RealClimate logo

Six Degrees

Filed under: — eric @ 25 November 2007

“Alarmism” is a term that gets bandied about a lot. It is often said that one should not call out “fire” in a crowded building. But it really depends, one might say, on whether the “calling out” is done in such a way as to simultaneously prevent a stampede and prevent anyone getting burned.

This riddle was very much on my mind as I sat down to write my thoughts on Mark Lynas’s book, Six Degrees: Our Future on a Hotter Planet (London: Fourth Estate, 2007). I don’t read much popular science literature, and I doubt I would have read this book if I hadn’t made the mistake of referring to it (in a negative manner) in the comments section of a RealClimate post. I don’t think my error was very grave. What I actually said was that if what I had heard about the book from the press materials were true, then the book was probably alarmist and not worth reading. But I don’t blame the author for asking me to read the book and see for myself. He said that the press (in this case Sunday Times (London)) had misconstrued what he says in the book, and he assured me that is was all based on very careful review of the scientific literature. I was thus both curious and obligated to read the book.

Mark Lynas will no doubt be pleased that I very much like the book. To be sure, it is alarming, but the question of whether it is alarmist is a more difficult one, and I don’t think the answer lies in debating the book. Rather, it lies in looking closely at the underlying science the book builds on. I don’t intend to do that here, but I do think that all climate scientists (particularly those that talk to the public) ought to read this book, and ask themselves a question. I’ll get to that question at the end, after saying a bit more about the book.

Six Degrees, as the title suggests, is comprised of six main chapters (plus an introduction and a conclusion). Each of the main chapters examine what the earth might look like as we raise the planet’s temperature by 1o, 2o, etc. degrees Celsius, based on what the scientific literature has to say about it. Laying out the book this way makes for a good logical progression of ideas, and a fair bit of suspense. Very few people, Lynas says, have got “the slightest idea what two, four or six degrees of average warming actually means in reality, and I’m sure he is right.

In Chapter 1, at 1o, we have predictions of, for example, an annually ice free Arctic ocean. Yes, quite plausible and supported by the literature, and perhaps occurring a little sooner than expected. At 2o, we have, “so whilst southern China can expect more flooding as the two-degree line is approached, the oceanic time lag means that it may take much longer for the rain-bearing summer monsoon to reach the drought-stricken north.” Yes, certainly plausible based on the studies Lynas cites. At 4o, we have “with global sea levels half a meter or more above current levels, [the Egyptian city of] Alexandria’s long lifespan will be drawing to a close. Even in today’s climate, a substantial part of the city lies below sea level, and by the latter part of this century a terminal inundation will have begun. … a rise in sea levels of 50 cm would displace 1.5 million people and cause $35 billion of damage.” Alarmist? Hardly. A 50 cm rise in sea level, is well within the conservative IPCC projections, even for temperature rises less than four degrees.

At 5o and 6o, the book really does start to sound alarmist, with the analogy to Dante’s Inferno – used to good literary effect throughout the book – coming very much to the fore. At five degrees, we have “an entirely new planet is coming into being – one largely unrecognizable from the Earth we know today. At six degrees, “… the pump is primed … not for flourishing palm trees in Alaska, but for the worst of all earthly outcomes: mass extinction.”

Aha, say the skeptics! It is alarmist after all. But is it? Lynas’s reference to the “entirely different planet” actually refers to the fact that at five degrees, the “remaining ice sheets are eventually eliminated from both poles.” That’s entirely true. And unlike in Gore’s discussion of sea level in Inconvenient Truth Lynas does emphasize the long timescales (thousands of years) in this case. Furthermore, there is published research that raises the likelihood of the significant loss of ice sheets at lower temperatures, and Lynas could have claimed certainty of a disappearing Greenland ice sheet in an earlier chapter. That he doesn’t do that is characteristic of the book: it doesn’t tend to go beyond the published literature. This is what Lynas claims at the outset — “all of the material in the book comes from the peer-reviewed scientific literature” – and I think he does an admirable job.

And that brings us back to the question I promised to raise at the beginning, which is this:

If a reading of the published scientific literature paints such a frightening picture of the future as Six Degrees suggests – even while it honestly represents that literature – then are we being too provocative in the way we write our scientific papers? Or are we being too cautious in the way we talk about the implications of the results?

173 Responses to “Six Degrees”

  1. 1
    Andy Revkin says:

    The value of the approach taken by the book, and the IPCC process, is that it takes us on a sobering journey into various futures, just as Dickens’s Ghost of Christmas Yet to Come did for Scrooge. Scenarios are a vital tool for designing responses. It’s very distinct from some of the popular tactics used lately, which Eric rightly questions above.

    The question remains, will humans shift gears, like Scrooge did, or will current needs win out over future risks, however disconcerting?
    Andy Revkin ( )

  2. 2
    Michael says:

    In response to your question, I would argue much too cautious and much too reticent. Mark’s book is an excellent book and is one which I use with audiences (mainly industrialists) to work through what an industrial landscape might look like and how an economy might function as we go through the degrees. The book provides a very clear and logical framework by which to analyse economic and industrial scenarios – degree-by-degree.

    [Response: I think it is interesting that the very first two responses answer the question I posed in nearly the opposite way, though they both seem to agree with me on Lynas’s book. I could say a lot more on this, but I will just suggest that it would be good to be clear, in saying “we are too cautious” or “we are not cautious enough”, who the “we” refers to. I think it is not clear in Revkin’s response, above, who is employing the “tactics” he refers to.

    Indeed, I edited my question a bit after posting it, because it was not clear whom I was talking about. In the original version, David Archer pointed out that it sounded like I was putting down Lynas’s book at the end. I was not. For full disclosure, what I originally said was “If a reading of the scientific literature paints such a frightening picture of the future as Six Degrees suggests – much more frightening than most scientists would paint, at least on the record – then are we being too provocative in the way we write our scientific papers? Or are we being too cautious in the way we talk about the implications of the results? ” Hopefully the edited version is clearer. –eric]

  3. 3
    David Wilson says:

    the IPCC consensus, which indeed reflects a wider scientific consensus, has done a great service to us all, due in part I think to the generally conservative conclusions drawn in it, it is also understood that some or many of the scientists involved in AR4 (and its predecessors) hold less conservative views, it is a balancing act, that’s what you get when there is a political side to it, and my personal opinion of this particular site (if that is the ‘we’ your questions refer to) is that you are doing very well – as your review of the book shows clearly

    the book sounds interesting, I will see about getting a copy, thanks.

    ps – there seems to be a bug in this comment interface, I am using IE6.0, the text of my comment disappears under the brown column to the right, and my preview comes up with patchy yellow shading (?)

  4. 4
    Joe Alderman says:

    Falsely calling out “Fire” in a crowded theater is not protected free speech. It is protected if the theater is actually on fire. Then it is a duty to warn your fellow citizens of the danger.

  5. 5
    Mark Lynas says:

    Thanks for this Eric – I always heave a sigh of relief when ‘proper scientists’ (as opposed to literary reviewers for the popular media) give the book a thumbs up. I’m writing an updated version for the US market which will be published by National Geographic in February (to be accompanied by a full-length documentary, going out on NGTV and voiced over by none other than Alec Baldwin) where I am changing some of the emphasis a little in order to discourage fatalists – so many readers have come back to me feeling discouraged that I wanted to make it clearer that everything about above 2 degrees is a ‘what if’ scenario rather than a prediction of doom. At the moment you could read it and conclude that if we haven’t peaked global emissions by 2015 then all is lost, which is not the case at all. It’s all about probabilities, really.

    Anyway, I won’t ramble on too much, but I think the answer to your question Eric may lie in the difference between an individual paper and a synthesis effort – I was trying to take a holistic ‘earth systems’ perspective using a huge amount of aggregated material, all published in the peer-reviewed literature, and including both modelling outputs and a paleoclimate perspective. Of course, as some have pointed out, this is exactly what the IPCC does, and I think my conclusions are largely consistent with the AR4, if voiced in rather less cautious language!

  6. 6

    “Alarmism” is an alarming word for all people with open minds. As Richard Lindzen’s visit to Rutgers showed recently (, “alarmism” is now the foil for climate disclaimers. The use of “alarmism” is distinctly similar to Creationists now using “Darwinism” as their foil. Eugenia Scott gives a great presentation in showing how Creationist has cribbed “evolution” from their writings and replaced it with “Darwinism.” I the -ism gives it an appearance of a belief system rather than science. The climate disclaimers not only have the “fire in the theater” sense of “alarm” but the the belief system of an -ism.

    Ken Miller

  7. 7
    Chris C says:

    a summary of Lynas’ book

    alarming but not alarmist

  8. 8
    Andrew says:

    I am working with Al Gore’s The Climate Project and I often hear him being criticized for his discussion of sea-level rises of 20 feet. I think it is a distortion to claim that he fails to give the timeframe of 1000 years for this melting, because in fact, he is not talking about melting. Rather, he is talking about these ice sheets becoming unstable due to the formation of moulins that drill down from pools that form at the top of the ice sheet and go all the way to the bedrock, where they might then form a film of water that could lubricate a drifting of the ice sheet into the ocean. My understanding is that the timeframe for something like this occuring might be a lot sooner than 1000 years, but there is much uncertainty about the likelihood of this happening. Perhaps someone from RealClimate could advise me of the possibility of the Greenland Ice Sheet becoming so unstable. And if it is possible, it would certainly not take as long as the melting of the entire ice shee t in place. I talk to groups about moulins and lubrication and then show the increased ice earthquake activity on Greenland over the last 15 years. I want to be on firm ground when doing this. Please advise.

    [Response: Certainly this could happen faster than 1000 years. The Laurentide ice sheet did this repeatedly during glacial times; they are called Heinrich events, and the sea level rose by 1-5 meters in one to a few centuries, is what I’ve read. These events can’t be simulated by models yet, so there’s no way we could predict if Greenland could pull a similar Heinrich maneuver. David]

  9. 9

    I had Six caveats about Six Degrees, but am glad to see much to enlighten here.

    The book (UK edition) seems to imply that global average temperature could rise by 6 C by the end of the 21st century. On page 102 a temperature rise of 0.4°C per decade is described as a ‘likely scenario’; page 127 points to a 3°C rise by 2050; on page 223, 5°C is ‘a few decades from now’; and Chapter 6 outlines a scenario for 6°C by 2100. Please correct me if this is wrong.

    Confusion compounding uncertainties about probable time frame for temperature rise seems to be quite common in some places. A paragraph in a recent article in the International Herald Tribune said:

    “Citing a World Energy Outlook from the agency last week, [International Energy Agency] officials said that if current development trends continued unchanged, total carbon emissions would rise by 57 percent by 2030, leading to a global temperature increase of 6 degrees Celsius, or 10.8 degrees Fahrenheit, by 2030.”

    It seems the IEA officials did not actually say that — ‘merely’ that the global average temperature could eventually stabilise at that some way down the line.

    Can someone offer further insight into the probable rates of rise in global average temperature on a given set of scenarios (taking account of various possibilities with regard to feedbacks in the carbon cycle etc)?

    [Response: Thanks for the link to your review of six degrees. Very thoughtful. To answer your question, it all comes down to the uncertainty in climate sensitivity and the uncertainty in how much CO2 we produce… See this recent post on uncertainty.]

  10. 10
    bigTom says:

    I think it essential that the science be seen to be nonpartisan, i.e. the highest priority of science is elucidating the truth, not supporting a particular point of view. Of course science has been under severe attack by politically motivated forces trying to claim the later. Unfortunately the charge, though unfounded sticks with a significant proportion of the public. We should probably leave the synthesis and the informing of the public largely in the hands of pubicizers such as Mark, and Al Gore etc. Of course the scientific community should be carefully monitoring and advising these groups, so that what they say is in reasonable accordance with our understanding.

  11. 11
    Gene Hawkridge says:

    I’m going to have to get a copy of the book to read, too.

    One of the things I’ve been wondering about, and it does not sound to me like the book deals with this, is the question, what will the socio-political consequences be of rising sea level and changing climate?

    What will happen, for example, if 100 million Bangladeshis “inundate” neighboring areas of Myanmar and India, as their near-sea level homes are inundated by a rising sea? What will happen in the USA if California’s central valley is flooded, and the midwest dries up? Will Canada build a fence and try to thwart an “invasion” of starving US citizens? In light of the current US attitudes many hold on immigration, some might see such a situation as poetic justice. I see the potential for major social and political upheavals with truly sobering consequences.

  12. 12
    Alastair Breingan says:

    I also read 6 Degrees recently, and was impressed by the clear and unemotional writing style. I don’t have the knowledge to critique the science quoted though I try and keep very informed on the subject, but found the book very frightening.

    In terms of your question I believe that the scientific consensus is inevitably somewhat late and is, in climate circles, maybe still anticipating the scorn of the deniers which used to be heaped on anything they didn’t like. As such it often reads as if it’s a bit tentative.

    One of the major problems is how to give a sense of urgency without being alarmist. One option would be to combine the simpler book conclusions for each degree rise, with a percentage based chance of reaching that rise within various periods. So as an example each year after the UNFCCC report on emissions, RealClimate could produce a document which assumes these emissions and growth in emissions and states:-

    Under the current growth case we see a
    75% chance of a 1 degree rise over 25 years
    25% chance of a 2 degree rise over 25 years
    5% chance of a 3 degree rise over 25 years

    75% chance of a 2 degree rise over 50 years
    25% chance of a 3 degree rise over 50 years
    5% chance of a 4 degree rise over 50 years

    1 degree rise Ice free Artic..
    2 degree rise Monsoon disruption..
    4 degree rise Good chance Australia becomes uninhabited etc…

    Even if the science is still a bit vague on the percentages, this allows a rational decision on how quickly we must change, which is, now that the deniers are all but dead or in exile, the major remaining issue.

    I think that focusing on the next 50 years (rather than 100 years as often seen) allows people to think within their own lifetime, and I don’t believe most understand the extent of the worst case disruption within 50 years. Thus while not being sensationalist it clearly brings the worst case to the fore.

  13. 13

    Thanks Eric, Hansen’s recent publications on scientific reticence and sea level rises make a cogent argument that the answer to your questions is the latter – scientists are being too cautious in the way they talk about the implications of the results. This has important implications for policy-makers. There are some good reasons for scientific reticence normally and it is unlikely to change so policy-makers need to take it into account.

    Hansen (2007) comments:

    “Reticence is fine for the IPCC. And individual scientists can choose to stay within a comfort zone, not needing to worry that they say something that proves to be slightly wrong. But perhaps we should also consider our legacy from a broader perspective. Do we not know enough to say more?”

    Policy-makers need to carefully consider the implications of scientific reticence for climate change policies.

    Even the most stringent international policy responses on the table at present set a course to stabilise mean global temperature rises at 2-3°C above pre-industrial levels.

    The stated objective of the EU is to stabilise mean global temperature rises at 2°C, but the emission reduction targets they propose (most significantly, 60% by 2050) appear more likely to lead to a 3°C rise. The IPCC (2007a) report suggests a global reduction of emissions of 60% by 2050 will put the world on track to stablise around a 2.4°C rise.

    If the world adopts an objective of stabilising mean global temperature rises at 2-3°C above pre-industrial levels, Hansen et al (2006) comments have a nagging logic on likely sea level rises:

    “Sea level was 25-35m higher the last time that the Earth was 2-3°C warmer than today, i.e. during the Middle Pliocene about three million years ago.”

    While the IPCC (2007b) estimated sea level rises of 0.18-0.59cm this century it acknowledges, “Models used to date do not include uncertainties in climate-carbon cycle feedback nor do they include the full effects of changes in ice sheet flow, because a basis in published literature is lacking.”

    In the light of the IPCC’s caveat, Hansen’s point about sea level rises suggests trying to stabilise mean global temperature rises at 2-3°C above pre-industrial levels is lunacy and we need to do much better.


    Hansen J, et al (2006) “Global temperature change” 103(39) PNAS 14288, available at

    Hansen J (2007). “Scientific reticence and sea level rise”. Environ. Res. Lett. 2. doi:10.1088/1748-9326/2/2/024002, available at

    IPCC (2007a), WGIII Summary for Policy Makers, available at

    IPCC (2007b), WGI Summary for Policy Makers, available at

  14. 14

    Eric says:

    [[a rise in seal levels of 50 cm would displace 1.5 million people and cause $35 billion of damage.]]
    Somebody’s got to stop those seals!

    [Response: Corrected. Thanks!]

  15. 15
    David B. Benson says:

    Andrew (8) — You ought to be able to find considerable information on the rise of sea stand since Last Glacial Maximum (LGM). In particular, the portion of that rise called Melt Water Pulse 1a (MWP1a) produced a most rapid sea stand rise.

    I’m an amatuer at all this, but I am under the impression we might well see 0.4 meter sea stand rise by 2050 and maybe thrice that by 2100. I am also under the impression that nobody seems to have any certainties about the matter, just concerns. Dr. James Hansen has recently expressed such concerns in The Threat to the Planet: Dark & Bright Sides of Global Warming, a .pdf file found on his web site:

    Do come back to inform use of the results of your investigations!

    Regards, David

  16. 16

    Gene Hawkridge writes of socio-political upheavals with sobering consequences. Einstein wrote of the bomb that everything had changed except the moral nature of mankind or words to that effect. And Gore calls the climate crisis a moral question. The building is on fire. I’m telling my neighbors quietly but firmly, “There is a fire. Move quickly & carefully to the exits. Pass it on.” Except in terms of climate I mean move quickly to phase out carbon etc. This will take a spiritual revolution of compassion for all beings on earth…

  17. 17
    Charles Muller says:

    Sorry, I’ve not reed Lynas book.

    IMO, the more you’re alarmist (or “provocative” for Eric question), the more you fuel scepticism. Because an efficient alarmism needs to elude uncertainties, to focus on some scenarios or sensitivities without mentionning the others, to project on a very long term with a very low significativity for people’s concern (state of the Earth in 2500 or 3000), etc. and all that can be easily and rationally dismissed as a one-sided presentation of the problem. As the credibility of a scientific message is proportionnate to its objectivity, such an attitude seems counterproductive. And there are already “alarmist” claims from lobbies whose it is the job to do that, I don’t understand what would be the gain for climate scientists.

    (Secondarily, speculations about decennal T slope of the 2050s or 2150s are less intersting than explanations about current trends – sceptics better argument for the moment is that there is no trend at all for T since 2001, according to Hadley, UAH or RSS, so that intrinsic variability or other factors are underestimated. I think RC writers do a better job when they deal directly with climate mechanisms, not with public expression on climate).

  18. 18
    Edward Greisch says:

    “Are we being too provocative in the way we write our scientific papers? Or are we being too cautious in the way we talk about the implications of the results?”

    Is the wrong question. You are being too short term. You need to be more like the paleontologists. 5 groups of paleontologists are talking about the coming extinction of Homo Sapiens in about 200 years. You don’t need to be like the nuclear power industry. They should talk about how much safer nuclear power is than coal. They use too many numbers. The public does not think at all like scientists of any kind. The public needs a world wide web that can actually tell them the truth. Here is a post I wrote for Alternet recently:

    Reference: “Web Dragons” by Witten, Gori and Numerico 2007.

    The search engines do not understand the web pages they find for you. They are
    just machines. They have no idea of whether or not the web pages they find tell
    the truth. In the US, we have “freedom of speech,” which means that nobody has
    to prove that anything is true before publishing it. We also have a coal industry
    that has a gross income of $100 BILLION per year. That $100 BILLION per year
    could be easily sunk by the nuclear industry unless you can be persuaded that
    nuclear power is dangerous. [The truth is that a coal fired power plant puts 100
    times as much radiation into your environment as the nuclear power plant. The
    truth is also that natural background radiation is 10 times what you get from a coal
    fired power plant.] Do the coal companies have an incentive to lead you astray?
    Yes. Is $100 BILLION per year enough incentive? Yes. Can the coal industry
    afford to hire doctors, economists, environmentalists, website designers, computer
    scientists, psychologists, advertising agencies, and lots of other people on $100
    BILLION per year? Of course. Can the coal industry afford to set up hundreds
    of web pages on hundreds of computers in hundreds of locations and “game” the
    search engines on $100 BILLION per year? Yes. And they do.

    How hard is it to find the truth on the web? Very hard. Most web sites have a
    monetary reason for existing. People who know the truth and are willing to tell
    you the truth don’t have much economic reason to do so. It is hard to make money
    by telling the truth. Nobody ever went broke by underestimating the intelligence
    or overestimating the gullibility of the average person. So how are you going to
    find out the truth for sure? There is only one way. You have to become a
    scientist. You will have to spend a minimum of 4 years in college to get the
    minimum degree, the B.S. You should really spend more like 15 years and get a
    post doctoral degree.

    Scientists do not vote on what is the truth. There is only one vote and Nature
    owns it. We find out what Nature’s vote is by doing Scientific [public and
    replicable] experiments. Scientific [public and replicable] experiments are the
    only source of truth. [To be public, it has to be visible to other people in the
    room. What goes on inside one person’s head isn’t public unless it can be seen on
    an X-ray or with another instrument.]
    Science is a simple faith in Scientific experiments and a simple absolute lack of
    faith in everything else. Do not trust any human, not even yourself. Trust only
    the experiments that you personally perform. Otherwise, you will be misled.

  19. 19
    Lou Grinzo says:

    Thanks very much for this posting, as it addresses one of the “must get to this soon” books on my list, even if it does give away the ending, so to speak.

    On the larger issue of how scientists (and we scientist wanna bes) should approach this situation, I try as much as possible over on my own web site to go wherever the data leads me and nowhere else. The problem is that the data associated with global climate change and peak oil are pointing with increasing and alarming certainty toward truly unpleasant outcomes.

    Whether the speaker is a genuine climate scientist, like many on this site, or an economist who’s studied energy issues for many years, like me, I think the moral obligation is the same: Tell the truth as accurately and fully as possible, and with a degree of spin or salesmanship or whatever you want to call it that’s dictated by the probability and unpleasantness of the predicted outcomes.

    I’ve talked over on my site about how far is too far in selling these ideas. I’ve had numerous people ask me in e-mail and once in an interview with a local paper if James Howard Kunstler really believes everything he says, or if he’s peak oil’s version of Ann Coulter–someone who merely puts on a colorful persona and says whatever will sell books. I’m increasingly convinced that it’s neither, and that Kunstler is intentionally yelling fire in the theater because that’s the only way to alert enough people to a situation that could, with enough indifference, turn into a real conflagration.

    Regardless of whether that blatant guess on my part about what drives Kunstler is accurate, it’s still a valid question: How much salesmanship is too much, even when used for the purest of motives?

    I’ve thought about this a lot, and honestly, I don’t know the answer.

  20. 20

    Thanks for this Eric and Mark Lynas.

    I stated in an earlier article titled “Hot Air in the Media Contributes to Global Warming!”

    We don’t need to be alarmist just because the alarms are ringing. Instead, while the alarms are ringing, we need to be calm and think this through in order to conceive an effective plan to mitigate the amount of disruption to economic, geographic, agricultural, social, environmental, biologic and even military systems. We need to be real when it comes to understanding science and assessment.

    I think it’s starting to sink in, although there is still a tremendous disinformation campaign being waged (moose farts cause global warming, volcanoes put out more Co2 that humans, soda cans??? etc.).

    Some of the key components of potential challenges as I see it are:

    Human Migration
    Latitudinal Climate Shift

    People love to attack the word ‘alarmist’ just because its easy from the cheap seats (these types read articles more than science and seem to have trouble with reason and the concept of open minded as well as scientific analysis of relevant data). But pretty much anyone looking at the data can hear the bells ringing and they are just going to get louder.

    There are a lot of things in the potentials here but one can imagine pretty easily. Lots of moisture in the air likely translates to increased snowfall (that melts faster), increased rainfall (that dries faster), regional climate shifts that disable growing regions (so food supplies will be a concern).

    The rapid recognition of the problem and its ramification will alter our industry and commercial systems. Human population is expected to peak according to the UN and begin to fall off again. This will be intertwined with all of the above and all the potential degrees of constraint that will occur in the earth systems.

    It certainly seems obvious that the problem is non linear as pointed out by relevant science and is showing up in the physical record in an increasingly strong data and relevant models.

    So alarms are ringing and for those that are looking at the data its pretty obvious.


    I’m a pilot. Most pilots whether low or high hour have had some interesting experiences in the air. alarming situations happen. When you are in the cockpit and an alarming thing happens, you can’t freak out, because that won’t help. If you want to stay safe or even alive, you methodically go through your check lists and procedures to evaluate the situation, and take methodical courses of action based on findings during those steps.

    When an alarm goes off it is not time to be ‘alarmist’ in the scary freaked out sense that some would like to portray it as; it is time to calmly examine the situation and deal with it in an appropriate and meaningful manner.

    There is nothing wrong with relaying the alarm either. Those that would quell the alarm might wish to remember that on the Titanic or any other large human emergency situation, delay often can translate into more lives lost (fires, hurricanes, tornados all with early warning systems specifically designed to save lives).

    All the fine scientists here and elsewhere, working on this, are the early warning system. If we ignore the alarm, then we will deserve what we get. The problem is that some of us are not ignoring it and we don’t want to have to pay the price for others ignoring it. A confounding problem at best.

    The longer we wait, the more energy all these potentials get and that will eventually translate to economic and human costs. The earlier we heed the warning the less economic and human impact. It’s really just common sense.

  21. 21
    Hank Roberts says:

    Andrew, I think your question (about ice sheet stability) is the big one not yet very clearly stated; lots of publications, not enough numbers, no model or mechanism worked out.

    Hansen et al.’s recent paper on icecap stability is currently critiqued at Stoat.

    Glad to hear something from you about Gore’s current presentation, we keep hearing about the old movie and that’s long out of date on new science.

    It _sounds_ like Gore’s current slide show may be rather less ‘alarming’ than Hansen et al. on the subject of icecap stability.

    The past ‘rapid’ change events took several thousand years; the current comparable change in GHG is on top of the last natural rapid rise and is going to take a few hundred.

    Comparable? There must be some way to compare, but how?
    May I suggest leaving this thread for the “Six Degrees” book discussion, and check out Hansen and commentary on icecaps at Stoat?

  22. 22

    I agree a six degree shift in the century to come is plausible. But I part company with Lynas over a matter of dimensional analysis. He’s talking temperature, and I mean Latitude.

    Both are valid metrics for discussing the impact of climate change.

    The evolution of anything can be modeled in a single dimension, but natural history, like human existence, unfolds in three and evolves over time. Drive south in midwinter and you’ll see what I mean. Geographically, the 48 States span about 20 degrees of latitude. Climatologically, their mean temperature spans about as many degrees C.

    Miami and Minneapolis are ~20 degrees and ~20C apart, and it gets roughly two degrees F. warmer for each 100 miles you put between yourself and the North Pole–100 years of unregulated fuel consumption has moved America South about one degree.

    If you accept the IPCC range, the present debate centers on whether the next century can shift it further by the length of Vermont, or Illinois? Shifting the coordinates of the debate brings a biogeographic corollary to light. Warming extends tropical and temperate biotremes uphill at the expense of holocene boreal refugia.

    [Response: Russell, I think you need to learn a bit more about the patterns of climate change. You seem to be applying the global mean uniformly everywhere, whereas high latitudes warm more than low latitudes and land warms more than ocean. In the estimates we worked up for Mayor Daley’s climate task force, by 2100 the midrange IPCC sensitivity under the A1F1 emission scenario (a high end scenario, which the world is tracking pretty well right now) gives Chicago a climate rather like East Texas. Further, warming does not extend the tropical biome to higher latitudes. To do that, you’d have to change the strength of the seasonal cycle, the length of day, and the rainfall pattern as well. A warmer world introduces fundamentally different ecotypes than those we’ve had in the past two million years. –raypierre]

  23. 23

    Mark Lynas (#5) wrote:

    … where I am changing some of the emphasis a little in order to discourage fatalists – so many readers have come back to me feeling discouraged that I wanted to make it clearer that everything about 2 degrees is a ‘what if’ scenario rather than a prediction of doom. At the moment you could read it and conclude that if we haven’t peaked global emissions by 2015 then all is lost, which is not the case at all. It’s all about probabilities, really.

    I am rather discouraged with today’s political climate, both at home and abroad, although I do see reasons for a degree of hope. However, one point that I prefer to emphasize — and which is suggested by what appears to be your book’s central conceit — is that things could generally be a great deal worse. And the magnitude of the destruction will increase in a roughly exponential fashion with the change in the long-term, global average temperature. As such, no matter where we are in this century, we have reason to bring things under control — and the costs of not doing so mount the longer we remain on the current trajectory.

    Incidentally, I myself had been under the impression that your book might be “alarmist,” but a certain Lynn Vincentnathan convinced me otherwise, and now eric has convinced me that reading your book will be a great way of introducing myself to more of our current understanding of climate change, perhaps even acting as a kind of jumping-off point for learning about the literature — although I should perhaps try to avoid hysteresis.

  24. 24
    Steffen Christensen says:

    Here, here, Alastair! The IPCC scenarios are actually rather dreadful to unmangle, as they are detailed and manifold in number. I’ve been using A1B as a reference “business-as-usual” scenario in my modelling, but the scientific papers on the subject seem to like to show the profile of all the A1 scenarios. That makes it hard to understand what’s going on, really. It might be of interest to the community to note that the APEC 2007 “aspirational” targets of reducing energy intensity to 75% of 2003 levels by 2030 actually results in higher CO2 emissions in 2030 than ANY of the IPCC scenarios. I calculate 17.8 gigatons of Carbon per year for this level of intensity “reduction”. The highest emissions of any IPCC scenario is 16.4 gigatons for A1FI. This is of particular relevance to those of us here in Canada, since our prime minister is now leading the charge to make these APEC targets the de facto plan post-Kyoto.

  25. 25

    A sense of alarm is only appropriate. The remaining question is how to sound the alarm in a way that will spur action for a change of course. All too often we talk as if the general population or even those people with most influence are an undifferentiated mass. Many people will only get off the dime if you scare the pants off them, which does not require exaggeration, IMHO. Many other people insist that nothing too scary be said or they will turn away because they are uncomfortable, but are they the action types anyway?
    Don’t we have to accept that people deserve the truth? Or are truth in discourse and even democracy concepts that are luxuries that we humans have shown we don’t necessarily deserve? I think truth and democracy are essential to keep the current elites (dominated by fossil fuel interests) under some control and headed in the least harmful direction.
    The current level of crisis is due to the fact that much action has been blocked over the last 20 years. Who wouldn’t be alarmed at the prospect of those who created this situation being in charge of it’s resolution?

    John Atkeison
    Director of Climate and Clean Energy Programs
    Alliance for Affordable Energy
    New Orleans, LA

  26. 26
    S. Molnar says:

    Re #10: I think bigTom is wrong from a tactical (or is it strategic?) point of view, although his goal is admirable. If anyone, especially a scientist, tones down his public statements in anticipation of attacks from those who oppose rationality, then the attacks have succeeded. Public figures and popularizers of science are too easily dismissed if they are not publicly backed up by scientists such as James Hansen. I’m sure Hansen and at least some of our hosts on this site were shocked at being demonized for presenting science to the public, but now that the battle has been engaged, there is nothing to be gained and much to be lost by retreating to the periphery.

  27. 27
    Jason says:

    Speaking of alarmists…

    I am wondering what climate scientists think of James Lovelock. I found some of his book a bit confusing, repetitive and contradictory, but wonder, does he have a kernel of truth regarding the models he has worked on that suggest a breakdown of the ocean sink and rapid change to new, hotter stable state? The fact that the current climate models don’t incorporate the long-term feedbacks he does makes me anxious. Is his recent book taken seriously? Does he speak as a realist who isn’t afraid to tell it like it is (or might be)?

    [Response: I wrote a post on Lovelock’s latest book here. David]

  28. 28
    Alexander Harvey says:

    I really wish that Alexandria was not used as an example of the threat of sea level rise. It has been disappearing into the Med. for many a year and will doubtless continue to do so. Much of the Hellenistic harbour and associated works are several metres below sea level.

    Yes, genuine sea level rise will not help but it is a weak example as the most of the damage will still be the result of other causes.

    Similarly it pains me when other places like SE Endland including the London basin are highlighted and the sea level rise is stated as the threat. The whole are is sinking and will doubtless continue to sink. Again genuine sea level rise will not help but much of the coastline is doomed to a watery fate no matter.

    I am sure that their must be better, less contentious, more genuine, albeit less dramatic exmples.

    Best Wishes

    Alexander Harvey

  29. 29
    Mike Hart says:

    My family operates a small farm in SW Australia. Previous owners kept fastidious data on rainfall and temps, that data shows us we are tracking the IPCC models very accurately indeed, except we are ahead on temp rises and changing weather patterns, about +0.10 degrees, rainfall is increasingly erratic and the stable falls from high pressure systems have effectively dissappeared. We have over ten years of this sort of data. What was once a cool temperate mountain area is becoming increasingly sub-tropical. We are seeing subtle but discernible shifts in the ecology. Our farm will be a arid desert highland in thirty years.

    Alarmist hardly, hard to get the folks out of the theatre when it is on fire when they cannot pull themselves away from the show!

  30. 30
    Danny Bloom says:

    I agree that Mr Lynas’s book, and he has a good blog too, is alarming, but not alarmist. As Mr Revkin wrote above, first post: “The value of the approach taken by the book, and the IPCC process, is that it takes us on a sobering journey into various futures, just as Charles Dickens’s story [Ghost of Christmas Yet to Come] did for Ebenezer Scrooge. Scenarios are a vital tool for designing responses… The question remains, will humans shift gears, like Scrooge did, or will current needs win out over future risks, however disconcerting?”

    News that Mr Lynas is rewriting some of the UK edition for the upcoming US edition is welcome news, and should help the book reach more people with its important message.

    I also see my polar cities research is being alarming, but not alarmist. I hoping and working to try to make sure that humans do shift gears, ASAP. But it will take some time, of course. Most likely, 30 more generations…

    Danny Bloom, Polar Cities Research Project,

  31. 31
    Alexander Harvey says:

    From the little I have gathered I like the basic premise of the book if it has decoupled cause from effect. It is doublessly imformative to sketch out what various degrees of warming might imply.

    Futurism was invaluable in enlightening the opinions of those who were interested in likely outcomes of nuclear conflict of varying total yields in the 1960s.

    Irrespective of how much or how little warming occurs it is good to have a reference that puts the consequences into perspective.

    As for being alarmist, were the futurist’s predictions of the outcome of a maximum exchange nuclear munitions alarmist?

    Well back then the BBC certainly thought so as did some of the rest of the media and some parliamentarians.

    I refer to the drama-documentary “The War Game” completed in 1965 but not shown on TV until 1985.

    Although considered too alarmist for broadcast TV (it was pulled and shelved) it was no exaggeration of the consequences of nuclear wargasm. I found it painfall to watch especially as much of it was shot in and around where I live.

    Now if somebody would be brave enough to put together a similar drama on the consequences of drastic climatic change that would be something. The power of imaginative drama is (or at least was) of major importance in the forming of public opinion. If you want to move people it is better to aim at the heart not the head.

    Best Wishes

    Alexander Harvey

  32. 32
    Donald Oats says:

    Thanks for giving a (short) clear review of the book; I look forward to reading it.
    With regards to the intersection of politics and global warming, the Australian Liberal Party have been overwhelmingly rejected by voters on Sat 25th Nov 2007 (Oz time). The new Prime Minister, Kevin Rudd (Australian Labor Party), ran on a platform which included ratifying Kyoto as soon as possible, *and* personally attending the Bali meeting in December.

  33. 33
    Danny Bloom says:

    re: Post No. 31, above: “Now if somebody would be brave enough to put together a similar drama on the consequences of drastic climatic change that would be something.”

    You mean, like “The Day After Tomorrow”? You are right, we need TV movie and feature movies with big stars to show the drastic future that MIGHT await future generations if and when catastrophic climate change does a number, so to speak, on Planet Earth’s human populations, not to mention the animals and plants. I am sure Hollywood is already writing such scripts and getting production plans in place, for more Day After Tomorrows. A movie about what might be like in a sustainable polar retreat for survivors of global warming might provoke discussion, too. We need lots of movies, lots of scenarios, to wake people up, so these scenarios might never really come to be. It’s not entertainment anymore. I am working on a spec script now titled “Polar City Red”, an alarmist movie with a happy ending. I want a happy ending. I insist on a happy ending.

  34. 34
    Joe Duck says:

    are we being too provocative in the way we write our scientific papers? Or are we being too cautious in the way we talk about the implications of the results?

    Having just dived into the Climate controversies I’m become convinced that the science is excellent but the interpretations of the science are too alarmist, though usually the alarmism comes from outside of the science community. Time to check out his blog, as Lynas appears to be suggesting there otherwise. One challenge for those who worry a lot about *eventual* catastrophic conditions is the mistake of thinking technology won’t change over the next decade, let alone the next century. It will change *dramatically* and is likely to significantly reduce risks in many areas.

  35. 35
    Richard LaRosa says:

    Re: Mike Hart #29. What do you think of this idea for SE Australia? Use floating solar collectors to evaporate seawater to increase orographic rainfall. Australia furnishes an ideal situation because it has a central desert which heats up by afternoon during most of the year. Heated air, which rises, is replaced by air drawn in from the coast. A mountain range on the east coast causes this ocean air to rise and expand, causing precipitation that provides fresh water to the inland slopes of the mountains. This was a fertile area used for agriculture and water supply, but it is suffering from a drought. A large area of the southeast coastal waters covered with solar evaporator rafts could increase the moisture content of this air inflow and provide needed rainfall. Of course it is not easy to maintain a uniform depth of seawater on a solar collector tray that is heaving and tilting in a rough sea. You don’t want to be heating some water only to have it slosh out of the tray when it rides a wave before it can evaporate. We will need some pumps operated by a photovoltaic panel to keep the water spread out over the evaporator tray. No battery storage is needed because the evaporator only works when the sun shines. The economic model is good here because the equipment and the benefits are concentrated near the heavily populated capital region of Australia. The development and operation could be supported through taxation.

  36. 36

    Joe Duck (#34) wrote:

    One challenge for those who worry a lot about *eventual* catastrophic conditions is the mistake of thinking technology won’t change over the next decade, let alone the next century. It will change *dramatically* and is likely to significantly reduce risks in many areas.

    Regarding that affordable flying car they promised me in the 1950s — I’m still waiting.


    Honestly, though, technological progress will depend in no small part upon how hard the global economy is hit. I am not sure that the economy is in that great a shape as it is — or for that matter have much reason to expect to get considerably better in the foreseeable future. The longer we postpone action, the more committed we will be to our present course. Likewise, the cost of a given project tends to rise quite rapidly as the time for its development becomes shorter.

    But I do have hopes for technology, particularly in the area of genetic engineering. And energy — if we set our money and minds to it.

  37. 37
    cat black says:

    It’s pretty clear that any commentary that doesn’t support BAU will be shortly labeled “alarmist”. That really is the only defense, now. “I don’t have to pay any attention to you, sir, because you are one of those alarmist types.” All neatly tied up. And vague appeals to mythical future technology changes is worse. People clearly do not comprehend our reliance of fossil fuels and how everything “new” is tied relentlessly to oil or gas in some form.

    Thus I don’t imagine that 6 degrees C is in any way out of the question. In fact I cannot imagine any substantive changes in behavior or expectations until we hit 2 degrees C, the N Pole is ice free, and the GIS slips its moorings and slides at once into the N Atlantic.

    At that point I expect to encounter a renewed interest in what exactly was a “solar economy” and how did people get by 300 years before. Though 300 years ago they still had primeval forests and rivers, bountiful seas, human-scale development and farming practices, and a global population something under 1 billion. Which is the point when the light finally comes on and people look around themselves in wide wonder and increasing terror.

  38. 38
    Chris C says:


    When people start treating “The Day After Tomorrow” and “Waterworld” as non-fiction movies which will happen in 20 years, then yes. But actually, I think that a more intelligent person still might not get what is going on- a summary of what a kid in a debate I had said: “sure, polar bears might be in trouble, but a lot of other animals will thrive, we might get some more heat waves but also more mild winters, a few more storms.” I don’t think the public perception is much more alarming than that summary, do you?

    Not a very convincing scenario worth spending 1% of the world’s economy on fixing. Time to scare people a bit, but there is no reason to exageerate to do it.

  39. 39
    Lawrence Coleman says:

    I plan to read the book. What I do know is that as pointed pointed out in Gore’s ‘An inconvenient truth’, most people do have the frog in a bucket syndrome. The IPCC in my view was too cautious even in it’s last ammendment to the report. It should have scared laypeople and political leaders, kicked them in the butt, presented it’s case soo empathetically, soo in your face that no-one could ignore it..or say well I’ll work on that tomorrow. We need shock tactics!..and I apologise for those of weak fortitude who cant hack the truth and scuttle off to some forgotten and deserted part of the world with their wife and kids, a couple of goats and a sand pit to hide their heads in. The rest of us who feel every bit the kick in our pants and see the storm clouds on the horizon need to get our act into gear. Every-one of us can contribute to the solution, I don’t guarantee at all that we will be successful but we have literally no other choice in this matter. The amount of pollution that the average citizen produces bar the CO2 emitted from industry make up a large percentage. If every household became virtually carbon neutral that alone would make a tremendous impact to the national goal..40-50% or more. Carbon neutality should become national policy and enforcible by law, whether it’s a huge factory or yours and my house. We ALL have a vital part to play.

  40. 40
    pete best says:

    The books six degrees deals with climate sensitivity in the context of a doubling of preindustrial CO2 emissions. Nearly everyone including real climate appears to be stating thats the climate is sensitive to around 3C of warming (mean) but temperatures of 6 degrees cannot be ruled out. However recent work by Hansen in particular casts doubt on the IPCC work in regard to climate sensitivity in regard to not upsetting the politicians and the contrarians and doubters and doubts that it is 3 degrees, just like he doubts sea level rise will be as low as is forecast and that Greenland and arctic sea ice levels will have disappeared a lot more than currently forecast/projected.

    So what is this new angle of AGW that can see more warming than what is being currently forecast by the IPCC. Well it appears that models cannot reproduce certain hothouse events of earths past solely on CO2 alone and the potenital missing ingredient not in the models is climate feedbacks (long term ones according to Hansen) which the models have not evaluated as yet.

    The literature appears to be mounting on this subject with lovelock and Hansen leading the debate. Could science have underestimated climate sensitivity?

    [Response: The six degrees discussed here is the actual temperature rise that is conceivable – not just what you get at 2xCO2. – gavin]

  41. 41

    It is a strange day when I do a review of your review on my blog a month and a half before you post your review on Just curious, why did you decide to put more specifics in your RC post than your Nature entry?

    As an off-topic question, has RC thought about doing a review of the utility of the DSCOVR satellite? Eli Rabett seems to fully support the endeavor. And Desmogblog has a 6 part investigation that is starting to look rather interesting. Avoiding any discussion of the politics and the blatant abuse of the freedom of information act is one thing but discussing the science and utility of DSCOVR would certainly be something that would belong on an apolitical and scientific blog.

  42. 42
    Cody Griffin says:

    After watching this debate over climate change for the past 30 years I am simply astounded at the sheer volume of ignorance concerning earth’s history.

    It is irrefutable that earth is warming…today. It is irrefutable that it has done so numerous times in the past 541 million years long before man could have caused it.

    How is it that climatologists …supposedly learned people… are concentrating on only the past 600,000 years which is a mere one thousandth of the sedimentary history of the earth? They are ignoring the past half a BILLION years! Why? I think I know why.

    Morover, since we all know that climate change has happened hundreds even thousands of times in the past, then what makes us think this one time in earth’s long established history this episode of warming is man’s fault? That is tantamount to claiming the upcoming summer season will be man’s fault even though it has been going on naturally for hundreds of millions of years! [edit]

    Cody Griffin

    [Response: This argument is logically flawed. It’s as if the person walking away from the scene of a fire with an empty kerosene can and matches claims that it can’t have been arson because fires have always happened. What matters is the burden of proof this time, not all the other times. -gavin]

  43. 43

    Gavin :
    Since the subject is “Alarmism” what Lynas shows the impressionable on his web site ought to serve as a wake up call-

    [Response: Um.. You obviously didn’t read what I wrote. You say in your blog that “Eric Steig wonders how anyone could possibly think Six Degrees author Mark Lynas capable of ‘Alarmism?'”. I don’t wonder that at all. I think it is a very natural (and possibly correct) reaction. The harder question is whether it really is alarmism. If you have a *cogent* argument about this, I’d be delighted to hear it. -eric]

  44. 44
    Nick Gotts says:

    re #36 (Timothy Chase) “Joe Duck (#34) wrote:

    One challenge for those who worry a lot about *eventual* catastrophic conditions is the mistake of thinking technology won’t change over the next decade, let alone the next century. It will change *dramatically* and is likely to significantly reduce risks in many areas.

    Regarding that affordable flying car they promised me in the 1950s — I’m still waiting.”

    You might also have mentioned the domestic robots, artificial superintelligences, bases on the moon and Mars, electricity “too cheap to meter” (from nuclear power), and the cure for cancer. Of course technology will change over the decade (I would be interested to hear whether Joe expects “dramatic” changes over that period, which is the one in which we have to take serious action to prevent likely disaster, and if so, what), and will change a lot over the century. But it still won’t be magic; and so far advances in technology have generally meant increases in energy demand. Relying on some unspecified breakthrough to save us is no more rational than saying AGW doesn’t matter because The Rapture is due. (In fact, I’ve seen the technological “Singularity” people like Ray Kurzweil fortell described as “The Rapture of the Nerds”.

  45. 45
    tamino says:

    I think we have a pretty good idea of a range of possible temperature increase over the next century, about 2 to 6 deg.C. I don’t think we have a very good understanding of the effects of that warming on planet earth, or on human society. Will sea level rise half a meter or 5 or more? Will tropical cyclones become the scourge of every coast or will some other factor (like wind shear) actually reduce them? Will we see hardships we can handle, albeit with difficulty and great cost, or another PETM mass extinction? I don’t know.

    But there are some things we do know. If the warming is 6 deg.C instead of 2, the chances of apocalyptic disaster are far far greater. And there’s no way in hell we’re gonna get “lucky” and get off scot-free. At the very least we’ll have heck to pay, at the worst there’ll be hell to pay.

    I do *not* think climate scientists are being alarmist, I think they’re being far too timid in public statements of the danger. Of course it’s wrong to say that we *will* suffer 20 ft. or more of sea level rise, devastating drought everywhere, collapse of the ocean food chain and of agriculture worldwide, 120-deg.F heat waves in Kansas, and a dozen cat-5 or cat-6 storms every season. But we *might*. It’s crucial that the climate science community stop the “soft sell” epitomized by IPCC. I understand that it’s a natural consequence of the conservatism of large organizations, and just part of the way science is done — extraordinary pronouncements are risky to one’s scientific reputation. But there’s too much danger to avoid any longer having the “balls” to tell it like it really *might be*.

    It’s like a physician who knows the patient is in life-threatening danger. Not necessarily terminally ill, but in mortal peril. Would it be ethical for this physician to avoid painting a vivid portrait of what might happen, including the worst-case scenario, even though the prognosis is unclear? Certainly not. The doctor has to make it clear: you MUST quit smoking NOW. No ifs, ands, or buts.

    So to the climate scientists I say, start sounding a lot more alarms. From what I can tell, Hansen is the only one even coming *close* to doing the job. Give ’em hell, Jim.

  46. 46
    pete best says:

    A quote from the article states:

    In its 2007 Fourth Assessment Report, the IPCC said that “Arctic sea ice is responding sensitively to global warming. While changes in winter sea ice cover are moderate, late summer sea ice is projected to disappear almost completely towards the end of the 21st century” (IPCC, 2007a: 776). But even before they were drafted, the 2007 IPCC projections were well behind the physical reality in the environment. In late 2005, Tore Furevik of the Geophysical Institute in Bergen had graphically demonstrated that “the recent [Arctic] sea-ice retreat is larger than in any of the (19) IPCC models” (Furevik, 2005). In December 2006, data was presented to a American Geophysical Union conference suggesting that the Arctic may be free of all summer ice by as early as 2030 and likely by 2040 (Holland, Bitz et. al., 2006) – setting up “a positive feedback loop with dramatic implications for the entire Arctic region” (Amos, 2006). This was affirmed by studies published in March and May 2007 (Serreze, Holland et al., 2007; Stroeve,Holland, et al., 2007) which led Penn State climatologist Richard Alley to comment that the ice sheets appear to be shrinking “100 years ahead of schedule” (Spotts, 2006).

    100 years ahead of schedule!! Now having read nearly all of the posts on this site for the past two years I know that real climate has commented on this in a recent article but appeared to reassure us that this was not the case and that IPCC models still held out under scrunity. Has real climates stance changed any in the light of current sea ice rate of loss?

    Are long term climate feedbacks not currently in the IPCC models possibly increasing climate sensitivity?

  47. 47
    Gareth Evans says:

    I have not read the book, though I did see a summary in the UK Independent Newspaper earlier this year. This is a quote from an introduction to the book posted on the web:

    One Degree
    Deserts invade the High Plains of the United States, in a much worse repeat of the 1930s dustbowl. Whilst the epicentre is Nebraska, states from Canada in the north to Texas in the south suffer severe agricultural losses. Mount Kilimanjaro loses all its ice. The Gulf Stream switches off – perhaps, plunging Britain and Europe into icy winter cold. Irreversible feedbacks take hold in the Arctic as ice disappears, and the permafrost line shifts north. Rare species wiped out in the Queensland rainforest, Australia. Coral reefs around the world suffer increasing losses from bleaching and are wiped out. Coral atolls submerge under the rising seas.

    At one degree the Gulf Stream switches off? On the basis of what evidence? This is not what IPCC say. This single statement, a claim without scientific basis, in a web published introduction to this book casts doubt and deters many readers at the outset.

    I was a complete sceptic when I started to follow the debate on global warming / climate change some 18 months ago. Now I firmly believe global warming and climate change are happening – based on the scientific evidence. There are still many sceptics out there, however, including some of our very best scientists (outside of climate science).Convincing others is not easy and pronouncements of this nature, that have no proven scientific basis, make the task a lot harder.

    I may still read the book but with much lower expectations based on this introduction. Climate science is not a precise science and no one really knows what the future holds. It is essential, therefore, to be as accurate and objective as possible and to stick to the known facts based on observation and monitoring.

    The Gulf Stream cut off at one degrees Celsius increase in temperature – this is not a scientific verifiable statement, it is not the scientific way to make such statements, and it is alarmist (in the absence of supporting evidence).

    Gareth Evans

  48. 48
    Susanne Munk says:

    I enjoyed reading this entry very much but it made me wonder: How would you define mean temperature for an entire planet and how would you test if it is changing? Perhaps this has been discussed here before?

  49. 49
    john mann says:

    re 42.

    Well I’m just a humble software engineer and I like to think that I’m not entirely ignorant of earth’s history, and I very much doubt that the contributors to this blog are either.

    AIUI the emphasis on the climate of the Holocene arises because of the better data from this period, and also because the continental configuration has (obviously) been closer to that of today. The previous half billion years, or more if you prefer, tend to be glossed over as the time differentiation in the geologic record does not permit such fine scale variations to be seen.

    A further problem with long-time-scale variations is that geological processes come into play, but they work on _much_ longer time scales than any human intervention. To give an example, Raymo and Ruddiman proposed that it was the uplift of the Himalayas that caused the Quaternary cooling, due to the drawdown of CO2, but this was a very stately process compared to dumping half of the planet’s accumulated organic carbon into the atmosphere in a few hundred years.

    So if you have any _other_ explanation of why climatologists (Hey Gavin, I’m doing that course I asked your opinion on, does that make me one too???) are ignoring past history, why don’t you share it with us?

  50. 50
    Lawrence Coleman says:

    Look from a buddhist perspective it’s all cause and effect, what goes around-comes around as far as I’m concerned. I’ve had a gutful of people, close friends included who’s fate! it was planned to happen! or the rapture is at hand!. Ocassionally I’ve checked myself thinking the same thing too..but only for a fleeting nano second. The fact is we have caused this by our own hands, not solar cycles, not sunspots/flares etc, and we have to get out of this mess by our own hands also.
    44 Nick Gotts: Whether or not technology can bail us out remains to be seen, but I am optimistic. It all depends on perceived urgency. Depends whether the majority of world leaders and power brokers perceive the urgency and are willing to work in collaboration with other countries, unifying their respective scientists and engineers to put their minds together…if and when that happens we can acheive a lot..a hell of a lot! Unimaginable degrees of innovation, invention, production and utilization can occur. New technologies would be fast tracked..or as needs to be the case..super-fast tracked. I was reading David Suzuki’s forum and there they mentioned new technologies being developed to develop chemical compounds that could be released into the atmosphere in vast amounts to kill off or transform CO2 molecules into something else..hopefully safe for the biosphere?? Dutch reseachers are working on ways to make solar cells equally efficient across the entire chromatic spectrum..if that could be linked to sliver cell tech..WOW! New Technologies will have a huge part to play in cO2 reduction especially technologies that can be mass produced in China or India or other parts of Asia and more importantly effectively utilized by those respective countries as well. If the US comes up with an amazing innovation to cut CO2 methane or produce O2 it should be made available to the developing countries at prices they can easily afford. As I said in earlier posts the rest is up to us as householders..the decisions we make.