In a fiery speech yesterday, Sen. Sheldon Whitehouse (D-R.I.) ”calls out” “climate deniers.” In the first half of the speech he goes ad hominem, attacking opponents as “front groups” who take payola from “polluters” to “confuse” the public by selling “doubt” as their product.

First a bit of free advice for the good Senator:

Your team has been playing nasty from day one. It didn’t get you cap-and-trade, it didn’t get you Senate ratification of the Kyoto Protocol, and it’s not going to get you a carbon tax.  

Vilification doesn’t work because biomass, wind turbines, and solar panels are not up to the challenge of powering a modern economy, and most Americans are too practical to believe otherwise.

So by all means, keep talking trash about your opponents. The shriller your rhetoric, the more skeptical the public will become about your bona fides as an honest broker of “the science.”

Okay, let’s examine Sen. Whitehouse’s argument. He accuses skeptics of peddling “straw man arguments,” such as that “the earth’s climate always changes; it’s been warmer in the past.” Well, it does, and it has! Many studies indicate the Medieval Warm Period (MWP) was warmer than the current warm period (CWP). A study published in July in Nature Climate Change concludes the Roman Warm Period (RWP) was warmer than both the MWP and CWP. The Northern Hemisphere was substantially warmer than the present for thousands of years during the Holocene Climate Optimum (~5,000-9,000 years ago). Arctic summer air temperatures were 4-5°C above present temperatures for millennia during the previous interglacial period.

None of this is evidence man-made global warming is not occurring, but Sen. Whitehouse sets up his own straw man by making that the main issue in dispute. What the paleoclimate information does indicate is that the warmth of the past 50 years is not outside the range of natural variability and is no cause for alarm. The greater-than-present warmth of the Holocene Optimum, RWP, and MWP contributed to improvements in human health and welfare. 

Sen. Whitehouse says skeptics also knock down a straw man when they deny extreme weather events prove the reality of climate change. “No credible source is arguing that extreme weather events are proof of climate change,” he states. Again, it’s Sen. Whitehouse who whacks a man of straw. The problem for skeptics is not that people like Al Gore or the editors of Bloomberg cite Hurricanes Katrina or Sandy as “proof” of global warming, it’s that they blame global warming (hence “polluters”) for Katrina and Sandy. They insinuate or even assert that were it not for climate change, such events would not occur or would be much less deadly. As the Senator does when he says climate change ”loads the dice” in favor of events like Sandy and is “associated with” such events.

I freely grant that heat waves will become more frequent and severe in a warmer world (just as cold spells will become less frequent and milder). However, there is no persuasive evidence global warming caused or contributed significantly to the European heat wave of 2003, the Russian heat wave of 2010, the Texas drought of 2011, or the U.S. midwest drought of 2012. A slew of scientific papers finds no long-term trend in Atlantic hurricane behavior, including a recent study based on 370 years of tropical cyclone data. Similarly, a U.S. Geological Survey study finds no correlation between flood magnitudes and atmospheric carbon dioxide (CO2) concentrations in any region of the continental U.S. over the past 85 years.

More importantly, despite long-term increases in both CO2 concentrations and global temperatures since the 1920s, global deaths and death rates related to extreme weather declined by 93% and 98% respectively. The 93% reduction in annual weather-related deaths is particularly noteworthy because global population increased more than 300% since the 1920s.

Although weather-related damages are much bigger today, that is because there’s tons more stuff and lots more people in harm’s way. For example, more people live in just two Florida counties, Dade and Broward, than lived in all 109 coastal counties stretching from Texas to Virginia in the 1930s. When weather-related damages are adjusted (“normalized”) to account for changes in population, wealth, and inflation, there is no long-term trend. So although a “greenhouse signal” may some day emerge from weather-related mortality and economic loss data, at this point global warming’s influence, if any, is undetectable.

Sen. Whitehouse dismisses as a “gimmick” skeptics’ observation that there has been “no warming trend in the last ten years” (actually, the last 16 years).  He contends that the 20 warmest years in the instrumental record have occurred since 1981 ”with all 10 of the warmest years occurring in the past 12 years.” That may be correct, but it is beside the point. A decade and a half of no net warming continues the plodding 0.14°C per decade warming trend of the past 33 years. These data call into question the climate sensitivity assumptions underpinning the big scary warming projections popularized by NASA scientist James Hansen, the UN IPCC, and the UK Government’s Stern Review report.

Sen. Whitehouse says ”deniers tend to ignore facts they can’t explain away.” He continues: “For example, the increasing acidification of the oceans is simple to measure and undeniably, chemically linked to carbon concentrations in the atmosphere. So we hear nothing about ocean acidification from the deniers.” Not so. CO2Science.Org, a leading skeptical Web site, has an extensive (and growing) ocean acidification database. Almost every week the CO2Science folks review another study on the subject. Cato Institute scholars Patrick Michaels and Chip Knappenberger also addressed the issue on their old Web site, World Climate Report. They don’t share Sen. Whitehouse’s alarm about ocean acidification, but they do not ignore it. The Senator should check his facts before casting aspersions.

Sen. Whitehouse quotes NOAA stating that the rate of global sea level rise in the last decade “was nearly double” the 20th century rate. That is debatable. Colorado State University researchers find no warming-related acceleration in sea-level rise in recent decades.

Here’s the big picture. Scary projections of rapid sea-level rise assume rapid increases in ice loss from Greenland. In a study just published in Proceedings of the National Academy of Sciences, scientists used satellite gravity data to measure changes in Greenland’s ice mass balance from April 2002 to August 2011. The researchers estimate Greenland is losing almost 200 gigatons of ice per year. It takes 300 gigatons of water to raise sea levels by 1 millimeter, so Greenland is currently contributing about 0.66 mm of sea-level rise per year. At that rate, Greenland will contribute 6.6 centimeters of sea level rise over the 21st century, or less than 3 inches. Apocalypse not.

Sen. Whitehouse concludes by castigating Republicans for inveighing against unchecked entitlement spending and the fiscal burdens it imposes on “our children and grandchildren” while turning a blind eye to the perils climate change inflicts on future generations. But such behavior is not contradictory if the risk of fiscal chaos is both (a) more real and imminent than Al Gore’s “planetary emergency” and (b) more fixable within the policy-relevant future.

Here are two facts Sen. Whitehouse should contemplate. First, even if the U.S. were to stop emitting all CO2 tomorrow, the impact on global temperatures would be a reduction of “approximately 0.08°C by the year 2050 and 0.17°C by the year 2100 — amounts that are, for all intents and purposes, negligible,” notes Chip Knappenberger, whose calculations are based on IPCC climate sensitivity assumptions. Similarly, a study in Nature Climate Change concludes that aggressive climate change ”mitigation measures, even an abrupt switch to zero emissions, have practically no effect on sea level over the coming 50 years and only a moderate effect on sea level by 2100.”

Whether under a carbon tax, cap-and-trade, or EPA regulation, the U.S. would keep emitting billions of tons of CO2 annually for a long time. So whatever climate policies Sen. Whitehouse thinks Republicans should support would have no discernible impact on climate change risk. The costs of such policies would vastly exceed the benefits. Rejecting policies that are all pain for no gain is exactly what the custodians of America’s economic future are supposed to do.

In a recent study published in Procedings of the National Academy of Sciences (PNAS), NASA scientist James Hansen and two colleagues find that whereas “extremely hot” summer weather ”practically did not exist” during 1951-1980, such weather affected between 4% and 13% of the Northern Hemisphere land area during 2006-2011. The researchers infer that human-caused global warming is “loading” the “climate dice” towards extreme heat anomalies. They conclude with a “high degree of confidence” that the 2003 European heat wave, the 2010 Russian heat wave, and the 2011 Texas-Oklahoma drought were a “consequence of global warming” and have (as Hansen put it in a recent op-ed) ”virtually no explanation other than climate change.”

In a recent post, I reviewed studies finding that the aforementioned anomalies were chiefly due to natural variability. In another post, I summarized an analysis by Patrick Michaels and Chip Knappenberger, who conclude that “the 2012 drought conditions, and every other [U.S.] drought that has come before, is the result of natural processes, not human greenhouse gas emissions.”

But what about the very hot weather afflicting much of the U.S. this summer? Greenhouse gas concentrations keep rising, heat spells are bound to become more frequent and severe as the world warms, and the National Oceanic and Atmospheric Administration (NOAA) reports that July 2012 was the hottest July ever in the U.S. instrumental record. Isn’t this summer what greenhouse warming “looks like“? What else could it be?

University of Alabama in Huntsville (UAH) climatologist John Christy addressed these questions last week in a two-part column. In Part 1, Christy argues that U.S. daily mean temperature (TMean) data, on which NOAA based its report, ”do not represent the deep atmosphere where the enhanced greenhouse effect should be detected, so making claims about causes is unwise.” A better measure of the greenhouse effect is daily maximum temperature (TMax), and TMax records set in the 1930s remain unbroken. In Part 2, Christy argues that Hansen’s 10% estimate of the portion of land affected by extreme heat during 2006-2011 shrinks down to 2.9% when anomalies are measured against a longer, more representative climate baseline. 

NOAA’s claim that July 2012 was the hottest July ever is based on daily mean temperature (TMean) data. TMean is the average of daytime maximum temperature and nighttime minimum temperature (TMax + TMin/2). Whereas TMax “represents the temperature of a well-mixed lower tropospheric layer, especially in summer,” TMin “can warm over time due to an increase in turbulent mixing” near the surface. Land use changes such as urbanization, agriculture, and forestry tend to disrupt the natural formation of a shallow layer of cool nighttime air. There has been a lot of population growth and development in the U.S. since 1980, the last year of Hansen’s baseline period. Not coincidentally, most of the surface warming in the U.S. during the past three decades has been in TMin rather than TMax (see second graph below).

The point? TMin warming is not primarily due to the accumulation of heat in the deep atmosphere (i.e. the greenhouse effect). Consequently, averaging TMin with TMax produces a composite (TMean) that inflates the appearance of the greenhouse effect.

Christy’s colleague Roy Spencer produced a chart of TMax using the same weather stations as NOAA. Spencer found that July 2012 was very hot, but not as hot as the summers of 1936 and 1934. More importantly, far more all-time TMax records were set in the 1930s than in any recent decade.

In contrast, about as many TMin records were set in recent years as in the 1930s.

Christy comments:

There has been a relatively steady rise in high TMin records (i.e. hot nights) which does not concur with TMax, and is further evidence that TMax and TMin are not measuring the same thing. They really are apples and oranges. As indicated above, TMin is a poor proxy for atmospheric heat content, and it inflicts this problem on the popular TMean temperature record which is then a poor proxy for greenhouse warming too.

Although TMax is a better proxy than TMin for the greenhouse effect, only satellites can provide “direct and robust” measurements of the heat content of the global atmosphere. UAH satellite data do show that the Earth has been in a long-term warming trend (+ 0.14°C per decade since November 1978). However, the data also show that July 2012 was not the hottest July in the 34-year satellite record either for the continental U.S., the Northern Hemisphere, or the world.

Christy finds two main weaknesses in Hansen’s study. First, it assumes that changes in TMean accurately represent the effect of extra greenhouse gases. Second, it assumes that the distribution (bell curve) of weather anomalies during single 30-year period (1951-1980) represents natural climate variability over the past 10,000 years or so.

As discussed above, TMean “misrepresents the response of the climate system to extra greenhouse gases.” So Christy uses TMax data to estimate trends in hot weather anomalies. In addition, he calculated the spatial extent of North Hemisphere extreme heat anomalies during 2006-2011 using both Hansen’s baseline (1951-1980) and a somewhat longer baseline that includes the 1930s and 1940s (1931-1980). Christy’s results are much less dramatic than Hansen’s.

In the figure above, the top line (black-filled circles) shows the percentage of the Northern Hemisphere land area that the Hansen team calculated to have experienced anomalously high heat during 2006-2011. The next line (gray-filled circles) assumes the same base period (1951-1980) for gauging anomalies, but uses TMax from the quality-controlled Berkeley Earth Surface Temperature (BEST) station data. Although the “correlation between the two is high,” the spatial coverage drops by more than half, ”from Hansen’s 6-year average of 12 percent to this analysis at 5 percent.”

The third line (open circles) gauges TMax anomalies in 2oo6-2011 against a 1931-1980 baseline. The result is that 2.9% of the Northern Hemisphere land area experienced extreme heat anomalies — about a quarter of the Hansen team’s results. “In other words,” says Christy, ”the results change quite a bit simply by widening the window back into a period with even less greenhouse forcing for an acceptable base-climate.”

The lowest line (open boxes) uses an 80-year baseline (1931-2010) to identify extreme hot weather anomalies during 2006-2011. In this case, only 1.3% of the land surface in 2006-2011 experienced anomalously high heat.

One might object that the 80-year baseline includes the most recent 30 years of greenhouse warming and, thus, masks the impact of greenhouse gas emissions on the ‘natural’ climate. However, excluding the most recent 30 years, as Hansen does, is question-begging – it assumes what Hansen sets out to prove, namely, that the current climate is outside the range of natural variability. That assumption conflicts with studies finding that the Northern Hemisphere was warmer than present for several decades during the Medieval Warm Period and Roman Warm Period and for thousands of years during Holocene Optimum. Christy asks:

What is an accurate expression of the statistics of the interglacial, non-greenhouse-enhanced climate? Or, what is the extent of anomalies that Mother Nature can achieve on her own for the “natural” climate system from one 30-year period to the next? I’ll bet the variations are much greater than depicted by 1951-1980 alone, so this choice by Hansen as the base climate is not broad enough. In the least, there should be no objection to using 1931-1980 as a reference-base for a non-enhanced-greenhouse climate.

A study by NASA’s James Hansen and two colleagues, published Monday in Proceedings of the National Academy of Sciences (PNAS), finds that during the past 30 years, extreme hot weather has become more frequent and affects a larger area of the world than was the case during the preceding 30 years. Specifically, the study, “Perception of climate change,” reports that:

• Cool summers occurred one-third of the time during 1951-1980 but occurred only 10% of the time during 1981-2010.
• Very hot weather affected 0.2% of the land area during 1951-1980 but affected 10% of the land area during 1981-2010.

Hansen is the world’s best known scientist in the climate alarm camp and a leading advocate of aggressive measures to curb fossil-energy use. He and his co-authors are up front about the policy agenda motivating their study. The “notorious variability of local weather and climate from day to day and year to year” is the “great barrier” to “public recognition” of man-made climate change and, thus, to public support for policies requiring “rapid reduction of fossil fuel emissions.” When heat waves or drought strike, the authors want the public to perceive global warming. On Saturday, the Washington Post published an op-ed by Hansen summarizing the study’s results.

Heat waves will become more frequent and severe as the world warms; some areas will become drier, others wetter. Those hypotheses are not controversial.

What the Hansen team concludes, however, is controversial. The researchers contend that the biggest, baddest hot weather extremes of recent years — the 2003 European heat wave, the 2010 Russian heat wave, the 2011 Texas-Oklahoma drought, the ongoing Midwest drought – are a “consequence of global warming” and have “virtually no explanation other than climate change.”

There’s just one small problem. The reseachers do not examine any of those events to assess the relative contributions of natural climate variability and global warming. The study provides no event-specific evidence that the record-setting heat waves or droughts would not have occurred in the absence of warming, or would not have broken records in the absence of warming. 

The PNAS study (hereafter, “Hansen”) finds that the bell curve showing the distribution of extreme hot weather has steadily moved to the right as the planet has warmed from 1951 to 2011. Events that were once outliers (right hand tail) in 1951-1980 occur with increasing frequency in each subsequent decade, and today’s most extreme events did not occur in the baseline (1951-1980) period.

One question that springs to mind is whether 1951-1980 is an appropriate baseline for assessing trends in extreme weather. Consider the graph at the top of this page, which shows the U.S. Annual Heat Wave Index (source: U.S. Climate Change Research Program). In the U.S., the period of 1951-1980 was not representative or typical of prior decades.

In recent testimony before the Senate, University of Alabama in Hunstville climatologist John Christy made a by-the-numbers case that when data from the 1920s-1940s are included, there is no long-term trend in U.S. extreme heat events. Christy finds that:

• More state all-time high temperature records were set in the 1930s than in recent decades.
• More state all-time cold records than hot records were set in the decades since 1960.
• In a database of 970 weather stations, daily all-time high temperatures occurred more frequently before 1940 than after 1954.
• The 1930s set twice as many daily maximum temperature records than were set in the 1980s, 1990s, or 2000s.
• More Midwest daily maximum temperature records were set in the heat waves of 1911 and the 1930s than in the 2012 heat wave.
• The Palmer Drought Severity Index for the continental U.S. shows considerable interannual variability but no long-term trend from 1900 to the present.
• The upper Colorado River Basin experienced more frequent multi-decadal droughts in the 19th, 18th, 17th, and 16th centuries than in the 20th century.

Viewed in the context of Christy’s longer datasets, Hansen’s 1951-1980 baseline period looks anomalous, not the following three decades.

Hansen’s own plot of U.S. climate data going back to the 19th century also shows a period of pronounced warmth in the 1930s and 1940s, i.e. prior to his baseline.

Hansen is looking at all Northern hemisphere data whereas Christy is looking just at U.S. data. But the U.S. arguably has the best long-term weather data of any country in the world. What would have been the result had Hansen used only U.S. data and chosen an earlier period as the baseline, say 1925-1954, when there was far less greenhouse ‘forcing’ but many daily high temperature records? It is doubtful his statistical results would be anywhere near as dramatic.

Hansen argues that global warming, not weather patterns associated with drought (La Niña) and heat waves (atmospheric blocking), caused the 2003 European heat wave, the 2010 Russian heat wave, and the 2011 Texas-Oklahoma drought. La Niñas and blocking patterns ”have always been common, yet the large areas of extreme warming have come into existence only with global warming.” Therefore, Hansen concludes, today’s extreme anomalies have at least two causes, “specific weather patterns and global warming.”

This is spin, speculation, or ‘trust-me-I’m-the-expert’ assertion. Chase et al. 2006, a team of scientists from Colorado and France, found “nothing unusual” in the 2003 European heat wave that would indicate a change in global climate. Look at the global temperature map included in the study. During June, July, and August 2003, more than half the planet was cooler than the mean temperature from 1979 through 2003. Europe – a tiny fraction of the Earth’s surface – was the only place experiencing high heat. Does it make sense to attribute that local anomaly to global warming?

Figure explanation (courtesy of World Climate Report): 1000–500 mb thickness temperature anomaly for June, July, and August 2003. Green and blue tones indicate below-normal temperature anomalies.

Similarly, a National Oceanic & Atmospheric Administration (NOAA) analysis found that the 2010 Russian heat wave “was mainly due to natural internal atmospheric variability.” The study specifically addressed the question of a possible linkage to anthropogenic climate change:

Despite this strong evidence for a warming planet, greenhouse gas forcing fails to explain the 2010 heat wave over western Russia. The natural process of atmospheric blocking, and the climate impacts induced by such blocking, are the principal cause for this heat wave. It is not known whether, or to what extent, greenhouse gas emissions may affect the frequency or intensity of blocking during summer. It is important to note that observations reveal no trend in a daily frequency of July blocking over the period since 1948, nor is there an appreciable trend in the absolute values of upper tropospheric summertime heights over western Russia for the period since 1900.

The Texas-Oklahoma drought of 2011 was a record breaker. According to NOAA (State of the Climate in 2011, p. 166), “Several climate divisions in Texas, New Mexico, Oklahoma, and Louisiana, as well as the Rio Grande and Texas Gulf Coast river basins, had record low values for the Palmer Hydrological Drought Index in the 117-year record.” For Texas, 2011 was also a year of record heat. However, this correlation is not evidence that global warming was the principal factor. Detection and — more importantly — measurement of the impact of global climate change on the Texas drought requires a long and complicated analysis.

Texas State Climatologist John Nielsen-Gammon conducted a “preliminary analysis” of the role of global warming in the Texas drought. Although far from definitive, it is (to my knowledge) the most detailed and thorough analysis to date.  Nielsen-Gammon examines Texas drought and temperature data, climate modeling studies, and data on natural climate cycles (La Niña/El Niño, Pacific Decadal Oscillation, Atlantic Multi-Decadal Oscillation) to estimate the potential contribution of global warming. Here are some of his findings:

• Some IPCC AR4 climate models “at one extreme” project precipitation to increase in Texas, while others project a substantial decrease. “The general model consensus is that precipitation is likely to decrease a bit, but it’s not a sure thing.”
• The model-projected change is “smaller in magnitude than the past observed multi-decade-scale changes,” which indicates that “global warming is not going to be the dominant driver of mean precipitation changes, at least for the next several decades.”
• From 1895 to 2010, precipitation in Texas increased overall, by more than 10%.
• There has been no net change in Texas precipitation variability since 1920.
• Although the 2011 drought was the most severe 1-year Texas drought, it was not the most severe in the instrumental record. That distinction belongs to the 1950-1957 drought. Aside from 2009 and 2011, all the droughts that rank as most severe in at least 1% of the State occurred in 1956 and earlier.
• Texas summer temperature in 2011 was record-breaking because of the drought rather than the other way around. “This record-setting summer was 5.4 F above average.  The lack of precipitation accounts for 4.0 F, greenhouse gases global warming accounts for another 0.9 F, and the AMO [Atlantic Multi-Decadal Oscillation] accounts for another 0.3 F.  Note that there’s uncertainty with all those numbers, and I have only made the crudest attempts at quantifying the uncertainty.”

 Among Nielson-Gammon’s key conclusions:

So I conclude, based on our current knowledge of the effects of global warming on temperature and precipitation, that Texas would probably have broken the all-time record for summer temperatures this year even without global warming.

This drought was an outlier.  Even without global warming, to the best of my knowledge, it would have been an outlier and a record-setter.

* * *

Until we learn more, it is appropriate to assume that the direct impact of global warming on Texas precipitation interannual variability has been negligible, and that the future variability trend with or without global warming is unknown.

In short, Hansen’s sweeping assertion that global warming is the principal cause of the European and Russian heat waves, and the Texas-Oklahoma drought, is not supported by event-specific analysis and is implausible in light of previous research.

A concluding comment on what might be called Hansen’s political science is in order. Hansen believes the “great barrier” to aggressive action on climate change is the ”notorious variability” of weather and climate at local scales. But the public’s rejection of cap-and-trade, the collapse of the Kyoto-Copenhagen treaty agenda, and the GOP/Tea Party opposition to the Obama administration’s war on affordable energy are only partly related to public “perceptions” of climate change risk. More important is the fact that nobody knows how to run and grow a modern economy with zero-carbon energy.

The Breakthrough Institute develops this thesis in great detail in a collection of posts titled the “Death of Cap-and-Trade.” Because affordable energy is vital to prosperity and much of the world is energy poor, it would be economically ruinous and, thus, politically suicidal to demand that people abandon fossil fuels before cheaper alternative energies are available. But that is exactly what warmistas like Hansen urge the U.S. and other governments to do – lock up vast stores of carbonaceous fuel and penalize fossil energy use before commercially-viable alternatives exist.

As the Breakthrough folks argue, if you’re worried about climate change, then your chief policy goal should be to make alternative energy cheaper than fossil energy. Instead, the global warming movement has attempted to make fossil energy more costly than alternative energy, or to simply mandate the switch to alternative energy regardless of cost. Al Gore’s call in 2008 to “re-power America” with zero-carbon energy within 10 years is epitomizes this folly. More “moderate” variants would only do less harm, less rapidly.

Earlier this week, the Senate Environment & Public Works Committee held a hearing entitled “Update on the Latest Climate Change Science and Adaptation Measures.” Testimony by Dr. John Christy of the University of Alabama Huntsville is too valuable not to share with the millions (okay, hundreds) of folks who visit this site.

Christy is a data maven. He spends “tedious” weeks and months examining surface observations as well as weather balloon and satellite measurements to build “datasets from scratch to advance our understanding of what the climate is doing and why.” He uses the datasets “to test hypotheses of climate variability and change.” Yes, it’s called the scientific method, but much of what passes for climate science today is, in Christy’s words, ”opinion, arguments from authority, dramatic press releases, and fuzzy notions of consensus generated by a preselected group.”

Increasingly, we hear experts blame global warming for bad weather. Most acknowledge that no single weather event can be attributed to global climate change. However, they contend, the pattern of recent events – the sheer number and severity of heat waves, wild fires, droughts, freak storms — is exactly what climate scientists have predicted and must be due to mankind’s fuelish ways. Such assertions, Christy shows, are not based on real data.

One way to measure trends in extreme weather is to compare the number of state record high and low temperatures by decade. Many more state high temperature records were set in the 1930s than in recent decades. Even more surprising, “since 1960, there have been more all-time cold records set than hot records in each decade.”

There is no discernible greenhouse “fingerprint” in these data.

One might object that state temperature records are not informative, because the number of data points — 50 — is so small. So Christy also investigated “the year-by-year numbers of daily all-time record high temperatures from a set of 970 weather stations with at least 80 years of record.” He explains: “There are 365 opportunities in each year (366 in leap years) for each of the 970 stations to set a record high (TMax).” Adding the TMax days by year, Christy found that there were several years with more than 6,000 record-setting highs before 1940 but none with record highs above 5,000 after 1954. “The clear evidence is that extreme high temperatures are not increasing in frequency, but actually appear to be decreasing.”

Since climate change is a long-term phenomenon, Christy also calculates the number of record highs in 10-year moving averages. The figure below shows the trend line based on 704 stations that have at least 100 years of data.

Christy comments: “Note that the value for the most recent decade is less than half of what was observed in the 1930s.”

What about the heat wave of 2012 — isn’t it worse than any other year in the instrumental record? No. The graph below shows the number of record high temperatures for stations in “7 Central-US states where the heat is worst (AR-IL-IN-IA-MO-NE) and stations on the West Coast (CA-OR-WA).” For both the Central-US and West Coast, the largest number of TMax days occurred during the heat waves of 1911 and the 1930s. Although the Central-US has a large number of TMax days in 2012, the West Coast has very few, indicating that the current heat wave “is smaller than previous events.”

What about the current drought — is it part of a long-term trend that correlates with the ongoing rise in atmospheric greenhouse gas concentrations? The graph below shows the month-by-month percentage of the area of the U.S. classified as moderate to extreme for dryness and wetness by the National Oceanic and Atmospheric Administration (NOAA). Since 1900, there has been a high degree of year-to-year variability but “no long-term trend.”

Over a longer time frame, we find even greater climate variability. The photo below shows that trees grew on dry ground about 900 years ago “in what is now a Sierra Nevada alpine lake.” Christy comments: “This indicates that a drastic but natural change to a much drier climate must have lasted for at least a century for trees to have grown to these sizes on dry ground.”

A 500-year reconstruction of moisture in the upper Colorado River basin indicates that the 20th century was quite moist compared to the four prior centuries, all of which experienced multi-decadal droughts.

Source: Piechota et al. 2004

Christy emphasizes that he is not using these data to prove that U.S. weather is becoming less extreme or colder. Rather, his point is that “extreme events are poor metrics to use for detecting climate change.”

Christy’s testimony addresses other critical issues in climate science and policy. Here, I’ll briefly summarize just two points.

(1) Popular surface datasets are not reliable indicators of the greenhouse effect. Land use changes (urbanization, farming, deforestation) “disrupt the normal formation of the shallow, surface layer of cooler air during the night when TMin [daily low temperature] is measured.” Over time, TMin gets warmer, producing a trend easily mistaken for a global atmospheric phenomenon. That is one reason Christy has devoted much of his career to developing a satellite record of global temperatures. Satellite datasets “are not affected by these surface problems and more directly represent the heat content of the atmosphere.”

(2) Satellite data indicate that IPCC climate models are too sensitive and project too much warming. The graph below shows the results from 34 of the climate model simulations of global temperatures that will be included in the IPCC’s forthcoming Fifth Assessment Report. The thick black line shows the average model projection. The circles show the observed results from the two main satellite-based monitoring systems.

Last Thursday, the House Energy & Power Subcommittee, on a voice vote, approved H.R. 910, the “Energy Tax Prevention Act.” My colleague Myron Ebell blogged about it over the weekend in a post titled Inside the Beltway.

The present post offers additional commentary. The full House Energy and Commerce Committee marks up the legislation today and tomorrow.

Rep. Henry Waxman (D-Calif.) led the charge for the minority, claiming H.R. 910 “rolls back” the Clean Air Act. Wrong. H.R. 910 restores the Clean Air Act (CAA). Congress never intended the CAA to be a framework for greenhouse gas regulation, and never subsequently voted for it to be used as such a framework. The terms “greenhouse gas” and “greenhouse effect” never even occur in the Act, which was enacted in 1970, years before global warming was even a gleam in Al Gore’s eye. 

The CAA as amended in 1990 does mention “carbon dioxide” and ”global warming potential,” but only once, in the context of non-regulatory provisions, and each time followed by a caveat admonishing EPA not to infer authority for “pollution control requirements” or “additional regulation.” This language would have been superfluous and without legal effect if, as Waxman assumes, EPA already had authority since 1970 to control carbon dioxide as an “air pollutant” or regulate greenhouse gases in general based on their ”global warming potential.” The only time Congress spoke directly to the issue of global warming in the Clean Air Act, it instructed EPA not to jump to regulatory conclusions. For further discussion, see my columns EPA’s End-Run Around Democracy and Endangerment Smackdown: Should Congress Heed Russell Train’s Advice.

Waxman said H.R. 910 “overturns EPA’s scientific finding.” Reps. Ed Markey (D-Mass.) and Jay Inslee (D-Wash.) go further, asserting that Republicans are trying to repeal the law of gravity and the first law of thermodynamics. Rubbish. Nature is what it is. EPA’s assessment of the science is what it is. H.R. 910 takes no position on climate science. It does not presume to command Nature or rescind EPA’s assessment of the scientific literature. Rather, H.R. 910 aims to overturn the legal force and effect of the rule in which EPA published its assessment, the so-called endangerment finding.

As even Rep. Waxman might admit, science should inform, not dictate, policy. EPA, however, is using its allegedly scientific assessment to dictate policy. EPA’s Endangerment Rule obligates EPA to regulate greenhouse gas emissions from new motor vehicles, which then obligates EPA to impose CAA permitting requirements on stationary sources of greenhouse gases. In addition, the Endangerment Rule authorizes or obligates EPA to establish emission standards for other mobile sources (aircraft, marine vessels, non-road vehicles) and New Source Performance Standards (NSPS) numerous industrial source categories. EPA may even be litigated into establishing National Ambient Air Quality Standards (NAAQS) for greenhouse gases set below current atmospheric concentrations.

Thus, by publishing an assessment of the science literature, EPA authorized itself to ‘legislate’ national policy on climate change. America could end up with a climate regulatory regime more costly and intrusive than any cap-and-trade bill Congress has declined to pass, or any climate treaty the Senate has declined to ratify, yet without the people’s representatives ever voting on it. H.R. 910 would stop this trashing of our constitutional system of separated powers and democratic accountability.

Waxman said: “Some Republicans on the committee will argue today that this bill is not a rejection of science, but if they believed in the serious threat posed by climate change, they would have accepted our offer to work together without preconditions to develop a responsible plan for promoting clean energy and reducing carbon emissions.” Two problems here. First, Waxman confuses science with his view of the science. Some scientists, such as University of Alabama in Hunstville climatologist John Christy, who recently testified before the Energy and Power Subcommittee, take a decidedly non-alarmist view. 

Second, a “clean energy standard” (CES), like the failed Waxman-Markey cap-and-trade bill, is just another way of ”skinning the cat,” as President Obama put it. A CES is another way to “bankrupt” coal power plants and cause electricity rates to “necessarily skyrocket.”  Obama’s CES proposal aims at almost exactly the same mix of electricity fuels that the Waxman-Markey cap-and-trade bill would have created. A CES resembles a Soviet-style production quota and would probably be less efficient than cap-and-trade. Why should Republicans and Blue Dog Democrats who oppose cap-and-trade feel obliged to support something even worse?  

Waxman said: “It is hard to know how to respond when the other side calls H.R. 910 the Energy Tax Prevention Act but EPA has no authority to levy taxes, nor does the Agency propose to do so.” Rep. John Dingell (D-Mich.) made the same point, claiming that the sponsors had a “truth in advertising” problem, because EPA is not collecting revenues from taxpayers. This kind of nit-picky literalism misses the point. Granted, rhetoric can distort reality. An apt example is Waxman and Markey’s “American Clean Energy and Security Act,” which would have inflated gasoline prices, destroyed jobs, and increased our reliance on costly and unreliable wind and solar power.

Rhetoric, however, can also demystify convoluted agendas so that the public can understand who’s trying to fleece them. Although economists had long argued that a carbon tax is more efficient, the global warming movement preferred cap-and-trade because its economic impacts are less obvious. Calling it ”cap-and-tax” opened peoples eyes. Even though cap-and-trade was not strictly a tax, it would have some of the same effects as an energy tax, such as causing electric rates to “necessarily skyrocket.” EPA’s regs would similarly penalize fossil energy production and use, raising consumer energy prices. H.R. 910′s title spotlights this valid concern. As Subcommittee Chair Ed Whitfield (R-Ky.) later said, the bill would repeal a “de facto tax on energy.”

Rep. Mike Doyle (D-Penn.) argued that EPA’s greenhouse rules can’t be sending jobs to China because they apply only to facilities that are “new” or “drastically modified.” Two problems here. First, Doyle tacitly concedes that EPA’s rules could send future jobs to China, by discouraging firms to undertake new construction or major modifications. But that means the rules could be sending jobs to China already, because people invest today based on their expectations for the future (duh!). Moreover, EPA has announced that it plans to apply greenhouse gas performance standards to existing, non-modified coal power plants. Besides, the purpose of H.R. 910 is not merely to undo any economic damage that EPA’s greenhouse gas regulations have done since Jan. 2, 2011, when they took effect, but to safeguard America’s economic future for years to come.

Rep. Inslee denounced H.R. 910 as the “dirty air act” (not very original), asserting it would prevent EPA from fighting childhood asthma. If Inslee really believes that, then I have a bridge I’d like to sell him. To restate the obvious, carbon dioxide is not an asthma-triggering or -exacerbating air pollutant. EPA already has all the power it could possibly want under traditional CAA programs to control air pollution. U.S. air quality is not a major factor in childhood asthma. Asthma rates have risen even as air pollution has declined, and hospitalizations for asthma are lowest in July and August — months when smogs levels are highest. For further discussion, see Chapter 7 of Joel Schwartz and Steven Hayward’s book, Air Quality in America: A Dose of Realty on Air Pollution Levels, Trends, and Risks.
 
Rep. Eliot Engel (D-N.Y.) suggested that allowing EPA to regulate greenhouse gases through the CAA would grow the economy: “Since its adoption, the Clean Air Act has reduced key air pollutants by 60 percent, while at the same time the economy has grown by over 200 percent.” Yes, but who today would say that the economy is in great shape? Unemployment hovers near 10%. Imposing virtual taxes on energy can only impede recovery.

Small business is the main job creator. Environmental compliance already “costs 364 percent more [per employee] in small firms than in large firms,” according to the Small Business Administration Office of Advocacy. EPA’s Tailoring Rule shields small greenhouse gas emitters from CAA permitting requirements by effectively amending the statute’s numerical definitions of “major emitting facility.” If courts strike down the Tailoring Rule as a violation of the separation of powers, then small business compliance costs will “necessarily skyrocket.” Even if courts uphold the Tailoring Rule, EPA’s regulations will increase small business energy costs.

Waxman opined that H.R. 910 would jeopardize EPA’s model year 2012-2016 greenhouse gas tailpipe standards, on which auto companies have already based their plans, despite language leaving those standards in place. “The exception doesn’t address the issue of whether those standards can survive legal challenge without the endangerment finding,” he said. His point being that H.R. 910 would overturn EPA’s Endangerment Rule, without which EPA could not legally issue the Tailpipe Rule. True but irrelevant. As Subcommittee Counsel Maryam Brown noted, if Congress via H.R. 910 codifies the Tailpipe Rule, then there can be no legal challenge to it. 
 
Brown’s point also takes care of Waxman’s concern that a decoupling of EPA’s greenhouse gas motor vehicle emission standards from the National Highway Traffic Safety Administration’s (NHTSA’s) fuel economy standards would decrease greenhouse gas reductions by 30% relative to the joint rulemaking the agencies issued in May 2010. I’m not sure where Waxman gets that percentage. P. 25429 of the joint rule says that an automobile air conditioner (AC) system must be 30% more efficient than the current average to qualify for a greenhouse gas reduction credit. That’s the only place in the joint rule where the figure “30%” occurs.
 
EPA and NHTSA confirm that “there is a single pool of technologies for addressing these twin problems [climate change, oil dependence], i.e. those that reduce fuel consumption and thereby reduce CO2 emissions as well” (p. 25327). EPA estimates that 94-95% of motor vehicle greenhouse gas emissions are carbon dioxide from motor fuel combustion, the remaining portion coming from the refrigerants used in automobile AC systems. Thus, even if H.R. 910 did have the effect of decoupling EPA’s greenhouse emission standards from NHTSA’s fuel economy standards, there should be only a small decrease in greenhouse gas reductions relative to the joint rule’s projected baseline. 
 
Let’s also put things in perspective. EPA and NHTSA estimate their joint rule will avert 0.011°C of warming and 0.09 cm of sea-level rise by 2100 (p. 25637). Those effects are too small to be detected and make no practical difference to any public health or environmental concern. A 30% reduction in such puny “climate protection” is irrelevant.
 
Waxman also denounced H.R. 910 because California could not apply for another waiver to set even tougher greenhouse gas emission standards for cars manufactured after the 2016 model year. But EPA should never have granted California a waiver to establish its own greenhouse gas emission standards in the first place. The California program is massively “related to” fuel economy, and, as such, is preempted by the 1975 Energy Policy Act.

In addition, as Rep. Brian Bilbray (R-Calif.) ably argued, the waiver provision established by CAA Sec. 209 has no rational application to greenhouse gases. The CAA authorizes California to obtain waivers to go beyond federal motor vehicle emission standards because those are not tough enough to bring California, with its unique topography and meteorology, into attainment with federal air quality standards. There are no national air quality standards for greenhouse gases. Therefore, California has no need under the CAA to establish vehicle emission standards for greenhouse gases. Moreover, because greenhouse gases are well-mixed in the global atmosphere, greenhouse gases, unlike smog or soot, are no more heavily concentrated in California than anywhere else.

Engel argued that overturning EPA’s endangerment finding would be unprecedented in the history of the CAA. Counsel Brown countered that there is precedent for repealing EPA rulemakings and that EPA’s issuance of a ”stand-alone” endangerment finding, without accompanying regulatory requirements, is itself “unprecendented.” I would put the matter this way. EPA’s Endangerment Rule is “stand-alone” only as a publication. It is the trigger, prelude, and precedent for a cascade of regulations Congress has not approved. If the “finding” were merely that — EPA’s interpretation of climate science – then Congress would not be voting on it. The Endangerment Rule is separate only in the trivial sense that it was published before all the other greenhouse gas regulations that flow from it.

Rep. Markey argued that because H.R. 910 takes away EPA’s authority over greenhouse gases, it also takes away EPA’s authority to reduce oil consumption in aircraft, marine vessels, non-road vehicles, boilers, etc. And that is bad, he reasoned, because NHTSA has no authority to reduce oil consumption from such entities. Markey fails to grasp the implication of his remarks. If the nation’s fuel economy laws (1975 Energy Policy Act, 2007 Energy Independence and Security Act) do not authorize NHTSA to reduce oil consumption from entities other than cars and trucks, then Congress obviously did not authorize EPA to do so through the Clean Air Act, which provides no authority whatsoever to set fuel economy standards.

If Markey thinks EPA should be reducing oil consumption throughout the economy, then he should draft a bill, introduce it, and try building legislative majorities to pass it. But that would be hard work, and it might not succeed. So instead Markey wants EPA to play lawmaker and impose his will on the nation.

I would summarize the core premise of Waxman, Markey, and Inslee’s opposition to H.R. 910 as follows: We know what is good for America and the world. It’s a future without fossil fuels. We can’t persuade the people’s representatives to support our agenda and turn it into law. Therefore, it is necessary for EPA to ‘enact’ our agenda regardless of the defeat of cap-and-trade, the November 2010 elections, and the separation of powers. The triumph of our agenda is more important than any constitutional principle that might interfere with it.

Last week’s House Ways & Means Committee hearing on “scientific objectives for climate change legislation” contained much grist for skeptical mills.

Dr. James Hansen did not challenge any of Dr. John Christy’s specific arguments that UN climate models overestimate climate sensitivity. Instead, he advised Congress to ask the National Academy of Sciences for an “authoritative” assessment, because the science is “crystal clear.”

Hansen was quite harsh in criticizing Kyoto (an “abject failure”) and carbon trading (a politically unsustainable hidden tax for the benefit of special interests). He outlined a proposal for what he calls carbon “Tax & Dividend,” whereby 100% of the revenues would be refunded to the American people via monthly deposits to their bank accounts.

As I discuss here, Hansen’s beguiling proposal could decimate coal-based power in a decade or two, pushing electricity prices up faster than dividend payments increase, and saddling the economy with a growth-chilling energy crisis.