Topic: Energy and Environment

Current Wisdom: U.S. Precipitation Changes and Climate Model Expectations—If It Doesn’t Fit, You Must Acquit

The Current Wisdom is a series of monthly articles in which Patrick J. Michaels, director of the Center for the Study of Science, reviews interesting items on global warming in the scientific literature that may not have received the media attention that they deserved, or have been misinterpreted in the popular press.

In this Current Wisdom we report further on our ongoing effort to prepare comments on the latest, greatest (or, more aptly, most recent, most indecent) edition of the government’s assessment of climate change impacts in the United States (if you are interested in submitting your own comments, you should hurry, because the public comment period closes on this Friday, April 12).

A disturbing yet ubiquitous aspect of the current draft National Climate Assessment (and for that matter, both earlier editions of the NCA) is the use of future projections of climate change before demonstrating that they work in the recent past, as greenhouse-gas concentrations have increased.

Discussions of future impacts from changes in precipitation resulting from human emissions of greenhouse gases are everywhere in the report and they are usually bad—increased droughts, floods, and longer dry spells, for example.  The NCA folks weren’t quite so enthusiastic at generating many forecasts of salutary changes.  Perhaps Dr. Pangloss is their spiritual adviser. 

NCA’s precipitation forecasts turn out to be uglier than Candide’s fair Cunegonde became.  Do  the models accurately simulate past changes that have been observed? If the answer is “no,” then the whole impact exercise is meaningless because the models provide no reliable information about what the future may bring.

The answer isn’t just “no.” It’s NO, NON, ONAY, NEIN.

Getting Our Due

In the Diary feature of this week’s The Spectator, rational optimist Matt Ridley has a collection of rather random observations from his daily life that have him thinking about (or maybe wishing for since Old Man Winter has been slow to loose his grip in the U.K. and Western Europe, much like he has across the Eastern U.S.) anthropogenic global warming.

What has his attention is that global warming just doesn’t seem to be going according to plan. And for those who have bought into that plan, their plan-driven actions are starting to make them look foolish.

But it’s not as if we haven’t “told you so”—a fact that Ridley draws attention to in the closing segment of his article.

David Rose of the Mail on Sunday was vilified for saying that there’s been no global warming for about 16 years, but even the head of the Intergovernmental Panel on Climate Change [IPCC] now admits he’s right. Rose is also excoriated for drawing attention to papers which find that climate sensitivity to carbon dioxide is much lower than thought — as was I when I made the same point in the Wall Street Journal. Yet even the Economist has now conceded this. Tip your hat to Patrick Michaels, then of the University of Virginia, who together with three colleagues published a carefully argued estimate of climate sensitivity in 2002. For having the temerity to say they thought ‘21st-century warming will be modest’, Michaels was ostracised. A campaign began behind the scenes to fire the editor of the journal that published the paper, Chris de Freitas. Yet Michaels’s central estimate of climate sensitivity agrees well with recent studies. Scientists can behave remarkably like priests at times.

What we determined in our 2002 study was that the amount of global warming projected by the end of this century was most likely being overestimated.  When we adjusted the climate model projections to take into account and better match the actual observations, our best estimate of the amount of warming we expected from 1990 to 2100 was about 1.8°C (3.2°F), which was in the lower end of the IPCC projected range, and which Ridley correctly noted, we termed as “modest.”

Further, we anticipated the slowdown in the warming rate. Quoting from our 2002 paper titled “Revised 21st century temperature projections” (Michaels et al., 2002):

The ‘worst case’ warming now appears to be merely linear, subject to the modifications described in this paper. Furthermore, both Table 1 and Fig. 3 indicate that any exponential rise in atmospheric CO2 concentrations is weak at best. Consequently, the current linear warming may in fact be the adjustment to the exponential growth in CO2 that took place prior to 1975. Levitus et al. (2000) documented a warming of 0.06°C in the top 3 km of a large-area ocean sample over the course of 40 yr. A lag correlation between that deep-water record and the sea-surface temperature record from Quayle et al. (1999) is very suggestive that oceanic thermal lag maximizes around 35 yr (Michaels et al. 2001). Thus, the truly exponential phase of concentration growth in the atmosphere, which ended about 25 yr ago, should induce a linear warming for the next decade or two before it could actually begin to damp.

Now, more than 10 years later, more and more evidence is piling in that we were right, including several recent papers that apply a technique not all that dissimilar in theory than our own (e.g. Gillett et al., 2012; Stott et al., 2013).

So even though we still are largely ostracized, at least we rest assured that we were pretty much on target—and some people are starting to take notice.


Gillett N. P., V. K. Arora, G. M. Flato, J. F.  Scinocca, and K. von Salzen, 2012. Improved constraints on 21st-century warming derived using 160 years of temperature observations. Geophysical Research Letters, 39, L01704.

Michaels, P. J., P. C. Knappenberger, O. W. Frauenfeld, and R. E. Davis, 2002. Revised 21st century temperature projections. Climate Research, 23, 1-9.

Stott, P., P. Good, G. Jones, N. Gillett, and E. Hawkins, 2013. The upper end of climate model temperature projections is inconsistent with past warming. Environmental Research Letters, 8, 014024, doi:10.1088/1748-9326/8/1/014024.

Burning Books, Burning Witches, Burning Corn

Global Science Report is a weekly feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.”


History is littered with ideology gone awry.

The most recent example? Burning corn as a substitute for fossil fuels in an effort to mitigate anthropogenic climate change (which supposedly has a negative impact on the production of crops such as corn).

This is about as logical as publicity-stunt burnings of Harry Potter books because of objections to the contents within, which only results in more people buying and reading the books to find out what got the book-burners so inflamed in the first place.

With Harry Potter it was the fantasy world of witchcraft and wizardry. With corn ethanol it is the fantasy world of agriculturally damaging climate change.

A few years ago, a paper was published in the prominent scientific journal Science by Stanford’s David Lobell and colleagues that reported that human-caused global warming over the past 30 years resulted in a slowdown in global crop production. Modeling the climate response of the world’s four largest commodity crops—corn, rice, wheat, and soybeans—Lobell’s team calculated that as a result of rising temperatures and precipitation changes, global crop production was about 3 percent less than it otherwise would have been.

But consider this: The United States produces about 36 percent of the world’s corn. And about 40 percent of U.S. corn is used to produce ethanol for use as a gasoline substitute in an attempt to lower net carbon dioxide emissions from driving and reduce climate change. Globally, corn makes up 30 percent of total worldwide production of the four crops studied by Lobell’s group.

Multiply all these percentages out, and you get that the United States is burning a bit more than 4 percent of global crop production in an attempt to mitigate a climate-driven loss of 3 percent of the global crop production.

Rare “It’s Not as Bad as We Thought” Finding Published

Global Science Report is a weekly feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.

From the authors of a new paper just-published in the journal Nature Geoscience comes this surprising finding:

Tropical forests are less likely to lose biomass – plants and plant material – in response to greenhouse gas emissions over the twenty-first century than may previously have been thought.

A rare “not as bad as we thought” admission about the impacts of manmade global warming!

Not only that, but based on recent findings that the true climate sensitivity is much lower than climate models emulate—findings not incorporated in new study—the results are probably still even more “not as bad as they thought” than they thought!

Chris Huntingford from the U.K’s Centre for Ecology & Hydrology and colleagues coupled climate model projections to a land surface/vegetation model to see how the tropical forests in the Americas, Africa, and Asia respond to changes in atmospheric conditions. Their vegetation model includes interactions between terrestrial plants and influences such as temperature, precipitation, and the carbon dioxide concentration of the atmosphere (a plant fertilizer).

Unlike other studies which used a very limited selection of climate models and less sophisticated vegetation models, the Huntingford team found that in virtually all future simulations that the biomass of tropical forests increases over the course of the 21st century. This is a significantly different result than many previous which suggested that anthropogenic climate change would lead to, as Huntingford et al. put it, “catastrophic losses of forest cover and biomass.”

Perhaps most interestingly, the major driver for the biomass increase is the projected growth in atmospheric carbon dioxide concentration (thanks to our use of fossil fuels). The model projected changes in precipitation had little impact on the biomass predictions and the projected increase in temperature acted to decrease the biomass (although not as much as additional carbon dioxide acted to increase it).

Which is why the results probably get even better if there is less warming associated with carbon dioxide emissions than current generation climate models predict (new research suggest that climate models together produce about 50% more warming than they should).

The authors are quick to mention that uncertainty abounds, as our level of understanding of forest response to changing environmental conditions is not all that high. But even given these uncertainties, the authors are confident that their results of increasing biomass are robust. Here is how Huntingford described the situation in a press release:

The big surprise in our analysis is that uncertainties in ecological models of the rainforest are significantly larger than uncertainties from differences in climate projections. Despite this we conclude that based on current knowledge of expected climate change and ecological response, there is evidence of forest resilience for the Americas (Amazonia and Central America), Africa and Asia.

Resilience. A refreshingly honest assessment of an ecosystem response to climate change. And one that is probably a much more apt descriptor of natural systems than “delicate,” “sensitive,” or “fragile.”

Now if only the folks in charge of assembling national and international climate impact assessments would realize (or probably more accurately, admit to) this.

We are hard at work trying to focus their attention as we are vigorously reviewing the latest draft “National Assessment” of climate change.  We will leak out particularly juicy snippets in these pages when the time seems right.


Huntingford, C. et al., 2013. Simulated resilience of tropical rainforests to CO2-induced climate change, Nature Geoscience, 10.1038/NGEO1741.

Government Science

We started up Cato’s Center for the Study of Science to investigate how the government’s virtual monopoly funding of many branches of science results in unseemly mixtures of science, scientists, and the political process.

Lest anyone wonder why we do this, here is the “motto” of the U.S. government’s Global Change Research Program (with its annual $2.6 billion budget):

“Thirteen Agencies, One Vision: Empower the Nation with Global Change Science”


We are currently in the midst of reviewing the latest offering from the USGCRP—its assessment of the potential impacts in the U.S. from anthropogenic climate change. Guess what, “it’s worse than we thought!”

Nevermind that this new document has no problems using screeds from the Union of Concerned Scientists, various climate “alliances,” and literature greyer than a Russian Blue cat, in support of some of its more lurid claims. After all, the USGCRP has a “vision.”

Speaking of vision, if you want to look for yourself, download this turkey here. Public comments due by April 12, 2013.

Transit Ridership Falls Since 2008

The lies begin right in the headline of the American Public Transportation Association’s annual press release patting the industry on the back for carrying heavily subsidized riders last year. “Record 10.5 Billion Trips Taken On U.S. Public Transportation In 2012,” claims the press release headline.

The text reveals that it wasn’t actually a record at all, but merely the “second-highest ridership since 1957.” When was the first highest? In 2008, meaning the headline would have been more accurate if it had read, “Transit Ridership Falls Since 2008.”

Of course, as a lobby group, APTA is paid to promote the transit industry. Reporters are also paid to see through lobbyists’ lies, but unfortunately many of them simply modestly rewrite the press release while others add their own questionable analyses.

Source: Auto driving is from the Federal Highway Administration’s Highway Statistics series, while the transit numbers are from APTA’s own Public Transportation Fact Book.

Anti-auto writers gleefully report that transit ridership is growing faster than driving. While it is true that urban driving has stagnated since the 2008 financial crisis, the chart above shows that transit has a long way to go to catch up with driving. (Note that DC Streets Blog reports on total driving, while I use urban driving, which is a better comparison with urban transit.)

In 2012, transit carried about 1.8 percent of motorized urban passenger miles, which is about what transit’s share of urban passenger miles has been, plus or minus 0.1 percent, since 1993. Before then, it was 2.1 percent in 1990, 3.1 percent in 1980, and 4.7 percent in 1970. The roughly half a trillion dollars spent subsidizing transit since 1970 hasn’t done much good.

Another point APTA carefully neglects to mention is that urban population growth is the main source of transit ridership growth. Transit carried about 44 trips per urban resident in 2012, which is about what it has been, plus or minus 1 trip, since 2005. Prior to that, they grew since 1995, when they were just 38, but steadily shrank before then. In 1990, there were 47 trips per capita and in 1980 there were 51.

The press release also reports that the fastest growing form of transit is light rail. But it neglects to mention that that is mainly because of new construction. In fact, the miles of rail are growing far faster than rail riders.

In 1994, light rail carried more than 500,000 trips per route mile. By 1999 this had fallen below 400,000 trips per mile; by 2012 it was down to 300,000 trips per mile. With rising construction costs and falling ridership per mile, light rail is suffering from some seriously diminishing returns.

It is certainly reasonable to ask whether the stagnation of urban driving is a trend or simply a reflection of the recession and high unemployment rates among young people. But it is not reasonable to think that transit is providing an adequate substitute for urban driving.

According to the Federal Highway Administration’s traffic volume trends, urban driving declined by 11 billion vehicle miles between 2007 and 2012. Considering average occupancy rates, that’s roughly 16 billion passenger miles. In that time period, urban transit gained about 3 billion passenger miles, all of them between 2007 and 2008. To the extent that people really are driving less, it is more because they are traveling less than that they are riding transit more.

Did Global Warming Prevent a Record-Breaking D.C. Snowstorm?

Global Science Report is a weekly feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.”

We haven’t seen any media stories relating global warming to the Wednesday’s weather in D.C.

We are certain that this would not have been the case had more than 11.5 inches of snow accumulated at Reagan National Airport, as it would have set the District’s all-time daily March snowfall record. Exceeding 8.5 inches would have set the record daily March snowfall observed at DCA (an accumulation well within the forecast range) and would probably have generated some global warming comments (after all, they were already waiting in the wings).

Is it only us, or does it seem that postmortem analyses of weather events only include the “consistent with human-caused global warming” meme when the event caused harm and suffering?

If our pernicious industrial activity impacts “extreme” weather, doesn’t it impact the non-extreme as well?

Despite what the global warming alarmists would like you to believe, there are a lot more of the latter than the former!

So was Wednesday’s non-record-breaking non-extreme non-snowstorm in D.C. “consistent with global warming?”

The simple answer: sure!

The temperature was just a wee bit too high for the snow to stick. And human emissions of greenhouse gases have caused a wee bit of temperature rise. Voila! Consistency.