by Judith Curry

Red-teaming the the U.S. government’s Climate Science Special Report on the topic of sea level rise.

Steve Koonin as a new op-ed in the WSJ: A Deceptive New Report on Climate. that clarifies the need for a Climate Red Team. Excerpts:

One notable example of alarm-raising is the description of sea-level rise, one of the greatest climate concerns. The report ominously notes that while global sea level rose an average 0.05 inch a year during most of the 20th century, it has risen at about twice that rate since 1993. But it fails to mention that the rate fluctuated by comparable amounts several times during the 20th century. The same research papers the report cites show that recent rates are statistically indistinguishable from peak rates earlier in the 20th century, when human influences on the climate were much smaller. The report thus misleads by omission.

This isn’t the only example of highlighting a recent trend but failing to place it in complete historical context. The report’s executive summary declares that U.S. heat waves have become more common since the mid-1960s, although acknowledging the 1930s Dust Bowl as the peak period for extreme heat. Yet buried deep in the report is a figure showing that heat waves are no more frequent today than in 1900. This artifice also appeared in the government’s 2014 National Climate Assessment, which emphasized a post-1980 increase in hurricane power without discussing the longerterm record. The National Oceanic and Atmospheric Administration recently stated that it has been unable to detect any human impact on hurricanes.

Such data misrepresentations violate basic scientific norms. In his celebrated 1974 “Cargo Cult” lecture, the late Richard Feynman admonished scientists to discuss objectively all the relevant evidence, even that which does not support the narrative. That’s the difference between science and advocacy.

These deficiencies in the new climate report are typical of many others that set the report’s tone. Consider the different perception that results from “sea level is rising no more rapidly than it did in 1940” instead of “sea level rise has accelerated in recent decades,” or from “heat waves are no more common now than they were in 1900” versus “heat waves have become more frequent since 1960.” Both statements in each pair are true, but each alone fails to tell the full story.

Several actions are warranted. First, the report should be amended to describe the history of sea-level rise, heat waves and other trends fully and accurately. Second, the government should convene a “Red/Blue” adversarial review to stress-test the entire report, as I urged in April. Critics argue such an exercise would be superfluous given the conventional review processes, and others have questioned even the minimal time and expense that would be involved. But the report’s deficiencies demonstrate why such a review is necessary.

Finally, the institutions involved in the report should figure out how and why such shortcomings survived multiple rounds of review.

Mr. Koonin was undersecretary of energy for science during President Obama’s first term and is director of the Center for Urban Science and Progress at New York University.

Critique of the Draft of the CCSR discussion of post 1900 sea level rise

Steve Koonin has written an essay Critique of the Draft of the CCSR discussion of post 1900 sea level rise [link CSSR on SLR]

Executive summary. In discussing global sea level rise since 1900, the draft Climate Science Special Report (CSSR) notes that the rate of rise since 1993 is significantly greater than the average rate of rise 1900‐1990, but fails to mention the substantial and well‐established decadal‐scale fluctuations during the 20th century. In fact, the rates since 1993 are statistically indistinguishable from rates in the first half of the 20th century.

Read the whole thing, it is very concise and packs a well-documented punch. He provides the following recommendation for the CCSR draft:

Comparison with the literature shows that the CSSR draft misleads by omission in not mentioning both the strong decadal‐scale variability of GMSL rates during the 20th century and the fact that the most recent values of the rate are statistically indistinguishable from those during the first half of the 20th century.

This deficiency in the CSSR draft should be remedied before the report is released. For example, the draft CSSR Executive Summary statements quoted at the beginning of this document should be replaced with something like:

GMSL has risen 16‐21 cm since 1900, continuing a trend that began in the 19th century. The rate of rise has averaged 1.3 mm/yr since 1900, but has oscillated between about 0 and 2.5 mm/yr, with uncertainties of ±(1‐2) mm/yr. The rates since 1993 are at the high end of this range, but are not statistically different from those during the first half of the 20th Century.

Other modifications of the CSSR text itself follow straightforwardly, and a figure similar to one of the two immediately above should be included. It would also be useful to refer to that figure when discussing the projected average rates of rise for the various scenarios shown in Figure 12.4(a). For example, a rise of 2 meters (~six feet) by 2100 is equivalent to an average rate of ~24 mm/yr for the rest of this century, some 8 times larger than the highest observed rate to date. That would help illustrate for the non‐expert reader just how dramatic the projected changes are.

With such changes, the CSSR would more fully and correctly describe the data and would not misleadingly alarm the non‐expert reader into believing that recent rates of rise are unprecedented.

Red-teaming sea level rise

While we’re on the topic of red teaming sea level rise, I’m providing a recent presentation on sea level rise that I prepared for a client in the insurance industry who is interested in U.S. coastal sea level rise out to 2050 [link sea level ins]. I’ve been meaning to write this up into an essay, but I have been too busy, so I’m posting it for comments.

What my presentation does, beyond what Steve Koonin did, is reframe the sea level issue to look at much longer time frames and also the broader drivers for local sea level rise.

These represent two different angles on red-teaming: critiquing within the existing frame of an assessment report, versus reframing the analysis in a broader framework. Both are needed.