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Climate change and consequences on the ground

Filed under: — rasmus @ 13 March 2013

The link between extreme weather events, climate change, and national security is discussed in Extreme Realities, a new episode in PBS’ series Journey To Planet Earth hosted by Matt Damon.

The video features a number of extreme weather phenomena: hurricanes, tornadoes, floods, wild fires, and flooding. The discussion is about climate change and the consequences on the ground – or, how climate change may affect you.

It is important to ask what is the story behind the assertions made in the video. What scientific support is there for the link between such extremes and climate change?

Linking global warming to some of these extreme weather and climate phenomena has been tricky in the past. In some cases the record of past events may not be sufficiently complete to identify whether there is a dependency to the global state, mainly because many extremes are both rare and take place at irregular intervals. However, there has been substantial progress over the recent years.

Global climate models may provide a tool for studying such links, but they are designed to provide a picture of general large-scale features such as the greenhouse effect and how the air moves around, rather than local extreme phenomena. For some types of extremes such as heat waves, they can nevertheless provide valuable insight (Hansen et al., 2012).

Heat waves and droughts often extend over space and time, and the global climate models may provide a good representation of droughts and heat waves if they manage to predict the frequency and duration of high-pressure systems and the soil moisture associated with these events.

The way the air flows is in some circumstances difficult to predict, for instance where the storms move (storm tracks) and changes in the large-scale atmospheric circulation. The reason for this is described in earlier posts on chaos and climate, and was first discussed by Lorenz.

The climate models manage to reproduce the Hadley cell, El Nino Southern Oscillation, the Jet streams, the Trades, and the westerlies, but not tornadoes, derechoes, and thunderstorms. They do not provide the details needed to describe the local climate and many extreme phenomena affecting society and ecosystems.

Our knowledge about extremes and climate is based on more evidence than just climate model results. One elegant example is the recent paper in PNAS by Petoukhov et al., (2013) based on mathematics, physics, and measured air flow.

From physics, we know that different conditions such as soil moisture and cloud micro-physics both affect weather extremes, although different types and on different scales. Convective storms and tornadoes, as opposed to heat waves, have in the past gone undetected and tend to pass below the radar of the global climate models.

New studies, such as Petoukhov et al., (2013), are emerging in the scientific literature that provide additional support for a link between climate change and a wider range of extreme phenomena. These are based on our physical understanding, observational data, new ways of analysing data, and attribution studies (Coumou and Rahmstorf, 2012).

We are also learning more about local convective storms, and a recent example is provided by the Swedish Rossby Centre, reporting that showery convective rainfall type intensifies faster than the more spatially extensive stratiform type in response to warmer temperatures (Berg et al., 2013).

The analysis of the past observations has not always given a clear picture. So far, no clear connection has been found between the global warming and mid-latitude storms (or wind speed), and efforts comparing different ways to analyse past storm observations have only recently been published (Neu et al. (2012). If we understand why some analytical methods give different results for past storms, then we will be in a better position to detect potential dependencies to the state of the global climate.

Extreme events are a natural part of the climate system, and a climate change means that their frequencies and intensities may change. Detecting the changes in probabilities in rare events is statistically challenging. However, counting the recurrence of record-breaking extremes can provide an indication of whether the extreme values are changing (Benestad, 2008).

The consequences of a climate change involves some known aspects as well as some which we cannot predict. Extreme phenomena take place in certain environmental conditions, favourable for forming e.g. tornadoes, storms, or droughts. We also know that our models have their limitations, and that the range of possible outcomes can be fairly wide.

The incomplete knowledge is no different to any other field, as the future always seems to involve some surprises. Societies have traditionally tackled the absence of complete certainties by adopting various forms for risk analyses, e.g. fire brigades, police, defence, hospitals, and so on.

Better safe than sorry. Here, there are some known connections of concern. The bottom line is that we need pragmatic ways of dealing with issues that may have devastating effects for people or societies – and this is the red thread in ‘Extreme Realities‘.


  1. J. Hansen, M. Sato, and R. Ruedy, "Perception of climate change", Proceedings of the National Academy of Sciences, vol. 109, pp. E2415-E2423, 2012.
  2. D. Coumou, and S. Rahmstorf, "A decade of weather extremes", Nature Climate Change, vol. 2, pp. 491-496, 2012.
  3. P. Berg, C. Moseley, and J.O. Haerter, "Strong increase in convective precipitation in response to higher temperatures", Nature Geoscience, vol. 6, pp. 181-185, 2013.
  4. U. Neu, M.G. Akperov, N. Bellenbaum, R. Benestad, R. Blender, R. Caballero, A. Cocozza, H.F. Dacre, Y. Feng, K. Fraedrich, J. Grieger, S. Gulev, J. Hanley, T. Hewson, M. Inatsu, K. Keay, S.F. Kew, I. Kindem, G.C. Leckebusch, M.L.R. Liberato, P. Lionello, I.I. Mokhov, J.G. Pinto, C.C. Raible, M. Reale, I. Rudeva, M. Schuster, I. Simmonds, M. Sinclair, M. Sprenger, N.D. Tilinina, I.F. Trigo, S. Ulbrich, U. Ulbrich, X.L. Wang, and H. Wernli, "IMILAST: A Community Effort to Intercompare Extratropical Cyclone Detection and Tracking Algorithms", Bulletin of the American Meteorological Society, vol. 94, pp. 529-547, 2013.
  5. R.E. Benestad, "A Simple Test for Changes in Statistical Distributions", Eos, Transactions American Geophysical Union, vol. 89, pp. 389, 2008.

118 Responses to “Climate change and consequences on the ground”

  1. 1
    Paul Matthews says:

    Rasmus, the IPCC wrote a report about this last year, generally referred to as SREX. You can find it on the web.

    [Response: Yes, and it discusses some of the same issues, e.g. heat waves. But the SREX does not include many of the more recent papers cited here. And it does not appreciate some of the new analytical methods, e.g. recode-breaking statistics. -rasmus]

  2. 2
    Ken Rushton says:

    I believe the climate denialists have forced the discussion to the wrong test; the wrong argument.
    The “Greenhouse warming” effect is based on well known, simple physics. The null hypothesis should be “CO2 and other gases have caused and will cause less heat to leave Earth in the stratosphere. We know this because we have measured it, and because the Earth is x degrees warmer than it otherwise would be. The only unknowns are how long it will take to reach the new temperature and the exact increase level.”

    The null test should not be “the earth is not warming/climate change is normal/caused by …”

    Climate change denialists should be asked “what mechanism is keeping the physically expected warming from happening?”

    Ken Rushton, computer systems analyst

  3. 3
    Ray Ladbury says:

    Kan Rushton,
    I’m sorry, but it is time for a pedantic rant. Please do not use the term “null hypothesis” for a situation in which you are not comparing two statistical models. Null hypothesis has a very specific meaning. It is a tool of statistical methodology, nothing more. What is more, you never, ever, under any circumstances accept the null hypothesis–you simply conclude that your results are not sufficient to reject it.

    The proper term for the greenhouse effect is “generally accepted science”.

  4. 4
    CM says:

    The missing reference:

    Petoukhov, Vladimir, Stefan Rahmstorf, Stefan Petri, and Hans Joachim Schellnhuber. “Quasiresonant Amplification of Planetary Waves and Recent Northern Hemisphere Weather Extremes.” Proceedings of the National Academy of Sciences (March 1, 2013). doi:10.1073/pnas.1222000110.

  5. 5
    Doug Proctor says:

    “Climate change denialists should be asked “what mechanism is keeping the physically expected warming from happening?”

    Interesting point. An answer: the radiative forcing of CO2, including feedback (negative as well as positive), is still unknown – not in general terms, but in the specifics. This is why there are still Scenario A, B and C under discussion.

    If the forcing factor were well known, the only variables we would be dealing with are TSI and ppmv pCO2 increases. The first is minor and, as defined, considered insigificant for AGW projections. The second is fairly well known and could, for any given moment, be given a darn good figure. That would mean that a specific Scenario would be laid out. But they are not.

    If we consider the last 15 years of global temperatures in the light of continued CO2 warming, one must say that some cooling mechanism, say aerosols (perhaps the moderate volcanics) are playing a role. This suggests that the power of CO2 is equal to that of the aerosols, or close to it.

    However, if we consider that the 1975-1997 period was a period of “brightening” due to aerosol reduction (pollution controls), then we have to admit that SOME of the 1975-1997 period was not just CO2 warming. So the actual CO2 forcing is less than what is calculated simply by the changes in pCO2 and global average temperature.

    That would give us a top-down and bottom-up range for CO2 forcing. Which would limit Scenarios to, again, variations in CO2 increases and TSI changes.

    Note that the “cooling” factor doesn’t have to be aerosols, and could be the net effect of various things, including heat release-retention of the oceans.

    So to give an answer: the cooling mechanism is because the radiative forcing is not as strong as modelled relative to natural factors. The answer comes with suggestions for value limiting calculations and predictions for the next few years.

  6. 6
    ozajh says:

    Ken Rushton #2,

    Ray’s nomenclature issue aside, I think you’re giving the denialists WAAAAAAY too much credit here. They’re not, in the main, carefully re-framing the debate by forcing the discussion anywhere. They’re simply denying AGW, for whatever reasons they may have. These might range from commercial sponsorship (either direct or indirect) to sheer bloody-mindedness, as in the case of a person (I am outside the US) I know personally who refuses to accept the objectivity of the scientists because he himself spent decades in a government job in an area where everybody brought a political agenda to EVERY issue.

    The analogy I draw comes from a marriage break-up long ago, where I was asked as a numbers guy to advise a friend of my mother who was having difficulty getting an agreed house valuation. The other party was sticking to an absurdly high amount, given the location and the (extremely poor) state of repair. I eventually pointed out that this person was working backwards from the amount of money they wished to receive at settlement, and was simply advancing reason after reason for the high valuation to bolster their case for this amount, AND WOULD NOT STOP ARGUING.

    I see the same thing with denialists (as distinct from real sceptics). They are working backwards from their need or desire to deny AGW, and will keep arguing. Sometimes the arguments will seem (and indeed be) totally ridiculous, but that will NOT stop the denialists from continuing to advance them if they don’t have anything better.

  7. 7
    Keith Woollard says:

    Ray @ 3,

    It may well have a specific meaning in statistics, but it has a more general meaning in Science

  8. 8
    Ray Ladbury says:

    Keith Woollard,

    [edit] The null hypothesis is not ever, under any circumstances in this Universe a “viable” theory. You never accept the null hypothesis–you merely cannot rule it out relative to your actual hypothesis. The sole role of the null hypothesis is statistical hypothesis testing.

  9. 9
    Hank Roberts says:

    > null hypothesis:
    “Anything but the IPCC”
    > what mechanism?
    A hundred on offer; U-pick, mix and match
    > a more general meaning in Science
    [citation needed]. Seems to me any practice ignorant of statistics isn’t likely to be science, especially if it capitalizes “Science” in claiming it.

  10. 10
    Thomas says:

    Is it possible to extract information on metascale storms, by using the output from a global
    climate model to initialize state and provide boundary conditions for a regional climate model?
    One could pick and choose those days when the conditions are ripe for severe weather, and then
    see if say the twenty worst days on the globally warmed model produce more/stronger storms than
    for the control.

  11. 11
    Juliorf says:

    Is it too hard to go to the moon, eradicate smallpox or end apartheid? Is it too hard to build a computer that fits in your pocket? No? Then it’s not too hard to build a clean energy future, either.

  12. 12
    David B. Benson says:

    Definition of null hypothesis
    (in a statistical test) the hypothesis that there is no significant difference between specified populations, any observed difference being due to sampling or experimental error.


  13. 13
    Russell says:

    Mark Twain anticipated the linkage of climate change and national security over a century ago, when he observed that while whiskey is for drinking, water is for fighting over.

    Since evaporation consumes more water than irrigation in much of the world today, water conservation may soon rival warfare as an extension of politics. conflict management

  14. 14
    Alex Harvey says:

    Dear Rasmus,

    I think it would be useful to clearly distinguish between changes in extremes expected as a result of climate change in the future and changes in extremes that should theoretically be visible after the 0.8 K of warming seen since the preindustrial times. And since you mention the PBS documentary, it would be good to discuss the claims made in there too.

    The central theme of your post seems to be that we are making good progress in the science of extremes, and to that end you have cited a number of interesting recent studies. Beyond this I was not sure where you actually stand on the PBS documentary or in general on our knowledge of extremes.

    If I may: Do you stand behind the conclusions of the IPCC SREX? Do you stand behind the claims made in the PBS documentary? And if not, which claims do you agree with, which ones aren’t you sure about, and which ones do you dispute?

    It seems there is a whole lot of noise in the media about extremes – if I take the media at face value I would believe that it is ‘virtually certain’ that there will be more extreme cold events in the year 2100 as a result of climate change. This is, of course, the opposite of the conclusion of the IPCC SREX (and common sense).

    I think there is an opportunity in writing this post to assist in clarifying some of this.

    Kind regards,
    Alex Harvey

    Hi Alex, here is my position:

    [Response: Do you stand behind the conclusions of the IPCC SREX? Some of my views are expressed in two previous posts (here and here). I think that the SREX did not take into account some of the empirical-v
    based work on tropical cyclones and the record-breaking events, but on the whole, I think it provides a reasonable picture of what was out in the scientific literature at the time when it was written.

    Do you stand behind the claims made in the PBS documentary? The PBS is of a different nature and purpose to the SREX. The SREX is supposed to reflect and assess the scientific literature. The PBS episode is an expression of concern, and these are based on scientific studies, although for some of these, there is not yet always a clear picture, as discussed in my piece (tornadoes, storms).

    …which claims do you agree with, which ones aren’t you sure about, and which ones do you dispute? I’d say that I’m not sure about several of these questions, and the answers to these questions are still in the process of being formed.


  15. 15
    Peter Smith says:

    “123 weather records broken in 90 days of summer” – might be telling us something.

    These records ranged from the highest maximum temperature averaged over the whole of Australia for one day to daily rainfall totals at specific locations.

  16. 16
    T Marvell says:

    [Response: The idea of hypothesis testing and significance tests is not irrelevant. How does one conclude that a finding is acceptable? The CERN teams used 5 sigma as the standard for finding the Higgs boson. As far as I know there is no accepted standard like that for AGW. I find that the relationship between CO2 and temperature is well beyond 5s. But when you get into looking at the relationship between extreme weather events and AGW, there is nowhere near that much evidence. It’s tempting to study the weather, because that is what the general public sees most. But it is dangerous to draw conclusions and publicize them, because they are likely to turn out to be false, and that will detract from the credibility of climate science generally.

    [Response: 5s is appropriate for the CERN-type experiments with huge amount of data, but it’s totally impractical for weather – not even weather forecasts. With that confidence limit, a large part of science would not be published. -rasmus]

  17. 17
    Ranga myneni says:

    Climate change is real and we must take an educated approach to deal with it. Pathfinders need to inform the general population about the realities in a neutral tone. I am making an effort with a petition directed to the Secretary-General of the United Nations, Ban Ki-moon at

    Those who are interested in the cause, please join hands with me in my attempt to protect the Earth from anthropogenic climate change. Please sign the petition and share the page with your friends, family and colleagues who might be interested.

    -Prof. Ranga Myneni’

  18. 18
    Hasis says:

    Paul Matthews, were you being factious per chance?

    SREX: Authors and expert reviewers (p550)

    Torgrim Asphjell, Climate and Pollution Agency
    Rasmus Benestad, The Norwegian Meteorological Institute
    Tor A. Benjaminsen, Norwegian University of Life Sciences
    Elzbieta Maria Bitner-Gregersen, Det Norske Veritas AS

  19. 19
    Flakmeister says:

    The 5s criteria is a standard discovery criterion for a counting type experiment a la CERN.

    [Response: We are not talking about CERN here. When it comes to climate and weather, we are really dealing with risks for all intents and purposes – and there are different requirements to what is acceptable probabilities. -rasmus]

  20. 20

    #17, Edim–“How can anyone disagree with this?”

    From the bottom up: ‘this’ begins with a false premise; everything else follows from that. It’s the Inhofes of this world that are doing the misleading on AGW.

    #18, Salamano–Did you read the same post that I did? To me, it describes an ongoing process of looking to see what connections may exist, and better understanding those we do do exist.

  21. 21
    Radge Havers says:

    Re: @2

    Trying to frame the discussion. I sympathize with your desire to shift the default position past “Whu? Can this really be happening?” and to get on to solutions. It seems to me that the MSM treatment of this whole subject is very sluggish.

    FWIW, one attempt to cut through the fog by analogy:

  22. 22
    Ray Ladbury says:

    T. Marvell,
    Please, please, please tell me that you were not trying to hold particle physics to the same standards as particle physics.

    Off-topic warning

    The way particle physics works is that you reconstruct the putative masses of parent particles from the kinematics of the daughter particles into which they nominally decayed. If the “daughter” particles did not really come from a decay (a vertex detached from the original interaction site), they result in noise. If they did, then they ought to reconstruct the mass of the particle they came from. In the course of this exercise, you might generate hundreds or even thousands of such mass plots, each with a different set of kinematical “cuts” to limit the noise and bring out the signal. These cuts cannot be random–they should be motivated by physics. Nevertheless, given all the trials, it is just about inevitable that you would get 3 sigma effects even if there were no particle to reconstruct.

    So, 5 sigma in particle physics ain’t really five sigma of certainty. My doctoral dissertation (which is sinking into the obscurity it so richly deserves) was in experimental particle physics.

  23. 23
    Hank Roberts says:


    “Chip Knappenberger and Pat Michaels, climatologists affiliated with the libertarian Cato Institute and skeptical of dire climate change predictions, concede the “non-record-breaking non-extreme non-snowstorm” was “consistent with global warming.” But they conclude the involved interplay between global warming and complicated storm processes make it “virtually impossible to know” the overall effect.”

    The post has some good info along with the ‘advocacy science’ denial quote.

  24. 24
    Joe Beach says:

    I would love some professional feedback
    I have just authored/published “The Green Game,” about Eco-responsibility, green politics, youth and education in a twist filled, exciting mystery. The Green Game is an onion with many layers. It is about real and fictional businesses. Three students develop an internet game based on voting on green issues that changes the world. The “Green Game” is an enteraining message filled novel, ideal for a discussion between teens and parents. If you are interested it is available at my e-store with a discount. The discount code is NW6BBYBS. It is also available in Kindle and paperback at Amazon. More is available at my web site Any help getting the green word out help will be appreciated. Joe Beach 952-920-9160

  25. 25

    An intriguing item on a possible (though ‘longshot’) mitigation measure:

  26. 26
    S.B. Ripman says:

    This comes from a non-scientist who follows this site and other sources in an effort to understand what the future may bring, climate-wise, for the place where I live now and for where my family and I may relocate to in the future. I am appreciative of the work of the climate scientists and of those who provide such knowledgeable commentary in this section.
    There appears to be discouraging subtextual narrative coming from many of the sources. It goes something like this: “Given the amount of CO2 already dumped into the atmosphere, and the amount that will inevitably be dumped in the future because of the world’s existing fossil fuel-dependent infrastructure, we must resign ourselves to the damage to come, and our present efforts will make little difference so we may as well just give up on any conscious, political effort to change the infrastructure and instead just sit by and let the process be managed by market forces. Plus the world’s governments are useless in the face of this climate catastrophe anyway.”
    This narrative gains traction in part because scientific prediction of future climate is by necessity couched in terms of probabilities and alternate scenarios and science lingo … and the times are still far off when the worst effects of the warming will be felt. For someone like me the future is filled with great uncertainty. It’s hard to chart a course.
    I wish I could find a clear and simple prediction of the future path of climate change for the next 100 or so years, one where the author uses his/her best guesses as to what scenarios will play out. Such a prediction would be more science fiction than science, involving assumptions regarding future politics, technical innovations, adaptation, etc. But for a layman such as myself it would be useful. If any of you folks out there knows where to find this — from as reputable a source as possible — your recommendations would be much appreciated.

  27. 27
    JoeT says:

    Ranga Myneni @16. It’s good to see Prof. Myneni post here. Perhaps you’ve addressed this question elsewhere and if so my apologies for the repetition. I have a question as to whether your views were accurately represented in the Wall Street Journal editorial by Matt Ridley back in January, entitled “How Fossil Fuels Have Greened the Planet”

    In the article, Ridley refers to your work that the Earth has been greening over the last 30 years and says that there are two possibilities to explain this result, changes in the climate (meaning increased warmth or rainfall) and increased carbon dioxide. He then goes on, allegedly quoting you:

    “Dr. Myneni reckons that it is now possible to distinguish between these two effects in the satellite data, and he concludes that 50% is due to “relaxation of climate constraints,” i.e., warming or rainfall, and roughly 50% is due to carbon dioxide fertilization itself. In practice, the two interact.”

    I note that the part where he says “roughly 50% is due to carbon dioxide fertilization itself” does not actually have quotation marks around it. Prof. Myneni — did Matt Ridley put words in your mouth or did he accurately represent your views and your research. Thank you in advance for addressing this matter.

  28. 28
    Killian says:

    My first thought on Matt Ridley is, why discuss denial at this point in history? It’s time to go all Nike on this and Just. Do. It. Buuut, since it’s been brought up, the best response to Ridley’s piece is that it is a classic case of cherry picking.

    While the thought had been earlier on that CO2 might increase growth well into the future, we have since found that CO2 response is mixed (C3 vs C4 plants)…

    and heat will limit plant growth in the long run.

    Further, CO2 preferentially supports some sorts of plants that give us fits, such as increasing growth in allergenic plants. We reach negative returns quickly in terms of extreme weather affecting crops.

    The problem with some some aspects of climate science is the basing of discussion in averages rather than effects of extremes. As we all know, averages are more a fantasy than extremes are; they don’t really exist in our day-to-day world. I believe this underplays the urgency and leads to some degree of complacency.

    Ridley chooses to ignore every negative effect of FF’s on greening, such as death of soils, desertification, eutrophication, weather extremes, long-term effects of CO2 and heat, etc.

    Whether or not Ridley correctly quoted Ranga Myneni or not is almost irrelevant. If Myneni’s work has found what Ridley said, it is as expected up to a certain point with AGW and will not be the long-term result of higher CO2. If he distorted it, well, that is what climate denial is and is certainly expected from someone with Ridley’s views. Do note Ridley does not link to Myneni’s work, at least not in the version I found access to. If this is true in the WSJ version, too, then Ridley most likely is not wanting people to read the whole work.

    I do think these two points from the conclusions are perhaps most germane:

    The tight coupling between temperature and vegetation seasonality hides the fact that vegetation seasonality in the Arctic is accelerating over time (landscape greening rate increasing over time) and decelerating (greening rate slowing down over time) in the Boreal regions.

    So we get Arctic Amplification and negative crop effects, or at the very least diminishing returns, and desertification might be a reasonable interpretation of this, no?

    It should be clear to all that the extremes of temperatures, relatively thin soils, short growing seasons and extent of melting permafrost is not likely to make the northern latitudes highly productive farming areas any time soon. At the same time, crop losses from extreme weather events (floods, high and low temps, e.g. false spring in the US in 2012) are already causing crop losses in the mid-latitudes.

    Therefore, we do not know how vegetation seasonality (i.e. plant growth, species distribution) will change in the future.

    While Ridley wants to imply this is all just *great* news, the research concludes the future is not at all clear.

    Safe to say, and not intending to speak for the good Dr., Ridley’s (to be overly kind) interpretation, or at least his implication, is invalid.

  29. 29
    Killian says:

    25 S.B. Ripman said I wish I could find a clear and simple prediction of the future path of climate change for the next 100 or so years

    When the worst case scenario is not yet known, and keeps getting worse and worse, the best risk assessment is to plan for the worst case scenario as currently known and perhaps a bit more.

    However, the effects of climate are and will continue to be highly variable from location to location. First step? Choose your location.

    Second step, find all you can on future scenarios and see where your chosen area falls on such maps, paying attention primarily to high temperatures, precipitation, water sources and climate zones. Be sure to adjust for changes in climate zones. (They are creeping northward at roughly one zone further north per decade. See U.S. climate maps for the last 20 years and note changes. Updated every ten years; most recent was within the last three years. By 2100 Michigan will potentially have Texas’ climate, e.g. Detroit currently has northern Kentucky’s former climate.)

    Third, learn about homestead establishment. (The principles involved will be applicable regardless of where you are going to be.) Then start planning specific to your location.

    There is no book that could do this for you unless you found an author that was both prescient and writing about the same climatic zone you intend to be in. Shortcut: take a permaculture course or read up on it.

  30. 30
    Susan Anderson says:

    S.B. Ripman,

    I don’t know whatall that was about, but I do think you’d best ignore it. Your “simple” question is the holy grail of results, unattainable and beckoning like the pot under the rainbow. Scientists are doing their best, but uncertainty will reign, augmented by a massive confusionist campaign deeply imbedded in the profit motives of some of the wealthiest corporations on earth and their deluded or dishonest followers.

    For a layperson’s mix of information, I’d recommend ClimateCentral:

    I also borrow a favorite statement from a friend who like me is a little impatient with the boundaries of science:

    The thing about models, in the present instance, is that they are incapable of reproducing the current situation – not having all the necessary inputs – and the rapidly compressing timescale. These modelers were thinking in terms of decades or hundreds of years, when it may well all turn on a dime.

    We are stuck with scientists’ best efforts to model a complicated and chaotic system, checked by real-world observations of all kinds. But when you see obscurantism creeping in as an argument for do-nothingism, you can be almost sure this is calculated and dishonest.

    In terms of action, just do what you can, all that you can, to influence your legislators to stop sticking their heads in the sand. Then look around at what is happening and make practical arrangements if you can – community, energy, gardening, water, and the like. In short, use your noggin. It’s getting *choose a swearword* obvious!

    Given our propensity to seek the easy way out, we will no doubt make things a whole lot worse with some temporary geoengineering scheme like sulfur dioxide that in the long run will complicate and magnify consequences. Our faith in others’ ability to take care of our problem at some remove in time or space is legion.

  31. 31
    Susan Anderson says:

    Spoke a little hastily – some of the “whatall” was quite sensible, but that doesn’t make me take back any of the rest of it.

    fwiw, I’m a layperson too, but I prefer to admit my ignorance and accept expertise where it can be found. This is one of the trustworthy places to find some of the most skilled people at work.

  32. 32
    Phil Scadden says:

    Flakmeister – there is really good reason why accelerator experiments have 5/6s rather than usual 3s common in other science. Do you know what it is? (Hint – same reason doesnt apply in many other sciences).

  33. 33
    Hank Roberts says:

    For S.B. Ripman:

    I suggest printing these wallet-size and handing them to anyone saying “we must resign ourselves to the damage to come, and our present efforts will make little difference so we may as well just give up ….”

    In fact, collect the whole set:

  34. 34
    andrew adams says:

    S.B. Ripman,

    I don’t think it’s controversial that given the amount of GHGs we have already pumped into the atmosphere we have already committed ourselves to a certain amount of climate change and there is nothing we can do now to prevent that. It doesn’t necessarily follow though that we should give up on the possibility of concerted political action to minimise the consequences and to mitigate as far as possible against even more serious climate change. You will certainly hear people arguing that such concerted action is a pipe dream but they will mostly be either outright contrarians, or those who like to portray themselves as the “reasonable middle ground”.

    And that’s what gets me about some of the arguments made by such people. They like to portray people like myself and many of the commenters here as “alarmists” and “doommongers” and accuse us of having an overly pessimistic outlook, but actually I think most of us believe that although the threat we face is very serious it is one that humanity is capable of addressing both from a practical perspective and in terms of building the necessary political will for such action to happen. It is not us arguing that any such attempts are necessarily doomed to failure and/or will wreck the economy and send us back to the stone age. Yes, the lack of progess so far can be dispiriting but I would say that overall our outlook is realistic but also optimistic, as opposed to the contrarians and others whose outlook is either absurdly panglossian WRT the effects of climate change or excessively “alarmist” about attempts to address it.

  35. 35
    Flakmeister says:


    It has been called the “look else where” effect…

    If you peruse the H-> gamma gamma papers from the LEP era and if you look closely, at one point there was close to a 4 sigma “signal” at 30 GeV in the combined Z peak, 130, 136 GeV root(s) OPAL data…

  36. 36
    BallyWho says:

    you don’t need need tipping points to justify CC anymore. Any science I’m aware of recognizes extreme events as non-normal and pretty near impossible to deal with In a meaningful quantitative way, Black swans they are as far as descriptions go.
    Thirty years of developing the body of knowledge called Climate Science has put the world in a position to deal with planning for CC.pretty responsibly.New Orleans and Long Island can better design their leaves/sea-walls to withstand future storms. Chinese builders of a new coal-fired power plant (they need one a day) can figure out how to make it as climate friendly as possible.
    Try David Victor’s book; he proposes moving forward with local approaches based on capabilities. iMO his approach can be made to work

  37. 37
    Chris Dudley says:

    “Global climate models may provide a tool for studying such links, but they are designed to provide a picture of general large-scale features such as the greenhouse effect and how the air moves around, rather than local extreme phenomena. For some types of extremes such as heat waves, they can nevertheless provide valuable insight (Hansen et al., 2012).”

    I don’t think you have the reference right here. That paper had little to do with models and was very much observation based.

  38. 38
    Hank Roberts says:

    Having just seen the new movie “Chasing Ice” — I highly recommend finding a showing if you can find a showing near you:
    Else, eventually, they’ll have a DVD/Blue-Ray distribution with extra material.

    I saw a presentation with one of the filmmakers — among his comments he said they went repeatedly to the scientists interviewed, to get the presentation right and the brief excerpts well supported. The film spends only a few seconds apiece with the scientists, on the basic information about change over time, and does a good job of using presentation graphics, not just talking heads, for those.

    The movie is almost all filmed outdoors, and almost entirely about the work of getting long time exposure cameras out onto the ice and getting the interim results together (many of the cameras are still in place and still collecting images — Greenland, Iceland, and Alaska).

  39. 39
    Hank Roberts says:

    Folks, you can’t cross-reference by the big gray number.

    Those are assigned each time you open the page.

    (As I understand the software — I’m a reader, not a Contributor/scientist):

    Since the last time you looked, a boring response may have been moved to its proper place, or a thoughtful one delayed for reading and then posted with a comment added inline. The big gray number changes to reflect that.

    Here’s how to indicate who you’re replying to:
    Mention the name/nym and quote the timestamp — this thing: 15 Mar 2013 at 10:04 AM

    To copy it as a link, hilight, right-click, “view source” and select all, copy that, paste it in).

  40. 40
    Edward Greisch says:

    26 S.B. Ripman: “Drought Under Global Warming: a Review” by Aiguo Dai
    The future still depends on present and future actions of large groups of humans.

  41. 41

    The question is not whether or not humans are the culprit that lead to global warming. The question should be a collective consciousness that realizes that there is a problem and what can we do as a society to try to repair the problems that are happening as a result.

  42. 42
    Fred Magyar says:

    Dear Prof Ranga Myneni @17,

    while I salute you for trying to make a real difference in the world, unless your proposal somehow seriously addressess the dynamics of global population growth and the the issues of physical limits of resources on a finite planet, I believe your attempts will be doomed to failure. What you are asking for can only be accomplished with profound and radical paradigm change everywhere on the planet. Given what I have learned about human nature, over the soon to be 60 years, that I have spent on this planet I find that extremely unlikely.

    Besides humanity´s CO2 footprint and ecological footprint I think we should also be concerned with our Thermodynamic Footprint. There are too many people on a finite planet consuming too many resources and trying to use more ecosytem services than the ecosytems can possibly provide. We have constructed a highly complex, and now quite fragile artificial ecosystem upon which we depend for our survival. The entropy of this system is exponentially diverging from what used to be an ecologically stable thermodynamic equilibrium.

    RealClimate already does a superb job of addressing our CO2 footprint.
    So no link is necessary for that here.

    Here´s a link to some data on our Ecological Footprint:

    A Quick Primer in Ecosystem Thermodynamics 101:

    Ecosystem Thermodynamics, meet Joseph Tainter´s collapse of complex societies.
    Thermodynamic Footprint

    This can´t continue for much longer. All the world´s current leaders are fiddling while the planet burns, in more ways that one. In comparison, Nero was but a rank amateur…

    If any economists are reading this and are still clinging to the hope that the current paradigm has a snowball´s chance in hell, or for that matter, the way things are going, even in the Artic… please consider that all economies are wholly owned subsidiaries of Global Ecosystems Inc. The irony of the fact that both the word ecology and economy have the same Greek root should also not be lost on you.

    Disclaimer: not that I really expect too many economists are stopping by at this site.

    Fred Magyar

  43. 43
    Hank Roberts says:

    > Turnkey Websites says:
    > 16 Mar 2013 at 1:03 AM
    That link “Turnkey Websites” is a blogspambot, a clever one — ‘oogle it.

  44. 44
    Xav Ier says:

    I Believe the only positive answer we can give back to the issues of our time, are home grown food, permacultural landscaping, community healing and energy harvesting, just like they describe over there

  45. 45
    S.B. Ripman says:

    Edward Greisch says:

    “The future still depends on present and future actions of large groups of human.”

    Thank you Mr. Greisch and others for the wise commentary. Aren’t we all doing our best, at the ballot box and with our pocketbooks, and at the pulpit when avilable to us, to bring about positive action?
    What I’m really hoping to find out, here and at other sources, is just how bad things are going to get in the next 100 years. It seems fair to assume that the governments of the world are going to be feckless for about 10 or so more years but then the shrinkage of the world’s ice fields and the weather disruptions are going to force sanity on them and we’ll finally see some major, concerted action to address the problem. But by then the atmosphere will be much more polluted than it is now and the warming process will continue for decades and centuries. And future generations will curse us and curse us, as we moulder in our gradually warming graveyards.
    So with the help of this dialogue it appears I’m answering my own question. The most likely scenario is one of the more pessimistic ones posited by the IPCC, and things are going to get quite bad, and now is the time to plan accordingly.
    ps. I’m not sure the permaculture approach works very well when applied in a world with a rapidly changing climate.

  46. 46
    Susan Anderson says:

    Hank Roberts, I find a tilde “~” indicating “approximately” does the job, with the name. The numbers do change, so using them without a name is not helpful.

    SBR, you don’t want much, do you? (just kidding) Scientists are doing their best, but absolute knowledge is unlikely at any time, and in a chaotic system less so.

  47. 47
    Alexandre says:

    Benestad 2008 link is pointing back to this page.

  48. 48
    Bill Piper says:

    In answer to the point ‘what can we do while the world burns’ and similar, I have launched a website that gives us something to do. It is called It shows you where to go to pressure decision makers to do the right thing – a a small action, granted, but an action nonetheless. It is hard to get it noticed among the billions of websites now floating in the ether. Any ideas for it’s improvement and therefore value welcome, at the contact us link, thanks.

  49. 49

    The 5 sigma thing again. I thought that was dead and buried a long time ago. If you run the same experiment 100,000 times, eventually you may get lucky, so you have to have extremely high confidence that any observation isn’t chance before you claim a new finding. Read this if you still don’t get it.

  50. 50
    Paraquat says:

    #27 – Ridley refers to your work that the Earth has been greening over the last 30 years and says that there are two possibilities to explain this result, changes in the climate (meaning increased warmth or rainfall) and increased carbon dioxide. He then goes on, allegedly quoting you:

    “Dr. Myneni reckons that it is now possible to distinguish between these two effects in the satellite data, and he concludes that 50% is due to “relaxation of climate constraints,” i.e., warming or rainfall, and roughly 50% is due to carbon dioxide fertilization itself. In practice, the two interact.”

    Among the AGW denialist crowd, many have taken the fallback position that if global warming is real, it’s actually a good thing because it will make the Earth greener.

    I’ve given that a little thought. Will people in the 22nd century be thanking us for making the world more tropical? I conclude that, for the most part, no. Yes, warming could be seen as a positive for the residents of Greenland and Siberia – assuming that can keep the hoards of climate refugees away. Those who likely not thank us are the billions of human inhabitants who live in the non-Arctic regions and will have to deal with heat waves and crop failures. Those who reside in low-lying regions may have to flee to higher ground (goodbye New York City, Amsterdam, Shanghai, etc).

    On the other hand, the greening may benefit reptiles. Dinosaurs could stage a comeback. I’m sure that they will be grateful to us.