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New Study Finds No Evidence Of Global Warming Increasing Extreme Rainfall

September 10, 2016

By Paul Homewood 

 

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http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0307.1

 

This paper, published last month, has some relevance to recent attempts to blame the Louisiana floods on global warming.

 

ABSTRACT

Precipitation extremes have a widespread impact on societies and ecosystems; it is therefore important to understand current and future patterns of extreme precipitation. Here, a set of new global coupled climate models with varying atmospheric resolution has been used to investigate the ability of these models to reproduce observed patterns of precipitation extremes and to investigate changes in these extremes in response to increased atmospheric CO2 concentrations. The atmospheric resolution was increased from 2°×2° grid cells (typical resolution in the CMIP5 archive) to 0.25°×.25° (tropical cyclone-permitting). Analysis has been confined to the contiguous United States (CONUS). It is shown that, for these models, integrating at higher atmospheric resolution improves all aspects of simulated extreme precipitation: spatial patterns, intensities and seasonal timing. In response to 2×CO2 concentrations, all models show a mean intensification of precipitation rates during extreme events of approximately 3-4% K−1. However, projected regional patterns of changes in extremes are dependent on model resolution. For example, the highest-resolution models show increased precipitation rates during extreme events in the hurricane season in the CONUS southeast, this increase is not found in the low-resolution model. These results emphasize that, for the study of extreme precipitation there is a minimum model resolution that is needed to capture the weather phenomena generating the extremes. Finally, the observed record and historical model experiments were used to investigate changes in the recent past. In part because of large intrinsic variability, no evidence was found for changes in extreme precipitation attributable to climate change in the available observed record.

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-16-0307.1

 

As we often see, the computer models show more intense rainfall, because that is what they are programmed to say. As so often though, when the observed record is analysed, no evidence of such is found:

Finally, the observed record and historical model experiments were used to investigate changes in the recent past. In part because of large intrinsic variability, no evidence was found for changes in extreme precipitation attributable to climate change in the available observed record.

 

 

USHCN Data

Talking of the historical record, USHCN say their three stations in Louisiana, with the most complete and long running data, are Calhoun, Jennings and Lafayette.

Below are the USHCN whisker plots of daily rainfall.

 

broker

brjoker

brloker

http://cdiac.ornl.gov/epubs/ndp/ushcn/ushcn_map_interface.html

 

There is no evidence at all of daily rainfall becoming more extreme in Louisiana in recent years.

7 Comments leave one →
  1. September 10, 2016 11:14 am

    Reblogged this on Climatism and commented:
    Another one bites the dust ☔️

  2. September 10, 2016 11:40 am

    Beyond the US, global analysis of precipitation data from weather stations shows wet places are not getting wetter, nor dry places drier.

    https://rclutz.wordpress.com/2016/05/07/data-vs-models-2-droughts-and-floods/

  3. September 10, 2016 12:37 pm

    But . . . Louisiana!?

    “A Central U.S. Gulf Coast extreme precipitation event has become more likely and more intense in 2016 than it was in 1900 as a result of climate change. Analyses based on observational precipitation data found clear positive trends in rainfall frequency and intensity . . . . . .
    Based on these different approaches – all of which are in agreement – the team found that human-caused climate change increased the frequency and intensity of the heavy rains such as the August 12 – 14 event along the Central U.S. Gulf Coast region.”

    https://wwa.climatecentral.org/analyses/louisiana-downpours-august-2016/

    • Mr GrimNasty permalink
      September 10, 2016 5:42 pm

      Jaime are you suggesting GIGO Models from a Rockefeller $ propaganda site invalidates real data?

  4. tom0mason permalink
    September 10, 2016 5:36 pm

    OT but may be interest to those that like a free and open Internet —

    You may all be interested in Obama’s plan to give away ICAAN to the UN.
    That will enhance freedom of speech? I think not.

    Ted Cruz outlines his objections here
    https://www.cruz.senate.gov/?p=press_release&id=2782

  5. September 12, 2016 1:49 am

    Reblogged this on Climate Collections.

  6. September 13, 2016 9:39 pm

    Reblogged this on kingbum78's Blog and commented:
    Computer models and the real numbers don’t match ya say? I can’t say I’m surprised

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