Heartland Institute’s NIPCC Report: “[G]lobal warming ceased around the end of the 20th cent. and was followed (since 1997) by 16 years of stable temperature.” [For fact checking & general commentary]

January 2, 2014 10:41 am2 comments

POSTED FOR COMMENTARY BY THE CCNF SCIENTIST COMMUNITY:

2013-NIPCC-Cover

“Global warming ceased around the end of the twentieth century and was followed (since 1997) by 16 years of stable temperature.”

http://www.nipccreport.org/reports/ccr2a/ccr2physicalscience.html

Source: “Climate Change Reconsidered II: Physical Science 2013 Report of the Nongovernmental International Panel on Climate Change.” The Heartland Institute.

THE FORUM'S COMMENT THREAD

  • Here’s a true statement: global mean surface temperatures increased relatively rapidly during the last few decades of the 20th century, but have been relatively steady during the past 16 years.

    What makes my statement true and the NIPCC statement dubious? At first blush they seem to be saying the same thing about global temperatures. The key difference is that my statement is a statement about data, and the NIPCC statement is a statement about a process. The NIPCC makes its mistake by equating the presence or absence of a process (global warming) with the values of sixteen data points.

    Global warming is the tendency for global mean temperatures to gradually increase as a result of mankind’s release of previously sequestered greenhouse gases. Whatever global warming does to temperatures, it does in addition to whatever happens to temperatures naturally. That includes volcanic activity, El Niño, the Atlantic Multidecadal Oscillation, and other random weather and climate phenomena, all of which can cause the global temperature to go up or down in a particular year or a particular decade.

    The recent flattening of the temperature trend has several possible explanations, two of which are: (1) global warming has stopped, or (2) the other natural stuff is causing a downward trend just as large as the upward trend caused by global warming. To distinguish between these possibilities, one can look at whether greenhouse gases have stopped increasing (they haven’t) or whether the energy imbalance caused by those greenhouse gases has gone away (it hasn’t).

    The fact that other natural factors are still strong enough to cancel out global warming for a decade and a half does mean that global warming still isn’t strong enough to be overwhelming. But, alas, the process of global warming is still taking place.

    For more on how natural variability is temporarily cancelling out the effect of global warming, see my Climate Abyss blog entries http://blog.chron.com/climateabyss/2012/04/about-the-lack-of-warming/ and http://blog.chron.com/climateabyss/2013/08/learning-from-the-hiatus/

  • This statement in the NIPCC report makes a few mistakes (also highlighted by John Nielsen-Gammon):

    – It wrongly suggests that the timeseries of surface air temperatures over 16 years is indicative of the longer term (multi-decadal) forced trend (what John calls 16 data points vs the process).
    – It wrongly suggests that surface air temperatures is all there’s to global warming (whereas most excess energy ends up in the oceans which appear to be warming, including over this same period).
    – Something that has more recently been quantified, so can’t really be held against them, is that the surface temperature data have a cool bias by ignoring large parts of the (rapidly warming) Arctic.

    The warming that is expected at any point in time depends on a few things:

    – The climate forcing (how is the energy coming in and going out of the system changing?)
    – The climate sensitivity (how much warming would we eventually expect after equilibrium has been reached)
    – The climate response time (how fast is equilibrium reached)
    – Natural variability

    The “positive” (warming) climate forcing from greenhouse gases has been counteracted in the past decade by a “negative” (cooling) climate forcing due to a very inactive sun and due to more reflective aerosols (from volcanoes and from China). On top of that, La Nina conditions prevailed over this time period so this mode of natural variability added more coolness so to speak. To what extent the sensitivity and response time are different from what we thought it was is harder to pin down (e.g. paleo-estimates differ from what may be deduced from the transient changes during the past 150 years).

    A few years ago I took a more detailed look at the previous NIPCC report (http://ourchangingclimate.wordpress.com/2009/06/13/the-nipcc-report/) and found it wanting. It’s a good example of cherrypicking one’s way to a preferred conclusion and it is not a reliable source of scientific information. I concluded the following:

    This report exhumes a very strong and unfounded faith in negative feedbacks from nature, which are hypothetical with sometimes sketchy, often contradictory, and sometimes no evidence of actually operating at a globally significant scale. This highlights an inconsistent view of uncertainty, and an unwillingness to weigh the evidence: “If it causes cooling, the uncertainty (or lack of evidence) doesn’t matter; if it causes warming, it’s too uncertain (and no evidence strong enough) to matter”.

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PUBLIC COMMENT THREAD

  • http://atmo.tamu.edu/profile/JNielsen-Gammon John Nielsen-Gammon

    Here’s a true statement: global mean surface temperatures increased relatively rapidly during the last few decades of the 20th century, but have been relatively steady during the past 16 years.

    What makes my statement true and the NIPCC statement dubious? At first blush they seem to be saying the same thing about global temperatures. The key difference is that my statement is a statement about data, and the NIPCC statement is a statement about a process. The NIPCC makes its mistake by equating the presence or absence of a process (global warming) with the values of sixteen data points.

    Global warming is the tendency for global mean temperatures to gradually increase as a result of mankind’s release of previously sequestered greenhouse gases. Whatever global warming does to temperatures, it does in addition to whatever happens to temperatures naturally. That includes volcanic activity, El Niño, the Atlantic Multidecadal Oscillation, and other random weather and climate phenomena, all of which can cause the global temperature to go up or down in a particular year or a particular decade.

    The recent flattening of the temperature trend has several possible explanations, two of which are: (1) global warming has stopped, or (2) the other natural stuff is causing a downward trend just as large as the upward trend caused by global warming. To distinguish between these possibilities, one can look at whether greenhouse gases have stopped increasing (they haven’t) or whether the energy imbalance caused by those greenhouse gases has gone away (it hasn’t).

    The fact that other natural factors are still strong enough to cancel out global warming for a decade and a half does mean that global warming still isn’t strong enough to be overwhelming. But, alas, the process of global warming is still taking place.

    For more on how natural variability is temporarily cancelling out the effect of global warming, see my Climate Abyss blog entries http://blog.chron.com/climateabyss/2012/04/about-the-lack-of-warming/ and http://blog.chron.com/climateabyss/2013/08/learning-from-the-hiatus/

  • http://ourchangingclimate.wordpress.com/ Bart Verheggen

    This statement in the NIPCC report makes a few mistakes (also highlighted by John Nielsen-Gammon):

    – It wrongly suggests that the timeseries of surface air temperatures over 16 years is indicative of the longer term (multi-decadal) forced trend (what John calls 16 data points vs the process).
    – It wrongly suggests that surface air temperatures is all there’s to global warming (whereas most excess energy ends up in the oceans which appear to be warming, including over this same period).
    – Something that has more recently been quantified, so can’t really be held against them, is that the surface temperature data have a cool bias by ignoring large parts of the (rapidly warming) Arctic.

    The warming that is expected at any point in time depends on a few things:

    – The climate forcing (how is the energy coming in and going out of the system changing?)
    – The climate sensitivity (how much warming would we eventually expect after equilibrium has been reached)
    – The climate response time (how fast is equilibrium reached)
    – Natural variability

    The “positive” (warming) climate forcing from greenhouse gases has been counteracted in the past decade by a “negative” (cooling) climate forcing due to a very inactive sun and due to more reflective aerosols (from volcanoes and from China). On top of that, La Nina conditions prevailed over this time period so this mode of natural variability added more coolness so to speak. To what extent the sensitivity and response time are different from what we thought it was is harder to pin down (e.g. paleo-estimates differ from what may be deduced from the transient changes during the past 150 years).

    A few years ago I took a more detailed look at the previous NIPCC report (http://ourchangingclimate.wordpress.com/2009/06/13/the-nipcc-report/) and found it wanting. It’s a good example of cherrypicking one’s way to a preferred conclusion and it is not a reliable source of scientific information. I concluded the following:

    This report exhumes a very strong and unfounded faith in negative feedbacks from nature, which are hypothetical with sometimes sketchy, often contradictory, and sometimes no evidence of actually operating at a globally significant scale. This highlights an inconsistent view of uncertainty, and an unwillingness to weigh the evidence: “If it causes cooling, the uncertainty (or lack of evidence) doesn’t matter; if it causes warming, it’s too uncertain (and no evidence strong enough) to matter”.

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