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  1. History is littered with examples of accepted scientific opinions that turned out to be utterly incorrect. Thie issue seems to be less one of veracity than having reasons to believe any particular theory. Even if global warming, in the main, turns out to be without merit, one can not reasonable deny its predictions merely because it’s “inconvenient.” If wishes were horses, and all that.

    Comment by jhm — 27 Oct 2006 @ 8:01 AM

  2. Let’s assume, for the sake of argument, that we will not alter the climate to such an extent as to escape the glacial pattern we’ve had for the last three million years.

    I know most scientists don’t lke to engage in spectulation but I would be very interested in everyone’s best estimates/guesses -whatever you want call it – as to when global cooling will begin.

    [Response: This is answered by #10, #15 and #4. The answer is, probably 50 kyr for a real ice age – William]

    Comment by Jim Cross — 27 Oct 2006 @ 9:07 AM

  3. I always thought the lyric refers to nuclear winter.


    [Response: Could be, its rather hard to know. I assume it was Strummer picking up the Zeitgeist and may not have known exactly himself. I always wanted to ask, but its too late now – William]

    Comment by John Gribbin — 27 Oct 2006 @ 9:38 AM

  4. When will the next ice age begin?

    Back in the 1970s, by analogy with the sketchy chronology then available for the last cycle or two, it was plausibly argued that it would begin within a few thousand years. (Speculations that it could come sooner were based on anthropogenic cooling through air pollution, which probably did indeed have a substantial cooling effect at the time, although it was soon recognized that greenhouse gases would have a stronger effect in the long run.) See my historical essay.

    More recently, it has been recognized that each ice age cycle is different because fluctuations in the Earth’s orbit, which set the timing of ice ages, vary from cycle to cycle. An Antarctic ice core record of climate published in 2004 went back 750,000 years through a previous cycle where the orbital elements had been similar to those in our own cycle. The results confirmed elaborate calculations of orbits that indicated that the next ice age would not come naturally within the next ten thousand years or so, maybe in 20-30,000 years.

    There is unfortunately another possible answer to the question. If we reach a “tipping point” of feedback between warming and greenhouse emissions, where the Earth lurches into a state without Arctic ice, then the next ice age might be delayed far longer.

    ref.: EPICA community members (Eric Wolff et al.) (2004), “Eight Glacial Cycles from an Antarctic Ice Core.” Nature 429: 623-28. See also reports in Science (November 25, 2005): 1285-87, 1313-21.

    Comment by Spencer Weart — 27 Oct 2006 @ 10:09 AM

  5. About “nuclear winter”, is it foolish to think that aerosols released from nuclear testing in upper atmosphere have contributed to the cooling phase 1950-70 ?

    [Response: Not foolish, but wrong. I don’t have any figures to hand but have asked about this before: the effect just isn’t that big – William]

    Comment by muller.charles — 27 Oct 2006 @ 10:28 AM

  6. Re #2:

    “Let’s assume, for the sake of argument, that we will not alter the climate to such an extent as to escape the glacial pattern we’ve had for the last three million years.”

    Also for the sake of argument: I don’t think we can, since we already have.

    Comment by Alan — 27 Oct 2006 @ 10:48 AM

  7. Re: 2[Jim Cross]

    I thought that was essentially the basis for the 1970’s global cooling scare:

    Look there are these glacial cycles in the ice cores. They’re probably caused somehow* by periodic eccentricities in the Earth’s orbit. Oh, it seems like we are “overdue” another ice age. Gosh, temperatures have been going down a bit for the last couple of decades. Er…

    * I don’t honestly think we know enough about the ice age onset mechanisms to be able to predict when the next ice age would have been were it not for Anthropogenic warming. The best that could be done would be a correlation with orbital dynamics, but that misses out the subtleties of the intermediate steps. I think the climate models are still too computationally expensive to have been able to run an “onset” scenario in a credible way. The most that they have done [as far as I know] is to reproduce the climate of the Last Glacial Maximum.

    Also, it’s Ruddiman’s argument that humans already altered the climate to the extent that we averted another ice age even before the onset of industrialisation.

    So [and I know you were only asking for the sake of argument], it’s less a question of whether we will alter the cliamte to escape the glacial pattern of the last 3 million years, as it is that we have already done so.

    Comment by Timothy — 27 Oct 2006 @ 10:57 AM

  8. An’ you know what they said – well some of it was true!

    I too thought Clash were referring to the nuclear winter…

    Now, Inhofe would be so much cooler and so much more relevant had he engaged to similar topics. Oh, well.

    Comment by natassa — 27 Oct 2006 @ 10:59 AM

  9. When one takes the unbroken temperature record from 1998 to 2004 from 101 US weather reporting locations, the Annual Average Temperature for these 101 locations is dramatically cooler since 1998. Adding in the Annual Average for 2005 dilutes the downward trend some, but the fact remains that every year since 1998 has been cooler than 1998. And those who are so sure global warming is increasing tell us that we are getting warmer and warmer, year by year. Ain’t so! These same people tell us that 1998 was the warmest year on record. Probably so if the record only goes back to about the 1970’s. But when you look at the long time Annual Average Temperatures back to 1900 or even further back, 1998 is only one of several unusually warm years, and looses it’s first place ranking to several other years. I’m talking about actual weather that happened, was recorded and is available for anyone to look and and analyze.

    Comment by Wayne Byerly — 27 Oct 2006 @ 11:11 AM

  10. As a more direct response to #2 than my previous effort, I can recommend reading RealClimates previous post on this subject [linked to in the article above under “We’ve done this all before“]. In that it appears that recent research [~2000] suggests the current interglacial, in the absence of human effects, could last for 50,000 years.

    Comment by Timothy — 27 Oct 2006 @ 11:17 AM

  11. Someone at Newsweek has a sense of humor, probably not an editor.

    The phrase “wasn’t ‘wrong’, in the journalistic sense” seems an allusion to Pauli’s comment on a paper that it was not merely not right, it was not even wrong, as revived in Woit’s recent book.

    And someone — a Newsweek editor? — must be spinning anti-sensewise, to have jammed so much nonsense into their final sentence:
    “… society elected not to follow one of the possible solutions mentioned in the NEWSWEEK article: to pour soot over the Arctic ice cap, to help it melt.”

    Oh no?
    So where is this how you say “Arctic ice cap” now, Mr. Newsweek Editor? _ice_cap_?!

    NASA – ….. the ice covered with soot …

    Check back in 30 years if Newsweek’s still publishing for the next article, concluding

    “There was no Arctic ‘ice cap’. There isn’t even ice …”

    Comment by Hank Roberts — 27 Oct 2006 @ 12:16 PM

  12. Re #4

    So you think we’ve already reached the point where we have permanently broken from the glacial pattern – cooling will never happen (at least any time in the next few thousand years)?

    Just asking.

    Comment by Jim Cross — 27 Oct 2006 @ 12:18 PM

  13. Apparently this Isaac Asimov quotation is well-known, but I just discovered it yesterday. It’s excellent, and worth pointing out here just in case anyone else hasn’t read it:

    “John, when people thought the earth was flat, they were wrong. When people thought the earth was spherical, they were wrong. But if you think that thinking the earth is spherical is just as wrong as thinking the earth is flat, then your view is wronger than both of them put together.”

    Comment by mlmitton — 27 Oct 2006 @ 12:19 PM

  14. Re #5
    As far as I understand it (drawing on my recollections of a lecture Hansen gave here at Yale a few weeks back), the actual net forcing associated with Milankovich cycles is relatively small, but it tends to trigger massive feedbacks (e.g. polar ice expanding, lowering albedo, cooling, expanding more) that “snowball” into a glacial period. Given that arctic sea ice is already set to disappear given current levels of GHGs in the atmosphere, there is little chance that this feedback will contribute to an ice age any time in the foreseeable future. Perhaps some of the Realclimate folks could provide a clearer explanation though…

    Comment by Zeke Hausfather — 27 Oct 2006 @ 12:26 PM

  15. Among the things not known in the 1970s:

    Science 23 August 2002: Vol. 297. no. 5585, pp. 1287 – 1288 DOI: 10.1126/science.1076120

    An Exceptionally Long Interglacial Ahead? — A. Berger and M. F. Loutre

    “Today’s comparatively warm climate has been the exception more than the rule during the last 500,000 years or more. If recent warm periods (or interglacials) are a guide, then we may soon slip into another glacial period. But Berger and Loutre argue in their Perspective that with or without human perturbations, the current warm climate may last another 50,000 years. The reason is a minimum in the eccentricity of Earth’s orbit around the Sun…..”

    Comment by Hank Roberts — 27 Oct 2006 @ 12:30 PM

  16. Newsweek’s correction is worse than the original. The original article reports on cooling as a speculative scientific curiousity, with grave potential implications, but clearly reports that “Our knowledge of the mechanisms of climatic change is at least as fragmentary as our data,Â�” concedes the National Academy of Sciences report. “Not only are the basic scientific questions largely unanswered, but in many cases we do not yet know enough to pose the key questions.” Admittedly the original put the more sensational cherry-picked factoids up front and ignored obvious details like the huge gap in time scales between current weather and descent into an ice age.

    Now, rather than acknowledging the modest deficiencies of the original, they’re treating it like a point prediction, and shifting the blame to some scapegoat scientists. If they had honestly appraised their own work, they would have recognized that they’d highlighted a set of opinions that were outliers. Since the scope of their research appears to have included only reading William’s web page, you’d think they’d have picked up on that. To say that In fact, the story wasn’t “wrong” in the journalistic sense of “inaccurate.” is a cop-out. The subhead, Why scientists find climate change so hard to predict, is even worse as it tars current scientists with the same brush, yet the article doesn’t address current prediction challenges in any useful way. The net result just lends credence to Inhofe’s red herring tactics.

    Comment by Tom Fiddaman — 27 Oct 2006 @ 12:45 PM

  17. This Newsweek article has taken on the status of an urban myth.

    But also in 1975 the New York Times said earth was Heating
    Scroll down to where it has the subtitle “Effect of Heat Waste”.

    The NYT notes concern over CO2 levels and fears that production of energy ‘heat waste’ will generate so much heat as to have a major climate impact. That did represent an emerging scientific concern of its time.

    In 1975 the National Academy of Science (NAS) applied for funds to “Establish a national climatic research program”.
    Some journalists went to town to try and convince readers this was important stuff. After all their job is to try and produce articles that’ll sell copies. As I’m sure their editors impress upon them.

    The NY Times 1975 article was based on the same story as Newsweek’s “Cooling world”.

    So don’t blame scientists, it was different approaches by (doubtless hard pressed) journalists.

    The Newsweek article was written by staff writer, Peter Gwynne. (Who still works as a freelance science writer and is doubtless deeply unhappy this is being dragged up after all this time. Hey ho.) It wasn’t written by a climatologist or member of the NAS.

    Nor is Newsweek’s conclusion -Global Cooling – based on any scientific paper published in a scientific journal. It certainly doesn’t cite any.

    Comment by Tim Dennell — 27 Oct 2006 @ 1:08 PM

  18. I am old enough to remember the 70s; I was 40 in 1973. I remember seeing articles of this kind, but they were clearly speculative in nature and without any firm scientific consensus behind them. My response was that it was an interesting idea but not one worth spending any significant time worrying about. When fears about global warming arose in the late 80s, my response was similar. It just didn’t seem plausible to me that humans could do enough to affect climate in a significant way. But as I learned more about the science behind the concerns, I became convinced pretty early that this was something to think about and try to avert. One major difference which should have been apparent even to a lay person was that fears of an impending ice age ran their course and we heard little about it after a while, but concerns about warming didn’t go away as evidence mounted. Indeed the case became stronger and stronger. In any case, the less obvious lesson of the ‘Boy who Cried Wolf” tale is that sometimes there really is a wolf.

    Comment by Leonard Evens — 27 Oct 2006 @ 1:37 PM

  19. We shouldn’t forget that a certain amount of not completely understood changes in weather patterns continue to make seeing the longer-term patterns difficult. Just because there are a few years of cooling mixed in with a few years of warming is, of course, really meaningless in trying to ascertain what climate is doing long term. Melting Arctic sea ice, shrinking glaciers, and increased rate of Antarctic ice flow, these are, I think, far more reliable and objective gauges to long-term climate trends than are local temperature measurements. Rising CO2 levels are also particularly poignant as a driving force. Recent reductions in average ocean temperatures may very well be a result of massive ice melting, and would also influence air temperatures to an extent, and thus these may counterintuitively signal the ongoing effects of global warming (in the long term). Sea level seemingly keeps rising, too, and at an accelerated rate from what it was just a decade ago.

    Comment by Gene Hawkridge — 27 Oct 2006 @ 2:01 PM

  20. “London Calling” is one of the great rock songs of all time. Thanks for reminding me of it. I wouldn’t try reading too much into it as far as climate science goes. It’s poetry, not science — one of those late 20th century apocalyptic visions like Jefferson Airplane’s “House at Pooneil Corners” (from the great Crown of Creation album) or REM’s “The End Of The World As We Know It.”

    Comment by SecularAnimist — 27 Oct 2006 @ 3:05 PM

  21. This discussion of recent history reminds me of something I read in the 90’s. Unfortunately I’m not very good at using ‘the Google’, and I can’t find a link. There was a time when a large number of scientists opposed CO2 limitations and signed a petition of some sort. The reason wasn’t that they thought that CO2 emissions could not enhance greenhouse warming; rather, they were concerned that the uncertain climate benefits of CO2 limitation policies could not justify keeping the third world poor (and without access to fossil fuels). I believe the letter/petition was in 1994. It’s interesting to me that back then the science wasn’t attacked irrationally. The focus was on the policy, where it should have been. Ah, the good ol’ days.

    Comment by Steve Latham — 27 Oct 2006 @ 3:17 PM

  22. Re #9,

    1998 was not the start of a cooling trend, it was merely a single anomalously high year due to El Nino.

    And you are equally incorrect about the time period for which 1998 (or 2005) was a record. It is for sure a 150 year record, almost definately a 500 year record, probably a 2000 year record, likely a 12000 yr record, likely a 125Kyr record.

    Comment by Coby — 27 Oct 2006 @ 3:21 PM

  23. wow, they linked to Connolley’s website but misrepresented it’s content. William, just curious, when you talked to them did you stress the point that these predictions where never made in peer review? They seem to portray your conversation a little differently.

    Everyone: There is a Rate this story at the end of an article. Make sure you give it a 1 star!.

    Comment by wacki — 27 Oct 2006 @ 3:31 PM

  24. Re #21

    Steve, there were at least four petitions put out in the 1990’s. They are the Heidelberg petition , the Oregon petition, and two Leipzic Declarations. They are completely bogus and were put out by the usual supects Singer, Seitz et al. The Heidelberg petition did not argue against climate change, though it is sometimes presented as though it does. It called for honesty in using science to solve and describe environmental problems. So ironic that the publishers used it so dishonestly.

    Ian Forrester

    Comment by Ian Forrester — 27 Oct 2006 @ 6:56 PM

  25. “The lesson to take from this is the obvious one: not to take your science stories from the mass media…” William, I think you’re being much too cautious here. It’s obvious to me that you should not believe any stories from the mass media, although I admit that I haven’t restricted my sampling to your single example.

    Comment by S. Molnar — 27 Oct 2006 @ 7:01 PM

  26. One of the implicit points in the frequently pointed to graphs from the various Hansen et als, which is explicitly stated in many of the same papers and Hansen’s presentations is that we are entering (indeed are already in) a state where there can be no ice ages.

    Comment by Eli Rabett — 27 Oct 2006 @ 10:20 PM

  27. Discussion by itself is worthless, if we wait to take action until the signs are evident (like pollution today), we miss our oppertunity to avoid what our children WILL have to deal with.

    Comment by Robert Wagner — 27 Oct 2006 @ 10:24 PM

  28. Re: #4, 6, 10,15

    Thanks to everyone who responded to my invitation (Post #2) to speculate on when global cooling might begin.

    Regarding post #15, I’d love to read the â��An Exceptionally Long Interglacial Ahead?â�� article. Is it posted anywhere that doesn’t require membership or subscription?

    I find it rather odd that most put global cooling very far in the future or, perhaps, never happening at all. We have had three million years or so of a somewhat regular pattern of cooling and warming. The interglacials have typically been about 10k years. We’ve been in this interglacial about 11.5k years. No one seems to understand exactly how the astronomical influences, which seem fairly certain to exist, are augmented to produce the magnitude of the heating and cooling effects. Yet some seem to think we’ve stepped outside of history because of a few extra ppm of CO2 in the atmosphere. Well, maybe we have. Or, maybe the extra CO2 is driving us ever faster to a tipping point not understand at this point that leads to global cooling.

    For my own speculation, I’ll invoke Gott’s Principle. If we are 11.5k years into this interglacial, we can be 95% certain it won’t end in less ~300 years and 95% certain it won’t last longer than ~450,000 years.

    [Response: The interglacials have typically been about 10k years – simply repeating this won’t make it true. Look at, for example, . Can you spot the regular 10kyr interglacials? But this is a case where we have theory to guide us, based on the orbital variations, which is better than relying on extrapolating past cycles – William]

    Comment by Jim Cross — 28 Oct 2006 @ 12:03 PM

  29. Would someone up on the maths care to comment?

    Comment by andrew worth — 28 Oct 2006 @ 12:28 PM

  30. Thanks Ian (#24), but it was much more specific than either the Heidelberg Appeal or the World Scientists’ Warning To Humanity (suggesting that it was a bit later than ’92). Maybe it was just a letter from a few people, but I thought it would be something big enough that I would be able to find it again.

    Comment by Steve Latham — 28 Oct 2006 @ 1:12 PM

  31. I totally agree with the thought that discussion of climate change, whether it is cooling or ‘warming’ is worthless – unless we act on it NOW! If we keep only discussing we are going to miss the bus at probably the last chance to save planet earth.

    Scientific theories and statistical data on temperature variations and global warming are important. However what are we seeing? What is the common man actually experiencing in terms of climate variations? Across the Globe summers are turning warmer, winters milder, ice caps and glaciers are melting and the oceans are rising; and this can be seen and experienced by the common man in Canada, Europe, India and the far corners of far-east.

    We are polluting our atmosphere, like never before, with fossil fuels and toxic emissions and if we don’t control this now it will be too late! Each one of us has our individual responsibility to ACT NOW and minimize polluting the atmosphere and clean up the environment.

    Comment by AspiDJ — 28 Oct 2006 @ 1:44 PM

  32. When will the next ice age begin?

    Re: #4 and similar comments which repeat the erroneous belief that there is no concern with the abrupt start of the next ice age, due to insolation similarities of the current period to ice age cycle 11.

    The following is justification as to why there is a real concern with a sudden start to the next glacial cycle.

    In the 1990’s paleoclimatologists’ discovered evidence in the Greenland ice sheet core data that the periodic 200yr, 500yr, 1500yr, 8000yr, etc. climate changes (up to 20C drop in the Greenland ice sheet temperature) were rapid not gradual events. For example, the Greenland ice core data shows that the Younger Dryas cooling event occurred in a 5 year period (Younger Dryas is the name for a climate change from the current interglacial Holocene, warm period, back to the Wisconsin glacial, cold period, that occurred 12,800 yrs ago).

    The Greenland ice core finding was not expected (the old consensus belief was that climate changes were gradual) and many at first stated the planet’s climate could not possibly change that rapidly. (The doubter’s suggested that the ice core data was flawed.) A second Greenland ice core was drilled. The second set of ice core data corroborated that the changes were very, very, rapid.

    The question is now not did the Rapid Climatic Change Events (RCCEs) “Rickies” occur, but rather what is causing them? What are the forcing function(s) that could possibly cause such a rapid and extreme change in the planet’s climate?

    Broecker suggested that the “Rickies” such as the Younger Dryas could be due to a sudden stoppage of the thermohaline conveyor. Broecker hypothesized that a sudden release of ice sheet melt water down the St. Lawrence River, rather than the Mississippi River caused an abrupt stoppage of the thermohaline conveyor and that the stoppage of the conveyor caused the Younger Dryas. Later evidence showed that Broecker’s hypothesis was not correct. Paleoclimatic data shows that ice sheet melting has very low for 1000 yrs before and after the Younger Dryas and that the St. Lawrence River flow was lowest during the period of the Younger Dryas. Beside the problem of what could possibly cause the sudden stoppage of the thermohaline conveyor, there is the problem as to why would the hypothesized change of flow from the Mississippi River to St. Lawrence River, occur periodically. Finally, climate simulations and fundamental climatic reasoning shows that the affect on the Northern Hemisphere climate due to the stoppage of the conveyor is not sufficient to account for the observed change. It is fortunate, that a stoppage of the conveyor is not catastrophic (2C expected drop in European winter temperatures and possible winter freezing of the Baltic Ocean) as there is evidence that the conveyor flow has reduced by 30% and may stop in the near future. (It did briefly stop Nov. 2005).

    Another hypothesis as to what could be causing periodic rapid changes to the planet’s climate is that there are periodic solar events which affect cloud formation. The solar hypothesis is currently being investigated.

    [Response: This is badly garbled. In particular, no-one has seriously suggested solar forcing to explain the rapid climate changes in the last glacial – William]

    Comment by William Astley — 28 Oct 2006 @ 3:17 PM

  33. for Steve, #30, et al. You’re probably thinking of the referenced Oregon Project aka “The Petition Project”.

    It had some minor credibility problems, mostly automatic ad hominems from the folks who didn’t like the 17,000 or so scientists (predominately) who expressed doubt with GHGs causing global warming. [Though the same folks are fully supportive of the 1200 or so (mostly) politicos who put out the IPCC reports.]


    While our earth may be heating up disastrously (I personally doubt it, but I might be wrong… and what do I know??) I think the science verdict is still out irrespective of the near-manic pep rally going on by the proponents. I think its potential risk demands an even greater full-fledged scientific investigation, and, btw, one that considers the “aginers” rather than dissing them out of hand as “outlyers”. But to cost our economies probably $40 trillion to fully implement Kyoto because some ‘don’t like the pollution’ is a bit of a stretch. It’s possible that this fully accepted theory might prove utterly incorrect like so manay before, as jhm (#1) points out. The risk still warrants spending lots (more) bucks on research, but not utterly destroying the economy.

    [Response: A better ref for the Oregon petition is You’re wrong about the economics, but we avoid that here anyway – William]

    Comment by Rod Brick — 28 Oct 2006 @ 3:48 PM

  34. >15, 28
    When you can’t find something with Google, try Google Scholar; view html, view the related links — you may find the actual article; you’re sure to find enough quotes from it and citations to it to get the information.–+A.+Berger+and+M.+F.+Loutre

    Comment by Hank Roberts — 28 Oct 2006 @ 3:52 PM

  35. The Pacific Decadal Oscillation � An Observed Phenomenon in Global Climate and Pacific Ecology with Implications for Flooding and Drought in Australia.

    Global temperatures of the 20th century showed a warming phase to the 1940�s, a cooling phase to the 1970�s and renewed warming to 1998. The Pacific Decadal Oscillation (PDO) is mainstream science, can explain some of the observed warming and has significant implications for flooding and drought in Australia.

    Figure 1: Global Surface Temperature Anomalies (Source: Goddard Institute for Space Studies)

    In the past century cool PDO regimes prevailed from 1890-1924 and again from 1947 to 1976, while warm PDO regimes dominated from 1925 to1946 and from 1977 to 1998.

    Figure 2: October-to-March averaged PDO indices. Positive values indicate warm phases of PDO, while negative values indicate cool phases of PDO. Solid curve shows a 5-year running average for each time series. (Source: Joint Institute for the Study of the Oceans and the Atmosphere)

    The Pacific Decadal Oscillation (PDO) is a natural climate phenomenon that has been traced back in trees and coral for more than 400 years. The divergent climate states were first discerned in arctic fisheries in 1996 but have since been discovered in changing abundances of anchovies and sardines in Monterey Bay (having given rise to John Steinbeck’s novel Cannery Row) and in Australian multi-decadal rainfall trends.

    Australia has good flood records going back more than 100 years. It has been known for some time that Australia experiences decades long periods of drought and, alternatively, decades long periods of flooding. Recent flood analysis suggests that the phenomenon is a result of long term modulation of both the frequency and intensity of La Nina and El Nino events in the El Nino Southern Oscillation (ENSO).

    An effect on global temperatures should be anticipated from a phenomenon that involves the ENSO. More frequent and intense El Nino leads to higher global temperatures � as seen in the last warm phase of the PDO. Conversely, more frequent and intense La Nina in a cool phase of the PDO results in lower global temperatures.

    Beginning to disentangle the PDO effects from other climate forcings in the temperature record requires consideration of a full cool/warm cycle from 1947 to 1998. The resultant trend in temperature increase is 0.07 degrees C per decade rather than the 0.2 degrees C trend obtained from consideration of the last warm phase alone. This is a significant moderation of the warming trend.

    The PDO index moved into negative territory after 1998 � but has since settled back into the positive. Global temperatures have not increased since 1998 suggesting that the effect of a cool phase of the PDO is being felt. If so, the effect will last for decades and will moderate global warming. The cyclical nature of the PDO with a period of 20 to 30 years over a long time strongly suggests, if history remains any guide, that a phase shift is likely in the near future if it has not already occurred.

    The powerful climate signal of the PDO is not included in the climate models because, quite simply, there is no agreed explanation for the observed phenomenon. This is a current limitation of the models when confronted with, as yet unexplained, real world climate variations occurring over periods of decades to millennia.

    The implications of a cool phase of the Pacific Decadal Oscillation include a decades long and large increase in rainfall, cyclones and flooding in eastern and northern Australia.

    As the Joint Institute for the Study of the Oceans and the Atmosphere says, from â��a societal impacts perspective, recognition of PDO is important because it shows that “normal” climate conditions can vary over time periods comparable to the length of a human’s lifetime.â��

    Comment by Robert Ellison — 28 Oct 2006 @ 10:11 PM

  36. Re: Comment 32 which outlines the issue of Rapid Climatic Change Events, RCCEs.

    Reviewer’s Comment: “In particular, no-one has seriously suggested solar forcing to explain the rapid climate changes in the last glacial.”

    There is currently no accepted explanation as to what is causing the observed periodic rapid climatic change events, throughout the last and past glacial periods. Solar variance is most certainly on the short list of suspects. The following is an excerpt from M.Christl et al’s (2004) paper in the Journal of Atmospheric and Solar-Terrestrial Physics, which explains how the sun could affect the earth’s temperature:

    “A leading candidate to explain the link between relatively feeble solar fluctuation and climate is the effect of solar (magnetic) modulated galactic cosmic rays (GCR) on cloud formation (Editors of science, 2002). … their contribution to the global radiation climate forcing is estimated to be about -28 W/m^2 (Hartman, 1993). This is one order of magnitude larger than the radiative forcing caused by the anthropogenic greenhouse gases (IPCC, 2001).

    The observed rapid climate change events, “RCCEs” are becoming stronger based on a significant increase in atmospheric dust in both the Antarctic and Greenland ice cores during the last glacial period, as compared to past glacial periods. For example, see figure 1, “Dust (ug kg-1)” from the EPICA Dome C Ice Core, from the article “Eight glacial cycles from an Antarctic ice core”, which was published in the June 10, 2004 issue of Nature.

    [Response: This has nothing at all to do with rapid change during the last glacial. And there is no consensus on them being periodic. If there was a strong solar signal in climate, then you would need something like GCRs to explain it, though – William]

    Comment by William Astley — 28 Oct 2006 @ 11:59 PM

  37. When will the next ice age begin? Do ice ages begin gradually?

    The current insolation received at the critical latitude of 65N is the same as it was 18kyr ago, during the Last Glacial Maximum, (Laskar 1990; Berger & Loutre 1991). July 4th the earth is at its greatest distance from the sun (156 km) at the aphelion. January 3rd the earth is closest to the sun (146 km) at the perihelion. This orbital configuration is posited to initiate an ice age (Warm winters which increases snow fall and cold summers which enables there to be a gradual build-up snow.)

    Past interglacial periods have lasted no more than 10 thousand years. Is this interglacial different? Why?

    [Response: If what you said about interglaical length was true, then this one would be different in that its lasted more than 10 kyr already – William]

    Comment by William Astley — 29 Oct 2006 @ 12:39 AM

  38. Re #28 and “Yet some seem to think we’ve stepped outside of history because of a few extra ppm of CO2 in the atmosphere.”

    It’s not “a few extra ppm,” laddie buck. It’s 380 ppmv now compared to 280 before the industrial revolution. My calculator says that’s a 36% increase. I rarely hear 100 ppm described as “a few ppm.”

    Comment by Barton Paul Levenson — 29 Oct 2006 @ 7:38 AM

  39. Re #29 and “Would someone up on the maths care to comment?”

    Surely. Earth’s present IR flux up from the ground is 390.1 Watts per square meter, corresponding to a temperature of 288.0 K. Add 3.7 so that the flux is 393.8, and the temperature only moves up to 288.7, indicating a temperature sensitivity of only 0.7 K for doubling CO2. Similarly, the flux up at top of atmosphere (TOA) is 239.3 W m^-2, corresponding to 254.9 K. Raise it to 243.0, and the temperature becomes 255.9, for a temperature sensitivity of 1.0 K. Looks like the bad guys won this one.

    Except that they didn’t. Their math is fine, their climatology stinks. The IPCC temperature sensitivity of 3.0 K for doubling CO2 ADDS IN ALL THE KNOWN FEEDBACKS. The figure for CO2 doubling by itself, with no feedbacks, is 1.2 K (Houghton 2004). Thus these guys’ estimate is quite in line with the IPCC estimate.

    The reference to “the seminal work of Sherman Idso” is a joke. I have critiqued some of Idso’s work myself, and it is not only wrong, it is in some places deliberately misleading. For his greenhouse line drawn between Venus and Mars, there were ten figures available from the literature on the bolometric Bond albedo of Mars. Idso chose the darkest of the ten. Thus the Martian effective temperature was way high, so the Martian greenhouse effect came out as way low, surface temperature minus effective.

    Beware of greenhouse denialists bearing gifts. There is frequently a worm or two in the apple they offer you.

    Comment by Barton Paul Levenson — 29 Oct 2006 @ 8:34 AM

  40. What wonderful insight and thought provoking information this page has to offer. I’m just an average Joe seeking information so I may make informed decisions of my own. I’ve surfed the net a fair bit about our earth’s current climetology but in no way profess to be knowledgable. This site seems to have reached the level of sophistication not found on other web sites.. Here’s what this average Joe has determined through the net.
    1. The earth’s average temperature has risen dramatically since the Industrial Revolution although there has been marked warming and cooling trends during that period. However it has been mostly warming.
    2. Interglacial periods have a track record of ~10K years. This pattern might be, could be, possibly, somewhat or maybe not be influenced by the earth’s orbit, tilt, solar radiation output (maybe not), etc.
    3. Current measurments of CO2 are ~380 ppm which is very much higher than in recent history (~60K years) but no where near some levels experienced in the past 10 million years.
    4. There is several graphs and depictions that GHG emissions lag just slightly behind global warming (graphs I saw of ice sheet data). This then causes more warming which in turn causes more GHG, etc
    5. Man made GHGs are contributing to Global warming. However the earth produces large amounts of GHG regardless of man.

    The question I have is this. If all 6 billion humans ceased to exist tomorrow (call it Kyoto on steroids), what percentage of TOTAL GHG emissions would be eliminated? I seem unable to find the amount of impact that man has on the global climate vs. the impact that good old Mother Nature has. I understand somewhat about Carbon sinks and that currently the rate of total GHG emission does not equal the rate of absorption. There is a plethora of information screaming that man is causing catastrophic climate damage due to GHG emissions with out any comparison to TOTAL GHGs including water vapour. Anyone care to speculate regarding a scenario without man in the equation. Can anyone enlighten me to what was the cause of the massive climate changes the earth experienced pre man. I have no doubt that the earth is warming quickly. What would be the impact if suddenly the earth was devoid of all humans, thus eliminating the human production of GHGs. Thank you for your consideration. I’m sorry for barging in out of the blue and asking this, but it seems I could get the straight goods right here.

    It seems to me that we are pretty much hooped anyways.

    [Response:The human contribution to CO2 is roughly 20 times the natural volcanic flux that maintains the atmosphere’s CO2 content in the absence of industrial activity. –raypierre]

    Comment by David (Average Joe) — 29 Oct 2006 @ 3:16 PM

  41. Re: #9

    Your conclusions are as mistaken as the “facts” on which they are based. But thanks for giving most of us a good laugh.

    101 weather stations across the U.S. is only a small fraction of the available data; there are over 1200 U.S. stations in the global historical climate network. And *even if* you included all U.S. stations, and came to the same conclusions (which you wouldn’t), the contiguous U.S. is only about 5% of the surface area of the *globe*.

    We’re not your typical global-warming discussion group. *Lots* of us have looked at “actual weather that happened, was recorded and is available for anyone to look and and analyze.” I get the impression that your perspective on this issue is as narrow as the geographic slice on which you base it.

    Comment by Grant — 29 Oct 2006 @ 3:26 PM

  42. David (Average); lots of sources. Here’s one:
    “Levels of several important greenhouse gases have increased by about 25 percent since large-scale industrialization began around 150 years ago (Figure 1).
    During the past 20 years, about three-quarters of human-made carbon dioxide emissions were from burning fossil fuels.”

    Comment by Hank Roberts — 29 Oct 2006 @ 5:31 PM

  43. Re 40.

    Hank provided some good links. Here is my 2 cents.

    Keep in mind that it is the Total net (sources-sinks) that is important. Natural CO2 sources are larger than the anthro component BUT if you take proper account of the sinks then one finds that the anthro contribution has a BIG effect on the net. Were are emiiting more that the natural sinks can keep up with and until when/if we get serious about carbon sequestering, we are not providing much in the way of sinks. If you earn 10K$ a month and your “natural” level if spending is about the same, you will find that you can go broke or get rich if you change your income or expenses an amount that is small when compared to 10K (but large when compared to your “natural” income-minus-expenses).

    As for the relationship between CO2 and the very important GHG H2O, see Basicly H2O has such a short residence lifetime in the atmosphere it turns out that levels of other longer lived GHS’s end up controling the amount of H2O in the atmosphere (in part because there is a strong relationship between the amount of H2O air can hold and it’s temperature).

    Comment by David donovan — 29 Oct 2006 @ 7:16 PM

  44. Hiya folks,

    I think Jo Strummer might have meant the Gulf stream shutting down (like in November 2004! TimesOnline, Nature etc)… whilst the rest of world warms, which is why London is drowning:-)

    regards, Mark

    [Response: Not sure why the GS shutting down would drown London – unless some mystical association of oceans comes in. Also not so sure that was one of the ideas floating around in those days – William]

    Comment by mark schneeweiss — 29 Oct 2006 @ 9:17 PM

  45. Re: 40 “If all 6 billion humans ceased to exist tomorrow”

    New Scientist‘s October 12 issue had a lead feature on just such a thought experiment, and – miracles – it’s not behind their subscriber-only archive wall. It’s an interesting and thought-provoking read.

    “Carbon dioxide, the biggest worry in today’s world because of its leading role in global warming, will have a more complex fate. Most of the CO2 emitted from burning fossil fuels is eventually absorbed into the ocean. This happens relatively quickly for surface waters – just a few decades – but the ocean depths will take about a thousand years to soak up their full share. Even when that equilibrium has been reached, though, about 15 per cent of the CO2 from burning fossil fuels will remain in the atmosphere, leaving its concentration at about 300 parts per million compared with pre-industrial levels of 280 ppm. “There will be CO2 left in the atmosphere, continuing to influence the climate, more than 1000 years after humans stop emitting it,” says Susan Solomon, an atmospheric chemist with the US National Oceanic and Atmospheric Administration (NOAA) in Boulder, Colorado. Eventually calcium ions released from sea-bottom sediments will allow the sea to mop up the remaining excess over the next 20, 000 years or so.”

    Comment by Gareth — 29 Oct 2006 @ 10:16 PM

  46. As an interested amateur looking at the issues under discussion I see little evidence of other effects caused by man and nature being added to the computer modelsâ?¦
    What about man made cooling effects that offset CO2 and methane production?
    Such as aircraft aerosols emissions, the Hamatan (movement of Sahara dust clouds over Africa â?? sunlight reflector) and large South Asian forest fires are all sunlight reflectors.
    Every time I read about aircraft emissions adding to the CO2 in the atmosphere I never see any reference to the contrails which reflected sunlight.
    Also deforestation due to man made activities does this decrease or increase sunlight absorption?

    The other thing is no one seems to be taking account off is human history in consensus taking.
    A few hundred years ago the scientific consensus was the world was flat and also that witches existed. Looking at it this way makes you wonder what the value of scientific consensus is worth.
    Just my two pennies worthy of comment for what itâ??s worth.

    Comment by Olly — 30 Oct 2006 @ 3:37 AM

  47. Re #46 and “A few hundred years ago the scientific consensus was the world was flat and also that witches existed. Looking at it this way makes you wonder what the value of scientific consensus is worth.”

    1. Educated people have known the world is round since about 300 BC, when Eratosthenes measured its circumference. The idea that Columbus proved the world was round is a myth.

    2. There is an analogy between the global warming consensus and the witch trials, but it’s not the analogy you think. Scientists of the day never did believe in witches; the witch craze was a mass movement from the bottom up, a popular consensus. The academics of the day condemned it — the faculty at Tubingen issued a statement that it was “better to cure the soul than to torture and kill the body.” Johann Weyer, now known as “the father of modern psychology,” attributed confessions of witchcraft to mental illness. The analogy to the global warming consensus is obvious. The academics were telling people the popular beliefs were wrong and dangerous. but they got overruled by the politicians.

    Comment by Barton Paul Levenson — 30 Oct 2006 @ 7:57 AM

  48. Olly,

    A few hundred years ago the people believed that the world was flat, but the scientist knew differently. Why do you think Columbus tried to sail round the world. Why do you think the Queen of Spain financed him?

    Witches were burnt quite recently but not at the insigation of scientists. Many of them were scientists themselves. Galileo only escaped the stake by recanting his science.

    Comment by Alastair McDonald — 30 Oct 2006 @ 9:46 AM

  49. re #42

    great, but do you have a source where has anyone actually measured it? (CO2 from fossils should have a different isotope signature from present day CO2, should I would have thought it would be reasonably easy to do.)

    Also, do you have a source for CO2 diffusion? There are very few winds that cross the equator, so does CO2 is the southern hemisphere CO2 level delayed wrt to the northern hemisphere?

    Comment by Tim Hughes — 30 Oct 2006 @ 11:48 AM

  50. Re: Olly

    There are many different forcings taken into account beyond simple CO2 emissions. See and for some good examples of the different forcings considered, and their relative magnitudes.

    Comment by Zeke Hausfather — 30 Oct 2006 @ 12:20 PM

  51. Olly, ask your librarian for help — you seem to be missing a whole lot of easily found information.
    Just one example, the reports here (each of which has a long list of references that your school or city library can help you find and read):

    Comment by Hank Roberts — 30 Oct 2006 @ 12:34 PM

  52. Re: 33 and the Oregon Petition Project, we took the time to look up some of the signers in Connecticut.

    “It had some minor credibility problems, mostly automatic ad hominems from the folks who didn’t like the 17,000 or so scientists (predominately) who expressed doubt with GHGs causing global warming. [Though the same folks are fully supportive of the 1200 or so (mostly) politicos who put out the IPCC reports.]”

    We found very few scientists- mainly engineers and grad students, and the scientists were in totally unrelated fields. The only academic climate scientist we found (and contacted) was aghast that his name was on it and asked to be removed. The list doesn’t include city, title, or institution, making it pretty much useless.

    Its scientific neutrality is compromised by a. poor science and b. policy statements like:

    “Mankind is moving the carbon in coal, oil, and natural gas from below ground to the atmosphere and surface, where it is available for conversion into living things. We are living in an increasingly lush environment of plants and animals as a result of the CO2 increase. Our children will enjoy an Earth with far more plant and animal life as that with which we now are blessed. This is a wonderful and unexpected gift from the Industrial Revolution”

    Comment by Roger Smith — 30 Oct 2006 @ 1:02 PM

  53. Re #33: OK, I know you all don’t discuss economics here, but I wish that you, or SOMEONE, would try to apply the same sort of rational analysis to the economic issues as this site does to the science. On the one hand, I see statements like “…to cost our economies probably $40 trillion to fully implement Kyoto…”; on the other, I find that my personal anti-CO2 efforts (which range from CFL light bulbs to driving a Honda Insight instead of an SUV or – more likely! – 911 Porsche) mostly wind up saving me money. This disconnect really puzzles me. Can anyone point to sites or sources that discuss it?

    Also re #46: Witches do exist. I’ve known several, and in fact used to date one.

    Comment by James — 30 Oct 2006 @ 1:24 PM

  54. Where I work, this 1970’s idea of global cooling is brought up by the public almost weekly. I personally state that if you read the peer-reviewed journals, that “global cooling” never had even close to a scientific concensus. However, by comparison, global warming in the peer-reviewed journals, has a strong scientific consensus. The difference is between day and night.

    Comment by Richard Ordway — 30 Oct 2006 @ 1:35 PM

  55. William those Wikipedia links come up empty. Something may need a redirect. I’ve had to do that often in my work there.

    [Response: I found and fixed one (the graph) that had the sentences full stop in it (wordpress is not as clever as mediawiki) – William]

    Comment by Mark A. York — 30 Oct 2006 @ 1:51 PM

  56. I prefer global warming to ice ages….. so did the dinosaursâ?¦. Until those pesky glaciers formed and made much of the earth uninhabitableâ?¦.
    From the research I have seen there appears to be slowly rising co2 from some source even before man that then peaks and for some reason falls rapidly ushering in a new ice ageâ?¦.

    Comment by lars — 30 Oct 2006 @ 2:24 PM

  57. Re: 53 (James)
    For a good current economic analysis of the costs of climate change and GHG abatement, see the Stern Review by the former chief economist of the World Bank, Nicholas Stern.

    Comment by Zeke Hausfather — 30 Oct 2006 @ 5:19 PM

  58. Tim Hughes at #49:

    Yawn, yes, people have measured the isotope ratios for CO2, and there are changes consistent with the increases in CO2 being caused by fossil fuel burning. For example see this RealClimate post which I found by putting the words “CO2” and “isotope” in the handy search box in the top right of all RealClimate pages. I would have thought that would have been relatively easy to do [and it was].

    Also, if you find the Mauna Loa CO2 measurements [sorry too lazy myself to provide the link], then you find they have also been measuring O2 levels, which show a decrease [presumably due to combustion]. I think you could also find those graphs in the IPCC report [which although now about to be replaced is still an invaluable starting point for climate-related questions. After all if you’ve thought of it, it’s likely that someone else already thought of it and wrote a paper on it…]

    As to the diffusion, thing, well… Lets just say that you are *massively* wrong about there being “very few winds that cross the equator

    The geography textbook picture of the Hadley Circulation has ascent at the equator with the circulation splitting at the top to go north and south and then descending in the sub-tropics, before completing the loop back to the equator in the form of the trade winds. This simple picture would suggest that there are no winds that cross the equator since the winds either meet, divide or ascend at the equator. However, it is a gross simplification.

    Generally speaking the Hadley circulation ascent occurs at the latitude where solar heating is at a maximum. Due to the tilt in the Earth’s axis, this latitude varies, north and south of the equator, during the year. You basically only get one half of the Hadley Circulation at a time, and it *crosses* the equator. No diffusion required.

    Comment by Timothy — 30 Oct 2006 @ 8:16 PM

  59. #37 – Typical Northern Hemisphere bias. When it is summer in the NH it is winter in the SH.

    That’s where most of the water is…

    An immediate return to an Ice Age does not look likely.


    Comment by Robert — 30 Oct 2006 @ 9:18 PM

  60. #44 aargh, i only really meant that it is just about possible, in London, to say ‘an ice age is coming’ (due to Gulf Stream shutdown), whilst sea level is rising (due to a warming world) and ‘london is drowning’.

    Obviously, its a bit of a stretch to suggest Mr Strummer was that expert, although I think he was a very bright bloke.

    My GS shutdown idea was prompted by the mildly surprising news that the GS did shutdown partially, for all of 10 days, in November 2004 (as reported in the British press on friday of last week, based on a report in Nature).

    regards, Mark

    Comment by mark schneeweiss — 30 Oct 2006 @ 11:14 PM

  61. ==== Post # 46 said: ====
    A few hundred years ago the scientific consensus was the world was flat and also that witches existed. Looking at it this way makes you wonder what the value of scientific consensus is worth.
    Just my two pennies worthy of comment for what itâ??s worth.

    Scientific consensus in modern times has been wrong on issues far less complex then GW.

    One fine example of a consensus being a group of wrong-thinking experts is in the treatment of ulcers. The medical, and scientific “consensus” was that stress, diet or alcohol caused ulcers and that changes to diet, medication, lifestyle changes, and in some instances, surgery, were the appropriate treatment.

    When Drs. Barry Marshall and Robin Warren demonstrated that a bacteria,
    H. pylori, was the cause of nearly all ulcers, their evidence was ridiculed and ignored by the majority of gastroentology specialists and other medical experts for years.

    A consensus can have value and often does; still some uncertainty must be attached to any consensus.

    Comment by Paul G — 31 Oct 2006 @ 4:18 AM

  62. A hodgepodge of replies:
    1) It’s fine that this site is not concerned with economics, but individuals should be. Maybe meeting Kyoto would cost far far less than “$40 trillion” if all of the wishful new technology would magically fall into place — highly unlikely though I suppose possible. Short of that it will cost societies a bundle, in the tens of trillions, though any precise estimate can neither be proven nor refuted: “40” sounded close.
    2) yeah, a few of the 17,000 signatures in The (Oregon) Project were bogus — insignificant; Most, as readily admitted by the sponsors, were credentialed academics but not necessarily from climatology. I think that is much better than the 50% politicos in IPCC (probably 2/3 with some scientific bent, 1/3 just activist hacks — and I’m being generous here.) I think it hurts the credibility of the scientific proponents to support the latter with a yawn and then squeal like a stuck pig because a few of The Project signers have PhDs in Math or History.
    3) While I tend toward the “deniers” (I prefer lay iconoclast) and think this site does too much blind cheerleading, I also think this site is far and away the best, most thorough, and academic climatology site out there. The biases at least stem mostly from scientific inquiry, not gut feel.

    Comment by Rod Brick — 31 Oct 2006 @ 2:02 PM

  63. # 56 “From the research I have seen there appears to be slowly rising co2 from some source even before man that then peaks and for some reason falls rapidly ushering in a new ice ages”

    First, check this real climate website for “carbon cycle”. Second, how I understand how the carbon is naturally added or taken away from the atmosphere is that the oceans are likely responsible for a huge amount of this natural increasing and decreasing of CO2 naturally.

    If I am not right, someone please correct me. Let’s walk through it.

    We can prove (through ~one million year-old ice cores, ~50 million year old ocean bed sediment cores, 11,800 year tree ring segments, ~200,000 year old lake bed sediment cores, stalagmites and sheer rocks [geochemistry] that the natural carbon cycle goes up and down for at least 320 million years in natural cycles of about 26,000 and 41,000 and 100,000 year cycles and permutations therof. This is due most likely to the Earth’s wobbling (26,000 year cycle), tilting (41,000 years) and changing its orbit around the sun (100,000 years). (The mathematics were worked out around 1917 by Milankovitch)

    This changes the amount of sun energy reaching Earth and where on Earth it hits strongest and during what season. So now let’s warm the Earth up naturally (from the northern hemisphere in this case although it could possibly also start in the southern hemisphere due to a heating equator -makes more water vapor and moving the pacific warm pool, which might change ENSO “part of El Nino” which might change high low pressure systems which might change warming winds around Earth, etc.).

    No matter what, the sunlight hitting the Earth changes according to at least these three natural cycles of 26,000 years, 41,000 years and 100,000 years. Now Earth starts warming up a little in the northern hemisphere, in this case. Ice melts and exposes dark land and dark ocean. Now, 90% of sunlight is absorbed by the dark surfaces instead of 90% being reflected. the atmosphere and ocean heats up a little.

    1. The warmer ocean cannot hold as much CO2 (like a warm pop drink), and more CO2 stays in the atmosphere acting as an increasingly thick greenhouse gas and the tempeature increases even more.

    2. With the warming, huge ice sheets melt and the winds subside alot (when formerly cold, the ice caps would force the cool wind to suddenly get cold, descend and pick up speed. The formerly cold winds used to carry dust. It contained iron. Plant plantkon ate the iron and massively expanded in the oceans. Plant plankon also absorbs CO2 out of the air (it is a plant) and sinks to the bottom carrying CO2 with it. 70% of the Earth’s surface is ocean.

    In this process, the equator gets warm, drastically increasing water vapor, which is a warming greenhouse gas and possibly changing the position of the pacific warm pool.

    Now the permafrost (covering ~ 20% of the Earth’s land surface) gets warm. It holds a heck of a lot of CO2. Permafronst largely consists of frozen plants up to 8000 feet deep. Afterall, plants absorb CO2 and release it when they die…even if it is 11,000 years later. So if you warm up the permafrost…you release a lot of CO2.

    Another completely different way to increase CO2 and cause global warming is to naturally increase carbon dioxide by having volcanoes about the size of the United States that last for 100,000s of years that dump what is called flood basalts up to sometimes an estimated 18,000 feet deep (siberian traps for example). Volcanoes now dump about 1% of the CO2 every year into the atmosphere that humans do. Carbon 12 to carbon 13 isotope ratios tell us this.

    Volcanoes then according to many peer-reviewed journal articles such as Geology, Science, Nature, Geotimes, Oceanography, etc., possibly caused CO2 levels to drastically rise and very possibly caused catastrophic global warming leading to four out of five of the Earth’s mass-extinctions.

    New geochemical evidence of this is being discovered from a long-sought missing link- …ie. biomarkers of anaerobic bacteria (chlorobiaceae) that also had to have sunlight to live -biomarkers such as isorenieratane.

    The proposed CO2 kill mechanism is that volcanoes produced CO2. CO2 caused warming. Oceans could not “hold” 02. 02 normally keeps massive amounts of nasty hydrogen sulfide bacteria and hydrogen sulfide at a “chemocline” layer in the ocean…hydrogen sulfide is normally destroyed by mixing with 02. The warm ocean surfaces don’t sink- so o2 does not go into the ocean at the poles. Hydrogen sulfide level (chemocline) rises to the surface killing most O2 breathing life below it. An ocean mass extinction now results.

    Hydrogen sulfide enters the atmosphere in massive amounts and reacts with (destroys) O2 taking a fatal amount of O2 out of the atmosphere. Now a mass extintion starts on land due to anoxia. Hydrogen sulfide reacts with the ozone layer (O3)(a form of oxygen) and depletes it to the point much life now dies also due to ultra violet radiation (UV) and now a mass extintion results. Possible evidence of this has been found through altered fossil spores that resemble current UV-damaged fossil spores.

    Geochemical evidence indicates that this process on Earth probably starts at around 1000 PPM CO2 in the past.

    Comment by Richard Ordway — 31 Oct 2006 @ 5:07 PM

  64. re # 63. It wasn’t just that a few of the signatures of the Oregon Petition were bogus. See:

    As wikipedia points out, the petition can’t be taken seriously because virtually *none* of the signatures could be confirmed.

    Here is what wikipedia says about the attached article to the Oregon petition:

    The senior author of the article was Dr. Arthur B. Robinson, a biochemist (not a climate scientist) and a Christian fundamentalist. The second and third authors were Drs. Sallie Baliunas and Willie Soon of Harvard-Smithsonian Center for Astrophysics. Both of these individuals have strong ties to the George C. Marshall Institute, which has taken a skeptical position on global warming since the 1980s and has received extensive financial support from the oil industry. The fourth and final author was Zachary W. Robinson, Arthur Robinson’s 22-year-old son.

    Here’s what it says about the signatures:

    One newspaper reporter said, in 2005:

    In less than 10 minutes of casual scanning, I found duplicate names (Did two Joe R. Eaglemans and two David Tompkins sign the petition, or were some individuals counted twice?), single names without even an initial (Biolchini), corporate names (Graybeal & Sayre, Inc. How does a business sign a petition?), and an apparently phony single name (Redwine, Ph.D.). These examples underscore a major weakness of the list: there is no way to check the authenticity of the names. Names are given, but no identifying information (e.g., institutional affiliation) is provided. Why the lack of transparency?

    You make it sound like all but a few of the 17,000 signatures could be confirmed, when in fact, virtually none of the 17,000 could be.

    Comment by Paul Tremblay — 1 Nov 2006 @ 2:50 PM

  65. Re 62

    The biases at least stem mostly from scientific inquiry, not gut feel. This statement is somewhat ironic given that you seem to have picked a number by gut feel, “40” sounded close. Nevertheless $40T is not wildly off if you take the highest cost estimates you can find and multiply them by a 100 year horizon with no discounting. But then you should be comparing the $40trillion to global GDP over that period, which would be on the order of 100x as big.

    Bogus signatures on the Oregon Petition were not insignificant, they were the norm. I once did a spot check of about 100 phds myself. After winnowing out hopelessly common names I was left with a sample of about 30, out of which I was only able to identify one as having remotely relevant credentials (a meteorologist as I recall).

    Comment by Tom Fiddaman — 1 Nov 2006 @ 5:32 PM

  66. RE 63

    I’ve read this scenario before about astronomical influences triggering CO2 release that leads to warming and melting.

    Does the scenario work in reverse during cooling?

    Cooling triggers oceans to absorb C02, causes ice to accumulate. Wait a minute! I thought CO2 was largely responsible for the warming. How did the cooling begin with all that CO2 in the atmosphere?

    Comment by Jim Cross — 1 Nov 2006 @ 5:58 PM

  67. Re #65 and previous: Seems to me another problem with the $40 trillion or so estimates is that there’s too much opportunity for funny accounting, which counts costs but not benefits, and places numbers in different columns of the ledger depending on the goal of the person making the estimate. To go back to the personal for an example, the “economist” who wants a high number for the cost of addressing GW looks at me buying a Honda Insight (about $20K new) instead of a Hummer ($90K?), and says Aha! Chalk up that $70K difference as a cost of global warming!

    Comment by James — 2 Nov 2006 @ 1:12 PM

  68. Re #63
    Thank you Richard. You have allowed me some more understanding of this very complexed subject. I am trying to decipher the Anthropogenic component of GW. By your account that spans eons, Anthro influences have in the past (at least pre industrial revolution) been minimal. And further back than 6M years ago been non exsistent since by all accounts man was non exsistent.

    To the respones I got to my #40 post, I thank you. I gleamed some more insight from the graph labelled “Global Carbon Cycle” which is at the following link. .

    If I’ve done my math correctly, and if the graph has valid data, then the current Anthropogenic contribution to CO2 emmisions is 2.863%. Can someone enlighten me if I am incorrect in assuming that if all 6 billion humans ceased to exist tomorrow, global CO2 emmisions would reduce by only 2.863%.

    [Response: Well, you are only about a factor of 10 wrong. Anthropogenic CO2 is around 30% of current concentrations – but even if emissions ceased today, you wouldn’t return to pre-industrial conditions for thousands (if not hundreds of thousands) of years. See: and – gavin]

    Comment by David (Average Joe) — 2 Nov 2006 @ 1:24 PM

  69. Thanks for the feed back Gavin but the below is a direct cut and paste from the link you posted which refutes a conclusion like mine.

    POSTER: “Therefore, the probable effect of human-injected carbon dioxide is a miniscule 0.12% of the greenhouse warming”. RESPONSE: That’s just 0.03*0.0365 of course – but even that is calculated wrong (it should be 0.11% by my calculator). But from our numbers, it would be between 3 and 8%.

    Yikes there’s that pesky 3% number again.
    I’m still wondering about cyclically high levels of CO2 that have been record in ice sheets etc. that pre date man which had nothing to do with industrial emmissions. Perhaps some of that CO2 has been hanging around for the “hundreds of thousands of years” you quoted.

    [Response: 3% to 8% of the total greenhouse effect (that’s around 33 C and growing). The ice age cycles in CO2 are principally due to CO2 coming into and out of the ocean – those timescales go up to around 1000 years or so. However, we are not taking CO2 out of the ocean, we are adding it in to the system from fossil fuel reserves. This is ‘new’ carbon and the final balance will only occur when that new carbon has been removed completely – the timescale for that is deep carbonate sequestration and chemical weathering which is on the order of 100,000 years. The best proof of that is from the PETM (55 million years ago) where it took about that long to remove the spike of carbon associated (possibly) with a huge methane clathrate event. -gavin]

    Comment by David (Average Joe) — 2 Nov 2006 @ 3:16 PM

  70. I’m catching on now. Anthropogenic emissions are new introduced carbons that have been sequestered in fossil fuels and have not been introduced into the atmosphere until recently. In the past ( pre industrial revolution) naturally occuring events (like the possible methane clathrate event you mention) were the cause of high CO2 build ups.

    Comment by David (Average Joe) — 2 Nov 2006 @ 3:57 PM

  71. Re #69, #70

    I’m still not quite catching on.

    Yes, I think anthropogenic CO2 is increasing CO2 and is having a warming influence.

    If we could eliminate human influence, I think that CO2 is a secondary player in the bigger picture of climate change. In other words, it augments warming when it rises and augments cooling when it falls. It isn’t the main player driving the cycle.

    Whether we have entered some new cycle because of human influence is still an open question.

    Comment by Jim Cross — 2 Nov 2006 @ 7:44 PM

  72. Re #71: Jim Cross, I am not sure what you mean by ‘some new cycle’, but as I know understand the matter, even if all extra carbon dioxide emmisions ended today, it would still take about 100,000 years to get rid of it. This leaves open what the influence of a ‘main player’, orbital forcing, is going to be over that time. In particular, the next good chance of an ice age starting is in about 50,000 years. So maybe that ice age won’t start. The next good change is in about 100,000 years. So maybe that one will. (But note the next two good changes are in 600,000 and 650,000 years into the future…)

    Comment by David B. Benson — 2 Nov 2006 @ 8:04 PM

  73. Re #68: I think you are confused between the human contribution to the annual carbon cycle, and our contribution to carbon dioxide levels in the atmosphere during the past century.

    The annual transfer of carbon dioxide between the Earth’s surface and oceans, and the atmosphere, is about 200 gigatonnes (Gt) of carbon per year. That means 200 Gt C both enters and leaves the atmosphere, as shown in the chart you linked. The human contribution to that cycle is about 7 Gt, or about 3.5% of the total.

    However, the human portion is in addition to the pre-existing natural equilibrium. About half of that extra carbon dioxide remains in the atmosphere each year, while the other half is absorbed by the land and oceans. That is why the amount of carbon dioxide in the atmosphere has risen by about 30%, as Gavin said.

    Comment by Blair Dowden — 2 Nov 2006 @ 8:25 PM

  74. Re #73
    Hello Blair,

    Here’s a quote from your post:

    “However, the human portion is in addition to the pre-existing natural equilibrium.”

    I understand you mean one day to the next for equilibrium.

    The long term graphs I’ve looked at of the earth’s natural cycle doesn’t suggest that there ever has been an “equilibrium”. Here’s a graph:

    One thing I am wondering about on this graph is that it appears that the trend is: The Earth Warms. CO2 Increases shortly thereafter. The Earth Cools. CO2 decreses shorly thereafter. I didn’t have my reading glasses on when analyzing it, so I wondering if my interpertation of this trend, according to the graph, is correct.

    Comment by David (Average Joe) — 3 Nov 2006 @ 12:12 PM

  75. Re #74: David (Average Joe), my understanding is that your interpretation is correct. According to orbital forcing theory, ice ages have started and then the carbon dioxide follows (down) a few hundred years later. Reverse that when ice ages end. But over shorter intervals, there used to be a quasi-equilibrium, excepting for volcano super-eruptions, etc.

    Comment by David B. Benson — 3 Nov 2006 @ 2:49 PM

  76. Re #72

    My choice of words “new cycle” was poor.

    What I was trying to say is that we find ourselves in one of two circumstances:

    1- We are still living in a interglacial and eventually – maybe a long time in the future – glaciation will begin again.

    2- Human influences have fundamentally altered the pattern and we are in new territory.

    By the way, I haven’t seen much discussion about Muller’s theories that it is orbital inclination and possibly space dust that has been driving climate for the past million years or so. Even if he is right, it doesn’t mean an ice age is right around the corner, but it might mean it is a little closer than some of the postings on this site might lead one to believe.

    Comment by Jim Cross — 3 Nov 2006 @ 7:22 PM

  77. Re #22 (Coby):

    >… the time period for which 1998 (or 2005) was a record.
    >It is for sure a 150 year record,

    This is correct (if we consider that the distribution of observations, especially those of sea surface temperature, has been adequate to estimate the global mean since the middle 19th century).

    >almost definately a 500 year record, probably a 2000 year record,
    >likely a 12000 yr record, likely a 125Kyr record.

    These are possible and there seems to be no clear evidence against them, but they cannot be strongly claimed either.

    This personal view of mine is supported by the concluding remarks of the report by a committee chaired by G.R. North, which I think the best review available today concerning this point.

    National Research Council, 2006: Surface Temperature Reconstructions for the Last 2,000 Years. Washington DC: National Academy Press.

    This is still in press, but its preprint is available at .

    The report concludes that we can say that the last part (a few decades) of the 20th century is warmest in the last 400 years with high confidence, and that it is “plausible” (though we cannot put quantitative confidence) that it is warmest in the last millennium, but that it is much less certain to mention a certain single year as the warmest in the millennium.

    Comment by Kooiti Masuda — 4 Nov 2006 @ 3:11 AM

  78. #17 (Tim Dannell) reminded me ….

    Global warming due to waste heat was indeed one of the subjects of speculations, besides global cooling, in the 1970s.

    I happen to have a Japanese edition of this book …
    Wilcox, H.A. 1975: Hothouse Earth. New York: Praeger.
    This is a popular (not professional), somewhat alarmist, but serious outlook of global warming due to waste heat and of its consequences.

    More interesting are the professional works of Mikhail Budyko, one of the most active climatologists in the Soviet Union then.

    As commented by Spencer Weart to Gavin’s article here on 28 June 2006 ( ), he suggested in 1974 to inject aerosols in the stratosphere to mitigate global warming. But global warming by what? I was surprised when I checked what he actually said in his books “Climate and Life” (Russian 1971(*), Japanese 1973, English 1974(*)) and “Climatic Changes” (Russian 1974(*), Japanese 1976, English 1977(*)). I had read them in the 1980s, but did not read these parts so carefully then.

    (For the references marked with asterisks(*) here, see Weart’s bibliography at .)

    In these books, Budyko tried to discuss climate of coming centuries. His outlook for the rest of the 20th century was dominated by global cooling due to anthropogenic aerosols (though it was by no means certain). But he considered that global warming by waste heat (which would grow in an exponential manner) would dominate in the late 21st century. Perhaps he assumed that nuclear fusion would become practically available to fulfill unfettered demand of human society. He did not ignore CO2 as a factor leading to warming, but he thought that most of anthropogenic CO2 would not accumulate in the atmosphere.

    In the former book he just cursorily mentioned a possibility to control warming by adjusting the “dust” loading in the atmosphere. In the latter book he suggested the idea more seriously, with explicit mention to sulfate aerosols in the stratosphere. It seems that he learned a lot from SCEP(*) and SMIC(*) reports which were both published in 1971. In “Climatic Changes“, he also emphasized necessity of careful assessment about adverse effects of (deliberate as well as inadvertent)
    climate modifications.

    In his later book “The Earth’s Climate: Past and Future” (Russian 1980, English 1982 published by Academic Press, Japanese 1983), his focus moved to CO2. He collaborated with Ronov, a geochemist who made inventory of carbonate rocks, to reconstruct the history CO2 level in the last 600 million years. It seems that this work provided him better insights of the carbon cycle, and that it also convinced him of the importance of CO2.

    Budyko also had pointed out the possibility of “snowball earth”-type catastrophe with a simple climate model (Russian 1968(*), English 1969(*)). Probably it contributed somewhat to the “zeitgeist” of global cooling. But the model was that of steady states, and the “catastrophe” here is a concept rather mathematical. This model is not quantitatively realistic in itself at any time scale, but has some relevance in the problem of glacial cycles at the time scale of tens of thousand years. It is probably not relevant to his centennial-scale outlook.

    Comment by Kooiti Masuda — 4 Nov 2006 @ 3:23 AM

  79. By the way, William also mentions a popular lecture by Isaac Asimov in 1974 at his web site … .

    I was surprised at the one-sided view on climate change Asimov presented, because he had described global warming due to anthropogenic CO2 very accurately (in hindsight) in a popular non-fiction book “Is Anyone There?” published by Doubleday (New York) in 1967. (I read its Japanese edition as it was published in 1968, and perhaps this was my first source of knowledge about the role of CO2 in the earth’s climate.)

    In Chapter 13 “Evolving atmospheres” (note: this title is my back-translation from the Japanese version), he described the atmosphere of Venus (utilizing then quite new information obtained by spacecrafts), and explained why it is so hot by “the greenhouse effect”. In the last part of the chapter he mentioned the (then) recent growth of CO2 content in the earth’s atmosphere, and warming and sea level rise as its probable consequences. As far as natural science goes, it is remarkably similar to such present-day popular articles that are faithfully based on the reports of IPCC WG1. In his cursory remarks about (what we call) adaptation and mitigation, however, Asimov’s stance seems to be that of a science fiction writer.

    I do not think that he forgot this logic by 1974 (though he may have forgotten the fact that he himself wrote it). Surely he was influenced by someone (perhaps Reid Bryson) who said that the effect of “dust” would be overwhelming.

    Comment by Kooiti Masuda — 4 Nov 2006 @ 3:29 AM

  80. Re #71 and “Whether we have entered some new cycle because of human influence is still an open question.”

    That the current warming is largely anthropogenic is not really an open question at all. It’s thoroughly established at this point by something like 1,000 different peer-reviewed studies, taking into account all kinds of Earth-system phenomena. The debate is over among scientists; global warming is happening, and we’re doing it.

    Comment by Barton Paul Levenson — 4 Nov 2006 @ 6:33 AM

  81. It is clear to me that modern humans have no real concept of what cyclic behaviour our planet undergoes and what controls it, with or without modern civilisation impacts. Interestingly Australian aborigines, who have the longest known human recorded history (observations passed down the generations), tell of yearly cycles consisting of two to eight seasons based on wet,dry,hot,cold and wind, a 10-12 year cycle, a 100year+ cycle and an even longer 10000years+ cycle that is known only as fire or ice.
    Not to long ago it was ice age……. must be nearly fire age then. Anyone sweating? Not me! :)Tim

    Comment by Tim Evans — 4 Nov 2006 @ 7:42 AM

  82. RE: Comment Response to #69

    Dr. Schmidt;

    Would it not make more sense to “recycle” the Carbonate rather then sequester it. After all it is not only the Carbon you are removing from the atmosphere; but, oxygen as well. (Yes, I am considering Methane production at 1/2 the energy value of Petrol.) If the additional carbon was removed from the surface of the planet would there be enough to support the current human population and the likely expansion of the population in another 43 years? How much surface carbon must be present to meet the demands of the human population or the rest of the Biosphere and at what population densities? References regarding these questions are welcome?

    Dave Cooke

    Comment by L. David Cooke — 4 Nov 2006 @ 11:22 AM

  83. All this debate about global warming vs global cooling is a clear symptom of the state of climate science. All claims not withstanding …


    An important criteria for a scientific theory is that it make testable and measurable predictions. After decades of debate and thousands of papers all we have are computer models that cannot even correctly predict the average temperature at a given locality next year.

    Scientists who have criticized the computer models that the global warming side present are invariably painted as oil-industry lackeys or are pointed to so called validations of the model that are not validations at all. If the science is good, why the need for ad-hominem attacks? Why don’t the climate scientists just accept that they do not yet understand the science well enough to make valid predictions? Why the haste among climate scientists to push for a political agenda based on flimsy science?

    Every year, we see measurements that do not support the climate models at all. Do climate scientists accept that the models are probably incorrect? No, they insist that there is some “forcing” or an “oscillation” or an “unpredictable anthropogenic input” or some other spur of the moment made-up jargon which when taken into account will make the model correct. Or so they claim. They get back to their computers, tweak the models and lo, and behold, the models now predict the temperatures correctly since 19-forgotten up to the latest measurement. Of course, the predictions for the succeeding year will not be correct again and the iteration continues ad-infinitum. This is not science, this is charlatanism. If that is all climate science has going for it then it should just close shop and insert itself under mathematics as an exercise under the chapter on polynomial interpolation.

    Climate science can end the debate on global warming right now. All it needs to do is publish a prediction that will predict the temperature in selected areas, say Greenland or Antarctica for the next ten years and then let us see how well it does. To make the test valid, a different party will select the areas to be tested, not the creator of the models. Either do that or admit climate science does not yet have much science behind it. NASA can build a spacecraft and send it to a target on Jupiter millions of miles away. Accurately; right down to the millisecond. Can climate science do something similar?

    If it cannot, then work on the science first and leave public policy and political agendas to the politicians.

    Comment by Robert Punzalan — 6 Nov 2006 @ 11:38 AM

  84. Re: #83

    All this debate about global warming vs global cooling is a clear symptom of the state of climate science.

    Do you actually believe that there *is* a debate about global warming vs global cooling, except in the imagination of denialists? There isn’t; that’s the whole point of the post.

    An important criteria for a scientific theory is that it make testable and measurable predictions. After decades of debate and thousands of papers all we have are computer models that cannot even correctly predict the average temperature at a given locality next year.

    Back in 1988, James Hansen made three predictions of future global average temperature. He stated that his “scenario B” was the most likely trajectory, while scenarios “A” and “C” were unrealistically hot/cold, but possible if unexpected forcings were greater or less than predicted. It’s now 2006, and what has happened since then? Hansen’s predicted scenario “B” turned out to be right.

    I suspect you won’t accept any conclusions from climate science until GCM models can correctly predict the final score of the 4th game of the 2017 world series.

    Comment by Grant — 6 Nov 2006 @ 2:36 PM

  85. Robert Punzalan, please read the following:

    That is just for the first half of your post. The second half is just you projecting your own ignorance of the state of climate science and GCM’s onto a very different reality.

    Comment by Coby — 6 Nov 2006 @ 3:39 PM

  86. re: 83, which I suspect is another “drive by” posting.

    The content of #83 is simply anti-science and the scientific method. The fact that the writer refers to a “debate” about climate is prove of that. The peer-reviewed science is unequivocable.

    Comment by Dan — 6 Nov 2006 @ 5:45 PM

  87. Re #83: “If it cannot, then work on the science first and leave public policy and political agendas to the politicians.”

    Who is to judge the state of the science? The scientific community has already weighed in on the state of the science. There is, for example, the Joint Statement by 11 national science academies including the U.S. National Academy of Science. One might guess that these folks might be better qualified than you to determine what the state of the science is.

    You are, in fact, the one who is politicizing things by trying to take the judgement of the science away from the scientific community and pull it into the political realm.

    The culture wars involving the teaching of evolution show that there are always some people…even enough to have signficant political clout…who will not accept science and will claim until hell freezes over that scientific doubt still exists when the science conflicts with strongly held beliefs. We see the same thing happening in regards to climate change.

    Comment by Joel Shore — 6 Nov 2006 @ 8:51 PM

  88. Just in case the good people of this forum don’t want to take William Connelly on his word, I bought a copy of the 1975 NAS climate action report. Scans of the forward are at the bottom of the blog post:

    A Wooden Stake in Newsweek’s Global Cooling Heart

    Comment by Wacki — 6 Nov 2006 @ 11:55 PM

  89. Re #83 and “Every year, we see measurements that do not support the climate models at all. Do climate scientists accept that the models are probably incorrect?”

    What measurements are we seeing that do not support the climate models at all? What are you talking about? Care to give some specifics? The only measurements I’ve seen are the ones that confirm the models, except where the models turned out to be too timid! I have 120 years of time series data for CO2, sunspots and mean global annual surface temperatures, if you’re interested.

    Comment by Barton Paul Levenson — 7 Nov 2006 @ 8:13 AM

  90. If the sun were “turned off,” the temperature of the atmosphere would be with only 28°C above absolute zero, viz.-245°C. With the sun and the “greenhouse gases”, but without water, the average temperature on earth would be of- 11°C (resulting from a daytime mean temperature of approximately +135°C and a nighttime temperature of approximately-175°C). The moon provides such conditions at night. CO2 would delay the cooling towards the absolute minimum only for a short time. Its functioning on earth is not so much different.

    Comment by Angi — 7 Nov 2006 @ 10:49 AM

  91. Back in 1988, James Hansen made three predictions of future global average temperature. He stated that his “scenario B” was the most likely trajectory, while scenarios “A” and “C” were unrealistically hot/cold, but possible if unexpected forcings were greater or less than predicted. It’s now 2006, and what has happened since then? Hansen’s predicted scenario “B” turned out to be right.

    Is it? I’d say Scenario C is closer to the reality – particularly when you consider that JH included random volcanic eruptions in his models. Pinatubo in 1991 was the last one. If the models were re-run with the correct timing of volcano eruptions there would be even more divergence from actual measurements.

    [Response: Not so. Look at the latest results – the divergence is minimal. Your eye is drawn to periods where there is an apparent divergence due simply to the interannual noise – results from Scenario B and C don’t diverge in a statistically significant sense for a number of years yet. – gavin]

    Comment by John Finn — 7 Nov 2006 @ 12:03 PM

  92. Do you actually believe that there *is* a debate about global warming vs global cooling, except in the imagination of denialists? There isn’t; that’s the whole point of the post.

    According to Mr. James Hansen himself, there is a debate. See here. While the article was written years ago, the same situation still applies today. Or maybe you haven’t heard of Lindzen, Lomborg and Sen. Inhofe? (Of course, according to your views, these people don’t count because they are stupid or oil-industry lackeys, right? Do you understand the meaning of the term ad-hominem?)

    I find views attacking me as anti-science and lumping me with the fundamentalists rather funny because I happen to have a BS degree in Physics and am an atheist. I am not active in physics any longer since my primary work now is IT related and not physics.

    But, since when has a debate about some point of science considered to be anti-science? Debates are part of science, and whether you like it or not, it is part of the way that science grows. There was a debate about whether nebulae are composed primarily of gasses or composed of stars. There is a debate today about string theory vs standard theory. There are heated debates about Everett’s Multiverse interpretations of quantum mechanics vs the Copenhagen interpretation of Born et al. These are all natural signs of the evolution of scientific knowledge.

    Curiously (from my point of view) there is no unscientific emotionalism nor ad-hominem attacks in the debates on quantum mechanics and string theory. No one smears the Copenhagenists as fundamentalists nor the Everettians ever been labelled as left-wing wackos. Why?

    [Response: You might want to spend some time on the physics blogs. Those string theorists fight dirty. – gavin]

    Because, so far, string theory has not been invaded by politicians nor by people with hidden political agendas. Maybe if the environmentalists and the opposite side hold off from their finger pointing, their accusations, their name-calling and their ad-hominem attacks some real science may actually be made.

    Make no mistake about it, there is a climate change debate and these scientific debates occur because the knowledge is not yet robust nor complete enough.

    What measurements are we seeing that do not support the climate models at all? What are you talking about? Care to give some specifics?

    I can give at least one. The cooling of the oceans is something that the models have not anticipated.

    New scientist

    Real Climate.

    Opinion piece.

    But nevermind that surprising news, right? Because according to you, if the ice-sheets melt then of course the oceans should cool somewhat. Yeah, right. Hindsight is rather perfect, isn’t it? Still, the models didn’t anticipate this.

    [Response:The oceans are on a long warming trend- the latest numbers just moderated how much warming there has been. Interestingly, the Hansen piece you point to above actually predicted that the oceans were going to be warming (in 1997) years before the data came out (2001). ]

    There are other measurements that do not agree with climate models. I am just too lazy to find the references.

    Now, before you pull your hairs out in frustration and start attacking me as a global warming denier, perhaps I should tell you that I believe there is global warming. Yep, thousands of years ago, there was an ice age and our present time is a warm age. I also believe that we are not yet at the end of that warm age and that further warming is expected.

    However, I am not convinced that global warming is caused by human activities. I believe most dire projections of catastrophe and disaster are sensationalist and not supported by the current state of knowledge in climate science. The anthropogenic contribution is where, I think, most of the debate is. Global warming is a fact. What causes it is still under debate.

    You are, in fact, the one who is politicizing things by trying to take the judgement of the science away from the scientific community and pull it into the political realm.

    The Kyoto Protocol is in the realm of Politics and not science. Maybe you don’t agree but there is nothing scientific about the Kyoto Protocol because it is not the scientists who will implement it and force it upon the population but the politicians. Before pushing the Kyoto Protocol down the throats of the millions of an unwilling population perhaps you should ask first if there is enough science to back it up?

    The Kyoto Protocol is not like the low-fat diet protocol. While there is still a debate about the the role of fat in health, doctors are all too willing to recommend the low-fat diet protocol because even if the science is not yet clear, there is, at least, no long term nor short term deleterious effects of the diet. Can you honestly say the same thing about the Kyoto Protocol?

    Comment by Robert Punzalan — 7 Nov 2006 @ 1:12 PM

  93. Re: #92

    You state:

    According to Mr. James Hansen himself, there is a debate.

    Nobody I know denies that there is a debate about global warming, principally over whether or not it’s caused by human activity. But this is *not what you said*. From your first post:

    All this debate about global warming vs global cooling is a clear symptom of the state of climate science.

    Yes, your original post referred to a debate about global warming vs global cooling. That this is a fallacy is the point of the post. When I mention this, you refer me to an article by James Hansen regarding the debate about global warming in general. You’d make a much better impression if you simply admitted your mistake.

    Ironically, you yourself later state

    Global warming is a fact. What causes it is still under debate.

    Probably the most revealing part of your latest salvo is this:

    Or maybe you haven’t heard of Lindzen, Lomborg and Sen. Inhofe? (Of course, according to your views, these people don’t count because they are stupid or oil-industry lackeys, right? Do you understand the meaning of the term ad-hominem?)

    I never mentioned any of them (neither did *any* of the respondents to your post), and never called anybody “stupid” or “oil-industry lackey” (neither did *any* of the respondents to your post). You’re trying to put words in my mouth, then insult me for them! Do YOU understand the meaning of “ad hominem”? How about “straw man”?

    [Response: To all participants in this conversation. No more discussion about who insulted who. Stick to the science or get deleted. -gavin]

    Comment by Grant — 7 Nov 2006 @ 2:54 PM

  94. Robert, I hope you didn’t adopt that low-fat recommendation too quickly and assume there was no downside without reading up on it. For example:

    Low cholestrol, serotonin and violence
    Monday March 16 6:19 PM EST Low Cholesterol Linked To Violence
    NEW YORK (Reuters)–Lowering cholesterol could trigger changes in brain …

    Comment by Hank Roberts — 7 Nov 2006 @ 2:58 PM

  95. The Clash are showing the depth of their understanding by chorusing, “The ice age is coming”. This is a snarling prophecy that the Gulf Stream, which brings warm waters to the British Isles and keeps our winters mild, might shut off. If Greenland’s ice sheet melts then the massive freshwater flow will interrupt the Gulf Stream, and we would be plunged into a temporary ice age.

    And the rest of the album London Calling can be heard as a punchy green scream – Brand New Cadillac is a warning about gas guzzlers, Lost in the Supermarket warns of the grocersâ?? monopoly and food miles, while Four Horseman is a menacing warning about our carbon-consuming lifestyles – “Four Horsemen [of the Apocalypse] and it’s gonna be us”.

    Well, that’s one way of looking at it, anyway.

    Comment by Mike Frost — 7 Nov 2006 @ 5:55 PM

  96. Re #91 and “Yep, thousands of years ago, there was an ice age and our present time is a warm age. I also believe that we are not yet at the end of that warm age and that further warming is expected.”

    You may be a physicist, but you’re no astronomer. Tracking the Milankovic cycles which govern ice ages, the Earth should now be COOLING, not WARMING. So “we’re coming out of an ice age” doesn’t cut it.

    Comment by Barton Paul Levenson — 8 Nov 2006 @ 7:19 AM

  97. On the contrary, Milankovic cycles predict we are now close to the peak of a warm period (see link). Aborigines also say we are in a warming period due to their observations of their environment (based on plant blooming and animal behaviour)

    Comment by Tim Evans — 8 Nov 2006 @ 6:35 PM

  98. Re #97 and “On the contrary, Milankovic cycles predict we are now close to the peak of a warm period (see link). Aborigines also say we are in a warming period due to their observations of their environment (based on plant blooming and animal behaviour)

    I checked out your link and found one chart on a time scale of hundreds and thousands of kiloyears. It doesn’t have the resolution required to make the kind of statement you made. In any case, note that the present interglacial has now gone on far longer than average. I stand by my point — in the absence of growing greenhouse gases, the Earth would be cooling, not warming.

    Comment by Barton Paul Levenson — 10 Nov 2006 @ 8:06 AM

  99. Ref 98# ” ”
    I believe the graph has enough resolution to substantiate my claim. But hey, show me something better or any proof to back your comments and you might be able to convert me. Problem with all this is its so subjective, “in the eye of the beholder”. Objectivity needs time to occur, as the aborigines know only too well.

    [Response: There is nothing subjective about orbital forcing. It’s one of the most well calculated terms in the whole field. Look at Figure 1 in Schmidt et al (2004) – It has the insolation change from 6000 yrs BP to the present. There was more insolation then in NH summers (by about 20 W/m2 for Jul 60 N) and in the annual mean, slightly less in the tropics (about 5 W/m2 in the annual mean) and an increase in late autumn insolation in the Southern hemisphere. Google for more info. – gavin]

    Comment by Tim Evans — 10 Nov 2006 @ 7:41 PM

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