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Seven Years Ago, An IPCC Lead Author Exposed Critical Weaknesses of the IPCC Foretelling Tools

Written by Bob Tisdale, wattsupwiththat.com

NCAR’s Dr. Kevin Trenberth was a lead author of the IPCC’s 2nd, 3rd and 4th Assessment Reports.  Near to the publication of the IPCC’s 4th Assessment Report 7 years ago, Kevin Trenberth Dr. Trenberth penned a blog post at Nature.com Predictions of climate—a blog post that exposed many critical weaknesses in the climate models used by the IPCC for divining the future of climate on Earth.  The post was filled with extraordinary quotes, including:

  • …none of the climate states in the models correspond even remotely to the current observed climate.
  • In particular, the state of the oceans, sea ice, and soil moisture has no relationship to the observed state at any recent time in any of the IPCC models.
  • Moreover, the starting climate state in several of the models may depart significantly from the real climate owing to model errors.
  • … if the current state is one of drought then it is unlikely to get drier, but unrealistic model states and model biases can easily violate such constraints and project drier conditions.
  • However, the science is not done because we do not have reliable or regional predictions of climate.
  • So the science is just beginning.
  • We will adapt to climate change. The question is whether it will be planned or not?

Those are powerful statements.  Please read Trenberth’s blog post in its entirety.  You’ll find those quotes were reinforced by much of the remaining text.   Occasionally, Trenberth interjected what could be considered global warming dogma to temper the critical aspects of the remainder.

One of Trenberth’s statements stands out as self-deception, plain and simple:

The current projection method works to the extent it does because it utilizes differences from one time to another and the main model bias and systematic errors are thereby subtracted out. This assumes linearity.

Seven years later everyone knows the “current projection method” does not work.  The climate science community has known all along that Earth’s climate is chaotic and non-linear.  It was only a matter of time until their “current projection method” failed, and it didn’t take long.

Additionally, if the “current projection method” had worked, the climate-science community would presently not be scrambling to come up with excuses for the slow-down (hiatus) in global surface temperature warming. And they’ve come up with so many excuses, I’ve lost count.

I reminded people of this Trenberth blog post in a comment on the WattsUpWithThat cross post of one of my recent blog posts On the Elusive Absolute Global Mean Surface Temperature – A Model-Data Comparison.  In the WUWT comment, I quoted the Trenbeth blog post:

None of the models used by IPCC are initialized to the observed state and none of the climate states in the models correspond even remotely to the current observed climate.

Then I noted:  In other words, the models used by the IPCC were never intended to replicate Earth’s climate. They, therefore, cannot be validated or invalidated.

At this time in a blog post, I normally go on to illustrate and discuss numerous climate model failings.  I’m going to deviate from my normal course and only provide a link to one post and it’s cross post.  It was published soon after the release of the IPCC’s 5thAssessment Report last year.  That post was Questions the Media Should Be Asking the IPCC – The Hiatus in Warming.  It was cross posted at Joanne Nova’s website as Six questions the media should be asking the IPCC.

Comments (1)

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    Mervyn

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    Here is a good one… Trenberth was one of the authors of a paper published in Climate Research titled State-of-the-Art Climate Models and Extreme Meteorological Events and Consequences (Volume 14, Number 30: 27 July 2011).

    It compared the projections of state-of-the-art climate models with what was known about the real world with respect to extreme meteorological events related to atmospheric moisture, such as precipitation and various types of storm systems, as well as subsequent extreme consequences such as droughts, floods, and wind damage.

    Here are some interesting extracts:

    [A]ll models contain large errors in precipitation simulations, both in terms of mean fields and their annual cycle (such as the spurious migration of the Intertropical Convergence Zone into the other hemisphere), as well as their characteristics: the intensity, frequency, and duration of precipitation, plus the amount (e.g. IPCC, 2007; Bosilovich et al., 2008; Liepert and Previdi, 2009).

    [I]t appears that many, perhaps all, global climate and numerical weather prediction models and even many high-resolution regional models have a premature onset of convection and overly frequent precipitation with insufficient intensity, (citing the work of Yang and Slingo (2001) and Dai and Trenberth (2004)).

    [C]onfidence in model results for changes in extremes is tempered by the large scatter among the extremes in modeling today’’s climate, especially in the tropics and subtropics (Kharin et al., 2007), which relates to poor depiction of transient tropical disturbances, including easterly waves, Madden-Julian Oscillations, tropical storms, and hurricanes (Lin et al., 2006).

    [M]odels produce precipitation that is too frequent and with insufficient intensity (Yang and Slingo, 2001; Trenberth et al., 2003; Dai and Trenberth, 2004; Dai, 2006).

    [M]ajor challenges remain to improve model simulations of the hydrological cycle.

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