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

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, Dr. Trenberth penned a blog post at 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 5th Assessment 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.

About Bob Tisdale

Research interest: the long-term aftereffects of El Niño and La Nina events on global sea surface temperature and ocean heat content. Author of the ebook Who Turned on the Heat? and regular contributor at WattsUpWithThat.
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11 Responses to Seven Years Ago, An IPCC Lead Author Exposed Critical Weaknesses of the IPCC Foretelling Tools

  1. Bob. I have been saying for several years that unless we know where we are relative to the natural cycles we can’t begin to estimate the small effect of anthropogenic CO2.
    The temperature projections of the IPCC forecasts have no foundation in empirical science being derived from inherently useless and specifically structurally flawed models. They provide no basis for the discussion of future climate trends As a foundation for Governmental climate and energy policy their forecasts are already seen to be grossly in error and are therefore worse than useless. A new forecasting paradigm needs to be adopted. See
    This post provides forecasts of the probable 650 years of coming cooling based on the 60 and 1000 year natural periodicities ( Figs 5 and 15 in the link) clearly seen in the temperature data and using the 10 Be and neutron record as the most useful proxy for solar “activity” on recent millennial time scales . We are just past the peak of the latest 1000 year cycle The simplest working hypothesis is that we are about to repeat the general temperature trends from 1000 AD on.
    The climate conversation needs to move away from the useless reductionist IPCC approach towards discussion of the timing and amplitude of the natural cycles and an understanding of the important regional differences in we might expect on a cooling world.

  2. Thanks, Bob. An excellent article.
    The Trenberth quotes are important. Chaotic and non-linear are the key words.
    We can learn from looking at the past reality, but we can not forecast skillfully for more than a few days.

  3. nzrobin says:

    Thanks Bob. Gems. The idea that the models don’t even need to fit the observed climate, and not verifiable speaks volumes. Keep up the good work.

  4. Green Sand says:

    OT Bob, it would appear that Unisys SST anomaly maps are back on line, still appear to have at least some issues, eg the Beaufort Sea which has been ice covered since the beginning of the month is showing positive anomaly? Well at least it is back, lets hope the same happens to the Nomads server asap.

  5. Bob Tisdale says:

    Green Sand, check out the following NOMADS link:

    IE says “webpage cannot be found”. I sure hope NOAA hasn’t disappeared the Reynolds OI.v2 data from NOMADS like they did the ERSST.v3 data. That would be a real tragedy.

  6. Thank you, Bob, for this valuable reminder.

    It’s been linked for inclusion in The Galileo Movement’s daily newspaper.

    Much appreciated.

    Malcolm Roberts

  7. Pingback: Many Thanks to Kevin Trenberth for Being Open-Minded | Bob Tisdale – Climate Observations

  8. Pingback: Climate Propaganda from the Australian Academy of Science | Bob Tisdale – Climate Observations

  9. Pingback: Climate Propaganda from the Australian Academy of Science | Watts Up With That?

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