Paper suggests a decrease of tropical cyclones ahead

More inconvenient results for Al Gore and the mouthpiece of “Forecast the Facts” Brad Johnson who like to claim that tropical storms will increase due to global warming.

A paper published last week in the Journal of Climate projects a 3-15% decrease of tropical cyclones throughout the 21st century, which seems to be inline with what has been observed so far:

Figure 1: Last 4-decades of Global Tropical Storm and Hurricane frequency — 12-month running sums. The top time series is the number of TCs that reach at least tropical storm strength (maximum lifetime wind speed exceeds 34-knots). The bottom time series is the number of hurricane strength (64-knots+) TCs.

The figure is from Dr. Ryan Maue’s paper Recent historically low global tropical cyclone activity published June 2011 at  Geophys. Res. Lett. in press PDF

The new paper is:

Projected changes in late 21st century tropical cyclone frequency in thirteen coupled climate models from the Coupled Model Intercomparison Project Phase 5

Journal of Climate 2013 ; e-Viewdoi: http://dx.doi.org/10.1175/JCLI-D-13-00010.1

Abstract

Changes in tropical cyclone (TC) frequency under anthropogenic climate change are examined for thirteen global models from the Coupled Model Intercomparison Project Phase 5 (CMIP5), using the OWZP TC detection method developed by the authors in earlier papers. The method detects large-scale conditions within which TCs form. It was developed and tuned in atmospheric reanalysis data, and then applied without change to the climate models to ensure model and detector independence. Changes in TC frequency are determined by comparing TC detections in the CMIP5 historical runs (1970—2000) with high emission scenario (representative concentration pathway 8.5) future runs (2070—2100). A number of the models project increases in frequency of higher latitude tropical cyclones in the late 21st century. Inspection reveals these high latitude systems were subtropical in origin and are thus eliminated from the analysis using an objective classification technique.

TC detections in eight of the thirteen models reproduce observed TC formation numbers and geographic distributions reasonably well, with annual numbers within ±50% of observed. TC detections in the remaining five models are particularly low in number (9—27% of observed). The eight models with a reasonable TC climatology all project decreases in global TC [tropical cyclone] frequency varying between 3 and 15 %. Large inter-model and inter-basin variations in magnitude and sign are present, with the greatest variations in the Northern Hemisphere basins.

These results are consistent with results from earlier generation climate models, and thus confirm the robustness of coupled model projections of globally-reduced TC [tropical cyclone] frequency.

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33 Responses to Paper suggests a decrease of tropical cyclones ahead

  1. Bloke down the pub says:

    And what is their prediction for a cooling world? You can bet that if temps decline and there is a resulting rise in TC, that there’ll be some who say ‘Ta Da , we always said there’d be more TC’s’

  2. lsvalgaard says:

    These results are consistent with results from earlier generation climate models, and thus confirm the robustness of coupled model projections of globally-reduced TC [tropical cyclone] frequency.
    When the models confirm one’s beliefs they are good, when they do not, they are no good…

    REPLY: Unfair Leif, that’s from the abstract, simply reproduced, and not a personal opinion or belief about models. – Anthony

  3. John West says:

    Batten down the hatches! Models predict less tropical storms, more sure to come.

  4. Andrew Kerber says:

    This is basic physics of course. Evidently a concept unknown to climate scientists. In order to generate energy, a requirement for cyclone, you have to have difference in energy level across a boundary. Since temperature are supposed to be increasing unevenly, with the polar regions increasing more rapidly, the overall temperature will become more consistent globally. This means of course that there will be less of a difference to generate the energy required for large weather event.

  5. Mike Bromley the Kurd says:

    Uhhhh….you’re joshin’ me, ain’t ya? I re-read this twice trying to figure out what they said. Nothing came to mind.

    “Inspection reveals these high latitude systems were subtropical in origin and are thus eliminated from the analysis using an objective classification technique.”

    An objective classification technique applied solidly to ephemeral zeros and ones in a hodgepodge of presuppositions? Sorry. Does not compute.

  6. Martin Clark says:

    Would be nice but I’m not convinced.
    We get cyclones that form in the west Pacific hot spot (Solomon Sea) that tend to track south and west. The common factors appear to be thunderstorms, and sea temperatures in excess of 24°C. Once the cyclone tracks over cooler seas, it tends to fizzle. Except when it doesn’t, eg Yasi 2011. High energy both sides of the Australian land mass. A re-run of 1974. Energy differences are not the whole story.
    On the other hand, BoM’s predictions have been fairly useless over a few years, way above what eventuated. I seem to recall the last prediction had no numbers estimated, just something like “normal or below normal” whatever that was supposed to mean.

  7. Pamela Gray says:

    From what I understand about models, you can pick from a LARGE variety (some with and even some without anthropogenic CO2 calculations) and then pick your model runs. Are there indications that this is another paper that cherry picked through the models and spaghetti runs to find what they believe they should find? If so, Leif’s comment is spot on regarding methodology. It is possible they may have picked the “one pine cone tree” that confirms a belief, hardly a scientifically valid or reliable method. AND that makes me wonder. How many runs and models didn’t? And did they throw them out as “bad models” or “bad runs”?

    We have had this conversation before regarding cherry-picked treemometers. The same discerning eye should be beamed on climate model methodology.

  8. Bob Tisdale says:

    A climate model study? Oy vey!

  9. Greg Goodman says:

    Saying TC freq is expected to drop because they move north sounds like a technicality. Since the models are still based os the usual models and the usual “senarios” , they are probably wrong on two counts but may be right in numbers.

    There may well be a reduction in ACE if “the pause” turns into a cooling.

  10. arthur4563 says:

    lsvalgaard says:
    lvasgarrd say” When the models confirm one’s beliefs they are good, when they do not, they are no good…
    No, gaard, they are good when they correspond to reality, as in this case.

  11. Greg Goodman says:

    arthur4563 says: No, gaard, they are good when they correspond to reality, as in this case.

    It’s a prediction so no one knows whether is correspond to reality, yet. Since it iis based on current GCMs , I doubt it will be correct but who knows.

  12. Richard M says:

    Models assume the planet will continue to warm more or less constantly. Since we have begun a multi-decadal period of cooling the chances these models are right (for the right reasons) is probably close to zero.

  13. Go Home says:

    Leif,
    I think the term that should be used is, the science isn’t settled. Certainly not by the models anyway. You see models do not search for consensus.

  14. Theo Goodwin says:

    Pamela Gray says:
    August 19, 2013 at 7:07 am

    Very well said. But I thought that we understood the “Climate Alarmist Scientific Method” is that you try different models until you get a result that is consistent with Alarmist claims and then you declare that the science is settled. Also, you declare that the result is based on the best physics because the best physics is “in” the model.

  15. NavarreAggie says:

    Jeff Masters’ sycophantic followers hardest hit. LOL

  16. Kevin Kilty says:

    Andrew Kerber says:
    August 19, 2013 at 6:13 am

    Martin Clark says:
    August 19, 2013 at 6:38 am

    These are natural heat engines and so temperature differences, or more correctly the area enclosed by the cyclone process on a T-S diagram, are the whole story, except that equator to pole difference is likely less important than sea surface to effective radiating temperature above–i.e. local thermal conditions greatly outweigh global ones.

  17. Kevin Kilty says:

    … eight of the thirteen models reproduce observed TC formation numbers and geographic distributions reasonably well, with annual numbers within ±50% of observed. TC detections in the remaining five models are particularly low in number (9—27% of observed)…

    Some years ago I was teaching engineering statistics and, as an example of a Poisson Process I decided to use major (cat 3,4,5) Atlantic basin hurricanes 1944-2000. Amazingly the observed numbers follow a Poisson distribution with an expected rate of 2.8 per year remarkably well. No physics involved, just a one-parameter process. As the standard deviation of a Poisson process is the square root of the average rate; observing the number of hurricanes in 8 of 13 model runs being plus or minus 50% of the average rate is very nearly the 68% that one would expect at plus or minus one standard deviation. Now, my data analysis was meant to be only illustrative, and covered a limited region, but it looks like all the physics involved in these complex computer models simply produces tropical cyclone features that are a Poisson process.

    Now, to determine whether or not TC frequency increases with time (warming) simply model the average rate of the process with time as reflected in observed hurricane frequency. I’ve used maximum likelihood to do this and find a rate of increasing hurricane frequency consistent with zero over 1944-2000.

  18. Kevin Kilty says:

    Correction: Rate of 2.5 not 2.8.

  19. RobL says:

    How many 100′s of billions of dollars would a 3-15% reduction in tropical storms save over 100 years?

  20. lsvalgaard says:

    lsvalgaard says:
    August 19, 2013 at 6:11 am
    When the models confirm one’s beliefs they are good, when they do not, they are no good…
    REPLY: Unfair Leif, that’s from the abstract, simply reproduced, and not a personal opinion or belief about models. – Anthony

    Unfair or fair, that is what people would say, just check the other comments…

  21. Antiactivist says:

    Save the hurricanes!

  22. Thomas says:

    From the SPM of the IPCC report:
    ” Based on a range of models, it is likely that future tropical cyclones (typhoons and hurricanes) will become more intense, with larger peak wind speeds and more heavy precipitation associated with ongoing increases of tropical sea surface temperatures. There is less confidence in projections of a global decrease in numbers of tropical cyclones.

  23. @GoHome 7:48 am.
    You see models do not search for consensus.
    Modelers do. Someone needs to fund their work and pay the bills.
    “What is 2+2?” “What do you want it to be? What will you pay for it?”

  24. John West says:

    @ Leif
    I’m confused.
    You quoted the abstract:

    “These results are consistent with results from earlier generation climate models, and thus confirm the robustness of coupled model projections of globally-reduced TC [tropical cyclone] frequency.”

    And commented:
    ” When the models confirm one’s beliefs they are good, when they do not, they are no good…”
    Which I interpreted as you accusing the authors of committing this particular sin to Logic and I agreed.
    But then Anthony comments:
    REPLY: Unfair Leif, that’s from the abstract, simply reproduced, and not a personal opinion or belief about models. – Anthony
    Which means he thinks you’re saying skeptics will accept these conclusions and methodology because it aligns well with our position.
    And you confirm his interpretation with this comment:
    ”Unfair or fair, that is what people would say, just check the other comments…”
    The evidence does not support your position.
    1) Anthony presents this as making it difficult for the Gore types without any endorsement of conclusions or methods. It seems reasonable that those advocating for action on climate change based on there being all catastrophes and no benefits to global warming would find it difficult (though not impossible) to say trust the models (chanting: the models are right) the world will get warmer and that will be bad and with the very next breath say don’t trust the models (the models are wrong), no cost/benefit analysis is required because global warming has no benefits.
    2) The comments aren’t generally “accepting”. I said to expect the opposite of whatever the models predict/project. Andrew Kerber basically says DUH, less temp differential would mean less vigorous energy transfer. Mike Bromley the Kurd basically says they didn’t really say anything. (LOL). Martin Clark says ”I’m not convinced”.Pamela Gray says: ”It is possible they may have picked the “one pine cone tree” that confirms a belief, hardly a scientifically valid or reliable method”. Bob Tisdale says: ” A climate model study? Oy vey! (LOL) Greg Goodman says: ”they are probably wrong on two counts”. Richard M says: ”the chances these models are right (for the right reasons) is probably close to zero.” RobL points out the monetary benefit of less Tropical Storms. Antiactivist wants to save the hurricanes. (LOL) Etc.

    Please feel free to clarify the meaning of the original comment, explain why you would have an opinion so poorly evidenced, or change your opinion based on the evidence.

  25. Bob says:

    “Changes in tropical cyclone (TC) frequency under anthropogenic climate change are examined for thirteen global models from the Coupled Model Intercomparison Project Phase 5 (CMIP5)”.
    “A paper published last week in the Journal of Climate projects a 3-15% decrease of tropical cyclones throughout the 21st century, which seems to be inline with what has been observed so far:”
    I’m not very enthusiastic about looking at the output of 13 models for such predictions. Given the variation on tropical cyclones, I doubt very seriously that most of the 3-15% decrease could be seen from the noise.
    Interesting, but nothing to get excited about until we have a few more years of data. All we can say is the frequency hasn’t gone up as the doom and gloom predictors foretold.
    Bob Greene

  26. Bill says:

    I agree that most of the comments do not just accept the results.

    There are plenty that say they don’t believe results of models blindly.

    Greg, I believe what the commenter above meant was that we have seen
    a recent decrease in hurricanes which one could say is consistent with
    what this paper predicts. However, as temp.’s have not warmed much the
    last 15 years and as there are 30 year cycles in hurricanes anyway, I’m not
    sure there is a clear pattern yet w.r.t. hurricanes and temperatures.

  27. lsvalgaard says:

    John West says:
    August 19, 2013 at 11:14 am
    Please feel free to clarify the meaning of the original comment
    Jeez, every day on WUWT we hear the constant ‘models are useless’ meme, and I was simply pointing out that I expected to hear it on this thread as well, which I did.

  28. taxed says:

    l think there is a link between the weakening of the Polar jet during the summer and the reducing of hurricane activity. Just has the Polar jet has become more variable during recent summers. So l think the same thing is happening with the atmosphere has a whole.
    Which is leading to a increase in wind shear and more variable wind activity, things that do not suit the forming of large hurricanes. lt would be interesting to see if over recent years that they as been a increase in the formation large hurricanes taking place later in the season. As the Polar jet become stronger and more stable.

  29. Richdo says:

    Moar models! We need moar models!

  30. sirboabtree says:

    928 days since last cyclone in my region. Townsville, Qld Australia.

  31. John West says:

    @ Leif
    “Jeez, every day on WUWT we hear the constant ‘models are useless’ meme, and I was simply pointing out that I expected to hear it on this thread as well, which I did.

    OH! See there, I was confused. You were right to expect us to be skeptical.

  32. Brian H says:

    Cooling affects the poles preferentially, which intensifies circulation, which generates TCs. Warming, the opposite.

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