Readers may recall a letter published in the Wall Street Journal (WSJ) in January 2012, signed by 16 climate contrarians, which we dubbed The Latest Denialist Plea for Climate Change Inaction.

Roger Cohen, William Happer, and Richard Lindzen (hereafter CHL) were 3 of the 16 signatories on that letter, and have published yet another in the WSJ a mere 7 months later. As we noted at the time, neither Happer nor Cohen has a single climate science publication to his name, while Happer is a member of two fossil fuel-funded climate denialist think tanks (George C. Marshall Institute and Global Warming Policy Foundation) and Cohen is a George C. Marshall Institute ‘expert’ who has previously worked for ExxonMobil. Richard Lindzen is of course a climate scientist, but quite possibly the most consistently wrong climate scientist on climate issues on the planet.

Suffice it to say that CHL do not have a great deal of credibility on climate science issues, which is perhaps why they continue to publish their opinions in the conservative mainstream media rather than subjecting their arguments to the scientific peer-review process. As we saw in January, the first WSJ letter was little more than a compilation of many long-debunked climate myths, and the quality of their arguments has not improved much in their second attempt. In fact the two letters bear some striking resemblances, for example both citing the climate opinions of Ivar Giaever, who we have previously seen has not even done the most basic climate science research.

In this post we will examine the claims made in the latest WSJ letter from CHL, with one in particular standing out above the rest.

WSJ – Home of the Whopper

Just last month we looked at a paper by Lindzen and Choi (2011) (LC11), which claimed to provide evidence for a climate sensitivity of less than 1°C, meaning that if the amount of CO2 in the atmosphere doubles, Lindzen argues that the average global surface temperature will only warm a total of <1°C in response.

As we discussed at the time, subsequent research has identified a number of fundamental errors in LC11 which have not been addressed, and in addition, virtually all other research using many different lines of evidence finds that climate sensitivity is very likely between 2 and 4.5°C for doubled CO2. At the time, we also noted that arguments for climate sensitivity <1°C depend entirely on LC11, because there has simply been little if any other scientific research in recent years finding such extreme low outlier sensitivity values.

“Since the body of research using multiple different approaches and lines of evidence is remarkably consistent in finding an equilibrium climate sensitivity of between 2 and 4.5°C for doubled CO2 (whereas a ‘low’ sensitivity would be well below 1.5°C), climate contrarians…attempt to replace it with this single study by Lindzen and Choi”

As if they were reading our post when they penned their WSJ article, this is precisely what CHL have done, claiming:

“It is increasingly clear that doubling CO2 is unlikely to increase global temperature more than about one degree Celsius, not the much larger values touted by the global warming establishment.”

How is this “increasingly clear”? The beauty of publishing an article in the mainstream media is that providing supporting evidence is unnecessary – the reader is expected to simply take CHL’s word for it. We can only assume that this ‘increasing evidence’ refers to the increase from essentially zero studies finding such extremely low climate sensitivity, to one fundamentally flawed study (LC11). While this can perhaps be construed as “increasing” evidence, it is hardly a strong or convincing case.

Extreme Weather Obfuscation, Again

Denying the link between climate change and extreme weather events is becoming a common exercise amongst climate contrarians, for example John Christy, Roger Pielke Jr., and Steve McIntyre. CHL join the extreme weather obfuscation party, and in fact refer to John Christy’s myth and misinformation-filled congressional testimony on the subject as “measured and informative” in the process. Perhaps they meant to say “misinformative.”

Their comments on the issue are in response to a previous WSJ article by Environmental Defense Fund President Fred Krupp, in which Krupp asserted:


“One scorching summer doesn’t confirm that climate change is real any more than a white Christmas proves it’s a hoax. What matters is the trend—a decades-long march toward hotter and wilder weather. But with more than 26,000 heat records broken in the last 12 months and pervasive drought turning nearly half of all U.S. counties into federal disaster areas, many data-driven climate skeptics are reassessing the issue.”

This was a perfectly reasonable and accurate opening to Krupp’s article, but CHL take issue with his measured words, describing them in less than flattering terms:

“Despite shrill claims of new record highs, when we look at record highs for temperature measurement stations that have existed long enough to have a meaningful history, there is no trend in the number of extreme high temperatures, neither regionally nor continentally. We do see the Dust Bowl years of the 1930s setting the largest number of record highs, at a time when it is acknowledged that humans had negligible effect on climate.”

They proceed to list several types of extreme weather events which they proclaim have shown no long-term trend. However, as we have documented, the link between climate change and many types of extreme weather has already been documented in the peer-reviewed literature. Here are just a few examples regarding precipitation, drought, and extreme heat.

Min et al. (2011):

“Here we show that human-induced increases in greenhouse gases have contributed to the observed intensification of heavy precipitation events found over approximately two-thirds of data-covered parts of Northern Hemisphere land areas.”

Dai et al. (2011):

“All the four forms of the PDSI show widespread drying over Africa, East and South Asia, and other areas from 1950 to 2008, and most of this drying is due to recent warming. The global percentage of dry areas has increased by about 1.74% (of global land area) per decade from 1950 to 2008.”

Zwiers et al. (2011):

“Therefore, it is concluded that the influence of anthropogenic forcing has had a detectable influence on extreme temperatures that have impacts on human society and natural systems at global and regional scales”

We also recently discussed Hansen et al. (2012), which showed that heat waves have already become both more intense and more frequent as a result of global warming. This is true on a global scale, on a hemispheric scale, and even just for the United States, although to a lesser degree (Figure 1).

Figure 1: Percent area covered by temperature anomalies in categories defined as hot (>0.43σ), very hot (>2σ), and extremely hot (>3σ). Anomalies are relative to 1951–1980 base period; σ is from 1951–1980 data.

As this figure shows, if we split summers from 1951 to 1980 evenly into ‘cold’, ‘moderate’, and ‘warm’ such that each occurred 33% of the time, we are now experiencing cold summers just 10% of the time and warm summers ~75% of the time, globally. However, this shift toward hot summers and heat waves doesn’t occur uniformly over the whole planet’s surface. CHL are correct to note that the USA experienced similarly hot conditions during the Dust Bowl 1930s, which Hansen et al. discuss explicitly in their paper:

“Temperature anomalies are “noisy” for the United States because of the small area of the contiguous 48 states (less than 1.6% of the globe), yet we can discern that the long-term trend toward hot summers is not as pronounced in the United States as it is for hemispheric land as a whole. Indeed, the extreme summer heat of the 1930s, especially 1934 and 1936, is comparable to the United States temperature in the most extreme recent years.

The large 1930s and 1940s anomalies in the United States do not obviate the conclusion that recent global warming, with high probability, is responsible for recent extreme anomalies.”

Despite the local warm period in the USA in the 1930s, there is still a clear long-term trend toward hotter summer temperatures in the middle frame of Figure 1. Additionally, the USA does not exist in a bubble. Our CO2 emissions are mixed throughout the atmosphere and thus impact the global climate; thus we cannot simply consider changes in our own climate while ignoring changes throughout the rest of the world, as CHL do. The global trend toward more frequent and intense heat waves is abundantly clear in this animation based on the results of Hansen et al. (2012).

More CO2 is Good for Plants? Really?

CHL proceed to repeat the grossly oversimplified myth that more CO2 is good for plants:

“CO2 levels are below the optimum levels for most plants, and there are persuasive arguments that the mild warming and increased agricultural yields from doubling CO2 will be an overall benefit for humanity.”

Given the recent climate impacts on wheat in Russia and corn in the United States, for example, this contrarian argument is a rather large pill to swallow. Quite simply, CO2 is not the only factor influencing plant growth. In fact side effects of increasing atmospheric CO2, like more heat waves and droughts, are far more important for crop growth than CO2 concentration. And as Dai (2010) showed, droughts are expected to become more common in a warming world, including in the USA (Figure 2 below).

Future drought. These four maps illustrate the potential for future drought worldwide over the decades indicated, based on current projections of future greenhouse gas emissions. These maps are not intended as forecasts, since the actual course of projected greenhouse gas emissions as well as natural climate variations could alter the drought patterns.

The maps use a common measure, the Palmer Drought Severity Index, which assigns positive numbers when conditions are unusually wet for a particular region, and negative numbers when conditions are unusually dry. A reading of -4 or below is considered extreme drought. Regions that are blue or green will likely be at lower risk of drought, while those in the red and purple spectrum could face more unusually extreme drought conditions.

For perspective, here is the PDSI map for the USA in July 2012, which produced the agricultural-crippling drought in the midwestern states.

Figure 3: PDSI for the USA in July 2012 (NCDC)

Note that dark red in Figure 3 corresponds to a PDSI of -4 and below, which corresponds to red in Figure 2. This current level of agriculture-crippling extreme drought is projected to become the norm in the USA just two decades from now, and drought intensity will only grow worse thereafter. Dai was recently interviewed by Andrew Revkin at the New York Times and noted that we’ve been lucky in the USA not to have experienced a lot of drought in recent decades, but that our luck on this front is unlikely to continue (emphasis added):

“In essence, I think the U.S. has been very fortunate to have experienced a wetting trend from the 1950s to the 1990s, in contrast to many other low- and mid-latitude land areas. However, this luck is about to run out, because the tropical Pacific sea surface temperatures apparently switched into a cold phase around 1999 that typically lasts for 20-30 years and brings below-normal precipitation and drought over much of the West and southern U.S. On top of that, the greenhouse-gas-induced global warming is predicted to cause severe drying in the coming decades over the U.S. Even if the tropical Pacific condition changes after 1-2 decades into a warm phase, the U.S. is unlikely to return [to] the wet conditions of the 1977-1999 because of the expected large drying from global warming.”

Yet CHL would have us believe that plants will benefit from more atmospheric CO2?

Contrarians Should Take their Own Advice

CHL did actually provide some useful advice in their article, for example:

“Whether increasing CO2 in the atmosphere is bad or good is a question of science. And in science, truth and facts are not the playthings of causes, nor a touchstone of political correctness, nor true religion, nor ‘what I tell you three times is true.’”

Despite these wise words, the contrarians expect us to do exactly that – accept the myths they are peddling because they keep repeating them over and over again in the mainstream media, each time with zero supporting evidence. Indeed whether increasing CO2 is good or bad is a question of science, and the scientific evidence clearly indicates that it is bad. If these contrarians believe otherwise, they should subject their evidence to the scientific peer-review process rather than publishing unsupported myths in the public sphere. The contrarians conclude their article saying:

“Let us debate and deal with serious, real problems facing our society, not elaborately orchestrated, phony ones…”

Again we entirely agree with this sentiment, and there is no more serious or real problem facing our society than human-caused climate change. CHL of course finish the quoted sentence by denying this reality, but they have provided no credible evidence why we should share their denial.