Over the last several weeks, I have been involved with comments and replies on the weblog Skeptical Science (SkS). Despite a rocky start (e.g. see) they finally engaged in constructive interactions, although they still often fell into snarky tones.
Here are their posts
One post of SkS that, given its context that they have spent so much time being critical of my conclusions and insisting on statistical analyses, is
which, the disclaimer to the contrary in one of the comments, clearly is intended to relate to me [reminds me of this cartoon by Tom Peterson of NCDC ]. :-)
My posts on my interaction with SkS include
Their comments focus on three issues that I have raised:
1. That the positive radiative forcing is less than 50% (and I used information from the literature to show how it could be 28%)
2. The reduction of heating of the upper oceans in recent years.
3. The lack of a continued warming in the lower troposphere over the time period since 1998 (and even more clearly since 2002).
On their comments on these three issues, their rebuttal of #1 is the only one where they have merit, in my view. The concluded that I double counted when I obtained the 28% value, and that several of the values I used were feedbacks, not forcings. Thus I countered that using a different approach, I could still show a value of 35%. Even they reported that the estimate of the positive radiative forcing is less than 50% [they reported on a value of 48% from Skeie 2011 which is a reduction of 4% from IPCC AR4]. SkS accepts a lower value of the positive radiative forcing from soot (black carbon), dismisses two other aerosol effects from NRC 2005 and ignores that some of the radiative effect from the added CO2 would have been adjusted for by a warmer climate system since its introduction.
I view the disagreement as to whether the value is 50% or 25% a minor issue, as we both agree it is a first order climate forcing.
However, if we want a better answer, they ignored was my fundamental question:
What is the current radiative forcing from the different human climate forcings with the water vapor overlap excluded?
I proposed a way to estimate this (which they also mostly ignored) -
- Use a column radiative transfer model (for all wavelengths – i.e. short and long wave) on a vertical profile of temperature, humidity and clouds at a sufficient number of locations (grid points) around the world (using all global reanalysis grid points) during a year (with hourly time intervals) to determine the baseline current radiative forcing. If resources permit, do more than one year. Calculate the global average radiative forcing by integrating over the year at each grid point. While radiative feedbacks, of course, are implicit in the vertical profiles, the radiative transfer model provides the instantaneous forcing at that time.
- Use the column radiative transfer model with these same soundings but [sensitivity test #1] change the CO2 level back to pre-industrial, [sensitivity test #2] change the aerosol load back to preindustrial, [sensitivity test #3] change the land cover back to natural, etc and express the values in Watts per meter squared.
- For each of these sensitivity tests, sum up the differences in radiative forcings to obtain the global annual average in Watts per meter squared.
On the three issues, with respect to items #2 and #3, they are ignoring the obvious in my view.
First, the figure below shows that warming on the upper ocean has been reduced in recent years. SkS spent a lot of time trying to argue that this is not significant and that one needs to perform statistical tests to show it is. The reason, as far as I can ascertain, is that see everything in the climate arena as involving the overarching study forcing of CO2 which they see as the dominate human climate forcing . Thus, such short-term excursions are “noise”. I agree we can not say anything about the long-term trends, but to ignore that heating of the upper ocean has mostly stopped ignores the obvious.
On their focus on a similar issue (#3) with respect to lower tropospheric temperature trends, they similarly conclude that any short-term excursion from a long-term linear warming is “noise” due to natural climate variations. Maybe they are right. However, to ignore the obvious that the warming of the lower troposphere has halted, when averaged over the time period 1998 (or 2002) to the present, ignores the obvious signal in the data. Below is the latest RSS MSU TLT data
Now, what SkS ignored in my questions to them was the lack of cooling in the lower stratosphere since about 1995; see below
My Final Comments
I appreciated the opportunity to engage on SkS, and will ask them a couple of further questions this week, but find they still persist in an argumentative manner of debate. Instead of focusing on areas of agreement, they repeatedly argue (often with snarky tone) the same points over and over again. Instead of accepting there is disagreement, they dogmatically insist that they are right. I suspect many readers turn off SkS because of the tone they use in the comments. That is too bad, as a site that accepts the IPCC but is willing to constructively and courteously debate science issues, is very much-needed. Hopefully, SkS will work to improve the tone of their weblog, and recognize that you can disagree on issues, but still respect those you are debating with. Snarky comments are not constructive.