable data set of global sea ice extent. The lack of such a data set hampers our ability to test our ideas about the impact of natural variability versus anthropogenic forcing on sea ice variability and change.
Analysis of climate dynamics and sea ice physical processes
The following factors impact the sea ice fate during the melt season:
▪ Thickness and compactness of sea ice at the beginning of the melt season: ice that starts out thinner is more easily melted away. Further, first year ice has different optical and thermodynamic characteristics than multi-year ice.
▪ Transport of ice through the Fram Strait (between Greenland and Europe), which depends on a combination of atmospheric and ocean circulation patterns
▪ Weather patterns that act to either break up or consolidate the ice
▪ Radiative forcing (which is dominated by the cloud patterns)
▪ Melting from below by warm ocean currents.
▪ Melting from above by warm atmospheric temperatures.
▪ Geographic distribution of the sea ice, which depends on a combination of all of the above
And all this is complicated by the fact that the minimum sea ice extent in an individual season doesn’t simply reflect that season’s weather processes, but also reflects the decadal history of sea ice characteristics, sea ice export and atmospheric and oceanic circulation patterns. And the sea ice extent itself influences the atmospheric and oceanic circulation patterns. Hence, the sea ice characteristics tend to be out of equilibrium with the thermal forcing in a particular year.
Older ice
Here’s the basic story as I see it. During the late 1980s and early 1990s, the circulation patterns favored the motion of older, thicker sea ice out of the Arctic. This set the stage for the general decline in Arctic sea ice extent starting in the 1990′s. In 2001/2002, a hemispheric shift in the teleconnection indices occurred, which accelerated the downward trend. A local regime shift occurred in the Arctic during 2007, triggered by summertime weather patterns conspired to warm and melt the sea ice. The loss of multi-year ice during 2007 has resulted in all the minima since then being well below normal, with a high amplitude seasonal cycle. After 2007, there was another step loss in ice volume in 2010. In 2012, the basic pattern of this new regime was given a ‘kick’ by a large cyclonic storm in early August.
Anthropogenic
So, what is the contribution of anthropogenic global warming to all this? It’s difficult to separate it out. The polar regions are extra sensitive to CO2 forcing and water vapor feedback, owing the low amounts of water vapor. However, any radiative forcing from greenhouse gases is swamped by inter-annual variability in cloud radiative forcing. In the bigger picture sense, greenhouse forcing is involved in complex nonlinear ways with the climate regime shifts. So there is undoubtedly a contribution from CO2 forcing, but it is difficult to find any particular signal in this year’s record minimum, other than the contribution of greenhouse warming to a longer term trend. In the overall scheme of what is going on with the sea ice, I think 2007 was the most significant event, followed by 2010. The big event in 2012 was the cyclonic storm, and the impact on ocean mixing may turn out to be more significant than the sea ice minimum.
There is a complex interplay between natural internal variability and CO2 forcing, with complex interactions among ocean dynamics and heat transport, sea ice dynamics forced both by atmospheric winds and ocean currents, and atmospheric thermodynamic forcing acting to determine recent variations in multi-year sea ice extent. Hence sorting dynamical versus thermodynamic factors and attribution to increased greenhouse gases is not at all straightforward.
So . . . what is the bottom line on the attribution of the recent sea ice melt? My assessment is that it is likely (>66% likelihood) that there is 50-50 split between natural variability and anthropogenic forcing, with +/-20% range. Why such a ‘wishy washy’ statement with large error bars? Well, observations are ambiguous, models are inadequate, and our understanding of the complex interactions of the climate system is incomplete

My own take, for what it is worth. It is is difficult in the extreme, if not intractable, to seperate out the anthropogenic green house gas contributions, from natural variability for recent atmospheric temperature rises. How much of said temperature increase caused what % of the artic sea melt is highly questionable because of the afore mentioned reason and other complicating factors (wind etc). Resulting in the subjective guesswork you see in the above articles.

Interestingly, one notices the disconnect in the tone used by atmospheric science professors in the article quoted above, as compared to many articles in the mainstream media and elsewhere. This highlights the fact imo, some of the science and much of the science output as communicated to the public and policy makers has been politicized and corrupted, mainly due to the far reaching monetary and social implications of policy stemming from AGW, it has been decided somewhere, there can be no room for doubt in the public mind and communication to the public on AGW, stems from there.

[santafe2]

Re: Polar Ice: Crushed or Cubed

My own take, for what it is worth. It is is difficult in the extreme, if not intractable, to seperate out the anthropogenic green house gas contributions, from natural variability for recent atmospheric temperature rises. How much of said temperature increase caused what % of the artic sea melt is highly questionable because of the afore mentioned reason and other complicating factors (wind etc). Resulting in the subjective guesswork you see in the above articles.

Interestingly, one notices the disconnect in the tone used by atmospheric science professors in the article quoted above, as compared to many articles in the mainstream media and elsewhere. This highlights the fact imo, some of the science and much of the science output as communicated to the public and policy makers has been politicized and corrupted, mainly due to the far reaching monetary and social implications of policy stemming from AGW, it has been decided somewhere, there can be no room for doubt in the public mind and communication to the public on AGW, stems from there.

While climate models aren't perfect, they do an excellent job of characterizing our climate's path. The he said / she said methodology used on this site only serves to make the science seem like it's still in question or as you said, intractable. The major aspects of natural variability are well understood. The forcing due to additional CO2 is also well understood. Curry isn't Monkton but her ideas are still noise at the edge of climate science.

I may not agree with Curry or find her work compelling, but I see no guesswork in either her work or Meier's. That said, you are correct that the corruption is palpable. Sides are forming and plan to make huge sums of money from global warming. Now that New York got it's butt kicked, politicians are jumping on the band wagon. If I remember correctly there was a time when EJ thought renewables were the next bubble. Maybe it's much bigger than that. Maybe global warming is the next bubble. There's nothing like having Wall Street get an environmental TKO to fire up FIRE. If so, this is going to be the mother of all bubbles.

[Diarmuid]

Re: Polar Ice: Crushed or Cubed

Santafe

Firstly thank you for the measured response, it is a refreshing change for what normally passes as conversation when discussing AGW.

You and I obviously see things differently I see mainly subjective opinions in the statements fronm the discussion on the Artic ice melt and very little testable or reproducible science wrt aCO2 attribution, forecasts and projections. I would bring to your attention the following quotes from the professors in question, as a way of illustration.

• • Ron Lindsay
    November 13, 2012 at 4:53 pm Log in to Reply
    I agree with Judith that the percent decline in sea ice due to greenhouse gases is rather uncertain. It depends on the time intervals considered for the base case and current state (how much natural variability is averaged out).
    I think we all agree that the AO, NAO, and PDO have little role in the long-term decline. I am less certain about the AMO, although I am inclined to think it too is a minor player. The Day et al. (2012) study suggests a contribution on the order of +/- 0.5 M km^2 for sea ice extent so a reversal in the AMO probably won’t reverse the ice decline. But given the small amount of heat needed to melt the ice at the rate we have seen (less than 0.5 W/m2 annual average), is it a hopeless task to find a definitive mechanism, particularly since the dominant forcing for ice anomalies likely changes from year to year?
  
  
• Walt Meier
  November 13, 2012 at 5:59 pm Log in to Reply
  I agree with both Judith and Ron that there is still fairly high quantitative uncertainty in terms of the amount of influence of greenhouse gases. But I think we’re all in agreement that GHGs are playing a significant, but not exclusive, role in the long-term decline of Arctic sea ice with the magnitude of the decline is enhanced to some degree by natural variability. What the balance is between these two influences is still a largely open question.
  The 50-70% range for GHGs that Judith mentions is probably a reasonable spread in capturing the potential range. I would lean more toward the high side of that range because the I don’t see the AMO and PDO having a large magnitude influence on summer ice. The AO does have a larger influence, but that has largely been lost in recent years.
  One final comment on Judith’s about the data. While our most complete dataset, the one we have the highest confidence in, is the passive microwave record, there is fairly complete coverage from operational ice charts back to at least the mid-1950s. And there are Russian ice charts for the Eurasian Arctic back to the early 1930s. Though not complete, these do extend the record and I think provide some sense of the interannual and decadal natural variability of the ice. There are indications of lower ice in the 1930s in the Russian Arctic [Reference 4 in my post], suggesting the influence (AMO?) of a multi-decadal cycle, at least in the Russian Arctic. But the data show a different character in terms of the seasonality and regionality of the lower ice conditions compared to the recent decline.

• Walt Meier
  November 14, 2012 at 6:15 pm Log in to Reply
  Following up from Judith’s comments:
  I agree that forced change (from GHGs) is intermixed with natural variability and separating out the two is difficult. And there interplay between the two, which I think is important because the impact of the natural variability on the ice may be changing as the ice changes in response to GHGs. For example, the AO has been observed to have a large effect on summer ice condition. When the winter AO is positive, thick ice tends to get pushed out of the Arctic through Fram Strait, leaving a thinner ice pack the following summer that is more likely to melt completely. The converse is true for a negative AO.
  Looking at plots of AO mode and September ice extent, the correlation is pretty good…until the early 2000s. Since then, the ice has continued downward even when the AO went strongly negative in the 2009/2010 and 2010/2011 winters.
  Similarly, we had a cold winter in the Bering Sea and a very late melt this past spring (perhaps related to the PDO). My thought was this year might be a relatively high year compared to recent years because that slow melt would impede later melt in the Beaufort and Chukchi Seas. But that did not happen. The August storm did help, as Judith mentioned earlier, but even without that storm we were heading toward a record or near-record low.
  What is different now? The ice is thinner. Thinner is more easily moved around and out of the Arctic, is more easily broken up into smaller floes (that are more susceptible to melt), and is more easily melted completely during summer. We’ve seen this in recent years in the Beaufort Sea. Historically, this region has been a nursery of old thick ice and the ice moved in a clockwise direction in the Beaufort Gyre aging and thickening over many years. However, in recent years, the ice in the gyre has not survived the summer. The nursery has become a graveyard. There is likely some influence of ocean waters, which may have a cyclical natural varying component, but the thinner, more broken ice is the larger factor.
  Our expectations for how the ice responds to natural variability is based upon a thicker ice cover, which may no longer be valid.
  I think this is one complicating reason why there is so much uncertainty in the proportion of human vs. natural influence and in what the future holds.
  My view of the future is that there will be increased variability in the ice pack and thus less predictability, at least for a time. When we reach “ice-free” conditions (i.e., <1 million sq km) is almost a moot point because that doesn't represent a point-of-no-return. The following year would likely have more ice and there will probably be a see-saw of very low vs. somewhat higher extents depending on the weather conditions. Even when first reach such conditions is uncertain due to such factors - how many storms will we get at key periods of the melt season, when will we have a strong AO winter that advects a lot of ice out during a winter, etc.?
  This is why projections from people like Peter Wadhams (who I agree would've been an interesting person to contribute) are not out of the realm of possibility even though I think they are highly unlikely. Nor would I disagree with Judith's comment that she doesn't have much confidence in projections in current projections
  By the way, I just saw that Peter Wadhams has an article in the upcoming issue of Scientific American, online here:
  http://www.scientificamerican.com/ar...e-save-sea-ice
  His comment on the latent heat physics is interesting, which may be an interesting jumping off point for another round of comments.
• Ron Lindsay
  November 14, 2012 at 9:52 pm Log in to Reply
  Estimates of the amount of sea ice decline due to greenhouse gases must come from models, and as Judith points out there are some uncertainties, but they are all we have … and they have a chance of being too conservative as well as too sensitive. I come back to the observation that ice volume is a much more consistent measure of the ice cover, showing much less year to year variability compared to the trend than ice extent or area. The CCSM3 model, for example, shows a clear separation in ice volume between the control and the A1B scenario as early as 1985, 10 to 15 years before the separation in ice extent (Schweiger et al 2011). The decline in volume is consistent with the PIOMAS estimates of ice volume (which is tied to the observed past weather and ice extent), given the uncertainties in both data sources. CCSM4 simulations show about a 50% decline in ice volume since the 1960’s with a typical ensemble spread on the order of 15%, so the CCSM4 runs indicate the decline in ice volume is about 3 times the natural variability, or about 70% of the decline is due to greenhouse gases. The decline in volume seen in the PIOMAS simulations is also very consistent, particularly if one focuses just on the Arctic Ocean since the late 1980’s. So I would go on the high side of the percentage loss due to greenhouse gases for ice volume and less for ice extent, maybe near 50%.
  It is possible there are large unknown sources of long-term natural variability, but I think the models and the observations show CO2 is the major cause of the decline. Other sources of large long-term variability (say 30 to 100 years) that could contribute substantially to the decline are mostly speculation. I also think the CO2 induced global warming will continue to cause a decline in the ice volume, even on a time scale of a decade or two. I agree with Walt that the summer ice will come and go for a number of years, depending n the weather and the winds, but when it first goes to near zero is quite hard to predict.

With regard to your statement.

The he said / she said methodology used on this site only serves to make the science seem like it's still in question or as you said, intractable. The major aspects of natural variability are well understood. The forcing due to additional CO2 is also well understood. Curry isn't Monkton but her ideas are still noise at the edge of climate science.

I believe this to be incorrect and at odds with even mainstream understanding. If you do not find Curry compelling I suggest you might take a look at this lecture from Tim Palmer (Cambridge / Oxford) where he speaks wrt to the uncertainties in climate models, you can check his credentials they speak for them selves. I think, I can say with quite a degree of confidence that forcing, feedbacks etc.. are not well understood at all, hence the large range within the temperature increase "projections" as a response to CO2 doubling, circa(1 to 6 degrees). This uncertainity is as I understand it, is increasing not decreasing, as more is uinderstood about the climate system and its underlying complexity. Tim Palmers video lecture, given to the AGU in 2010 can be found below if you are interested. Best Regards

http://www.agu.org/meetings/fm10/lec...eos/A42A.shtml

[Polish_Silver]

Re: Polar Ice: Crushed or Cubed

UIUC data.
Look at the total sea ice area, not just the "difference from mean". Artic summer ice is declining, but antarctic has barely budged.
The mean global temperature has only changed about 0.5C in the last century. Certainly within the range of natural variation.

http://www.ncdc.noaa.gov/paleo/globa.../medieval.html

[Chris Coles]

Re: Polar Ice: Crushed or Cubed

Discovered this illustration of OBSERVATIONS, rather than models. Food for thought?

http://neven1.typepad.com/blog/2012/...-catch-up.html

[LorenS]

Re: Polar Ice: Crushed or Cubed

At least 1/2 of the climate change skeptics exist for the very reason that the bulk of the "solutions" proposed by the politicians are pure bunk.

Cap & trade and Carbon credits are invitations to fraud, if not outright fraud from the start.
Keyoto - moving pollution to China India and Brazil doesn't help the planet it just moves even more US jobs off shore.

[charliebrown]

Re: Polar Ice: Crushed or Cubed

Help me understand ...

If you look at sea level since 1880, it looks like a pretty straight line rising. I don't see a ramp after say WWII where fossil fuely use eploded.
Perhaps the correlation between gw and sea level is not exact. If we use sea level as a proxy for global warming I would say something has been
happening since 1880. Unfortunately this is as far as the graph goes back.

Solar cylce?

I have heard by the anti agw people say that use of fossil fuels, although they add co2 to the atmosphere, also add soot and increase temperature increases atomospheric moisture, which makes the atmosphere more reflective so there is a natural damping of the CO2's effects.

I'm really not sure what to believe.

To me the agw thing smells like a tax grab.

I am trying to cut back. I have always bought small fuel efficient cars. I am replacing appliances with low energy versions when the old ones wear out. I wish
the gvt would but out, except for maybe solving chicken-and-egg type problems, and setting standards to enhance operability etc.

[santafe2]

Re: Polar Ice: Crushed or Cubed

Santafe

Firstly thank you for the measured response, it is a refreshing change for what normally passes as conversation when discussing AGW.

You and I obviously see things differently I see mainly subjective opinions in the statements fronm the discussion on the Artic ice melt and very little testable or reproducible science wrt aCO2 attribution, forecasts and projections. I would bring to your attention the following quotes from the professors in question, as a way of illustration.

You're welcome, this was a refreshing response. I'm sure we'll agree to disagree on some of this but let's have a discussion. As Meier says, CO2 attribution is "significant". From that we can assume it's not 10% and it's not 90%. Significant in scientist speak means serious but I'm not willing to call it over 50% because I can't yet prove it. There may be very short periods where climate variability. (ENSO, NAO, PDO, etc.) actually overtake the modern global warming trend and more adhoc variability like Pinatubo that overtake the trend for years. But the trend is upward. I hope we can agree on that. I see no down the up escalator inferences in your notes and that's huge if we're to have a meaningful discussion. If so, we may be past the nonsense that global warming does not exist. That the laws of thermodynamics have been undone. That additional CO2 as a significant cause, is a non issue.

I believe this to be incorrect and at odds with even mainstream understanding. If you do not find Curry compelling I suggest you might take a look at this lecture from Tim Palmer (Cambridge / Oxford) where he speaks wrt to the uncertainties in climate models, you can check his credentials they speak for them selves. I think, I can say with quite a degree of confidence that forcing, feedbacks etc.. are not well understood at all, hence the large range within the temperature increase "projections" as a response to CO2 doubling, circa(1 to 6 degrees). This uncertainity is as I understand it, is increasing not decreasing, as more is uinderstood about the climate system and its underlying complexity. Tim Palmers video lecture, given to the AGU in 2010 can be found below if you are interested. Best Regards

http://www.agu.org/meetings/fm10/lec...eos/A42A.shtml

+1, Palmer is a brilliant guy. And, Palmer does speak to the issue of uncertanty with regard to climate models and a more wonkish discussion of MMEs with authority since he's the guy or at least one of the main folks that pushed this idea forward. Not to discount the broadly excellent discussion regarding the history of climate modelling but he was talking his book toward the end. He has a new methodology he finds more compelling. We're certainly not going to get into the SPDE weeds here, because we're utterly unqualified. He wasn't even willing to go there with his audience. But his point was...we need funding. Exaflop computers are coming and I and my colleagues need full time access to one of these babies. BTW government people you need to step up. When he was done wowing us with the science, it was a stump speech. I'm not disrespecting him for it, hell we all give a stump speech when we need money. My 12 year old can do it.

My point is that in the middle of the stump he tossed out a bone to political conservatives. It might be this, it might be that. We might not know what we know, we need to reseach this more...political people, "I'm a smart, reasonable guy. Fund me.". To make sure I'm being clear, I have no ax to grind with regard to Palmer but this was a stump speech and we can't take too much away from the last few minutes of it and not assume it was driven by monetary necessity.

And it's not that I don't find Curry compelling, I find her marginalized, not unlike Hansen. I, of course, think Hansen is a great scientist and Curry is a whining pretender but there's no reason to go there because it's just opinion in the now. History will prove which of them is correct. No scientist can pull out their ninja political attitude and get kicked to the curb. Lindzen and Mann are great examples of scientists with attitude, the cred and the rhetoric to back it up.

The aggregate of current climate models, (MMEs), do not suggest a range of 1 to 6C degrees of warming for a doubling of CO2. We're currently slightly above a 40% increase in CO2 with .8C of warming. I understand that there are outliers in the scientific community like Lindzen and Curry that suggest cloud cover will save us from ourselves, (clouds will cause negative temperature feedbacks not positive feedback), but even that narrow argument is not one that a majority of peer reviewed papers take.

One final point. Palmer makes the grandchildren reference during the stump portion of his speech. That's a direct slap at Hansen, (Storms of my Grandchildren), and a perfect dog whistle. One side says what kind of world will we hand to our grandchildren and the other side says, not a bankrupt one due to climate change. This is a false dichotomy. There are a million paths in between do nothing and bankruptcy.

[santafe2]

Re: Polar Ice: Crushed or Cubed

The mean global temperature has only changed about 0.5C in the last century.

I think the accepted number regarding temperature change over the industrial period is .8C. or 1.44F. We should be careful to not characterize this as "only". Let me offer an analogy. We may be able to compare the earth's increase in temperature to one we understand better. A similar increase in our body temperature would be significant. Not alarming but cause for concern. A .8C increase for the earth is about the same as a 1.3C increase in our body temperature. That is, 98.6 to about 101. Not a crisis but we understand we have to get this under control. A doubling of change from here will create a crisis. As I said, just an analogy but one I find compelling.

[santafe2]

Re: Polar Ice: Crushed or Cubed

I have heard by the anti agw people say that use of fossil fuels, although they add co2 to the atmosphere, also add soot and increase temperature increases atomospheric moisture, which makes the atmosphere more reflective so there is a natural damping of the CO2's effects.

You can thank the Clean Air Act and other legislation for creating a lower particulate environment. The air is more clean today so less short wave light is reflected before it gets to the surface. I suppose we should blame that crazy lefty Richard Nixon for global warming. If we'd just left more of the dirt in the air we might not have this problem. Not to worry, China is apparently working on an excellent coal based solution.

[dcarrigg]

Re: Polar Ice: Crushed or Cubed

Help me understand ...

If you look at sea level since 1880, it looks like a pretty level line rising. I don't see a ramp after say WWII where fossil fuely use eploded.
Perhaps the correlation between gw and sea level is not exact. If we use sea level as a proxy for global warming I would say something has been
happening since 1880. Unfortunately this is as far as the graph goes back.

Solar cylce?

I have heard by the anti agw people say that use of fossil fuels, although they add co2 to the atmosphere, also add soot and increase temperature increases atomospheric moisture, which makes the atmosphere more reflective so there is a natural damping of the CO2's effects.

I'm really not sure what to believe.

To me the agw thing smells like a tax grab.

I am trying to cut back. I have always bought small fuel efficient cars. I am replacing appliances with low energy versions when the old ones wear out. I wish
the gvt would but out, except for maybe solving chicken-and-egg type problems, and setting standards to enhance operability etc.

It has sped up. Whether you believe the data is sufficient to prove anthropogenic effect is irrelevant As someone who lives near the ocean in the northeastern US, I can tell you that there is water where the volleyball courts were but a few years ago. And it's the same way up and down the coast around here. If you don't go for linear regression, but for a better non-linear fit (and anyone who tells you atmospheric phenomena are linear is wrong), you find a steep increase in the last decade and change.

Sure, the data is noisy. But ask any old yankee with salt in their veins. They'll let you know. The drink's coming.