Further Comment On The Dot Earth Post On “Climate Data, Trends and Peer Review”

Yesterday I posted a blog titled

A Myth About The Surface Temperature Record Analyses Perpetuated On Dot Earth By Andy Revkin.

To his credit, despite my criticism, Andy presented a rebuttal by Michael Schlesinger on his website. I have reposted Michael’s response below in its entirety, and then I follow with my comment.

POST FROM DOT EARTH

Roger Pielke, Sr., of Colorado State strongly criticized Michael Schlesinger’s assessment of the temperature data — http://wattsupwiththat.com… and Dr. Schlesinger sent this reply:

I have been expecting this comment, not from anyone in particular, but from someone – and here it is. Of course we have only one raw dataset comprised of all the world’s surface temperature measurements.

How could it be otherwise?

The different groups that have analyzed this single raw dataset have made different decisions in their analyses. For example, whether the station data should be averaged as is, or whether they should first be area-weighted for the region of their coverage.

It is because of the differences in analysis methods that the results of the 4 groups are not identical.

That is healthy.

So, one set of raw temperature data, of needs be, and several different decisions about how to analyze these raw data, all lead to the same conclusion – the Earth’s near-surface temperature has warmed by about 0.9°C (1.6°F) during the past 150 years.

The case of detecting climate change is closed, period, RPS or any other climate skeptic notwithstanding.

The next task is to attribute these detected changes in near-surface temperature to their causes, natural or not – us (and U.S.).

This can be done only with a climate model, either the simple one that I and Natasha Andronova applied in our year-2000 paper, referenced in my cotribution to Andy Revkin’s blog today, or with climate science’s most comprehensive climate models, our coupled atmosphere-ocean general circulation models.

As documented in the IPCC AR4, it is not possible to replicate the observed warming due to natural causes – the sun and volcanoes – alone. Such replication can be done only by including the effects of the human-generated increase in the concentrations of greenhouse gases.

Thus the case of the causes of the observed climate change is closed, period – RPS or any other climate skeptic notwithstanding.

What remains is to decide what to do about this, bury our collective heads in the sand and pretend that reality is otherwise, or take on the hard task before us of making the transition this century from the fossil-fuel age to the post fossil-fuel age.

As I am an engineer as well as a scientist, I challenge humanity to this great and singular task.

I will not be here much longer, so I can at most see only the beginning of this voyage.

But my 3 children and 6 grandchildren will be here to see whether or not we now behave in a responsible way to them and their progeny, and to our one-and-only planet.

To not do so would be to condemn billions of human beings, now and in the future, to death by climate.

THIS WE MUST NOT DO!

Michael

MY RESPONSE

First,  I am pleased that Michael Schlesinger has confirmed what I have reported; in that

“…we have only one raw dataset comprised of all the world’s surface temperature measurements.”

However, what this means is that the  0.9°C increase in the global average surface temperature during the last 150 years is guaranteed to be closely replicated by each of the research centers that are analyzing the data.  This close agreement was reported on in the CCSP 1.1 report as I reproduced in my post  

An Erroneous Statement Made By Phil Jones To The Media On The Independence Of The Global Surface Temperature Trend Analyses Of CRU, GISS And NCDC

An excerpt from the CCSP 1.1. report, as I reproduced in my post,  reads

“While there are fundamental differences in the methodology used to create the surface data sets, the differing techniques with the same data produce almost the same results (Vose et al., 2005a).”

Michael introduces another broader issue, however, in his  statement

“The case of detecting climate change is closed, period, RPS or any other climate skeptic notwithstanding.”

This statement is a further example of the narrow and closed viewpoint illustrated in the released CRU e-mails. I agree with Michael that we have detected human climate forcing effects. To label me as a skeptic, however,  is completely wrong (as Andy knows; e.g. see and see)

More importantly, I am disappointed in his failure to discuss the fundamental scientific issue that remains which is which of the two hypotheses below are correct:

Hypothesis 2a: Although the natural causes of climate variations and changes are undoubtedly important, the human influences are significant and involve a diverse range of first- order climate forcings, including, but not limited to, the human input of carbon dioxide (CO2). Most, if not all, of these human influences on regional and global climate will continue to be of concern during the coming decades. 

 

Hypothesis 2b: Although the natural causes of climate variations and changes are undoubtedly important, the human influences are significant and are dominated by the emissions into the atmosphere of greenhouse gases, the most important of which is CO2. The adverse impact of these gases on regional and global climate constitutes the primary climate issue for the coming decades.

 

 Hypothesis 2b was rejected in our joint paper (of which all of the authors are AGU Fellows)

Pielke Sr., R., K. Beven, G. Brasseur, J. Calvert, M. Chahine, R. Dickerson, D. Entekhabi, E. Foufoula-Georgiou, H. Gupta, V. Gupta, W. Krajewski, E. Philip Krider, W. K.M. Lau, J. McDonnell,  W. Rossow,  J. Schaake, J. Smith, S. Sorooshian,  and E. Wood, 2009: Climate change: The need to consider human forcings besides greenhouse gases. Eos, Vol. 90, No. 45, 10 November 2009, 413. An edited version of this paper was published by AGU. Copyright (2009) American Geophysical Union

 Michael Schlesinger clearly accepts Hypothesis 2b.  I invite him to discuss why he rejects Hypothesis 2a, since only one of these hypotheses can be correct.