Q & A: Global Warming

There was an interesting piece that appeared in the October 12 edition of the Seattle Times, “Q&A: Global warming — a world of evidence”. This follows up on a previous article by journalist Sandi Doughton in the October 9 issue of the Times, “The Truth About Global Warming”.

In the Q&A, a group of University of Washington scientists, including atmospheric scientist and climate researcher J. Mike Wallace, weigh in with answers to questions fielded from the paper’s readers. Many of the questions, such as “Isn’t it true that scientists in the 1970s said the earth was cooling?” are quite similar to those we’ve addressed here at RealClimate (see “The Global Cooling Myth”).

Wallace’s perspectives are particularly interesting because he is both a highly respected climate researcher (and National Academy of Sciences member) and, like a number of other long-time researchers in the field, was once a “skeptic” (in the best sense of the word) regarding the evidence for anthropogenic climate change. However, like many other such researchers, he has become convinced by the compelling weight of evidence indicating human influence on climate that has unfolded over the past decade, remarking that “with each passing year the evidence has gotten stronger — and is getting stronger still.

120 comments on this post.
  1. Tapasananda:

    it dont take a weatherman to see which way the wind blows

  2. David Donovan:

    Does anyone care to comment on the following Fox new opinion piece

    What Arctic Warming?
    Thursday, October 13, 2005
    By Steven Milloy

    In particular, is he being overly selective in his use of the data he has looked at > And what happend to sea ice cover say between the 20’s and 40’s ?

    Thanks Dave

    [Response: Hi Dave, we responded to an earlier, similar piece by Milloy here. -stefan]

  3. Bjorn van der Meer:

    Hello Realclimaters…can you give a brief statement on the importance or non-importance of Hurricane Vince?



    I would just be interested in an interpretation of that.

    Regards, B.

    [Response:The essential answer to this question is that one event doesn’t tell us much. This event simply adds to the statistics. So while it may provide a dramatic example of the apparent trend in hurricane intensity and/or frequency, it neither defines nor demonstrates that trend.–eric]

  4. Lynn Vincentnathan:

    RE #2, I have the faith that one day science will be able to tell us about each event, such as strange hurricanes, whether AGW played a role, and perhaps by how much. Unfortunately, by that time it will probably be too late to reverse GW, if it isn’t already too late — problem is, scientists can’t really tell us about that one way or the other, either.

    I’m sure it’s more than a 5% probability that AGW contributed to a hurricane (Vince) cropping up in a strange place. I figure since scientists don’t like to make claims unless there is less than a 5% chance they are wrong, we non-scientists can start reducing GHGs when there is a 5% or greater possibility we are causing harm.

    The way I look at it is by my reductions of GHGs, I’m helping in my tiny way to reduce that GW induced 50% extra intensity that Emmanuel found for the entire data set. Which hurricanes we will reduce in intensity by our GHG reductions, we don’t know, but since we care for all people, it doesn’t matter which ones we help reduce, as long as we keep helping to reduce them.


    I just read about another possible AGW positive feedback at:


    Seems warming may be increasing the “ozone hole,” which lets in more UV radiation, which increases the warming, increasing the hole, increasing the warming…..

  5. CharlieT:

    I assume that Fred Singer’s question is a non-question, but what is the answer ?

    [Response: Good assumption. The mixed layer of the ocean is mixed (pretty much by definition) thus the net fluxes at the surface (latent heat, sensible heat, long wave up and down, short wave down) warm or cool the whole layer. Diffusion/entrainment of the anomalous mixed layer temperature then allows the perturbation to diffuse into the deep ocean. There are some interesting details related to how the changes in the net fluxes affect the mixing, but since that is mostly done by the wind, it can be neglected in the first instance (although models do take this into account). Singer appears to think that long wave fluxes only affect the skin temperature and then somehow vanish. He is unfortunately confused. -gavin]

  6. Eli Rabett:

    Lynn, the usual answer is that while increasing greenhouse gas concentrations produce warming in the troposphere they also produce cooling in the stratosphere. Ozone hole production requires temperatures below ~197K. The rest is a very long story.

    There is another interesting issue. HOx can destroy ozone via catalytic processes. The normal stratosphere is water free, however increased emissions of methane lead to production of more water vapor, and eventually HOx in the stratosphre. Also warming of the tropopause (see global warming) allows more water vapor to leak through.

    More than you want to know at the Stratospheric Ozone Textbook http://www.ccpo.odu.edu/SEES/ozone/oz_class.htm and in Robert Parson’s FAQ at Bob Grumbines FAQ site http://www.radix.net/~bobg/

  7. PHEaston:

    In reply to a question about how did the Vikings grow wine in Norway (during the Medieval Warm Period (MWP)), Wallace says: “It’s possible that the Vikings were making wine from Concord-like grapes, which can grow in relatively cold climates.” That explains it then, no MWP. My understanding is there is a historians’ concensus that when the Vikings were at the height of their power, the regions they inhabited were warmer than they are now – including Scandinavia, Greenland and Labrador (ie. at least part of the North American mainland). I suspect its been discussed before on this site, but what are the key arguments for and against a MWP and whether it was a ‘local’ or global phenomenon?

    [Response: The topic has already been discussed in some detail on the site. The best place to start is our glossary entry on the “Medieval Warm Period” (due to a glitch we are in the process of trying to fix, most of our glossary items are currently not showing up in the “Glossary” page link). A site search on “Medieval Warm Period” yields many other instances of discussion of the topic on the site. -mike]

  8. Stephen Berg:

    Three more news stories on Climate Change:

    “Tropics Play More Active Role Than Was Thought In Controlling Earth’s Climate”:


    “Link Between Tropical Warming And Greenhouse Gases Stronger Than Ever, Say Scientists”:


    “Warmer Seas, Wetter Air Make Harder Rains”:


  9. Tom Rees:

    Re #7: Just what evidence is there that vines for wine were grown in Norway. anyway? Every time I hear this canard it gets futher North. First it was vines in York, then vines in Scotland, and now vines in Norway. It’ll be vines in the Arctic Circle next!

    But I’ve yet to see any evidence for these claims. The strongest evidence I know of is that grapes were grown in southern england, because these vinyards are listed in the Domesday book.

    You also have to remember that the economic pressures were different from what they are today. Wine was required for liturgical reasons, and the import/export trade was not too developed in the early millenium.

  10. Harald Korneliussen:

    You can grow grapes in Norway, if you are pleasantly situated (Hardanger, or perhaps places like Valldal or Glomset to name a few places close to me). However, the growth season is short and you run a high risk of losing the crop to bad weather. So Tom is right: it’s economically unfeasible today, but sacramental wine was very important in the middle ages.
    (I seem to recall that further north, like northen norway, iceland, greenland, where grapes just won’t grow, they had a papal permission to use something else than wine. I might be wrong.)

  11. Ferdinand Engelbeen:

    Tom, re #9

    There are some reports that there were (small) medieval vineyards in Scotland, probably restricted around cloisters for liturgical purposes. But the border where commercial vineyards were grown has been some 200 km more north than until a few decades ago, both in the Roman times as during the MWP. Now the climate is somewhere back to where commercial wine making was possible during the MWP and some former vineyards are reestablished on the sites which were abandoned during the LIA. See: “Winelands of Britain” and the map of the lecture & workshop.

    The same is true for vineyards in Belgium, which were abandoned during the LIA, the border – except in shielded valleys – was some 300 km more south, but slowly coming back now… Thus it seems that we are reaching again MWP temperatures in Europe, not more than that…

    [Response: Deducing temperature from commerical vineyards is fraught with problems. Transporting wine large distances is now very easy; during the MWP/LIA/past is was hard. So the incentive to grow grapes locally was much much stronger – William]

  12. Jeffrey Davis:

    My parents in the 1950s would buy a bottle of NY wine around Christmas. (Mmmm. Sugary concord wine.) So, I presume that there had been vinyards there for years before that. New York has a much colder climate than Britain.

  13. Sashka:

    To the North of New York City, there is Brotherhood winery. Quoting from http://www.hudsonriver.com/winetour.htm

    Brotherhood is America’s oldest continuously operating winery. It even stayed in business during Prohibition by producing government-sanctioned altar and medicinal wines. The winery’s John Jaques Building, named after Brotherhood’s founder, provides entry to the winery’s network of old subterranean caves, where wines are aged in a variety of oak vessels, some dating back to the 1840s. … Brotherhood produces an array of wines, from basic table wines like Chablis, Blush Chablis and Burgundy, to fortified wines, dessert wines and premium varietal wines, like chardonnay, Riesling, Cabernet Sauvignon and Pinot Noir.

  14. Lynn Vincentnathan:

    We had neighbors that grew grapes in Wisconsin, where the weather would usually dip well below 0 F in mid-winter (at least that’s what it was like 30 years ago when we lived there – can’t vouch for now). However, they only made grape juice, being tea-totalers. I think Wisconsin is quite a bit colder than N. Europe or Northern NY. You go far enough north & you start getting that mid-night sun effect – great for grape-growing.

    So, what’s the point? Maybe grapevines would even grow in the Arctic circle, at least after we really start warming?

    The latest contrarian argument: We all grow grapes, drink wine, get drunk, and become oblivious to GW,…or at least make sacramental wine, go to Mass, & repent of our GHG sins, before we reach that really hot place.

  15. dan allan:

    Well, not to sound too catty, but I have to admit, I got a kick out of two suggestions of AGW causes in the questions in the Q & A in the Seattle times: (1) the effects of heat from cigarette smoke, and (2) the effect of human body heat!

    Do you mean to say you guys haven’t included these important “forcings” in your models? In that case, you can count me as a skeptic! ;)

    Also, what about the WV effect of increased Chai consumption?

  16. Steve Latham:


    I followed the link in your response to #2 regarding Milloy. There is an interesting statement including Greenland in one of the first sentences:

    “The study describes the ongoing climate change in the Arctic and its consequences: rising temperatures, loss of sea ice, unprecedented melting of the Greenland ice sheet, and many impacts on ecosystems, animals and people.”

    I have read several times in posts from skeptics that Greenland is actually cooling. What is the best way to check such statements? Is there more recent summary info for Greenland?

  17. Eli Rabett:

    Most of the wines in New York were grown in the Finger Lakes Region, which has a rather nicer microclimate. OTOH, they still had to be rather hearty varieties.

  18. Blair Dowden:

    Re #16, I too would like to see a comprehensive summary of Greenland climate and ice thickness data. From what I see from the Global Historical Climatology Network (GHCN) of land temperatures and the Comprehensive Ocean-Atmosphere Data Set (COADS) of SST data, temperatures there were higher around the 1930’s than now, and there is not much long term warming trend, except for the past few years. I also understand that ice is melting near the coast, but thickening in the interior. It is not clear what conclusions can be drawn from this.

  19. Stephen Berg:

    Regarding the winery industry, Ontario has a wine industry with reds, whites, and is one of the world’s largest producers of ice wines.

    One risk is that climate change will warm Southern Ontario enough to cripple this lucrative ice wine industry, since a week of -7 C and lower is required to harvest these grapes. The resulting climatic variability will make it difficult for the temperature to remain somewhat steady – and not to get too cold as to reduce grape growth.

  20. Steve Bloom:

    Re #16 (Steve Latham):

    Fresh Greenland info at http://cires.colorado.edu/science/groups/steffen/greenland/melt2005/ . Apparently the high-altitude center is still cold enough to not be actively melting, but the overall rate is going up fast (which is probably more what we’re concerned with than average temperature). In any case, http://www.agu.org/pubs/crossref/2005/2005GL023552.shtml seems to make it fairly clear that things are getting toasty in Greenland; there’s a related story at http://www.lanl.gov/news/newsletter/092605.pdf . See also http://europa.eu.int/comm/research/rtdinfo/special_pol/04/article_2600_en.html for a more direct discussion of overall temperature.

    Then we have this fascinating skeptic article from Reason magazine: http://www.reason.com/rb/rb111004.shtml . Possibly this article is Milloy’s source, and what’s especially interesting about it is how very wrong so many skeptics (including Richard Lindzen and John Christy) can turn out be in just eleven months. Among other things, the author makes a big point that a paper from March 2004 by Chylek et al showed a cooling of Greenland, and that this study had somehow been censored from the Arctic Climate Impact Assessment. Notice that the first study I linked to above is a brand-new one by the self-same Chylek team, now finding that there is indeed rapid warming. With just an eighteen month interval between the two studies, this appears to be some sort of climb-down.

  21. Steve Bloom:

    Re #s 16 and 18: From the prior RC post, there’s also this extensive discussion of Arctic temperature, including Greenland: http://www.nersc.no/AICSEX/rep218.pdf . Also, I notice in Milloy’s article that his “expert source” was George Taylor, a “certified consulting meteorologist” and confirmed skeptic who has little expertise on climate and none on the Arctic. Now that’s scraping the bottom of the proverbial barrel.

  22. Ferdinand Engelbeen:

    Re #18,

    I have made a graph of all weather station trends of Greenland. Indeed, the temperatures in the 1930-1940 period were higher than thereafter and only in the last decade temperatures increased to near equal of that period again. The same is true for ice melting: All glaciers of Greenland are receding, but the breakup point of the largest tidal glacier (near Illulisat) moved faster inland in the 1930-1940 period than today.

  23. Ferdinand Engelbeen:

    Re #11 comment:


    The graph made by Prof. Selley is based on historical vineyards at one side and the climatological/geological possibilities today. In Roman times, grapes were grown where possible, as economics didn’t play a role. In the Medieval period, I suppose that economics were not a big item either. While the Romans did occupy Engeland up to the Scottish border (Hadrian’s wall…), the border for grape growing remained in south England.

    According to Selley, climate today is about the same as in the Medieval period to grow grapes (no matter the commercial side), but the border may shift more north, if the projections of increased temperature become true.

  24. Tom Rees:

    Re#16 Greenland temps. The problem is that the North Atlantic Oscillation has big effect in Greenland – the current positive phase is bringing cool to Southern Greenland and warmth to Northern Europe. Apparently, after taking into account the effects of the NAO, there’s a substantial underlying warming trend. See Scientist calculates Greenland warming

  25. Stephen Berg:

    Re: #20,

    The “Reason” article’s title is very a propos, in that there are “two sides to global warming.” However, unlike what they believe, there is the side which is correct and the side which is incorrect.

  26. Jeffrey Davis:

    The tangent about vines really seems to indicate that there are a lot of people who believe “in vino veritas”.

  27. Kok, Wim (Netherlands, Europe):

    This is only a short comment regarding research on global warming using information of wine production, vineyards and grape types.

    Indeed this is fraught with problems, not in the least because there are few plant species on earth like vitis vinifera which show so many varieties. Many historic vine species are yet fully unknown or, at best, only suspected to be of the variety X. Information is sparse. Moreover, the conditions under which these ancient varieties flourished are only very partially known. It seems to me almost impossible to deduct climatic trends from the study of vines only.

    A better and more widely known method is pollen-research. Changes in the composition of pollen contents (revealing many species and ecosystems) during the ages (geological record) may show more subtle variances in climatic conditions.

  28. Tom Fiddaman:

    Re “in vino veritas”

    Grape ripening as a past climate indicator

    Nature, Vol. 432, 18 November 2004.

    French records of grape-harvest dates in Burgundy were used to reconstruct spring-summer temperatures from 1370 to 2003 using a process-based phenology model developed for the Pinot Noir grape. Our results reveal that temperatures as high as those reached in the 1990s have occurred several times in Burgundy since 1370. However, the summer of 2003 appears to have been extraordinary, with temperatures that were probably higher than in any other year since 1370.

    Lots of other proxies at the WDC paleo mirror site.

  29. Gerald Machnee:

    The following is part of an article that was printed last year —
    {Vintage Wine Records Trace Climate Change to 1300s
    John Roach
    for National Geographic News
    November 17, 2004

    Connoisseurs may pore over grape-harvest records in search of the perfect vintage of wine. But a team of French scientists and historians is toasting the same records for the insights they yield on past climate.

    In Burgundy, France, as in other parts of Europe, the first officially decreed day of grape harvesting has been carefully noted in parish and municipal archives for at least 600 years.

    Using a scientific method known as phenology�in which the onset of various stages of plant growth are correlated with climate�the team was able to reconstruct spring and summer temperatures in Burgundy from 1370 to 2003. The findings are based on the harvest dates of pinot noir grapes. }

  30. wayne davidson:

    #16 #20 #24, Ask a Greenlander like I did, and get this as an answer: From Qanaq, situated North of Thule Air Force Base, with a sizable population of people still making tradionnal Kayaks, Boating season
    use to be Augsust-September, now it is June-December, shore sea ice after the long night is 50% thinner,
    temperatures have been unusually warmer for the last 5 to 10 years. There is no debate up here, it is substantially warmer. Basic Meteorology, Climatology must include data from populated areas.
    Imagine Northerners debating summer of 2005 cooling of NY city , without even talking to one single New Yorker, or taking data from a reliable New Yorker, how silly that sounds….

  31. Ferdinand Engelbeen:

    Re #20 (and others):

    All the graphs of Greenland ice melting start in 1979, in a notable cooler period than 1930-1940. If we may assume that the moving speed of a breaking up point of a glacier is a good indication for past temperatures, then have a look at the retreat of the largest Greenland glacier at Illulisat, West Greenland. If you look at it in detail, you can see that the retreat in the period 1929-1953 (24 years) was faster than in 1953-2003 (50 years).
    Thus all together, the retreat is the result of global warming at least since 1850, and the retreat was faster around 1930-1940 than today, when GHGs were not playing any important role.

    Chylek found a good correlation between one (1) Greenland station (Danmarkshavn) and global warming, according to him, without an influence of the NAO. But this is the only (!) station which starts measuring temperatures after 1950, again in a cooler period. The other station at the same latitude (~77N), Thule at the west coast, started measuring in 1947, with a higher temperature and a sudden cooling thereafter, comparable to the temperature drop of most other Greenland stations. And Thule parallels the Danmarkshaven temperature data until 1972, when it ceased operation. This indicates that the Danmarkshavn temperatures were not unique in trend, but that the data collection started after the warm period.

    There is a small sudden shift in NAO index around 1946 to positive, which may be the cause of the Greenland cooling, but in general temperatures were as high (or higher) than today in the 1930-1940 period, be it with an average neutral NAO. In recent years the average NAO index seems to go down to neutral too (which – in part – can explain the recent warming). But my impression is that there is not much correlation between the NAO and temperature in Greenland (the coldest temperatures are in a strong negative NAO period).

    Thus I am still waiting for a good explanation where the Greenland melting is linked to greenhouse gases…

  32. Gerald Machnee:

    We may note from history that central North America, especially Canada, was covered by a glacier. Eventually Lake Agassiz formed in Manitoba extending into USA, then the lake mostly disappeared.
    Likely there were not too many alarmed over the glacier’s retreat.

  33. Stephen Berg:

    Re: #32, “We may note from history that central North America, especially Canada, was covered by a glacier. Eventually Lake Agassiz formed in Manitoba extending into USA, then the lake mostly disappeared.
    Likely there were not too many alarmed over the glacier’s retreat.”

    Well, of course! There were very few people in the region at that time, and those few who were there were glad to be able to hunt and gather food in the region they once called home prior to the onset of the ice age.

    What were you trying to say here, Gerald?

  34. Gerald Machnee:

    RE #32 – What I was noting was that glaciers have come and gone. We are getting alarmed over retreating glaciers ( and some may be increasing). I feel we should be concerned with decreasing pollution emmission as well as being prepared for changes in climate(which would include extreme weather), both financially and with supplies, both of which were missing in Katrina.

  35. Lynn Vincentnathan:

    What this regional cooling data in more current times indicates to me is that it must be getting really hot in other places (& not all places are warming in lock-step), or we wouldn’t be having this increase in the AVERAGE of global temps.

    What the regional hotspots in the distant past indicate to me, is that there are other factors, aside from AGW, that can warm up places, which means we have to really get on with reducing GHGs. We wouldn’t want situations where AGW AND these other warming processes piggy-back or coincide, & really cause a lot of harm.

    Any other arguments? — I have answers.

    How about “in the past the GHG increase FOLLOWED the GW.” Well, that’s scary. It means we may be headed for some really nasty runaway GW, if we don’t drastically reduce our GHGs ASAP….because, of course, the fact that warming causes GHG emissions does not in any way at all disprove the well accepted fact that GHGs cause warming.

  36. Randolph Fritz:

    Since this seems to have turned into an open Q&A thread, I’d like to ask if there’s any opinions on the effects of global climate change on winter storms in the North American Pacific Northwest?

  37. James Annan:


    Ah, that’s the famous “Reason” article which says:

    Richard Lindzen says he’s willing to take bets that global average temperatures in 20 years will in fact be lower than they are now.

    Of course, it later became clear that he really meant he would accept such a bet if offered 50:1 odds in his favour, which doesn’t sound quite so dramatic :-) I predict that very little of that article will stand the test of time. But it is only fair to acknowledge that Ronald Bailey now openly accepts that warming is real and ongoing (“We’re all global warmers now”)

  38. wayne davidson:

    The point of many detractor contrairians fail to make, is reality in the field, from Iceland to Alaska, they always fail to bring out science field experts with accurate information, including the greatest ones, the hunters, we have them still, and they are extremely keen on the weather. Icelanders to Alaskans will state that there is unusual warming beyond the memories of their ancient cultures, but they are very seldom mentioned. Strange that some contrarians allege the Arctic Climate Impact Assessment was witheld some vital cooling information, just once, when they fail all the time to quote the real action from the ground or ice all the time.

    That is what is needed though, some break from the silence, for Northerners to write down what is going on, or for doubtful Southerners to contact them just as long as their doubts exists, climatologists mentioned above sum up very well what is going on, unfortunately they are often disavowed by the media, paralysed by formented confusion illusions, from the North it looks like the truth competing in a game of musical chairs.

    The whole contrarian stance is quite ridiculous though, defending the Carbon based pollution industry is ironically flawed, there is a lot more hysterical economy collapse fear mongering claims than environmentalists decrying the end of the world. But oil barons should not be afraid of an hydrogen based energy industry…….. There is a lot of H’s in one molecule of Crude Oil.

  39. Ferdinand Engelbeen:

    Re #38,

    As an interested outsider, I have looked at the temperature trends of all circumpolar stations. Alaska and East Siberia (30% of all stations) today have higher temperatures than in the 1930-1940 period. The rest of the stations (70%) don’t or just reach the temperatures of the previous warm period. But that was done a few years ago, may need some update.

    So you are right that current temperatures in Alaska are higher than in the past hundreds of years, be it that the warming started with a sudden shift of the PDO in 1976. But that is not true for Greenland and other places around the North Pole. Thus if one should ask the Inuit near Thule if there was less ice and longer summers in 1930-1940, the answer should be yes (as far as the human memory is reliable)…

    This brings us to the point that climate programs predict a two times faster warming at the poles than in the rest of the world. This is clearly not true, if you look at the Arctic as a whole over the past century, because the previous warming towards the ’30s was faster and higher than the recent one, while CO2 still was low. In my opinion, what Chylek has done is cherry picking one station of Greenland with a (too) short data series, to prove that the GCM’s are right. This is not scientific and together with the horror stories about Greenland ice melting, this will backlash on the credibility of climate science.

    That doesn’t mean that we shouldn’t reduce our dependence on fossil fuels as soon as possible, be it more for geopolitical reasons and pollution reduction than for fear for a runaway warming…

  40. Max Haberrecker:

    In a discussion about global warming, someone made the following statement:

    1.) There has never been a global warming model that has taken into account the leading contributor to global warming. The sun.

    2.) Fact: Just one volcano can emit more greenhouse gases than all of humanity in its entire existance. It has happened before, four or five times in human history alone. Yet, mother nature takes care of it. To think that mother nature cannot take care of that amount of gas, spread out over decades of time, is ridiculous.

    Can I have some comments or clarifications on this? Some links would be great too.

    Thanks in advance!

    [Response: Whoever made those comments has very little knowledge about the topic. I suggest you check out the “Climate Modeling” RC category link. There you will find numerous past postings dealing with the topic. The article on “Planetary Energy Balance” would in paticular be a good place to start. With regard to the source of modern increases in Co2 and other greenhouse gaes, few if any credible scientists would question that this is anthropogenic in origin. See this previous RC article on the topic. Volcanic outgassing is an important source of greenhouse gas concentrations on geological timescales, where the atmospheric concentrations are determined by a balance between outgassing from the solid earth and uptake of co2 from the atmospheric due to natural processes such as chemical and physical weathering, which are important on timescales of millions of years. Changes in this balance over time lead to the changes in greenhouse gas concentrations that have been observed to occur on geological (millions of year) timescales. These factors are important in understanding past warm geological periods (such as the early Cretaceous) when co2 levels are believed to have been several times greater than today. These processes are not believed to play any significant role on the timescales (centuries to millennia) of interest in discussions of anthropogenic climate forcing and climate change. -mike]

  41. Robert Simmon:

    re: #31

    The extent of tidal glaciers (like the Ilulissat Glacier) is not determined solely, or even primarily, by temperature. Interaction between the glacial terminus and the ocean (such as wave action and sea level), as well as the bathymetery of the sea floor govern the calving rate of the glacier, which determine the extent along with snow accumulation rate, flow rate, and melt rate (temperature). In general, tidal glaciers are cyclical, advancing over 1,000 years or so and then rapidly retreating for one or two centuries. To use the Ilulissat Glacier as evidence of a temperature trend (warming, cooling, or neither) is unwarranted

    Alpine Glaciers, on the other hand, can be good indicators of climate change, including temperature. Read: At the Edge: Monitoring Glaciers to Watch Global Change.

  42. Tom Fiddaman:

    Re #40

    I haven’t seen any recent estimates of volcanic emissions, but:

    Present-day carbon dioxide (CO2) emissions from subaerial and submarine volcanoes are uncertain at the present time. Gerlach (1991) estimated a total global release of 3-4 x 10E12 mol/yr from volcanoes. This is a conservative estimate. Man-made (anthropogenic) CO2 emissions overwhelm this estimate by at least 150 times.

    Even if Gerlach is wrong by two orders of magnitude, point 2) is baloney.

  43. wayne davidson:

    #39, We stand by what we are saying, it is warmer UP here in the High Arctic. That warming record of the
    40’s, had very little memorable impact compared to now. Resolute Bay was suppose to be built on Melville Island, but in 1947 there was so much old multi-year ice it was impossible to move ships a further 400 miles West or so. Today, there is nothing but open water over Barrow Strait with only new fast ice sheets in the Bay’s, there is no debate over which period was warmer. The weather is changing so much that elder hunters throughout Northern Canada can’t recognize some (warm) clouds, and the dominant winds have become unfamiliar, ice hunting seasons have shortened, in the old days that would have meant starvation, not only for Polar Bears. The fact that one study singled out one weather station pales in comparison to what is really happening. Any fixation about climate change should start first with a thorough synopsis of what is going on a wider geographical scale, it seems that this is not done, rather hand picked specific locations are too much analyzed instead of studying the whole picture. This leads to endless debates about how good one location is to study over another, it is after all Global Warming we are debating. Climatologists do just that, they include everything and they should be heard more often.

  44. Lynn Vincentnathan:

    Since we’re on Q&As, an engineer brought up a point about ice melting in a glass of water (in an attempt to shed light on glacier melt, etc). He said the glass of water stayed cold as long as there was ice, but heated to room temp pretty rapidly after the ice melted. Would this have any implications for Earth & GW?

    He also mentioned (I think) that the process of melting required a lot of energy (or gave off energy)?? – would this have any significance….

  45. Steve Bloom:

    Re #39 (FE): And here’s the aforementioned Greenland melting horror story: http://cires.colorado.edu/science/groups/steffen/greenland/melt2005/ . Yep, pretty horrible. Now Ferdinand can explain how this data is fraudulent (a little tough to do since the author is the leading scientist in the field) or how the record melting is really beside the point since we can be confident that Greenland isn’t warming anyway.

    Ferdinand, any large-scale climate trend is going to be uneven in the sense that there will always be local indicators that don’t follow the trend exactly or are even contrary to it (for a while, anyway). Just stand back and look at the big picture. The point here isn’t that anybody can prove that there has never been this extent of Greenland melting at some prior time in the Holocene, but that all of these indicators taken together (Arctic temperatures, low sea ice extent in summer *and* winter, permafrost melting, decreased snow cover, Greenland melting) indicate that the Arctic as a whole really is warming in an exceptional way. Absent some natural factor that could explain all of this happening at once, and none has been postulated, we are left with warming as a consequence of increased GHGs (and secondarily from soot deposition, although as I understand it this has yet to be well-quantified and is in any case a co-factor with GHGs).

  46. Steve Bloom:

    Below is the abstract of a fresh paper that adds to the already-strong argument for Arctic warming. The text is unfortunately available only to subscribers (of which I am not one).

    GEOPHYSICAL RESEARCH LETTERS, VOL. 32, L19602, doi:10.1029/2005GL024216, 2005

    Warming of the arctic ice-ocean system is faster than the global average since the 1960s

    Jinlun Zhang

    Polar Science Center, Applied Physics Laboratory, College of Ocean and Fishery Sciences, University of Washington, Seattle, Washington, USA


    Model results and observations both indicate warming of the world ocean from 1955 to 2003. Forced by reanalysis data, the model also shows that the warming of the arctic iceâ??ocean system is faster than the global average since the 1960s; there is a small but widespread increase in heat content of the Arctic Oceanâ??s waters and a larger increase of latent heat embodied in the oceanâ??s decreasing ice cover. From 1966 to 2003 the modeled mean world ocean temperature in the upper 700 m increased 0.097°C and by 0.137°C according to observations (Levitus et al., 2005); the modeled mean temperature adjusted for sea ice in the corresponding layer of the Arctic Ocean increased 0.203°C. The warming of the world ocean is associated with an increase in global surface air temperature, downward longwave radiation, and therefore net heat flux. The faster warming of the arctic iceâ??ocean system is associated with an amplified increase in arctic surface air temperature, downward longwave radiation, and net heat flux.

    Received 27 July 2005; accepted 1 September 2005; published 5 October 2005.

  47. Steve Bloom:

    See also this recent overview article on Arctic warming, which nicely summarizes the state of the science as of a few months ago: http://paos.colorado.edu/~dcn/reprints/Overpeck_etal_EOS2005.pdf .

  48. Ferdinand Engelbeen:

    Re #41,

    It may be that tidal glaciers in general are not good indicators of temperature. In the case of the very large (7 km wide, 100 m high above water front) Illulisat (Jacobshavn) glacier, the retreat started at or before 1850. But it is interesting that the rate of retreat of the breakup point parallels the local measured temperature (since 1880)…

  49. Ferdinand Engelbeen:

    Re #43,

    You are completely right for Alaska and East Siberia (Barrow is now an average 1°C warmer than around 1940 and 2°C warmer than around 1970), but the rest of the arctic was as warm or warmer than today in the 1930-1940 period. That is based on all circumpolar (over 67N) stations, not one or a few…

  50. Ferdinand Engelbeen:

    Re #45,
    The problem with ice extent/melting of Greenland is that reliable measurements are only available since the satellite era, which is 26 years young. The only indication of probable ice melting in the past is the temperature readings of nearby stations. If one looks at the trend e.g. for Illulisat/Jacobshaven (West Greenland), where ice melting is increasing with app. 0.5 million km2 per decade in the last decades, the yearly average temperature trend was flat 1880-1920, +3.5°C 1920-1930, variable (around a flat trend) 1930-1948, -3°C 1949-1994, +3°C 1995-2004
    Even more interesting: the summer (June, July, August) temperatures dropped from average +7°C in 1900-1980 to +3.1°C in 1983, and slowly went up again to +6°C in 2003-2004. Based on these figures, I suppose that the West Greenland ice melting was larger in the 1930-1950 period than in the 1985-2005 period…
    Alternative explanations may be that the Greenland ice melting has nothing to do with temperature, but with more insolation (less clouds), less precipitation, more soot deposit,…

    The horror story is not what the scientists present as data, but what the media make of a (too) short trend, including the complete melting of the Greenland ice sheet. As long as there is no good explanation why the Arctic was warm(er) in the 1930-1940 period, one can’t know what the trend will be in the next decade(s), let it be in a century or two.

  51. Ferdinand Engelbeen:

    Re #46,

    Not yet read the report, but I have read the Levitus e.a. papers. The same problem as for the ice melting emerges here: reliable (deep) ocean measurements are only available since 1955, the previous warming of the oceans is only known from sea surface measurements… Further, the abstract indicates that the faster warming of the Arctic Oceans is modeled, not measured… In Levitus e.a. 2005, figure #2 indicates that the heat content for certain latitudes (10N-30N) has increased 3-6 times more than for the 70N-90N latitudes…

  52. Dano:

    Check your inbox, Steve.


  53. Ferdinand Engelbeen:

    Re #47

    Indeed a horror story, extrapolated from a 30 years trend, from midst a cool period to midst a warm period. What if the story should have been based on a 70 years trend (warm, cool, warm)?

  54. Steve Latham:

    Three items: 1. Thanks to Steve Bloom for all of the references. 2. Thanks to Ferdinand for explaining his position on why he doesn’t accept AGW being responsible for arctic warming and why he doesn’t believe projections are credible. I don’t think he represents folks who claim that Greenland is cooling. 3. Ferdinand, given that I like your points regarding the shortness of various time series in the Arctic (notwithstanding Steve Bloom’s good suggestion that we look at the big picture), how many more years of warming trends that continue in general accordance with model predictions would it take to convince you? Or are future trends relatively unimportant, from your perspective regarding mechanistic understanding, because of warmth in the 1930s and 1940s when GHG concentrations were lower?

  55. Steve Bloom:

    Re #50 (FE): Here’s how the scientists writing in EOS summed things up:

    ‘The Arctic system is moving toward a new state that falls outside the envelope of glacial-interglacial fluctuations that prevailed during recent Earth history. This future Arctic is likely to have dramatically less permanent ice than exists at present. At the present rate of change, a summer ice-free Arctic Ocean within a century is a real possibility, a state not witnessed for at least a million years. The change appears to be driven largely by feedback-enhanced global climate warming, and there seem to be few, if any, processes or feedbacks within the Arctic system that are capable of altering the trajectory toward this “super interglacial” state.’

    That’s a pretty strong statement. What members of the media twisted their arms and made them say that? Ferdinand, your problem is with the scientific consensus itself, not the press coverage.

  56. wayne davidson:

    #49, A common problem of going back in time, say to the 1930’s, is that there were very few if any High Arctic stations North of 65 degrees. Especially over the North American Arctic, there might have been trading posts, but to my knowledge there were no stations. The record then is almost none-existent on the Canadian American side, while there surely was some stations on the Russian side. I can’t be critical on your point that it was warmer then, but I can be skeptical. There is after all the human record. A central Baffin elder living at about 70 North once told me that heating oil barrels froze in 1933, he said that it was the coldest year of his life. That does not sound like a warm period.

  57. Gerald Machnee:

    RE #56 – Being skeptical or anecdotal is not very scientific when facts are presented. In addition, many warming periods being quoted have about a 30 year span which means they began around 1975, which was in the miidle of a cool period.
    Heating oil is likely to freeze every winter in Baffin. One year (1933) does not negate a warm period. The warm period peaked around 1940 in most areas.

  58. Steve Bloom:

    OK, a couple of hours on Google Scholar reading papers and I find http://www.nersc.no/MACESIZ/Papers/ove04.pdf ., a thoroughgoing reanalysis of the entire surface record in the Arctic going back into the 19th century. The question of whether the long-term record supports the existence of the postulated 50-year trend (not 70-year) was of primary interest to them, and the short answer is that it doesn’t. The rest of the historic variability is explained, and the warming of the last 15 years is identified as both anomalous and very likely to be a consequence of GHGs. There’s an interesting discussion of the vulnerability of the Arctic under current circumstances to abrupt additional warming leading to loss of most sea ice, melting of all the permafrost, much more rapid melting of Greenland, etc.

  59. Blair Dowden:

    Re #56 – The GHCN-ERSST climate record indeed shows a record low winter temperature in 1934 (with 1933 close behind) in the eastern Arctic. I wonder how much this matters in light of the following.

    Re #55 – The same EOS report contains this statement: “Approximately 98% of the energy supplied annually to the Arctic system is advected from lower latitudes by the atmosphere.”

    Is this correct? If so, then arctic temperatures are merely a side effect of events further south, and this is the wrong place to look for evidence of global warming. Going back to basics, what is the basis for enhanced greenhouse warming in the arctic? The increased albedo from melting arctic ice should not matter very much, but the newly exposed cold surface water might absorb extra carbon dioxide, acting as a negative feedback on the whole system. Is there a estimate of how significant this might be? And what part do ocean currents play in the remaining 2% of arctic temperatures?

    As Ferdinand pointed out back in #31, the correlation between the NAO and arctic temperatures is not clear. There is certainly not a year by year match, if the data in this graph is correct. On the other hand, arctic temperatures do generally seem to magnify changes further south. I have not had the chance to read the Overland paper just provided. Maybe it will help.

  60. wayne davidson:

    #59, The elder, deceased, said it was colder then with 1933 very memorably colder. Your advection point is correct, however advection is the result of extensive cooling, sort of like a thermal engine where cold and warm air is continuously exchanged, this process slows down when the Arctic is warmer.
    The Arctic cools down substantially depending on how much heat is lost especially during the long night, it is an ideal location for determining Global Warming trends because of wider temperature discrepancies caused by apparently minor (CO2) changes.

    The current warming trend 1998-2005, has no precedent in recent Arctic memory, there were a few unique occasions when open water was seen during mid-winter over Barrow Strait, but this was at roughly 10 year intervals, now the intervals are totally irregular, but between Islands ice cover is not the best indication of warming, monthly temperature readings for the past 4 years or so, have been mostly above normal by 1 to the occasional 4 to 5 degrees. They rarely go below the 1951-1980 normal.

  61. Ferdinand Engelbeen:

    Re #54,

    Steve, re point 3: In my opinion, an extended trend of between 10 and 20 years in the future will make it clear in how far the recent warming is natural: if it is mainly internal natural variability, the 50(+) year cycle should stear to lower temperatures from now on. If it is solar, then the trend should level off by now (except if solar activity should change either side in the near future). If it is mainly greenhouse gases, the trend should go on to the positive side… Of course, a large volcanic eruption may – temporarely – change that all.

    Ten years will be enough to test (and adjust if necessary) the models to give a best fit of reality. Meanwhile, research for fossil fuel alternatives should be boosted, to drop in where possible, regardless if the models overestimate or underestimate the real influence of greenhouse gases…

  62. Doug Percival:

    I have two related questions. When will the Greenland ice sheet completely melt into the sea? And is there any reason in the world to think that it won’t?

    [Response: See Gregory et al, Nature(2004). The abstract is as follows:
    The Greenland ice-sheet would melt faster in a warmer climate and is likely to be eliminated — except for residual glaciers in the mountains — if the annual average temperature in Greenland increases by more than about 3 °C. This could raise the global average sea-level by 7 metres over a period of 1,000 years or more. We show here that concentrations of greenhouse gases will probably have reached levels before the year 2100 that are sufficient to raise the temperature past this warming threshold.
    See also this commentary in Nature. -mike]

  63. Ferdinand Engelbeen:

    Re #55,

    Steve, the problem is in the sentence: “At the present rate of change”, because that is based on the trend of the past 30 years. Of course that would implicate disaster on middle-long term. But one need to be cautious with the time frame. As said in the Overland e.a. paper:
    “Our decadal analysis reinforces the point made by other authors that care must be taken in selecting intervals for calculating linear trends. For example, from examining Fig. 2, Siberia and Alaska (stations 24â??37) would show a positive trend over the previous 40 yr in a regression analysis, even though the main feature was a single decadal warming episode in the 1980s that was followed by cool anomalies.”

    Re #58,

    The Overland e.a. paper indeed is interesting, as it shows the different trends in different seasons.
    This brings me to a correction: The drop in summer temperatures for Illulisat, Greenland, I mentioned in comment #50 is not true: As the Illulisat station ceased operation in 1980, I added the nearby Egedesminde station data. This was no problem for the yearly averages, as these are near identical for the overlapping period, but summer temperatures of Egedesminde show a constant bias of 3 C below Illulisat temperatures. Quite strange for nearby stations, but may be caused by local circumstances (prevailing wind direction from land or seaside?)

    Further, I don’t see that the 50(+) year oscillation is discarded, as that is clearly present in the PCA for winter pattern B (see Fig. 5). That the 1930-1940 period was warmer than present for the Arctic as a whole in winter is shown in the time-longitude plot of yearly averages in Figure 2. The warming was mainly around the Atlantic, Europe and West Siberia (there even until 1957). The difference with the current warming is that it now is more evenly distributed around the Arctic.

  64. Steve Latham:

    Thanks again Ferdinand (#61). But I fear that even with 10 years of continued warming (including natural variability around that warming trend), there will still be powerful people/entities arguing against AGW and, unlike you, against any actions to reduce anthropogenic GHGs. I suspect that even if temperatures increase faster than the expected trend, whereas some people will say “Look, AGW is even worse than we thought”, some other people will say “See, they don’t know anything about the climate — something else is responsible for this.” It will be an interesting 10 years until then, and frustrating for many.

  65. Lynn Vincentnathan:

    Re #59 & dark oceans not absorbing much more heat than white snow/ice.

    As a kitchen scientist & folklorist, I have this insight: “A watched ocean (esp if it’s deep) never warms….” I.e., maybe there IS some warming because of the lower albedo, but we just don’t know about it yet as we watch it day to day, because the sea is so massive & deep, such warming would be imperceptable at first…but like that watched pot, if we just turn away a while, then look again, presto, we may see it’s warming…

    Also that (diminishing) ice in the glass (sea) might be keeping the water cold, and when it’s all melted, the warming might happen fairly rapidly.

    But then I’m not a scientist…

  66. Blair Dowden:

    Re #62 – This New Scientist summary gives a slightly different picture of when the Greenland ice cap will melt than the abstract that was quoted.

    “If warming stabilises at 3 degrees Celsius, the ice sheet could survive for several thousand years. But if temperatures rise by 8 degrees Celsius, which several scenarios predict, then it would disappear in 1000 years.”

    [Response: I’m not sure I see any inconsistency between the two statements. It would of course be odd if there were an inconsistency. After all, Gregory, the primary author of the study in question, was the origin of both statements. -mike]

  67. Stephen Berg:

    Another bit about Tropical Cyclones, particularly those of the Atlantic sector. The following graph of hurricanes over the past 75 years can be found here:


    One can fairly easily visualise a best-fit line from around the 1930s to the present and see an increase in the number of storms. This may be, in part, due to increased populations, but since hurricanes are tough to miss, it is probably all-encompassing. (Heck, even 1920s technology had Marconi and Morse code telegraphing so ships’ captains could let others know about the storms.)

  68. Ferdinand Engelbeen:

    It seems that the melting of the Greenland inland ice is not yet for tomorrow. Thanks to Tom Rees at UKweatherworld, here a link to a story from Reuters about the latest satellite data which indicates that the overall ice sheet thickened 54 cm in the past 11 years. But the accuracy of the satellite is less for the (melting) edges, which may compensate for the thicking at higher levels…

    [Response:This is related to a new Science express paper (Johannessen et al, 2005) which gives some of the best data yet on the elevation trends for the last decade or so. Interestingly, much of the variability they see is related to the NAO index (high index implies less accumulation), but they are not able to give a full mass balance of the ice sheet (as you correctly say). There is a review paper on a similar topic by Alley and coauthors in this week’s Science as well. -gavin]

  69. Blair Dowden:

    Re #66 – The wording of the abstract quoted in #62 leaves the impression that 3 degrees of warming will melt the Greenland ice cap in 1000 years, although read very carefully it does not quite say that. The report says it will take 8 degrees to do that.

    The reality is bad enough. Why twist words to make it sound worse than it is?

    [Response:It is unfair to accuse the authors of twisting words. You are exploiting a highly semantic point (i.e., what the authors meant by “more than 3C”). The topic is in fact discussed in great detail in a review paper by Alley et al just out in this week’s Science. These authors note that a warming of 3.8C will lead to the eventual melting of the Greenland ice sheet. This is consistent with other studies indicating that 3C is an approximate threshold for the eventual melting of the Greenland ice sheet. There are no inconsistencies here. Now lets move on to other topics. -mike]

    Re #67 – I see no increase in the number of storms from looking at the graph, and I understand that warming ocean water is not linked to number of storms. It is linked to the intensity of those storms. However, I note that the most intense storms this year have passed through the Gulf of Mexico, which is a warm, shallow body of water. Unlike the Atlantic ocean, I do not believe there is a long term warming trend there.

    [Response:Your statement is not quite accurate. Wilma achieved the greatest strength (lowest central pressure: 882 mb) of any Atlantic Hurricane on record without entering the Gulf of Mexico. For a discussion of what can and cannot be concluded about possible relationships between recent Hurricane activity and climate change, please see our post on Hurricanes and Global Warming: Is There a Connection?. -mike]

  70. Keith Moulton:

    I was struck by John Wallace’s assertion (in the Seattle Times article) that “The warming is much more rapid than most of the natural variations we’ve seen in the past.” Is that true? I’m having trouble reconciling that statement with this paper by Kendrick Taylor, and to a lesser extent, ice core data. Looking by eye, the Vostok graph seems to show temperature rebounds after an ice age to be around 8 degrees C. in say, 6000 years. That by itself would seem to support Wallace’s statement, since it would work out to about 1 degree C. per 750 years. But that’s an Antarctica average based on air samples that were each gradually trapped in the ice over thousands of years. There must have been brief periods of very rapid temperature change mixed in there (certainly on the regional level) in addition to slower-warming periods, and I’m under the impression other data (such as Greenland ice cores and deep-sea cores) support that scenario as well.

  71. nanny_govt_sucks:

    #67 – “One can fairly easily visualise a best-fit line from around the 1930s to the present and see an increase in the number of storms.”

    What I see is a flat trend until about 1995 or so.

  72. Scott Church:

    It’s great to see this story getting attention here! I hail from Seattle and the ST is my home paper. As it turns out, Sandi Doughton interviewed me for this story and I provided her with much of her information on global warming skeptics and the tropospheric satellite record. It was great to be a part of it. – SC

  73. nanny_govt_sucks:

    Just found this:

    Greenland icecap thickens despite warming
    “Greenland’s icecap has thickened slightly in recent years despite concerns that it is thawing out due to global warming, says an international team of scientists.”

  74. Dan:

    re: 73

    Note that the article concludes by saying:

    “A separate study in today’s issue of Science reports that sea levels are probably rising slightly because of a melt of ice sheets.

    “Ice sheets now appear to be contributing modestly to sea level rise because warming has increased mass loss from coastal areas more than warming has increased mass gain from enhanced snowfall in cold central regions,” the report by a team led by Professor Richard Alley of Pennsylvania State University in the US says.

    “Greenland presently makes the largest contribution to sea level rise.””

  75. Stephen Berg:

    Re: #71, “What I see is a flat trend until about 1995 or so.”

    The rate of tropical storm and hurricane increase is certainly not great prior to 1995. However, I fit a best-fit line myself on the actual newspaper (of which I am a subscriber) and found a slight increase. What is alarming is the post-1995 record, which makes it look like the oceans have lagged in terms of temperature increase until the last decade. It now looks like the plaent is in for something terrible in this part of the world, and in other regions which are affected by tropical cyclones, a massive increase in the numbers and intensities of such storms.

    I know circulation patterns (currents) are primarily responsible for thermal transmission. In my view, however, the ocean-atmospheric couplet is becoming more and more of a factor in the warming or cooling of the oceans.

  76. Blair Dowden:

    Re #69 – I was wrong about Wilma. It strengthened in the Caribbean, which shows a clear pattern of warming, especially this year. It is reasonable to conclude that global warming played a part in Wilma’s intensity. I note that the RealClimate article confirms there is no link between sea surface temperatures and hurricane frequency (which is extreme this year), but it is linked to intensity (also high this year).

    Re #60 – I am still having a hard time understanding the statement “Approximately 98% of the energy supplied annually to the Arctic system is advected from lower latitudes by the atmosphere.” from the EOS paper, and confirmed by wayne davidson. Does this mean only 2% of the energy comes from the sun? Given that average arctic insolation is about 100 watts per square meter, this makes no sense. A better idea of the energy balance in the arctic might help me understand events there better.

    Speaking of Greenland cooling and the ice sheet thickening, I am struck by the image of northern surface air temperature change for 1980-1999 in the Nansen Environmental and Remote Sensing Center paper, p. 7. It shows Greenland as a small island of cooling in a large sea of warming. I guess ice caps are resiliant, but how long can this situation last?

  77. Steve Bloom:

    Re #s 59 and 65: The albedo change when sea ice melts is by no means considered to be insignificant. Quoting from http://nsidc.org/news/press/20050928_trendscontinue.html , the recent press release on this year’s record low sea ice extent:

    ‘The trend in sea ice decline, lack of winter recovery, early onset of spring melting, and warmer-than-average temperatures suggest a system that is trapped in a loop of positive feedbacks, in which responses to inputs into the system cause it to shift even further away from normal.

    ‘One of these positive feedbacks centers on increasingly warm temperatures. Serreze explained that as sea ice declines because of warmer temperatures, the loss of ice is likely to lead to still-further ice losses. Sea ice reflects much of the sun’s radiation back into space, whereas dark ice-free ocean absorbs more of the sun’s energy. As sea ice melts, Earth’s overall albedo, the fraction of energy reflected away from the planet, decreases. The increased absorption of energy further warms the planet.

    ‘â??Feedbacks in the system are starting to take hold,â?? argues NSIDC Lead Scientist Ted Scambos. Moreover, these feedbacks could change our estimate of the rate of decline of sea ice. â??Right now, our projections for the future use a steady linear decline, but when feedbacks are involved the decline is not necessarily steadyâ??it could pick up speed.â??’

  78. wayne davidson:

    #76, I am not sure also about that 98% figure, but there is definitely some very strong advection activity on a continuous basis, feeding heat to several distinct circumpolar geographical locations in the Arctic every day.

    I would like to ask a Gulf coast Climate/Historian a question, you never know, may be someone like Gulf Coast resident like Mr Wallace reads Real Climate.

    After speaking to a native Floridian who was around in the 40’s, I was surprised to learn that hurricanes then, didn’t seem to be as numerous as 2005. An account about those numerous hurricanes in the 40’s would be nice to hear about, since they are mentionned so oftenly as reoccuring today..

  79. Steve Bloom:

    Judith Curry, Kerry Emanuel and Kevin Trenberth have come out swinging and are now saying that there is a causal relationship between global warming, increased SSTs and stronger hurricanes.

    Curry is interviewed at http://pubs.acs.org/subscribe/journals/esthag-w/2005/oct/policy/pt_curry.html :

    “What you can do is show an unambiguous link between the increase in hurricane intensity and the warming sea surface temperatures. And if you look for why the sea surface temperatures are warming since the 1970s, you donâ??t have any explanation other than greenhouse warming.”

    Wow. There’s a more detailed joint statement at http://www.ametsoc.org/atmospolicy/EnvironmentalScienceSeminarSeries.html . I am *so* happy that these prominent scientists have decided to come out swinging. Among other things, in the interview Curry goes after Bill Gray, James O’Brien, Max Mayfield and Roger Pielke Jr. for the various negative roles they’ve been playing. (Chris Landsea is not named, but he’s there in spirit!) The timing with Wilma could not be better for this, of course. Yabba-dabba-doo!

  80. Keith Moulton:


    I’m sorry, Steve, the seminar where those three will appear is on October 25th. Today’s the 22nd. Only the first link offers any kind of statement, and it’s from Curry only, not the other two.

  81. Ferdinand Engelbeen:

    Re #76,

    Blair, one (again) need to be carefull with the time frame of the graph presented. The winter rate-of-change in the previous warming period was stronger between 1915-1935 (and the overall warming 1930-1940), than for the current one, as can be seen in the circumpolar stations which existed then, see Fig. 2, page 6 (3268) of the Overland e.a. papers.

    What is interesting in the Nansen Centre paper, is that much of the recent summer (and partly winter) warming seems to be outside the Arctic, in the mid-latitudes.

    Further, have a look at Fig. 1 of the Nansen paper: The difference between measurements and models still is large. The model underestimates the 1930-1940 warming as good for the Arctic as for lower latitudes, and underestimates the lower latitude recent warming, in my opinion as a result of overestimated influences of GHGs and aerosols at one side and underestimated solar influences at the other side. But that is more for the Modeller vs. modeller discussion…

  82. Steve Bloom:

    Re # 80 (KM): Keith, I do apologize (well, sort of) for the Flintstones reference (Wilma -> Fred -> yabba-dabba-doo), but I couldn’t resist. I’m not sure what the implied problem is with the seminar being on the 25th, but in any case to see the 1000-word statement from the three of them just scroll down on the second linked page. It’s powerful stuff.

  83. Stephen Berg:

    Thank you, Steve Bloom, for your links in #79. Curry, Emanuel, and Trenberth are certainly beacons in the fog!

  84. wayne davidson:

    #79 thanks Steve for the links.

    There is no debate as well with the few media savy scientists taking a stance against Global Warming, it is after all their “raison D’etre”, as they themselves get funded by Groups opposing the theory . But I recently read that 66% of Americans have already made the link between fierce Hurricanes and Global Warming, the attention spotlight will eventually change to “raison d’avoir” a better understanding, there is nothing more strong then being right.

    I am also ready to listen to the memories of Elders from the Gulf and Carribean about how similar 2005 is say to any year??? To counter the ‘matter of fact’ smug cycle theorists, there has to be a proper history recounted by climatologists capable of recounting that there was so called similar year(s), the “it was just as bad as in the 1940’s” ball is lobbed out, now we have to say, ho ya??? When then?? Name a year, say the horror stories (perhaps on a smaller scale). Then peers of that time can confirm or deny the veracity of it. Elders to the rescue! In the older days there were no NOAA’s, TV’s and internet, hardly any warning compared to today, frequent disatrous hurricanes like 05 would have been scarred in many memories.

    If there is no resonance with a previous years somewhat similar to 2004-05, there is none in the media now, nobody is saying its like 1949 all over again, therefore this adds to the formidable pile of evidence in favor of AGW, and also shows the weaker side of those negating AGW’s influence.

  85. Gerald Machnee:

    Re #79 – Following is a Q & A from the Curry interview –
    (Q – People can criticize the paper because you only went back to the 1970s. Can you actually see a pattern with such limited data?

    A – We do not have global data prior to 1970. We have data from 1945 to 1970 from aircraft in the North Pacific and the North Atlantic. Prior to 1945, we only have statistics on landfalling hurricanes.

    Now, events in the Atlantic comprise only 11% of global hurricanes, and U.S. landfalling hurricanes only comprise 1%. So trying to draw inferences about global hurricane activity from these statistics just doesn�t work. Using the sampling data from the Atlantic to understand what�s happening globally is like only sampling California voters to try and infer U.S. presidential preferences.

    If you look at landfalling hurricanes, the statistics are really just looking at California voters over 65 [laughs]. It�s a sampling error.

    Just to give you a counterexample, during the same time period, landfalling hurricanes in Australia have actually gone down. So if we had only relied on landfalling hurricanes we would have a different story. But clearly the Australian story doesn�t tell you anything about what is going on globally.)

    —-Curry uses an example of looking at voters over 65 when talking about landfalling hurricanes. However the work she refers to dating from 1970 to the present is like using voters under 35. She can write all the refereed papers in the world but the data is not complete whan you use half of a cycle.

  86. Gerald Machnee:

    Re #84 – You do not need to look for deceased elders in the computer age. The following site has the 10 deadliest, 10 costliest,and 10 most intense hurricanes:- http://www.cnn.com/SPECIALS/2005/hurricanes/
    RE – (To counter the ‘matter of fact’ smug cycle theorists, there has to be a proper history recounted by climatologists capable of recounting that there was so called similar year(s), the “it was just as bad as in the 1940’s” ball is lobbed out, now we have to say, ho ya??? When then?? Name a year, say the horror stories (perhaps on a smaller scale).)
    —Historical records exist beyond the elders. With very little effort you can find records of typhoons into the 1700’s killing 10’s of thousands. The years are there and are included in the previously named site.
    RE- (There is no debate as well with the few media savy scientists taking a stance against Global Warming, it is after all their “raison D’etre”, as they themselves get funded by Groups opposing the theory)
    — Do the forecasters in Miami Hurricane Centre get paid by special interests?

  87. Stephen Berg:

    Well, hello Tropical Storm Alpha! First time ever hitting the Greek alphabet.

  88. Steve Bloom:

    Re #85 (GM): By that very same logic, your speculation about natural cycles is entirely without basis. Now, tell me this: While it is well-known that there are all sorts of natural climate cycles, they all have a physical basis. The science is clear about the connection between enhanced SSTs and more powerful cyclones, but the skeptic/contrarian argument then goes that those enhanced SSTs must be the result of some natural cycle. What natural cycle, and what is its cause? Let’s see an analysis. The problem is that the enhanced SSTs are easily explained by global warming, and not so easily by anything else. Occam’s Razor, Gerald?

  89. Gerald Machnee:

    RE # 88 – It is unfortunate that many AGW proponents are in denial of the NAO. That cause of variation in SST’s has been around for centuries – longer than the short term used in many studies. Analysis – there are many sites describing this.

    [Response: Since no-one mentioned the NAO until now, it’s not clear why you think anyone is ‘in denial’ about it’s existence. There is a small influence on hurricane formation but there is no evidence that the NAO has long multi-decadal cycles (separate from a small forced response from the oceans or potentially from stratospheric processes) – it is best characterised by slightly red noise. -gavin]

  90. wayne davidson:

    #86, The question was how many year(s) were similar in nature to the 2004-05 period? Was not looking for a top 10 list, however the top ten most intense Hurricanes are from 10 individualized mostly sparsely separated years, but surprising isn’t it, none most intense were from the alleged infamous “hurricane crazy” 40’s, but at least 6 since 1960 . Distant past hurricane fear is something personal, unless you are an elder from down there you can’t connect the past with the present, it is a memory, something tangible which makes a lasting impression . Only a well studied person can give data suitable for proper comparisons. This is the time to hear from climate experts. As far as I can gather, there were no similar intense years, unless someone explains otherwise. Also cycles need to be convincing, example: El-Nino, like way more than 1 C fluctuations …..

  91. Gerald Machnee:

    RE #90 – For one year you can look at 1933. All the data back to 1851 are available at:

  92. Blair Dowden:

    Re #81 – Ferdinand, indeed the rate of arctic winter warming from 1920-1939 seems equivalent that in the last few decades, as seen in both the Overland et al paper, and the Nansen paper, figure 2. But figure 2 shows the 1920-1939 anomoly as localized in the arctic, as if the energy was transferred there from further south, while in recent decades it is only a small part of a global warming pattern.

    No explanation for the 1920-1939 warming is given other than “natural fluctuations.” The Nansen paper states “No positive correlation between arctic SAT and the NAO before 1950 is found â�� in fact, here we find that the correlation is negative (r ~ -0.39).” So it is not surprising that it is hard to model when it is not understood at all.

  93. Ferdinand Engelbeen:

    Re #79,

    Steve, as advocate of the devil (I must admit, I like that role…), may I point to the fact that the Webster, Curry e.a. paper starts in 1970. As Curry said, because from that date on, the data gathering was more global (although most oceans have good data since 1946). Thus any comparison with earlier data simply is impossible, because there are no reliable data (except for the Atlantic) for any pre-WWII period.

    But there were pretty rough hurricanes in the 1930-1940 period too, at least in the Atlantic, including the labor day 1935 hurricane which destroyed the Florida Key’s railway. That one had wind speeds up to 160 mph and the record lowest pressure (892 hPa), until hurricane Gilbert in 1988 and now Wilma (880 hPa).

    It is pretty sure that there is a link between sea surface temperatures (SST), the lack of wind shear and the total surface with high temperatures at one side and the number and strength of hurricanes at the other side (that is more than SST alone! See e.g. Chan and Liu). And from Gray e.a.:
    “When tropical cyclones worldwide are summed, there has actually been a slight decrease since 1995. In addition, it has been well-documented that the measured global warming of about 0.5 C during the 25-year period of 1970-1994 was accompanied by a downturn in Atlantic basin hurricane activity over this quarter-century period.”
    But they largely underestimated the 2005 hurricane season. Seems that hurricane prediction is as difficult as weather and climate prediction…

    It is pretty sure that the oceans – and the world in general have heated since the LIA, including rapid warming in the 1910-1930 period and the 1980-2000 period. The first increase anyway was mostly natural (solar induced) and the second was at least partly sun induced (and GHGs have helped but, in my opinion, less than what current models project).
    A few points:
    1. Solar indices indicate that solar activity never has been as high as in the recent period for the past 8,000 years (see Solanki e.a.). While there is little change since 1980, solar activity now is higher than in the 1930’s. Ocean temperature/heat content need a longer time to come into equilibrium.
    2. The pattern of ocean warming in the past decades only roughly matches the increase in GHGs. The heat content of the oceans shows a large sinusoidal curve (see Levitus 2005 figure 1), with cooling (while GHGs are increasing) and warming. Moreover, ocean models (Barnett e.a. 2005) significantly differ from reality for any oscillation between 10-60 years (see fig S1 in the supplement – that includes the 11 and 22 year solar cycles).
    3. There is a change in radiation balance 1985-2000 of the (sub)tropics, and a trend to less clouds. That induces an increase in insolation (~2 W/m2) directly absorbed in the oceanic surface, and an increase in IR radiation (~5 W/m2) back to space (from anywhere in the atmosphere or surface). The result (or the origin): an increase in SST of the tropics of ~0.08 C/decade. The change in cloud cover, neither the change in radiation balance is captured by any climate model (see Wielicki ea.
    Compare that to a global average 0.7 W/m2 change since 1980, attributed by the models to GHGs.

    Thus while some researchers link hurricanes to higher SSTs and global warming, others differ in opinion (btw, why are those not invited to the seminar? Would have been more interesting than a one-sided view!)

  94. Pat Neuman:

    Global temperatures were the warmest of the last 545 million years at the Paleocene/Eocene Thermal Maximum (PETM 55 mya).

    Between 95 and 68 million years ago, the interior of North America was covered by the Cretaceous Seaway.

    I am unaware of any heavy uplifting or sedimentation over the east/south areas of the Cretaceous Seaway lake bottom between 68 mya and 55 mya.

    Q: Is there any evidence that a shallow sea returned to parts of the east/south Cretaceous Seaway bottom area (FL, MS, LA, TX, OK, MO, IA, west MN, Manitoba) around the time of the PETM?

  95. Stephen Berg:

    Re: #93,

    There is also an apparent link between the number of Atlantic tropical cyclones and the atmospheric temperature. The following graph shows the number of Atlantic tropical storm systems from 1851-present:


    The graph seems to match up quite well with this graph:


    Of course, there is an apparent lag in storm numbers, but that is explained by the lag in oceanic warming compared to atmospheric warming, meaning it takes longer to warm water than it does to warm air. This leads me to think that we are nowhere near the peak of Atlantic tropical storms.

  96. Gerald Machnee:

    RE #89 Gavin – You note that NAO was not mentioned before. NAO and AMO have been noted in other threads or referenced. In #88 above a comment is made “The problem is that the enhanced SST’s are easily explained by global warming and not very easy by anything else”.(one denial)
    Well I think the reverse is more accurate as the global warming part is difficult to measure. It is more of a statistical association. On a Florida State University site, the following note is made – “For hurricanes occurring in the North Atlantic, climate factors include El Nino, the North Atlantic Oscillation(NAO), the Atlantic Multi-decadal Oscillation(AMO), and the Stratospheric Quasi-Biennial Oscillation(QBO). Hurricane climatology also includes the role global warming may have in hurricane activity.”
    There are also other sites relating the hurricane activity with the cycles.

  97. Dmitry Podborits:

    I am not a climate scientist, I just listen to their discussions on streaming radio.

    I wrote down my impressions and observations after listening to a roundtable titled “Is Global Warming Just Hot Air?”.

    My comments are here:

  98. Randolph Fritz:

    Since I never saw an answer to my question about the Pacific Northwest, I went and did my own homework and, yes, I think we have trouble. Here is part of a note I posted to local politicians:

    According to the Oregon Climate Service’s forecast for this fall and winter, “1995, the best overall match with this year (2005), had an abundance of extreme events: floods in November and February; ice storms in December and February; extreme wind storm (biggest in at least 15 years) in December.” In other words, we’re probably going to be hit hard this winter; I think it’s time to start preparing. In the future it seems likely we are going to have more runs of bad storm years, and I would like to see both forecasting directed to the possibility, and preparations made.

    Oregon Climate Service, “Fall & Winter Forecast 2005-2006”,
    Oregon Climate Service web page,
    UW/NOAA Center for Science in the Earth System (CSES) Climate Impacts Group (CIG), http://www.cses.washington.edu/cig
    UW Program on Climate Change, http://depts.washington.edu/uwpcc/

  99. Andrew Dodds:

    Re: 94

    See: http://www.scotese.com/Default.htm for a closer look, but..

    If I recall correctly, the time frame from 70 to 50 million years ago accomodates the opening of large chunks of the atlantic and finally the Artic ocean, allowing an ocean circulation regieme dominated by temperature difference instead of salinity differences. So in the late Cretaceous, the entire ocean would have been much warmer than today, and hence the same mass of water would occupy a greater volume. Even though the global surface/atmospheric temperatures may have been higher in the early Eocene, I don’t think this extends to the deep ocean.

    Additionally, there is a relation between ocean basin volume and seafloor speading rates, the higher the spreading rate the higher sea level is for a given climate/ocean temperature. However, this is a very hard relationship to bring out, because more seafloor spreading means more subduction and hence higher CO2 volcanic emission rates. So are your higher sea levels a result of ocean basin volume changes, ocean temperature changes or both? These are non-trivial questions to answer.

    Overall, direct comparisons of periods in earth history 30 or more million years apart are not simple. But it does not appear that N America was underwater during the Eocene.

  100. wayne davidson:

    #98, Another way of putting it would be “different climates”, good (nice and mild) for one zone, terrible (more rain/snow heavy winds) for another. Last few days Canadian High Arctic temperatures +11 C above normal with the monthly running mean at about +4 C, getting warmer.

  101. Blair Dowden:

    Re #93 – A look at the claim that solar activity is the highest in 8,000 years, from the Max Planck Society, shows a graph with a long period with little trend based on reconstructed data, followed by a sharp increase based on observational data. In fact, it looks a bit like a hockey stick. Where have I seen that before?

    [Response: We’ve discussed this point already in some level of detail in “Did the Sun hit record hights over the last few decades?”. -mike]

  102. Steve Bloom:

    Beta imminent, possible Gamma on the way: http://www.wunderground.com/blog/JeffMasters/show.html . A week ago I was guessing Delta for the final tropical storm of the season; now Epsilon may be conservative.

  103. Stephen Berg:

    Re: #102,

    The waters of the entire Caribbean and almost all of the Gulf of Mexico are above the 26 C (c. 80 F) threshold required for tropical storm formation. Some of the waters are even above 29 C still. It looks like (to me) the hurricane season will be extended. For how much longer than usual, I’m not sure.

    Perhaps, we’ll get several more letters into the Greek alphabet. (Here’s hoping none of these storms are retired, or else they’d have to use a different alphabet next time.)

  104. wayne davidson:

    # 103, It may take a long while before a cycle theorist comes up with a past example of such an extraordinary year. A clear retrospective from our best Climatologists are needed now, they can lay to rest many weak ill researched theories as they clearly can not explain this year.

  105. Gerald Machnee:

    Several factors other than SST will determine when the hurriane season will end. Even if SST Temperatures continue above 26 C that alone will not develop hurricanes or extend the season.

  106. Dan Allan:

    I still wish someone explain why models do not predict more hurricanes (only stronger ones) owing to AGW. One year doesn’t prove anything, what is interesting about 2005 season is that it shows the obvious: that higher SSTs extend the season in both directions, and extend the region of the ocean in which hurricanes may form. All of which, absent other factors, would seems to lead to an increase in both strength AND number of storms.

  107. Gerald Machnee:

    Re #106 – The higher SST’s would suggest that there is a larger area over which hurricanes could develop so this leads to a higher number. But in order to develop you need several other factors including a wave or impulse to start it. These are usually spaced out a bit so there will be an upper limit to the number that will develop. The beginning and end of the season is also controlled by the large scale pattern. As the high over the Atlantic drifts southward the season will end. Hope this helps somewhat.

  108. Dan Allan:

    re 107:
    Well…not anything I’m not aware of. So you need a wave or impulse to start a hurricane. So, if a larger portion of the ocean is of 26c or higher, that is just more area for waves and impulses to drift over and develop into TCs. As to length of season, yes, part of the end is the change in atmospheric conditions, but it is also cooling SSTs. For example, almost the entire north atlantic has been unfavorable for TC development the last week, but the SSTs are still so high that one of the only areas where a hurricance could conceivably form just formed one.

    This year had the busiest July on record and I believe also the most active October. The season seems extended.

  109. Stephen Berg:

    Re: #105: “Several factors other than SST will determine when the hurricane season will end. Even if SST Temperatures continue above 26 C that alone will not develop hurricanes or extend the season.”

    True, although SSTs are a principal determiner of tropical storm production.

  110. Gerald Machnee:

    It is pointless to debate which is the “most important” but the following 3 factors are all required. Removing any of them will essentially kill a hurricane or result in no development.
    * Warm sea surface temperatures.
    * Light winds aloft.
    * Rotation, or spin.(caused by the impulse or wave)
    One of the latest hurricanes was in December.

  111. Stephen Berg:

    Re: #110,

    Seeing that “Light winds aloft” and “Rotation, or spin (caused by the impulse or wave)” usually occur throughout the year, but SSTs above the threshold do not, should SSTs warm to the point where SSTs are above the threshold throughout the year, it is conceiveable that the hurricane season could be year-round, or at least the season could be extended greatly.

  112. Gerald Machnee:

    RE #111 – The light winds aloft in the hurricane prone areas do not occur year round, so that is one of the main reasons the season ends.

  113. Dan Allan:

    There is no one day when the winds aloft suddenly make hurricane development impossible during the fall. It is a gradual process. And it seems to me that during this transition-period, if SSTs remain above 26c over a larger part of the ocean, there would be more tropical cyclones.

  114. Gerald Machnee:

    Re #113 – And the transition period is now.

  115. Steve Bloom:

    Re #114 (GM): I think if you’ll look at the relevant web sites you’ll find that it’s not quite now. Right this moment things are not very favorable, but then such periods occur in the middle of the season. Overall, development over the course of the next couple of weeks looks reasonably favorable. We shall see. My guess remains Epsilon (i.e., three more tropical storms for this season).

  116. Stephen Berg:

    Maybe the public is catching on…

    CNN/USA Today/Gallup Poll. Oct. 21-23, 2005. N=1,008 adults nationwide. MoE ± 4.

    "Thinking about the increase in the number and strength of hurricanes in recent years, do you think global warming has been a major cause, a minor cause, or not a cause of the increase in hurricanes?"

    Major Cause / Minor Cause / Not a Cause / Unsure
    % / % / % / %
    36 / 29 / 30 / 5

    Sorry the alignment was not so good.

  117. Pat Neuman:

    Re: 99

    > Quote by Andrew Dodds/ If I recall correctly, the time frame from 70 to 50 million years ago accomodates the opening of large chunks of the atlantic and finally the Artic ocean, allowing an ocean circulation regieme dominated by temperature difference instead of salinity differences. So in the late Cretaceous, the entire ocean would have been much warmer than today, and hence the same mass of water would occupy a greater volume. Even though the global surface/atmospheric temperatures may have been higher in the early Eocene, I don’t think this extends to the deep ocean./ End Quote < -------------------------------------------------------------------- My comment: I think I see that. Perhaps that explains the methane burbs which preceded the Paleocene Eocene Thermal Maximum (PETM 55 mya), and the great loss of marine species versus the limited on extinctions on land, even though there was more rapid warming on land versus oceans.-------------------------------------------------------------------- > Quote by Andrew Dodds/ Additionally, there is a relation between ocean basin volume and seafloor speading rates, the higher the spreading rate the higher sea level is for a given climate/ocean temperature. End Quote < -------------------------------------------------------------------- My comment: I'm not sure where Antarctic was 70 million years ago, but reports show that India was moving into Asia about 50 million years ago when the Himalayas were built. I suppose the seafloor speading rates were higher 70 mya versus 50 mya. Might that be the biggest reason that Florida-Texas had swamps instead of ocean over them? -------------------------------------------------------------------- > Quote by Andrew Dodds/
    However, this is a very hard relationship to bring out, because more seafloor spreading means more subduction and hence higher CO2 volcanic emission rates. So are your higher sea levels a result of ocean basin volume changes, ocean temperature changes or both? These are non-trivial questions to answer. Overall, direct comparisons of periods in earth history 30 or more million years apart are not simple. But it does not appear that N America was underwater during the Eocene. End Quote < -------------------------------------------------------------------- My comment: I agree, > it does not appear that N America was underwater during the Eocene. < ----------------------------------------------------------------------------------------------------------- .. http://www.scotese.com/Default.htm for a closer look, …

  118. Pat Neuman:

    Re 99 should be: …
    Thus, global atmospheric temperatures were higher in the early Eocene (55-50 mya) than in the late Cretaceous (70-80 mya) while the deep ocean waters were cooler in early Eocene than in late Cretaceous. That would explain the lower sea level conditions of the early Eocene versus the late Cretaceous, even with the atmosphere hotter during the early Eocene than the late Cretaceous. The answer is in thermal expansion of the ocean waters, which was less in the early Eocene than in the late Cretaceous due to greater temperature stratification of ocean water is the early Eocene versus the late Cretaceous. I’m not sure we know much about the significance of effects of differences in salinity and seafloor spreading between the two periods, nor in the effects of the positions of the continents during the two periods. I think the most significant difference that’s responsible for the greater stratification during the early Eocene compared to the late Cretaceous is what the longer term climates were like preceding the two periods. The climate preceding the late Cretaceous (by 10s of myrs) was warmer than the late Cretaceous, but the climate preceding the Paleocene/Eocene Thermal Maximum (PETM) was colder, by myrs, than the early Eocene (52 mya) period. The 15 myrs preceding PETM, from 55mya to 70 mya, included the K/T event 65 mya, of which there is still much uncertainty about what really happened to climate during that short period of geologic time.

  119. Pat Neuman:

    Re: 188 concerning differences in sea level 70 mya and 50 mya:

    The answer is in thermal expansion of the ocean waters, which was greater in the early Eocene than in the late Cretaceous, due to greater temperature stratification of ocean water is the early Eocene versus the late Cretaceous.

  120. Mark A. York:

    How about this statement I just recevied denying global warming:

    “As to the global warming issue, the argument is so full of hype and scare tactics that I for one have decided that it is a political argument and not a scientific argument at all. In fact, while there is some evidence of a shrinking arctic ice cap in the Beaufort sea areas over the last decade, there is growth in the iceland glacier one of the largest in the world, there is growth in the section of ice due north of Canada (a map that Mark York put up) and there is a significant amount of research that shows that the antarctic ice cap is growing fairly rapidly while the Ross Ice shelf is shrinking.”

    He didn’t cite his source only the belief.