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:
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.
“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
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.
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.
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.
Moar models! We need moar models!
928 days since last cyclone in my region. Townsville, Qld Australia.
@ur momisugly 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.
Cooling affects the poles preferentially, which intensifies circulation, which generates TCs. Warming, the opposite.