The latest salvo in the debate between climate change "alarmists"* and "deniers"* over at the Wall Street Journal has been fired. It all began with a January 27 op/ed, "No Need to Panic About Climate Change," by 16 distinguished researchers who are skeptical that humanity faces an planetary emergency. In that op/ed they stated:
Perhaps the most inconvenient fact is the lack of global warming for well over 10 years now. This is known to the warming establishment, as one can see from the 2009 "Climategate" email of climate scientist Kevin Trenberth: "The fact is that we can't account for the lack of warming at the moment and it is a travesty that we can't." But the warming is only missing if one believes computer models where so-called feedbacks involving water vapor and clouds greatly amplify the small effect of CO2.
The lack of warming for more than a decade—indeed, the smaller-than-predicted warming over the 22 years since the U.N.'s Intergovernmental Panel on Climate Change (IPCC) began issuing projections—suggests that computer models have greatly exaggerated how much warming additional CO2 can cause. Faced with this embarrassment, those promoting alarm have shifted their drumbeat from warming to weather extremes, to enable anything unusual that happens in our chaotic climate to be ascribed to CO2.
Not surprisingly, the proponents of the one true climate science were annoyed and responded on February 1 with a long letter headlined, Check with Climate Scientists for Views on Climate Science. The 38 perturbed alarmists argued that the researchers who wrote the initial op/ed were unqualified to comment on climate science, likening it to the situation of consulting a dentist about cardiology. Contradicting the claim that global temperatures had stalled, the letter noted:
Climate experts know that the long-term warming trend has not abated in the past decade. In fact, it was the warmest decade on record. Observations show unequivocally that our planet is getting hotter. And computer models have recently shown that during periods when there is a smaller increase of surface temperatures, warming is occurring elsewhere in the climate system, typically in the deep ocean. Such periods are a relatively common climate phenomenon, are consistent with our physical understanding of how the climate system works, and certainly do not invalidate our understanding of human-induced warming or the models used to simulate that warming.
Thus, climate experts also know what one of us, Kevin Trenberth, actually meant by the out-of-context, misrepresented quote used in the op-ed. Mr. Trenberth was lamenting the inadequacy of observing systems to fully monitor warming trends in the deep ocean and other aspects of the short-term variations that always occur, together with the long-term human-induced warming trend.
In any case, I noted in my blogpost on the controversy, Climate Scientists Violate Their Own Advice, that the "real" climate scientists were themselves not above practicing a bit economic cardiology when it comes to recommending policies for addressing climate change. The 38 climate scientists stated:
It would be an act of recklessness for any political leader to disregard the weight of evidence and ignore the enormous risks that climate change clearly poses. In addition, there is very clear evidence that investing in the transition to a low-carbon economy will not only allow the world to avoid the worst risks of climate change, but could also drive decades of economic growth. Just what the doctor ordered.
I noted that none of the 38 signatories seemed to have any explicit expertise with regard to economics or public policy.
Now, the original 16 skeptical researchers have replied to the reply with a letter headlined, Concerned Scientists Reply on Global Warming. They carry on with the diagnostic metaphor:
We agree with Mr. Trenberth et al. that expertise is important in medical care, as it is in any matter of importance to humans or our environment. Consider then that by eliminating fossil fuels, the recipient of medical care (all of us) is being asked to submit to what amounts to an economic heart transplant. According to most patient bills of rights, the patient has a strong say in the treatment decision. Natural questions from the patient are whether a heart transplant is really needed, and how successful the diagnostic team has been in the past.
The letter goes on make it clear that the "concerned scientists" are unimpressed with the would-be climate clinicians diagnostic record:
In this respect, an important gauge of scientific expertise is the ability to make successful predictions. When predictions fail, we say the theory is "falsified" and we should look for the reasons for the failure. Shown in the nearby graph is the measured annual temperature of the earth since 1989, just before the first report of the Intergovernmental Panel on Climate Change (IPCC). Also shown are the projections of the likely increase of temperature, as published in the Summaries of each of the four IPCC reports, the first in the year 1990 and the last in the year 2007.
These projections were based on IPCC computer models of how increased atmospheric CO2 should warm the earth. Some of the models predict higher or lower rates of warming, but the projections shown in the graph and their extensions into the distant future are the basis of most studies of environmental effects and mitigation policy options. Year-to-year fluctuations and discrepancies are unimportant; longer-term trends are significant.
From the graph it appears that the projections exaggerate, substantially, the response of the earth's temperature to CO2 which increased by about 11% from 1989 through 2011. Furthermore, when one examines the historical temperature record throughout the 20th century and into the 21st, the data strongly suggest a much lower CO2 effect than almost all models calculate.
The Trenberth letter tells us that "computer models have recently shown that during periods when there is a smaller increase of surface temperatures, warming is occurring elsewhere in the climate system, typically in the deep ocean." The ARGO system of diving buoys is providing increasingly reliable data on the temperature of the upper layers of the ocean, where much of any heat from global warming must reside. But much like the surface temperature shown in the graph, the heat content of the upper layers of the world's oceans is not increasing nearly as fast as IPCC models predict, perhaps not increasing at all. Why should we now believe exaggerating IPCC models that tell us of "missing heat" hiding in the one place where it cannot yet be reliably measured—the deep ocean?
Given this dubious track record of prediction, it is entirely reasonable to ask for a second opinion. We have offered ours.
Much of the rest of the letter from the 16 "concerned scientists" is devoted to their description of what they regard as the political chicanery that has engulfed both climate science and public policy discussions of how to address climate change. It's well worth reading.
For more background on the debate over actual global temperature trends see my January 13 post, Skeptic Wins Global Warming Bet.
*What each side calls the other.