Christy's Recent Congressional Testimony: Some Thoughts

[donsutherland1]

With a chart from that May 2015 testimony now widely circulating on the Internet (see below), it makes sense to go to the actual testimony from which it was taken (http://docs.house.gov/meetings/II/II00/20150513/103524/HHRG-114-II00-Wstate-ChristyJ-20150513.pdf).

 

Christy's line of argument is that the climate models have failed to accurately represent mid-tropospheric temperature trends and tropical mid-tropospheric temperature trends. Therefore, in his opinion, one can't have confidence in their ability to project what the climate may do in the future.

 

He added:

 

As such greenhouse gas emissions cannot be used as a proxy for alleged climate change because our capability to demonstrate how greenhouse gases influence the already observed climate is so poor.

 

However, this testimony and sweeping statement appears to be badly flawed:

 

1. It did not address steadily rising Oceanic Heat Content (OHC) on account of the earth's persistent energy imbalance resulting from increased greenhouse gas forcing. This rise in OHC is consistent with growing greenhouse gas forcing.

 

2. The testimony compared model performance against slices of the atmosphere while remaining silent on ocean and land surface temperatures. The oceans and land masses account for virtually all of the earth's volume. Not addressing them leaves out the largest part of the picture and risks creating a compartmentalized illusion that may not represent climate reality.

 

3. Even where the modeling has flaws, basic principles of physics including but not limited to the greenhouse effect, allow scientists to reach informed judgments, even as a degree of uncertainty exists (e.g., sensitivity).

 

In sum, the single contribution the testimony made is that it informed Congress that the climate models have not well represented lower tropospheric temperature trends.

 

At present, there is increasing discussion that the oceans followed by the land masses, not the atmosphere, will provide leading evidence of climate change. If that's the case--and I suspect it is given the decoupling of trends in the lower and middle troposphere from OHC and land/ocean temperatures--Christy's testimony may be based on an expected atmospheric response depicted by the modeling that is already dated. Careful examination of the evidence arising from that discussion as to impacts on the ocean, land, and atmosphere may lead to understanding that will improve climate modeling in all areas.

 

Healthy and vigorous scientific debate is useful. The evidence should guide the conclusions and conclusions should be limited in scope to what the evidence shows.

 

Chart:

image hosting

[chrisf97212]

One can only wonder why Christy was testifying on this in the first place.