The Flawed Science in Al’s book, spelled out in detail:
“The most vulnerable part of the Earth’s ecological system is the atmosphere. It’s vulnerable because it’s so thin.” (p. 22)
Other parts of our environment are arguably more vulnerable and are clearly thinner: the hydrosphere (oceans and rivers), for example. Whatever is meant by “vulnerable”, it probably is poorly described as being a consequence of “thinness”.
“In particular, we have vastly increased the amount of carbon dioxide–the most important of the so-called greenhouse gases.” (p. 25)
Mt. Kilimanjaro
While “most important” is a subjective term, the implication that most of the existing greenhouse effect is due to CO2 is false: water vapor is the source of most of the existing greenhouse effect.
“The Sun’s energy enters the atmosphere in the form of light waves and heats up the Earth. Some of that energy warms the Earth and then is re-radiated back into space in the form of infrared waves.” (p. 26)
Solar energy reaching the Earth is about 42% visible light and 50% shortwave infrared. Some is reflected; only the absorbed portion heats the Earth. “Re-radiate” is a an incorrect and misleading term and should not be used; rather, the Earth and its atmosphere radiate longwave infrared as a function of its temperature, with the balance between this radiation and temperature mediated by the presence of greenhouse gases.
“The greenhouse gases surrounding Mars are almost nonexistent, so the temperature is far too cold.” (p. 26)
Mars’ atmosphere, although much thinner than Earth’s, is almost entirely CO2. The partial pressure of CO2 at the surface of Mars is 6.1 millibars, compared to 0.38 millibars at the surface of Earth. The greenhouse warming on Mars due to CO2 is greater than that due to CO2 alone on the Earth (but not that due to H2O). Mars is colder because it is further from the Sun and receives less than half the sunlight the Earth does.
“The problem we now face is that this thin layer of atmosphere is being thickened by huge quantities of human-caused carbon dioxide and other greenhouse gases.” (p. 27)
The Earth’s atmosphere is not thicker as a result of increased greenhouse gases; rather, the effects of changes in these gases are associated with the different absorptive properties of these minor constituents.
“Professor Revelle was the first scientist to propose measuring CO2 in the Earth’s atmosphere.” (p. 30)
Scientists had been measuring atmospheric CO2 since the 1800s, before Revelle was born. Guy Stewart Callendar identified the modern increase in atmospheric CO2 from such measurements about 20 years before Revelle’s project, which itself was motivated in part by Hans Suess’s identification of fossil carbon in atmospheric CO2. An article by Revelle and two coauthors in 1991 stated “The scientific base for a greenhouse warming is too uncertain to justify drastic action at this time.” (Singer et al., 1991). Gore instigated a campaign by J. Lancaster to slander the coauthors in 1992; one coauthor sued for libel and obtained an admission by Lancaster that Revelle had indeed participated in authoring those words (Singer, 2003).
“The pre-industrial concentration of CO2 was 280 parts per million. In 2005, that level, measured high above Mauna Loa, was 381 parts per million.” (p. 37)
Average CO2 concentration in 2005 at Mauna Loa was 379.75 ppm (Tans, 2006).
“It is evident in the world around us that very dramatic changes are taking place… This is Mount Kilimanjaro in 1970 with its fabled snows and glaciers… [Lonnie Thompson] predicts that within 10 years there will be no more ‘Snows of Kilimanjaro’.” (pp. 42-45)
The retreat of Kilimanjaro’s glaciers is not attributable to contemporary temperature changes. Kaser et al., 2004, cite a drastic drop in local atmospheric moisture around the late 1800s; Mason, 2003, cites deforestation around Kilimanjaro, resulting in a drop in local precipitation. Young and Hastenrath, 1991, list several potential factors but single out climate changes than occurred in the late 1800s-early 1900s. Cullen et al., 2006, conclude that Kilimanjaro’s glaciers have been out of equilibrium with local climate since about 1900, i.e. that their retreat reflects climate change a century ago, not climate change today. Thompson’s actual prediction is for loss of the ice fields in 9-14 years, between 2015 and 2020 (Thompson et al., 2002).
“Our own Glacier National Park will soon need to be renamed ‘the park formerly known as Glacier’.” (p. 46)
Glacier retreat has been ongoing in Glacier National Park since 1850 (USGS, 2003a) due to natural climate variations; the USGS suggests that with no additional warming the glaciers will likely be gone by 2100, with one model assuming continued warming predicting their disappearance by 2030 (USGS, 2003b). Even without the current warming blamed by some on humans, the glaciers of Glacier National Park would be disappearing since they have been out of equilibrium with the local environment ever since the end of the Little Ice Age in 1850.
“Almost all of the mountain glaciers in the world are now melting…” (p. 48)
All glaciers are losing mass to melting and gaining mass to precipitation. Losses outpace gains for most, but not all. Even at the regional level, some regions show net gains (Dyurgerov and Meier, 2005).
“The Himalayas… provide more than half of the drinking water for 40% of the world’s population… Within the next half-century, that 40% of the world’s people may well face a very serious drinking water shortage, unless the world acts boldly and quickly to mitigate global warming.” (p. 58)
Research suggests runoff reductions of only 1-8% under various climate change scenarios (Sharma et al., 2000). Dyurgerov and Meier, 2005, conclude that the mass loss of Himalayan glaciers from 1960 to 1992 was offset by mass gain of Tibetan glaciers (with little net loss or gain by Tibetan glaciers since then). Zhao and Moore, 2006, report that Himalayan snow accumulation has been steadily declining since 1840, predating any current climate change. Even if predictions were correct regarding disappearance of these glaciers, such melting would increase river flows in the period of time described by Gore.
(map, p. 59)
The white areas on the map represent high elevations, not glaciers; only a small fraction of this area (less than 10%) is covered by glaciers.
“1000 years of northern hemisphere temperature (° C)” (p. 63)
“But as Dr. Thompson’s thermometer shows, the vaunted Medieval Warm Period… was tiny compared to the enormous increases in temperature of the last half-century” (p. 64)
“Those global warming skeptics–a group diminishing almost as rapidly as the mountain glaciers–launched a fierce attack against another measurement of the 1,000-year correlation between CO2 and temperature known as “the hockey stick,” a graphic image representing the research of climate scientist Michael Mann and his colleagues. But in fact, scientists have confirmed the same basic conclusions in multiple ways–with Thompson’s ice core record as one of the most definitive.” (p. 65)
The depicted graph is not based on the ice core data of Thompson as claimed, but is the (mostly tree-ring based) proxy reconstruction of Mann et al., 1999, combined with the 1840-2000 surface measurement-based series of Jones et al., 1999. (Specifically, it is a defective reproduction of a figure from a secondary source.) The lack of variance before 1840 is relatively unique to Mann et al.’s methodology for combining proxies, a methodology which has been shown to have flaws (McIntrye and McKitrick, 2003) and appears to suppress temperature variations prior to the 20th century relative to other methods (Dahl-Jensen et al., 1998; von Storch et al., 2004; Moberg et al., 2005). The actual ice core-based reconstruction by Thompson et al., 2003, is based on only 6 tropical glaciers and shows a similar “hockey-stick” shape primarily due to the influence of two cores, while the other four cores show Medieval Warm Period temperatures very similar to modern temperatures.
“Nonetheless, the so-called global-warming skeptics often say that global warming is really an illusion reflecting nature’s cyclical fluctuations. To support their view, they frequently refer to the Medieval Warm Period.” (p. 65)
This is an inaccurate caricature of skeptical views, which really cover a wide range of views. First, a short-term warming that was part of a cyclical variation would be real warming, not illusional; second, “cyclical” does not accurately describe some of the types of natural effects described by the scientific community that could explain modern warming. More to the point, many (not all but many) “skeptics” believe that warming is now occurring, but simply disagree with Gore on the cause of this warming. Many scientists–some who agree with Gore on the magnitude of modern warming and some who don’t–also accept the historical evidence for a Medieval Warm Period either locally or globally as warm as temperatures today. By the same token, it should not be necessary for Gore to deny the Medieval Warm Period to assert that warming is occurring today.
“In Antarctica, measurements of CO2 concentrations and temperature go back 650,000 years… It’s a complicated relationship, but the most important part of it is this: When there is more CO2 in the atmosphere, the temperature increases because more heat from the Sun is trapped inside… There is not a single part of this graph–no fact, date, or number–that is controversial in any way or in dispute by anybody.” (pp. 66-67)
These measurements are directly of CO2 and deuterium (or oxygen-18 in other cases) in air bubbles in ice cores; the relationship of deuterium to temperature is indirect and requires assumptions regarding past isotopic abundances. The reconstructed temperature series is local, not global; similar ice core temperature reconstructions from other locations, while correlated with CO2 abundances, are not as strongly correlated as these series selected by Gore, possibly suggesting local influences. The claim that this correlation shows that more CO2 leads to higher temperatures is false: higher resolution studies of the ice cores show that the temperature increases came first, followed by CO2 increases. For the composite series shown in this graph, Siegenthaler et al., 2005, find the best match shows CO2 concentrations lagging 1,900 years behind the deuterium-derived temperature values. It is believed that the temperature changes led to changes in the balance between greenhouse gases in the atmosphere and greenhouse gases in locations such as the oceans. Apart from this, atmospheric CO2 does not trap heat (such a statement is linked to misunderstanding of the greenhouse effect); rather, CO2 and other greenhouse gases selectively absorb outgoing longwave infrared resulting in a radiative balance at a different global temperature than without the gases. The fact that the data within the graph is basically accepted in the scientific community is a separate issue from the fact that Gore is misinterpreting it.
“The top right point… shows current global temperatures. And the bottom right point marks the depth of the last ice age. That short distance–about an inch in the graph–represents the difference, in Chicago, between a nice day and a mile of ice over your head. Imagine what three times that much on the warm side would mean.” (p. 67)
The implied connection between these temperatures and climate is misleading. The ice core-based temperature series has a poor time resolution and does not reflect much larger temperature variations on timescales of years or decades. Further, the high correlation over this time period used to support Gore’s interpretation does not hold in the more distant geologic past (Royer et al., 2004).
“This graph charts the actual measurements of global temperature since the Civil War… And in recent years the rate of increase has been accelerating… The hottest year recorded during this entire period was 2005.” (pp. 72-73)
Gore does not give a source for this graph, but reportedly it is based on the GISS temperature series from NASA (Hansen et al., 2006), which only goes back to 1880. These and other similar series are composite averages based on ground-based and sea-based measurements, adjusted and averaged in various ways. Such series cannot absolutely specify the “hottest” year because the precise temperature values are highly dependent on the methodology used to average measurements and the selection of stations to be included in the averages. For example, the GISS series gives the three successively hottest years as 2005, 1998, and 2002. The UK Climate Research Unit series (Jones et al., 1999) instead gives 1998, 2005, and 2002, with 1998 0.1° C warmer than 2005 due to the 1998 El Nino event (Jones and Palutikof, 2006). The Global Historical Climate Network series gives 2005, 1998, and 2003 as the hottest years (NOAA, 2006). All of these series, however, show much greater warmings in the last three decades than more uniform sampling from satellite-based observations. This post-1970 warming bias may result from local effects such as the urban heat island effect, or from problems with the selection of stations used in the average and the adjustments applied to this data. With such relative extremes so heavily dependent on the particular methodology used, Gore is incorrect to make such an absolute claim without qualification.
“We have already begun to see the kind of heatwaves that scientists say will become much more common if global warming is not addressed. In the summer of 2003 Europe was hit by a massive heatwave that killed 35,000 people.” (p. 75)
This death toll is dominated by 14,082 deaths in France and 4,000 in Italy, both calculated by comparing observed deaths in August 2003 to what would “normally be expected” (UNEP, 2004); these deaths, predominantly among the elderly, have not been individually attributed to heat-related causes. The French government in particular offered these precise estimates after initially stating that there was no accurate way of measuring deaths from the heat. These death tolls partly reflect the aging population of Europe, but in the case of France have also been attributed to failed government and health care system response to the heat wave (BBC, 2003). More generally, despite the anomaly of the 2003 European heat wave, more accurate treatment of regional temperatures does not support the claim that regional heat waves are becoming more frequent (Pielke, 2006).
“In the summer of 2005 many cities in the American West broke all-time records for high temperatures… And in the East, a number of cities set daily temperature records…” (pp. 76-77)
Individual local highs and lows always occur, due to the chaotic variations in weather; when discussing climate, this is not an appropriate measure. (Note that Gore dismisses local measures of climate on p. 321.) Such highs are likely attributable to the urban heat island effect, not to global warming. According to the GISS-compiled temperature series for the lower 48 states, 2005 tied as the 9th hottest year on record; the hottest years, from hottest to cooler, were 1934, 1998, 1921, 1931, 1999, tie between 1953, 1990, and 2001, and tie between 1987 and 2005; 2005 was a full 0.4° C cooler than 1934 (Sato and Hansen, 2006).
“But scientists who specialize in global warming have been using evermore accurate computer models that long ago predicted a much higher range of ocean temperatures as a result of man-made global warming… The actual ocean temperatures are completely consistent with what has been predicted as a result of man-made global warming. And they’re way above the range of natural variability.” (pp. 78-79)
The global circulation models (GCMs) referred to still fail to replicate observed temperature changes from first principles; several phenomena are not well understood but are incorporated with empirical factors to produce the apparent agreement between models and past observations. But as more such empirical adjustments are applied, the models can be forced to reproduce a particular result without necessarily reproducing the physics correctly. Still, on several points, GCMs continue to fail the basic scientific test of making predictions which are subsequently verified (Pielke, 2006). The predictions from these models tend to be larger than empirical predictions for a given change in atmospheric CO2 (Lindzen, 1997). Indirect solar effects, which are highly correlated with climate, are ignored by these models. Any claim that observed changes are outside the range of natural variability necessarily assumes that natural influences have been constant, an assumption which has been questioned.
“As the oceans get warmer, storms get stronger… there is now a strong, new emerging consensus that global warming is indeed linked to a significant increase in both the duration and intensity of hurricanes. Brand-new evidence is causing some scientists to assert that global warming is even leading to an increased frequency of hurricanes, overwhelming the variability in frequency long understood to be part of natural deep-current cycles.” (pp. 80-81)
Gore acknowledges some limitations of the claimed global warming-hurricane link, but still claims a stronger consensus than what actually exists. In fact, the scientific community is divided as to whether recent peaks in hurricane activity are the result of a global warming trend or merely an indicator of natural cycles. The research which Gore apparently refers to (Emanuel, 2005; Webster et al., 2005) has been questioned (Pielke, 2005), and many researchers (including many in the NOAA) tend to attribute recent active storm seasons to natural cycles including the Atlantic oscillation (Elsner et al., 2000; Goldenberg et al., 2001; NOAA, 2005; Chan, 2006). Kloztbach, 2006, found that the recent increase in North Atlantic tropical storm activity was offset by a significant decrease in Northeast Pacific tropical storm activity, leading to minimal global change. Further, theoretical research has produced varying conclusions regarding the effect of any global warming on hurricane activity: some predict more storms, some predict the same number of storms but stronger storms on average, some models predict limited changes. Continuing research may yet identify and attribute a trend, but claims that this has already been settled are premature (Pielke et al., 2005; Michaels et al., 2006).
“The science textbooks had to be rewritten in 2004. They used to say, ‘It’s impossible to have hurricanes in the South Atlantic’. But that year, for the first time ever, a hurricane hit Brazil.” (p. 84)
Any textbook making such a claim would not have been credible before 2004. Two other weak tropical storms short of hurricane strength have been reported in this area during the last 40 years (Pezza and Simmonds, 2005). Rather than the “first time ever”, the “first recorded instance” would be more accurate.
“Also in 2004, the all-time record for tornadoes in the United States was broken.” (p. 86)
To imply a significance to this fact is misleading, since increased observations and technological methods permit the tallying of more weak tornadoes than ever before. No F5 tornado damage occurred in 2004 (McCarthy and Schaefer, 2005), and no trends regarding consistently measured tornadoes are observed (McCarthy, 2000). Gore also fails to acknowledge that tornado activity in 2005 was unusually low, with this the first year in which no tornadoes were reported in Oklahoma in the month of May.
“… less than a month before Hurricane Katrina hit the United States, a major study from MIT supported the scientific consensus that global warming is making hurricanes more powerful and more destructive… And then came Katrina… The consequences were horrendous…” (pp. 92-95)
Hurricane Katrina cannot be linked individually to any climate trend, human-caused or otherwise. Further, the uniquely disastrous consequences of Katrina are mostly a reflection of the fact that it struck a city below sea level protected by inadequate levees, with consequences worsened by inept government response at the city, state, and federal levels. Finally, there is no scientific consensus either on any trends regarding hurricanes or on the causes for any such trends, as previously discussed.
“Partly as a result, the number of large flood events has increased decade by decade, on every continent.” (p. 106)
This data cannot be used to support claimed trends in climate. Observed flood events are influenced by increasing population and distribution of people in flood-prone areas, as well as by land use changes which increase runoff during heavy rains. Studies on weather extremes show heavy rain events are more frequent in some locations and less frequent in others, not uniformly more frequent as Gore implies (Easterling et al., 2000).
“In 2005 Europe had a year of unusual catastrophes very similar to the one in the United States… Europe was experiencing a disastrous number of floods.” (pp. 106-107)
Mudelsee et al., 2003, examined flood records for the Elbe and Oder rivers in central Europe as far back as 1021 and 1269, respectively, and found no modern trend regarding the occurrence of floods.
“There has also been record flooding in China, which, as one of the planet’s oldest civilizations, keeps the best flood records of any nation in the world.” (p. 112)
Jiang et al., 2005, examined Chinese flood records for the Yangtze Delta from 1000 AD to the present and found the frequency of large floods was greatest from about 1500 to 1700; this was identified as the transition from the Medieval Warm Period to the Little Ice Age.
“Paradoxically, however, global warming causes not only more flooding, but also more drought.” (p. 112)
There is some tendency to claim that global warming will produce opposite extremes, which tends to make it impossible to scientifically test such claims, given that weather extremes such as flood events and droughts are natural aspects of a chaotic climate system. Gore makes the claims here that (1) global warming will causes regional changes in weather extremes and (2) such trends in weather extremes are observed. On point one, the general circulation models have deficiencies previously noted which are even worse with regard to predictions at the regional level. For some regions, various GCMs give contradictory predictions. On point two, individual events cited by Gore do not constitute a trend. Studies on weather extremes show heavy rain events are more frequent in some locations and less frequent in others and show little trends for droughts to date (Easterling et al., 2000).
“The map to the left shows what is projected to happen to soil moisture in the United States with the doubling of CO2, which would happen in less than 50 years if we continue business as usual… Moreover, scientists are now telling us that if we do not act quickly to contain global warming pollution, we will soon … more toward a quadrupling, in which case, scientists tell us, most of the United States would lose up to 60% of its soil moisture.” (p. 121)
These models are based on some questionable assumptions, including dominance of positive feedbacks in a perturbed climate state. The particular model used, the GFDL model, produces a greater sensitivity to a doubling of CO2 than either the median IPCC projection (GFDL, 2004) or recent empirical studies (Annan and Hargreaves, 2006). Further, while Gore’s only reference to the time needed for these changes is the claim that CO2 doubling could happen “in less than 50 years”, the depicted model results are for a doubling in 70 years followed by a few centuries’ climate stabilization, or a quadrupling in 140 years followed by a few centuries’ climate stabilization. Results are also seasonally dependent (summer is shown). Recently, greenhouse emission growth rates have slowed, so assumptions of a CO2 doubling in less than 50 years or a quadrupling do not appear appropriate. Hansen et al., 2000, suggest that non-CO2 greenhouse gases are the principal causes of recent warming, in which case the assumptions regarding accelerated carbon dioxide emissions are also inappropriate.
