Falsehoods in Gore's An Inconvenient Truth

Falsehoods in Gore's An Inconvenient Truth
compiled by Wm. Robert Johnston
Contents:
• Executive summary
• Details--the science
• Details--history, economics, etc.
• Links
• References
________________________________________
Executive summary: Al Gore's new book and movie, both titled An Inconvenient Truth, have been hailed by environmentalists--despite being filled with false or misleading claims about the science of global warming and related issues. This page details errors in the book (2006, Rodale Books), which in summary include:
• Misleading links between weather events and climate change: Climate is the average of weather conditions over long time periods; because the climate system is inherently variable, individual weather events are not indicative of trends. Nonetheless, Gore overwhelms the reader with many individual events, claiming this is global warming in action: a European heatwave, record daily highs in U.S. cities one summer, hurricane Katrina, floods in Europe and China, and more. To address the issue of climate change, all such events must be considered over time. As it turns out, in several cases such analysis refutes any claims of recent trends (for example, with regard to floods).
In other cases, the scientific community is engaged in much research and debate. Gore claims that there is "an emerging consensus" that hurricane activity is on the upswing due to global warming. The reality is that this is the subject of much debate in the scientific community: different researchers have produced contradictory conclusions, but the factors involved are far more complex than Gore admits, and research is continuing.
• Misrepresentation of data: Of the various graphs and other data Gore presents, some of it is misrepresented. Gore presents one graph, said to be temperature data derived from ice cores, to support the controversial claim of one research group--Mann et al.--that current temperatures are higher than anytime in the last 1,000 years. The graph is not the ice core data, however, but the Mann et al. data derived from tree rings and other proxies. The broader claim is questioned by many scientists as well--much research suggests that temperatures around 1100-1300 AD were about as warm as today--as well as the methodology used to support such claims. Gore uses another set of ice core data to claim that carbon dioxide concentrations have driven global temperatures for the last 600,000 years. He admits the actual relationship is "complicated", which is as close as he comes to admitting the fact that the temperature changes came first, and probably helped drive the carbon dioxide changes.
These aren't the only cases of sloppiness with data: Gore claims the hottest year on record was 2005, but in reality existing observations don't have the accuracy to discriminate between, say, 2005 and 1998, a hot year due to an extreme El Nino event. He claims that the increasing closures of the barrier's on Britain's Thames River show sea level is rising, but doesn't mention that the British government recently changed the rules for such closures, including closing the barriers to deal withlow sea level; and he claims that a particular bird species is "in trouble" in the Netherlands due to climate change, but researchers report no change in this bird population. He cites a peak in tornadoes in 2004 as further evidence, but this peak came from new technology permitting the counting of more weak tornadoes than ever before; comparison of consistent data shows no trends in tornadoes.
• Exaggerations about sea level rise: Gore claims that potential melting of ice sheets in Greenland and West Antarctic will force the "evacuation" of millions of people to escape sea level rise of 6 meters (20 feet). This flatly contradicts even the worst-case scenarios described by the scientific community. Most research indicates that such melting, even if it could occur, would take 1,000 to 5,000 years; the minimum timescale described by any researcher for such melting is still centuries. Even the United Nations' IPCC, source of the "consensus" analysis which still overestimates future warming, only predicts sea level rise of 0.1 to 0.8 meters (4 to 30 inches) in the next 100 years.
• Misleading claims about effects of climate change: Gore claims that the emergence of new diseases is related to global warming, but most of the diseases he lists have little or no relationship to climate. Even in the case of malaria, a disease with a stronger link to climate, health experts cite the management of human infrastructure and health systems as far more important factors. In other cases Gore neglects the strong influence of human resource management, as with linking occurrence of wildfires or pest outbreaks to global warming. He also claims global warming is causing a "significant" number of polar bear drownings, based on a report of four drowned polar bears; however, other researchers report the polar bear population is generally unchanged. Melting of glaciers on Mount Kilimanjaro and in Glacier National Park are cited as consequences of global warming, but in both cases these glaciers have been melting since the 1800s, when the Earth emerged from a period of global cooling.
• Reliance on worst-case scenarios: An underlying problem is that Gore seizes upon worst-case scenarios and presents them as fact--sometimes omitting important qualifiers. Much of the claims about the consequences of future global warming rely on climate models that Gore calls "evermore accurate", but significant questions about the reliability of these models remain, and the effects cited by Gore presume that the worse-case predictions of these models are the correct ones. More generally, climate change should be considered at the regional or local level, where impacts would variously be positive or negative--especially depending on how we choose to respond. Gore consistently discusses the most negative impacts, and even minimizes the possibility of positive change.
• False claims about scientific views on global warming: Gore asserts that the scientific community is in essentially unanimous agreement with his interpretation of global warming, and dismisses skepticism of global warming as an energy industry conspiracy. Not only are such claims false, they severely misrepresent the very process of science. Gore cites a flawed editorial from a science journal to claim that all published research agrees with the "consensus" view on global warming; in reality, much published research contradicts Gore's position on global warming, and a recent survey of climate scientists found the community fairly split on the claim that there is an imminent threat from human-caused global warming. Despite the abundance of scientific research contradicting his position, Gore instead concentrates on refuting a handful of skeptical claims from outside the scientific community--and can't even get the facts right on those. To add insult to injury, Gore repeatedly impugns the motives of scientists and non-scientists who question his "consensus" on global warming. Rather than confront the scientific facts, he stereotypes the critics and dismisses them based on imagined motives.
• Misleading claims about the responsibility of the United States: Gore says the United States is particularly to blame for the claimed global warming crisis, but doesn't give a fair view of the issues. He makes misleading comparisons of fuel economy standards in the U.S. and other countries; also, he criticizes the U.S. failure to ratify the Kyoto Protocol without acknowledging the ways in which the Protocol disproportionately targeted the U.S. economy. He also understates the economic adjustments required to attain the goals he sets.
• Conceptual errors: Gore's explanation of several topics, including the greenhouse effect, the relationship of carbon dioxide and global temperature, decline in Arctic Ocean pack ice, structure of the Greenland ice sheet, and ozone depletion, contain conceptual errors. He may indeed have a correct understanding of these issues, but what he communicates serves to perpetuate misconceptions on these subjects. Combined with the low reading level of the text, this tends to convey the lowest expectations of his readers.
Gore's portrayal of the subject of global warming is scientifically unsupportable; even some scientists who accept the premise of global warming have been willing to call him on some errors. His portrayal of scientific skepticism regarding global warming is shameful; science requires healthy criticism to progress. The effect of attempts by Gore and others to silence dissent is harmful to scientific understanding as well as its application by society. The effort to use such twisted science to further a political agenda is such a harm.
________________________________________
Details--the science:
• "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)
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 CO2from 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 CO2concentrations 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 CO2doubling 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.
• "Three years ago [the Ward Hunt shelf] cracked in half, to the astonishment of scientists. This had never happened before." (p. 128)
The Ward Hunt Ice Shelf had loss 90% of its area from 1906 to 1982, and only covered 443 sq. km at the time of the breakup, which occurred over the period 2000 to 2002 (Mueller et al., 2003). The breakup of this shelf was not particularly astonishing, given observed calving of icebergs over the preceding decades; the remarkable aspect was the emptying of low-salinity surface water from Disraeli Fiord, previously trapped by the shelf and overlying high-salinity water.
• "Since the 1970s, the extent and thickness of the Arctic ice cap has diminished precipitously. There are now studies showing that if we continue with business as usual, the Arctic ice cap will completely disappear each year during the summertime. At present, it plays a crucial role in cooling the Earth. Preventing its disappearance must be one of our highest priorities." (p. 143)
Studies of actual observations of Arctic sea ice show significant year-to-year variability (Laxon et al., 2003), which is not reproduced in the model studies Gore cites, indicating that they do not correctly simulate sea ice dynamics. The role of Arctic sea ice in affecting global climate by reflecting sunlight back to space is not uniquely crucial, since cloud cover over the same region has a similar effect, and clouds are not well simulated in the GCMs in question (Potter and Cess, 2004).
• "The reason this Arctic ice cap has been melting so quickly is first because it is much thinner than the Antarctic ice cap, since it floats on top of the Arctic Ocean. Second, as soon as a portion of the ice melts, there is a dramatic difference in the amount of heat absorbed from the sun." (p. 144)
Antarctica has a much colder climate than the Arctic because the thick icecap is built up to an altitude much higher than sea level. Many studies attribute the recent thinning of the Arctic ice cap not directly to more melting at a given location as Gore implies, but to changes in the winds and ocean currents that move the sea ice from one location to another (Hilmer and Jung, 2000; Laxon et al., 2003).
• "A new scientific study shows that, for the first time, polar bears have been drowning in significant numbers." (p. 147)
The "significant numbers" are four drowned polar bears observed in 2004 (Monnett et al., 2005). Of thirteen polar bear populations in Canada, only two show recent decreases while eleven show increases or no population change (Taylor, 2006); in Alaska, the two populations are relatively stable (NFS, 2002a; NFS, 2002b).
• "A study from the Netherlands, depicted below... As a result [of warming], the chicks are in trouble." (p. 153)
The depicted graph does not accurately represent the sensitivity of the great tit (which was the subject of the study, not the black tern depicted in the photo on p. 153) to the relative time of peak caterpillars/bird-hatching. The graph is reproduced from National Geographic, 2004, which appears to have arbitrarily chosen the widths of these curves, since their cited source (Both and Visser, 2001) does not report such data on the distributions of this data. Consequently, the graph exaggerates the sensitivity of the great tit to the change in peak caterpillar population. Some factors are not represented such as the birds adapting by finding other sources of food. The Scientific American article in question states "The gap between the schedules of the caterpillars and the birds has had no demonstrable effect so far on tit numbers" (Grossman, 2004).
• "Swiss frost days...invasive species..." (p. 154)
The graph is reproduced from National Geographic, 2004, which in turn reproduced it from Walther et al., 2002: both of these use the more accurate label "exotic species", while Gore uses "invasive species". Gore does not identify these species or the nature of this measurement: this represents broad-leafed plant species imported by humans to gardens and parks in southern Switzerland, which have subsequently spread from these locations. The actual methodology used to produce this data is discussed elsewhere (Walther, 2000; Walther, 2002) and may not be a linear indicator of the spread of such plant life. While such spread is influenced by milder local climate, it is also influenced by the selection and frequency of plants imported.
• "...14 million acres of spruce trees in Alaska and British Columbia that have been killed by bark beetles, whose rapid spread was once slowed by colder and longer winters." (p. 156)
The bark beetle outbreaks in the late 1990s reflected a combination of several warm winters and poor forest management practices, such as fire suppression practices (ADNR, 2004).
• "In fact, we are facing what biologists are beginning to describe as a mass extinction crisis, with a rate of extinction now 1,000 times higher than the normal background rate." (p. 163)
Known species extinctions in the last several centuries total about 1,000, with very few attributed to climate change. The estimates Gore refers to here are unconfirmed estimates which either assume that GCM predictions of future warming are reliable or consider the effects of phenomena apart from global warming.
• "Corals--along with many other ocean life forms--are threatened by the unprecedented growth of carbon dioxide emissions worldwide..." (p. 168)
Gore does not acknowledge significant variations in coral reef response to perturbations such as temperature or dissolved carbon dioxide. A recent review (Hughes et al., 2003) states "reefs will change rather than disappear entirely, with some species already showing far greater tolerance to climate change and coral bleaching than others."
• "In general, the relationship between the human species and viruses is less threatening when there are colder winters, colder nights, more stability in climate patterns, and fewer disruptions... Global warming pushes all of these boundaries in the wrong direction, thereby increasing human vulnerability to new and unfamiliar diseases, as well as new strains of diseases once under control... mosquitoes are profoundly affected by global warming... Some 30 so-called new diseases have emerged over the last 25 to 30 years. And some old diseases that had been under control are now surging again. One example is the West Nile virus..." (pp. 172-175)
Most of the "new diseases" in this sensationalist listing are irrelevant to climate change discussions, as the disease-spread mechanisms are poorly linked to climate or not linked to climate at all. Most of the new diseases listed on p. 174 are associated with human interaction/infrastructure changes, i.e. spread by global transportation, spread in closed artificial environments, spread mainly by direct contact with body fluids, etc. Claims regarding climate change-disease links must be limited to those diseases which have some relation to climate, such as mosquito-borne malaria. However, health experts point out that even for these diseases such claims exaggerate the dependence of disease spread on climate to the exclusion of other factors. Malaria, for example, is affected more by health care practices, degree of development, and degree of past control exercised. In particular, control of malaria has suffered from the opposition to the use of DDT for mosquito control (Roberts et al., 1997). Further, research indicates that estimates of climate-related malaria impact are exaggerated (Rogers and Randolph, 2001) and tend to disregard the body of knowledge about the disease (Reiter et al., 2004).
• "Once the sea-based ice shelf was gone, the land-based ice... began to shift and fall into the sea... This is one of the reasons sea levels have been rising worldwide..." (p. 184)
Current sea level rise, estimated at 2.8 centimeters per decade, is mostly attributed to thermal expansion of the oceans (Cazenave and Nerem, 2004), with additional contributions from net mass loss from mountain glaciers (IPCC, 2001). Glacial outflow as described is a minor contributor to current sea level change, given that ice accumulation on inland ice caps mostly offsets this.
• "Many residents of low-lying Pacific Island nations have already had to evacuate their homes because of rising seas." (p. 187)
The evacuations referred to cannot be linked to global sea level rise. Measurements of sea level change at Pacific Islands vary from island to island, with some showing rises and some showing drops. These changes are primarily the result of local geologic subsistence or uplift. The primary issue here is the increase of population living in the lowest locations on these islands, and the increase in more permanent habitations at such locations. The situation is somewhat analogous to the increase in flood-related damage in the United States, which results not from more floods but from more construction in areas known to be vulnerable to floods.
• "The Thames River... In recent decades, higher sea levels began to cause more damage... The graph below shows how frequently London has had to use these barriers... The resulting pattern is similar to many others that measure the increasing impact of global warming worldwide." (pp. 188-189)
Recent increases in Thames barrier closures reflect changes in the rules for such closures along with increasing closures to keep river water in, i.e. a response to relatively low sea level, not high sea level. The British government has stated that Thames barrier closures should not be considered an indicator for climate change (DEFRA, 2004).
• "The East Antarctic ice shelf...had been thought to be still increasing in size... However, two new studies in 2006 showed first that the overall volumes of ice in East Antarctica now appear to be declining..." (p. 190)
The one study related to East Antarctic ice volume is based on only three years' observations from the GRACE satellite and actually show no net change over the study period (Velicogna and Wahr, 2006). These results are somewhat model dependent, and other researchers using the same dataset have concluded that East Antarctic ice volume increased (Chen et al., 2006; Ramillien et al., 2006). The broader body of scientific research on this topic, using both measurements and models, shows East Antarctic ice volume has increased in the past few decades (IPCC, 2001; van de Berg et al., 2006).
• "In recent years, the melting [in Greenland] has accelerated dangerously." (p. 194)
While some recent research has described mechanisms for acceleration of glacier outflow in Greenland (Zwally et al., 2002), measurements of the cumulative mass balance for Greenland show that its contribution to sea level is about 0.1-0.4 millimeters per year, such that "dangerous" is not a useful term. Further, the current conditions in Greenland are not unprecedented; measurements show that temperatures in Greenland in the 1930s were about the same as temperatures today (Chylek et al., 2006; Vinther et al., 2006). In general, observed Arctic warmings are significantly less than predicted, also refuting the GCMs.
• "If Greenland melted or broke up and slipped into the sea--or if half of Greenland and half of Antarctica melted or broke up and slipped into the sea, sea levels worldwide would increase by between 18 and 20 feet." (p. 196)
The Greenland ice sheet cannot slip into the sea, since it is resting in a bowl-shaped depression produced by its own weight, surrounded by mountains which permit only limited glacier outflow to the sea. Gore's reference to "half of Antarctica" should be to "half of the West Antarctic ice sheet", which is the portion of Antarctica's ice comparable to Greenland in volume and the portion showing any sensitivity to climate change. Only with regard to the West Antarctic ice sheet have any scientists proposed any potential for accelerated outflow into the sea, but even under the most pessimistic scenarios described in the scientific literature this would take hundreds of years. The consensus of the scientific community is for estimates of thousands of years for both Greenland (Greve, 2000; Alley et al., 2005; Lowe et al., 2006) and West Antarctica (Oppenheimer, 1998; Vaughan and Spouge, 2002; Oppenheimer and Alley, 2004).
• "This is what would happen to Florida... San Francisco Bay... the Netherlands... Beijing... More than 20 million people would have to be evacuated... In Shanghai and the surrounding area, more than 40 million people would be forced to move... In Calcutta and Bangladesh, 60 million people would be displaced... The site of the World Trade Center would be underwater." (pp. 198-209)
The United Nations IPCC predictions for sea level rise over the next 100 years, even though they are based on models and assumptions which exaggerate warming over that period, are only 0.1 to 0.8 meters (median estimate 0.48 meters) (IPCC, 2001). As mentioned above, the consensus of the scientific community is that sea level rise of 6 meters/20 feet as described by Gore, even if it does happen, would take thousands of years. A minority view in the scientific community suggests scenarios in which this could occur in 250-400 years. Such timescales, which are longer than the history of the country that built the World Trade Center, would certainly not require any "evacuations". The depicted images also use a subtle technique to exaggerate the appearance of sea level rise: the post-rise images are from a more distant perspective, causing the remaining land to be even smaller in appearance.
• "The graph below shows the steady increase in major wildfires in North and South America..." (p. 229)
Such wildfires are less a reflection of any climate change and more a reflection of increases in population, poor historical management practices by the U.S. government of woodlands and grasslands, and increased use of fires for clearing forest in Latin America.
• "Moreover, since science thrives on uncertainty and politics is paralyzed by it, scientists have a difficult time sounding the alarm bells for politicians, because even when their findings make it clear that we're in grave danger, their first impulse is to replicate the experiment to see if they get the same result." (p. 260)
This statement mischaracterizes science. Many scientists are quite willing to "sound alarm bells", some whether or not the evidence justifies such concern. More generally, scientists are engaged in evidence-based testing of descriptions of the world we live in, and are disinclined to involve themselves in political applications of their work. Nonetheless, scientists are human beings and tend to be quite ready to call attention to hazards they discover, as is evident from a cursory inspection of the history of science in the public arena. It is unfair to suggest that scientists will tend not to call for attention to clear evidence of danger.
• "For example, the so-called global warming skeptics cite one article more than any other in arguing that global warming is just a myth: a statement of concern during the 1970s that the world might be in danger of entering a new ice age..." (pp. 260-261)
Gore is incorrect to claim that such references to past concerns about global cooling stem from a single article, or only from non-peer reviewed sources. Kukla et al., 1972, discussed the possibility of an ice age, and similarly the review by Kukla and Matthews, 1972, of a scientific conference titled "The Present Interglacial, How and When Will it End?" stated "several investigators showed ... if nature were allowed to run its course unaltered by man, events similar to those which ended the last interglacial should be expected to occur perhaps as soon as the next few centuries." To be clear, the scientific community was only beginning to evaluate long-term climate change, whether from natural or man-made causes, but such views were more widely disseminated (out of context) by the press and by environmentalists as well. The Newsweek article cited by Gore (Gwynne, 1975) is only one such example (it was cited by Rush Limbaugh in 2002, perhaps Gore's source of information); other such reports included an article in National Geographic (Mathews, 1976) and a vague statement by prominent environmentalist (Ehrlich, 1968). The point raised by "skeptics" here is not so much a reference to the vetted claims of the scientific community, but to the tendency of the popular media in general and some environmentalists in particular to take scientific claims out of context, to single out the worst case scenario from a range of possibilities, and to present this scenario as fact, as Gore does.
• "There is a misconception that the scientific community is in a state of disagreement about whether global warming is real, whether human beings are the principal cause, and whether its consequences are so dangerous as to warrant immediate action. In fact, there is virtually no serious disagreement remaining on any of these central points..." (p. 261)
This statement is false. A significant number of scientists reject the first two points, or would qualify any agreement. The third claim, that "consequences are so dangerous as to warrant immediate action," is likely rejected by a majority of the scientific community, particularly if the context is Gore's specific claims. To declare the debate over, as Gore does, is a rejection of scientific methodology. The survey by Bray described below (Bray, 2005) demonstrates a very mixed set of opinions in the scientific community.
• "Dr. Naomi Oreskes, published in Science magazine a massive study of every peer-reviewed science journal article on global warming from the previous 10 years... Percentage of articles in doubt as to the cause of global warming: 0%" (p. 262)
The cited "study" by Oreskes, a historian, comprised a review of only 928 abstracts identified by a search engine using the keywords "global climate change" (not "climate change" as her article originally claimed, as this yields 12,000 abstracts). Her results were presented in an opinion editorial in Science (Oreskes, 2004), days before the 10th Conference on Parties of the United Nations Framework Convention on Climate Change. The scientific method for validating research is to replicate results, and Oreskes' work fails this test. Review of the Oreskes' set shows at least two that explicitly reject the 'consensus position' within the abstract, even apart from the remainder of the paper. Peiser conducted a similar study of abstracts identified in a search for "global climate change": of 1,117 abstracts, he found that only 1% "explicitly endorse the 'consensus view'," 29% "implicitly accept the 'consensus view'," 3% "reject or doubt the view that human activities are the main drivers of 'the observed warming over the last 50 years'," and most take no position or are unrelated to the global warming hypothesis (Peiser, 2005). A 2003 survey by Bray (Bray, 2005) of 530 climate scientists asking "To what extent do you agree or disagree that climate change is mostly the result of anthropogenic causes?" yielded very mixed results: on a scale of one to seven, 56% agreed strongly to slightly (including 9% strongly) and 29% disagreed strongly to slightly (including 10% strongly). Letters on both of these studies, incidentally, were rejected by Science. Such superficial studies as that by Oreskes are biased by the obligatory acknowledgement of "climate change" that researchers must make in order to get research published, particularly in view of editorial bias such as that exhibited by Science.
• "The misconception that there is serious disagreement among scientists about global warming is actually an illusion that has been deliberately fostered by a relatively small but extremely well-funded cadre of special interests, including Exxon Mobil and a few other oil, coal, and utilities companies." (p. 263)
This is a slanderous misrepresentation of the nature of scientific debate on the issue of climate change. Many scientists, based on conclusions drawn from their examination of the evidence, hold sincere disagreements with some or all aspects of the global warming hypothesis as described by Gore. Some are falsely accused of financial ties to the energy industry, despite the fact that they may have difficulty obtaining funding from traditional sources with a pro-global warming bias. Whatever expenditures undertaken by the energy industry on public relations related to global warming, similar large expenditures have been undertaken by the environmentalist lobby. (And only one of these two lobbies has produced a major motion picture.)
• "In 1984 a dramatic hole in the ozone layer was discovered above Antarctica, just as the scientists forecasted." (p. 295)
The discovery of the ozone "hole", a seasonal partial depletion of ozone over Antarctica, was not consistent with the forecasts. The "hole" represented depletion phenomena specific to the the climate conditions and presence of cloud particles over Antarctica, a phenomena not anticipated.
• "Misconception 1 'Scientists disagree...'
"In fact... scientists overwhelmingly agree..." (p. 308)
The issue is not whether humans perturb the climate system at all, but whether they are the dominant driver for dangerous global temperature increases as Gore claims. As previously discussed, Gore is incorrect to claim of a strong scientific consensus on this point.
• "Misconception 2 'Lots of things can impact climate--so there's no reason we should single out CO2 to worry about.'
"We have become more powerful than any force of nature." (p. 309)
The real issue is whether the specific actions advocated by Gore--the Kyoto protocol, for one--will have a meaningful impact when considered against natural influences, known and unknown.
• "Misconception 3 'Climate naturally varies over time, so any change we're seeing now is just part of a natural cycle.'
"But these changes all took place with natural variations in carbon dioxide levels that were smaller than the ones we are now causing... we are outside the realm of natural climate variation. More CO2 in the atmosphere means warming temperatures" (p. 312)
Derived CO2 data predating the ice core data cited by Gore show CO2 concentrations several times greater than modern concentrations.
• "Misconception 4 'The hole in the ozone layer causes global warming'
(p. 313)
The ozone layer has ozone concentrations of about 6 parts per million--ten times higher than at the Earth's surface, but still a very minor constituent. Ozone absorbs only a narrow energy range of solar radiation; higher energy radiation is absorbed by the thin atmosphere at much higher altitudes, for example, and most radiation is visible or infrared radiation which can reach the surface. The ozone "hole" is a seasonal region where concentrations are noticeably lower, say 2-4 parts per million, limited to the polar regions. While more ultraviolet radiation reaches the surface in the polar areas when the hole is present than when it is not, the amount of radiation is still significantly lower than that reaching the surface near the equator. Despite the modeled effect of stratospheric cooling on ozone depletion, the ozone layer is currently recovering faster than some predictions.
• "Misconception 5 'There is nothing we can do about climate change. It's already too late.'
(p. 315)
Gore urges various specific actions, including regulatory actions, but does not discuss the negative consequences of these actions or the magnitude of their impact on the supposed problem.
• "Misconception 6 'Antarctica's ice sheets are growing, so it must not be true that global warming is causing glaciers and sea ice to melt.'
(p. 316)
The "new 2006 study" referred to by Gore (possibly Velicogna and Wahr, 2006) represents a minority opinion, with most scientific research indicating that the East Antarctic Ice Sheet is growing (for example, Chen et al., 2006; Ramillien et al., 2006; and van de Berg et al., 2006).
• "Misconception 7 'Global warming is a good thing...'
"Melting ice sheets are causing sea levels to rise, and if big ice sheets melt...millions of people will become refugees...Other predicted impacts...drought...flooding...new diseases." (p. 317)
Gore's predicted consequences are exaggerated, as previously discussed, beyond even the predictions based on models which arguably overestimate future climate change. Positive effects of climate change are generally ignored. Both globally and in the U.S., mortality from extreme weather events continues to steadily decline and is a minor contributor to overall mortality (Goklany, 2006).
• "Misconception 8 'The warming scientists are recording is just the effect of cities trapping heat...'
"People who want to deny global warming because it's easier than dealing with it try to argue that what scientists are really observing is just the 'urban heat island' effect... This is simply wrong. Temperature measurements are generally taken in parks, which are actually cool areas within the urban heat islands... Most scientific research shows that 'urban heat islands' have a negligible effect..." (p. 318)
Scientists who point out measurement bias due to the urban heat island effect are doing so because the evidence demands it, not from denial. Temperature measurements in urban "parks" are still subject to bias from the effect, since air throughout the urban area is heated by the effect. Scientific research has produced varying estimates of the amount of bias. Insufficient work has been done to examine bias in the principal surface-based temperature series cited in support of global warming.
• "Misconception 9 'Global warming is the result of a meteor that crashed in Siberia in the early 20th century'
(p. 320)
This spurious claim by Shaidurov, 2005, is not particularly relevant to the debate. Gore cites the effect of water vapor, the effect discussed by Shaidurov, but the larger body of scientific research on such asteroid/comet impacts cites the effects of dust, sulfur dioxide, and nitric oxides as more important to climate. These effects could be long-term for impacts larger than the 1908 Tunguska impact.
• "Misconception 10 'Temperatures in some areas aren't increasing, so global warming is a myth'
"Global warming refers to the rise in the average temperature..." (p. 321)
Gore is correct that local climate trends do not equate to global trends (although they are more relevant to discussion of climate change than point temperature highs and extremes discussed extensively by Gore earlier in the book). They do serve to indicate than any changes are not uniformly bad, as implied by Gore; they also can accumulate to discredit claims regarding regional trends claimed by some supporters of the global warming hypothesis. The claim that various measurement methods yield the "same general results" ignores the fact that the disagreements are significant enough to undermine the validity of the models used as the basis for most predictions of future calamity.
________________________________________
Details--history, economics, etc.:
• "In 2000 I ran for president. It was a long and hard-fought campaign that was ended by a 5-4 decision in the Supreme Court to halt the counting of votes in the key state of Florida." (p. 8)
More accurately, the ruling halted the selective recounting of some Florida ballots for the third or fourth time.
• "This is the last picture of our planet taken by a human being from space. It was taken in December 1972 during the Apollo 17 mission... What makes this image so extraordinary is that it's the only photo we have of the Earth from space taken when the Sun was directly behind the spacecraft." (p. 15)
Subsequent manned space flights routinely photograph the Earth from space--just not from as great a distance. Many other images show a full Earth, including daily images from geosynchronous weather satellites.
• "In the debates that ignite around famine relief, it is sometimes implied that Africans have brought this upon themselves through corruption or mismanagement. But the more we understand about climate change, the more it looks as if we may be the real culprit. The United States emits about a quarter of the world's greenhouse gases... We helped manufacture the suffering in Africa, and we have a moral obligation to try to fix it." (p. 117)
Gore progresses here from saying "we may be the culprit" to asserting "we helped manufacture the suffering." The science does not support such an assertion, or an attribution to the United States in particular. While the United States does produce 22.8% of global greenhouse emissions (and in doing so produces food and other goods exported to Africa), observations suggest that a large fraction of these emissions are also absorbed by land use practices in North America (Fan et al., 1998;Pacala et al., 2001). The policy practices blamed for African famines are mischaracterized as something Africans "brought... upon themselves"; more accurately, undemocratic African regimes unresponsive to the people they govern are widely acknowledged as engaging in practices which have increased suffering during famines.
• "Albert Gore Sr. ..." (p. 210)
Albert Gore Sr., after leaving Congress, served as vice president of Occidental Petroleum Company, as well as board member for both petroleum and coal companies. His support of civil rights was mixed; he voted against the Civil Rights Act of 1964.
• "Contributions to global warming... 30.3% United States..." (pp. 250-251)
Gore does not specify, but he appears to be referring to cumulative emissions, from the beginning of the industrial age to the present. This gives greater shares to nations that industrialized first, as compared to comparison of current emission rates. According to the Carbon Dioxide Information Analysis Center, of cumulative CO2 emissions from 1750 to 2003, the United States is responsible for 29.2% of the world total. For annual emissions in 2003 (the latest reported figures), the United States is responsible for 22.8% of the world total. For the same year, the People's Republic of China share was 16.3% and that of Europe was 17.4% (Marland et al., 2006).
• "The carbon exchange market... A similar approach can speed up the reduction of CO2 emissions. The European Union has adopted this U.S. innovation and is making it work effectively." (p. 252)
The European Union Greenhouse Gas Emission Trading Scheme crashed in May 2006, when exchange prices fell from $36 per metric ton of carbon to $11 per metric ton of carbon (EIA, 2006), due to reports of surplus carbon allowances for several countries. The market scheme will require significant adjustments before it is reopened in 2008; during the 2005-2006 experiment, no credits for carbon sequestration were included.
• "Carbon emissions per person... Carbon emissions per country/region" (p. 253)
This comparison of selected countries or regions conceals a variety of factors in per capita carbon emissions. In the nation-by-nation listing of per capita emissions by the CDIAC (Marland et al., 2006), the U.S. ranks below Qatar, the United Arab Emirates, Kuwait, Bahrain, Luxembourg, and Trinidad and Tobago. The United States ranks higher than Europe as a whole not only because of greater personal consumption by Americans but also because of greater requirements associated with winter heating and summer cooling, plus greater transportation requirements associated with lower population density. This helps explain why the U.S. per capita emissions are only 11-12% greater than those for Canada and Australia. The per capita emissions for Japan and the People's Republic of China are slightly misrepresented in the graph; they were 2.64 and 0.86 tons of carbon in 2003, respectively, slightly more than shown. The second graph is mislabeled; it is unclear what quantity Gore was trying to show.
• "At the beginning of 2001, President Bush hired a lawyer/lobbyist named Phillip Cooney to be in charge of environmental policy in the White House..." (p. 264)
Phillip Cooney was never in charge of the White House Council on Environmental Quality, but was chief of staff and was subordinate to James Connaughton, Council chairman. Final review of the cited documents included individuals other than Cooney. It could be argued that the Environmental Protection Agency, under administrator Stephen Johnson, is a more important expression of administration environmental policy. There is irony in Gore's criticism of Cooney's lack of scientific credentials; while Cooney has a bachelors degree in economics and a law degree, Gore has a bachelors degree in government and did not complete law school.
• "It is difficult to get a man to understand something when his salary depends upon his not understanding it. --Upton Sinclair" (pp. 266-267)
This statement could be equally applied to scientists who have a better chance of obtaining funding if they endorse the global warming hypothesis.
• "By ignoring scientific consensus on critical issues such as global climate change, [President Bush and his administration] are threatening the Earth's future." (p. 269)
The cited passage is an excerpt of a letter written to endorse John Kerry for president, and also criticized the Bush administration regarding immigration policy and federal funding of stem cell research. Of the 48 signatories, 22 had signed a petition opposing the war in Iraq. The cited statement arguably is an unscientific overstatement of their position.
• "...auto mileage standards... Yet the United States is dead last." (p. 272)
Gore does not compare consistent fuel economy figures here, and does not acknowledge that in most cases multiple standards are involved. The Chinese "standard", for example, is really 16 different minimum thresholds for each of 16 different weight classes, excluding commercial vehicles and pickup trucks; in 2005, these thresholds range from 19 to 38 mpg. In the United States, on the other hand, each manufacturer must meet a fleet average for two classes, 27.5 mpg for cars and 21 mpg for trucks in 2005. The graph implies Chinese standards are about 40-45% better than U.S. standards for 2005-7, but the World Resources Institute finds that "If the U.S. were to meet Chinese standards, fleet average fuel economy would need to increase by 5% for the Phase 1 (2005/2006) standards and by 10% for the Phase II (2008) standards" (WRI, 2004). There are significant differences in the transportation requirements, composition and growth of the vehicle fleet, etc., which are ignored in Gore's analysis. Gore singles out the government and auto manufacturers for criticism, but the fact is that if American consumers preferred smaller vehicles, fuel economy of the U.S. fleet would change. The reasons why Americans prefer larger vehicles (auto safety, larger family size, different needs, etc.) are ignored here.
• "But the auto companies are suing California to prevent this state law from taking effect--because it would mean that, 10 years from now, they would have to manufacture cars for California that are almost as efficient as China is making today." (p. 273)
The Alliance of Automobile Manufacturers is suing California, they say, because the regulation is in violation of federal law which gives the National Highway Traffic Safety Administration sole authority for establishing fuel economy standards.
________________________________________
Links:
• A Skeptic's Guidie to An Inconvenient Truth--by M. Lewis, Jr. at the Competitive Enterprise Institute.
• Gorey Truths: 25 Inconvenient Truths for Al Gore--by I. Murray at the Competitive Enterprise Institute.
• An Inconvenient Truth: Gore as Climate Exaggerator--by R. Bailey at Reason Online.
• The Discovery of Global Warming--by S. Weart at the American Institute of Physics.
• Rachel Goreson and Questions for Al Gore--by R. Spencer at TCS Daily.
• Inconvenient Truths Indeed--by R. C. Balling, Jr., at TCS Daily.
• An Inconvenient Truth--by P. Michaels at World Climate Report.
• The gods are laughing--by T. Harris at National Post of Canada.
• The Truth about An Inconvenient Truth--by H. S. Burnett at the National Center for Policy Analysis.
• An Inconvenient Truth--by J. Masters, at Weather Underground.
• Al Gore's movie--by E. Steig at RealClimate.
• And of course ... An Inconvenient Truth--the official web site!
________________________________________
References:
• Alaska Department of Natural Resources, Division of Forestry, 2004, "What's bugging Alaska's forests? Spruce bark beetle facts and figures," ADNR, on line [http://www.dnr.state.ak.us/forestry/insects/sprucebarkbettle.htm].
• Alley, R. B., P. U. Clark, P. Huybrechts, and I. Joughin, 2005, "Ice-sheet and sea-level changes," Science, 310:456-460.
• BBC, 14 Aug. 2003, "French heat deaths 'up to 3,000'," BBC News, on line [http://news.bbc.co.uk/2/hi/europe/3150097.stm].
• Both, C., and M. E. Visser, 2001, "Adjustment to climate change is constrained by arrival date in a long-distance migrant bird," Nature, 411:296-298.
• Bray, D., 2005, "The not so clear consensus on climate change," Dr. Dennis Bray, on line [http://w3g.gkss.de/G/Mitarbeiter/bray.html/BrayGKSSsite/BrayGKSS/WedPDFs/Science2.pdf].
• Cazenave, A., and R. S. Nerem, 2004, "Present-day sea level change: observations and causes," Reviews of Geophysics, 42:RG3001.
• Chan, J. C. L., 2006, "Comment on 'Changes in tropical cyclone number, duration, and intensity in a warming environment'," Science, 311:1713-1714.
• Chen, J. L., C. R. Wilson, D. D. Blankenship, and B. D. Tapley, 2006, "Antarctic mass rates from GRACE," Geophysical Research Letters, 33:L11502.
• Chylek, P., M. K. Dubey, and G. Lesins, 2006, "Greenland warming of 1920-1930 and 1995-2005," Geophysical Research Letters, 33:L11707.
• Cullen, N. J., T. Molg, G. Kaser, K. Hussein, K. Steffen, and D. R. Hardy, 2006, "Kilimanjaro glaciers: recent areal extent from satellite data and new interpretation of observed 20th century retreat rates," Geophysical Research Letters, 33:L16502.
• Dahl-Jensen, D., K. Mosegaard, N. Gundestrup, G. D. Clow, S. J. Johnsen, A. W. Hansen, and N. Balling, 1998, "Past temperatures directly from the Greenland Ice Sheet," Science, 282:268-271.
• Davis, C. H., Y. Li, J. R. McConnell, M. M. Frey, and E. Hanna, 2005, "Snowfall-driven growth in East Antarctic Ice Sheet assessment of long-term temperature trends," Bulletin of the American Meteorological Society, 86:497-504.
• Department for Environment Food and Rural Affairs, 2004, "Review of UK climate change indicators," DEFRA, on line [http://www2.defra.gov.uk/science/project_data/DocumentLibrary/GA01048/GA01048_2622_FRP.pdf].
• Dyurgerov, M. B., and M. F. Meier, 2005, "Glaciers and the changing Earth system: a 2004 snapshot," INSTAAR, on line [http://instaar.colorado.edu/other/download/OP58_dyurgerov_meier.pdf].
• Easterling, D. R., G. A. Meehl, C. Parmesan, S. A. Changnon, T. R. Karl, and L. O. Mearns, 2000, "Climate extremes: observations, modeling, and impacts,"Science, 289:2068-2074.
• Ehrlich, P., 1968, The Population Bomb.
• Elsner, J. B., K.-B. Liu, B. Kocher, 2000, "Spatial variations in major U.S. hurricane activity: statistics and a physical mechanism," Journal of Climate, 13:2293-3005.
• Emanuel, K., 2005, "Increasing destructiveness of tropical cyclones over the past 30 years," Nature, 436:686-688.
• Energy Information Administration, 2006, "International Energy Outlook 2006," EIA, on line [http://www.eia.doe.gov/oiaf/ieo/emissions.html].
• Fan, S., M. Gloor, J. Mahlman, S. Pacala, J. Sarmiento, T. Takahashi, and P. Tans, 1998, "A large terrestrial carbon sink in North America implied by atmospheric and oceanic carbon dioxide data and models," Science, 282:442-446.
• Goldenberg, S. B., C. W. Landsea, A. M. Mestas-Nunez, and W. M. Gray, 2001, "The recent increase in Atlantic hurricane activity: causes and implications,"Science, 293:474-479.
• Goklany, I. M., 2006, "Death and death rates due to extreme weather events: global and U.S. trends, 1900-2004," Goklany--Recent Papers, on line [http://members.cox.net/goklany/Extreme%20Events%20Note%20Hohenkammer.pdf].
• Greve, R., 2000, "On the response of the Greenland Ice Sheet to greenhouse climate change," Climatic Change, 46:289-303.
• Grossman, D., 2004, "Spring forward," Scientific American, 290(1):84-91.
• Gwynne, P., 28 April 1975, "The cooling world," Newsweek.
• Hansen, J., et al., 2006, "GISS surface temperature analysis," Goddard Institute for Space Studies, on line [http://data.giss.nasa.gov/gistemp/].
• Hansen, J., M. Sato, R. Ruedy, A. Lacis, and V. Oinas, 2000, "Global warming in the twenty-first century: an alternative scenario," Proceedings of the National Academy of Sciences.
• Hilmer, M., and T. Jung, 2000, "Evidence for a recent change in the link between the North Atlantic Oscillation and Arctic sea ice export," Geophysical Research Letters, 27:989-992.
• Hughes, T. P., A. H. Baird, D. R. Bellwood, M. Card, S. R. Connolly, C. Folke, R. Grosberg, O. Hoegh-Guldberg, J. B. C. Jackson, J. Kleypas, J. M. Lough, P. Marshall, M. Nystrom, S. R. Palumbi, J. M. Pandolfi, B. Rosen, and J. Roughgarden, 2003, "Climate change, human impacts, and the resilience of coral reefs,"Science, 301:929-933.
• IPCC, 2001, IPCC Third Assessment Report: Climate Change 2001: The Scientific Basis, Cambridge Univ. Press (Cambridge, UK).
• Jiang, T., Q. Zhang, R. Blender, and K. Fraedrich, 2005, "Yangtze Delta floods and droughts of the last millennium: abrupt changes and long term memory,"Theoretical and Applied Climatology, 82:131-141.
• Jones, P. D., M. New, D. E. Parker, S. Martin, and I. G. Rigor, 1999, "Surface air temperature and its changes over the past 150 years," Reviews of Geophysics, 37:173-199.
• Jones, P., and J. Palutikof, 2006, "Global temperature record," CRU, on line [http://www.cru.uea.ac.uk/cru/info/warming/].
• Kaser, G., D. R. Hardy, T. Moig, R. S. Bradley, and T. M. Hyera, 2004, "Modern glacier retreat on Kilimanjaro as evidence of climate change: observations and facts," International Journal of Climatology, 24:329-339.
• Klotzbach, P. J., 2006, "Trends in global tropical cyclone activity over the past twenty years (1986-2005)," Geophysical Research Letters, 33:L10805.
• Kukla, G. J., R. K. Matthews, and J. M. Mitchell, 1972, "The end of the present interglacial," Quarternary Research, 2:261-269.
• Kukla, G. J., and R. K. Matthews, 1972, "When will the present interglacial end?," Science, 178:190-191.
• Laxon, S., N. Peacock, and D. Smith, 2003, "High interannual variability of sea ice thickness in the Arctic region," Nature, 425:947-950.
• Lindzen, R. S., 1997, "Can increasing carbon dioxide cause climate change?," Proceedings of the National Academy of Sciences USA, 94:8335-8342.
• Lowe, J. A., J. M. Gregory, J. Ridley, P. Huybrechts, R. J. Nicholls, and M. Collins, 2006, "The role of sea-level rise and the Greenland Ice Sheet in dangerous climate change: implications for the stabilization of climate," in Avoiding Dangerous Climate Change, ed. by H. J. Schellnhuber, W. Cramer, N. Nakicenovic, T. Wigley, and G. Yohe, Cambridge Univ. Press (Cambridge, UK)
• Mann, M. E., R. S. Bradley, and M. K. Hughes, 1999, "Northern hemisphere temperatures during the past millennium: Inferences, uncertainties, and limitations,"Geophysical Research Letters, 26:759-762.
• Marland, G. T. A. Boden, and R. J. Andres, 2006, "Global, regional, and national CO2 emissions," in Trends: A Compendium of Data on Global Change, CDIAC (Oak Ridge, TN), on line at CDIAC [http://cdiac.esd.ornl.gov/trends/emis/meth_reg.htm].
• Mathews, S. W., Nov. 1976, "What's happening to our climate," National Geographic, 576-615.
• McCarthy, D., 2000, "Tornado trends across the U.S., 1950-2000," NOAA, on line [http://www.spc.noaa.gov/wcm/TornadoesandTrends_files/frame.htm].
• McCarthy, D., and J. Schaefer, 2005, "2004 year in tornadoes: what a year it was!," NOAA, on line [http://www.spc.noaa.gov/publications/mccarthy/tors2004.pdf].
• McIntyre, S., and R. McKitrick, 2003, "Corrections to the Mann et al. (1998) proxy data base and Northern Hemispheric average temperature series," Energy and Environment, 14:751-771.
• Mason, B., 2003, "African ice under wraps," Nature, on line [http://www.nature.com/news/2003/031117/full/031117-8.html].
• Michaels, P. J., P. C. Knappenberger, and R. E. Davis, 2006, "Sea-surface temperatures and tropical cyclones in the Atlantic basin," Geophysical Research Letters, 33:L09708.
• Moberg, A., D. M. Sonechkin, K. Holmgren, N. M. Datsenko, and W. Karlen, 2005, "Highly variable Northern Hemisphere temperatures reconstructed from low- and high-resolution proxy data," Nature, 455:613-617.
• Monnett, C., J. S. Gleason, and L. M. Rotterman, 2005, "Potential effects of diminished sea ice on open-water swimming, mortality, and distribution of polar bears during fall in the Alaskan Beaufort Sea," Minerals Management Service, on line [http://www.mms.gov/alaska/ess/Poster%20Presentations/MarineMammalConference-Dec2005.pdf].
• Mudelsee, M., M. Borngen, G. Tetzlaff, and U. Grunewald, 2003, "No upward trends in the occurrence of extreme floods in central Europe," Nature, 425:166-169.
• Mueller, D. R., W. F. Vincent, and M. O. Jeffries, 2003, "Break-up of the largest Arctic ice shelf and associated loss of an epishelf lake," Geophysical Research Letters, 30:2031.
• National Geographic, Sept. 2004, "A shift in seasons," National Geographic, 44-45.
• NOAA, 2005, "NOAA attributes recent increase in hurricane activity to naturally occurring multi-decadal climate variability," NOAA Magazine, on line [http://www.magazine.noaa.gov/stories/mag184.htm].
• NOAA, 2006, "Global surface temperature anomalies," National Climate Data Center, on line [http://www.ncdc.noaa.gov/oa/climate/research/anomalies/anomalies.html].
• NOAA Fisheries Service, 2002a, "Polar bear (Ursus maritimus): Chukchi/Bering Seas stock," NFS, on line [http://www.nmfs.noaa.gov/pr/pdfs/sars/ak02polarbearchukchibering.pdf].
• NOAA Fisheries Service, 2002b, "Polar bear (Ursus maritimus): Southern Beaufort Sea stock," NFS, on line [http://www.nmfs.noaa.gov/pr/pdfs/sars/ak02polarbearbeaufort.pdf].
• Oppenheimer, M., 1998, "Global warming and the stability of the West Antarctic Ice Sheet," Nature, 393:325-332.
• Oppenheimer, M., and R. B. Alley, 2004, "The West Antarctic Ice Sheet and long term climate policy," Climatic Change, 64:1-10.
• Oreskes, N., 2004, "The scientific consensus on climate change," Science, 306:1686.
• Pacala, S. W., G. C. Hurtt, D. Baker, P. Peylin, R. A. Houghton, R. A. Birdsey, L. Heath, E. T. Sundquist, R. F. Stallard, P. Ciais, P. Moorcroft, J. P. Caspersen, E. Shevliakova, B. Moore, G. Kohlmaier, E. Holland, M. Gloor, M. E. Harmon, S.-M. Fan, J. L. Sarmiento, C. L. Goodale, D. Schimel, and C. B. Field, 2001, "Consistent land- and atmosphere-based U.S. carbon sink estimates," Science, 292:2316-2120.
• Peiser, B., 2005, "Re: 'The scientific consensus on climate change'," Dr Benny Peiser, on line [http://www.staff.livjm.ac.uk/spsbpeis/Scienceletter.htm].
• Pezza, A. B., and I. Simmonds, 2005, "The first South Atlantic hurricane: unprecedented blocking, low shear and climate change," Geophysical Research Letters, 32:L15712.
• Pielke, R. A. Jr., 2005, "Are there trends in hurricane destruction?," Nature, 438(22):E11.
• Pielke, R. A. Jr., C. Landsea, M. Mayfield, J. Laver, and R. Pasch, 2005, "Hurricanes and global warming," Bulletin of the American Meteorological Society, 86:1571-1575.
• Pielke, R. A. Sr., 2006, "Are multi-decadal global climate simulations hypotheses? Have they been tested, and, if so, have the hypotheses as represented by the models, been falsified?," Climate Science, on line [http://climatesci.atmos.colostate.edu/2006/05/29/are-multi- decadal-global-climate-simulations-hypotheses/].
• Pielke, R. A. Sr., 2006, "Washington Post article on heat waves--balanced or biased," Climate Science, on line [http://climatesci.atmos.colostate.edu/2006/08/04/312/].
• Potter, G. L., and R. D. Cess, 2004, "Testing the impact of clouds on the radiation budgets of 19 atmospheric general circulation models," Journal of Geophysical Research, 109:D02106.
• Ramillien, G., A. Lombard, A. Cazenave, M. Llubes, and F. Remy, 2006, "Ice sheets mass balance from GRACE and corresponding contribution to sea level change," Geophysical Research Abstracts, 8:02330.
• Reiter, P. C. J. Thomas, P. M. Atkinson, S. I. Hay, S. E. Randolph, D. J. Rogers, G. D. Shanks, R. W. Snow, and A. Spielman, 2004, "Global warming and malaria: a call for accuracy," Lancet Infectious Diseases, 4:323-324.
• Roberts, D. R., L. L. Laughlin, P. Hsheih, and L. J. Legters, 1997, "DDT, global strategies, and a malaria control crisis in South America," Emerging Infectious Diseases, 3:295-302.
• Rogers, D. J., and S. E. Randolph, 2000, "The global spread of malaria in a future, warmer world," Science, 289:1763-1766.
• Royer, D. L., R. A. Berner, I. P. Montanez, N. J. Tabor, and D. J. Berrling, 2004, "CO2 as a primary driver of Phanerozoic climate," GSA Today, 14(3):4-10.
• Sato, M., and Hansen, J., 2006, "GISS surface temperature analysis: analysis graphs and plots," Goddard Institute for Space Studies, on line [http://data.giss.nasa.gov/gistemp/graphs/].
• Shaidurov, V., 2005, "Atmospheric hypotheses' of Earth's global warming," University of Leicester Department of Mathematics, on line [http://www.math.le.ac.uk/RESEARCH/APPLIED/VISITORS/MA-05-15--shaidurov.pdf].
• Sharma, K. P., C. J. Vorosmarty, and B. Moore III, 2000, "Sensitivity of the Himalayan hydrology to land-use and climatic changes," Climatic Change, 47:117-139.
• Siegenthaler, U., T. F. Stocker, E. Monnin, D. Luthi, J. Schwander, B. Stauffer, D. Raynaud, J.-M. Barnola, H. Fischer, V. Masson-Delmotte, and J. Jouzel, 2005, "Stable carbon cycle-climate relationship during the late Pleistocene," Science, 310:1313-1317.
• Singer, S. F., C. Starr, and R. Revelle, 1991, "What to do about greenhouse warming: look before you leap," Cosmos, 1:28-55.
• Singer, S. F., 2003, "The Revelle-Gore story: attempted political suppression of science," 283-297 in Politicizing Science: The Alchemy of Policymaking, ed. by M. Gough, Hoover Press (Washington, DC).
• Tans, P., 2006, "Trends in atmospheric carbon dioxide," NOAA ESRL, on line [http://www.cmdl.noaa.gov/ccgg/trends/].
• Taylor, M., 1 May 2006, "Silly to predict their demise," ArcticNet, on line [http://www.arcticnet-ulaval.ca/index.php?fa=News.showNews&menu=44&home=3&sub=1&id=133].
• Thompson, L. G., E. Mosley-Thompson, M. E. Davis, K. A. Henderson, H. H. Brecher, V. S. Zagorodnov, T. A. Mashiotta, and P.-N. Lin, 2002, "Kilimanjaro ice core records: evidence of Holocene climate change in tropical Africa," Science, 298:5593.
• Thompson, L. G., E. Mosley-Thompson, M. E. Davis, P.-N. Lin, K. Henderson, and T. A. Mashiotta, 2003, "Tropical glacier and ice core evidence of climate change on annual to millennial time scales," Climatic Change, 59:137-155.
• UNEP, 2004, "Impacts of summer 2003 heat waves in Europe," UNEP, on line [http://www.grid.unep.ch/product/publication/download/ew_heat_wave.en.pdf].
• USGS, 2003a, "Glacier monitoring in Glacier National Park," USGS, on line [http://www.nrmsc.usgs.gov/research/glaciers.htm].
• USGS, 2003b, "Glacier retreat in Glacier National Park, Montana," USGS, on line [http://www.nrmsc.usgs.gov/research/glacier_retreat.htm].
• van de Berg, W. J., M. R. van der Broeke, C. H. Reijmer, and E. van Meijgaard, 2006, "Reassessment of the Antarctic surface mass balance using calibrated output of a regional atmospheric climate model," Journal of Geophysical Research, 111:D11104.
• Vaughan, D. G., and J. R. Spouge, 2002, "Risk estimation of collapse of the West Antarctic Ice Sheet," Climatic Change, 52:65-91.
• Velicogna, I., and J. Wahr, 2006, "Measurements of time-variable gravity show mass loss in Antarctica," Science, 311:1754-1756.
• Vinther, B. M., K. K. Andersen, P. D. Jones, K. R. Briffa, and J. Cappelen, 2006, "Extending Greenland temperature records into the late eighteenth century,"Journal of Geophysical Research, 111:D11105.
• von Storch, H., E. Zorita, J. M. Jones, Y. Dimitriev, F. Gonzalez-Rouco, and S. F. B. Tett, 2004, "Reconstructing past climate from noisy data," Science, 306:679-682.
• Walther, G.-R., 2000, "Climatic forcing on the dispersal of exotic species," Phytocoenologia, 30:409-430.
• Walther, G.-R., E. Post, P. Convey, A. Menzel, C. Parmesan, T. J. C. Beebee, J.-M. Fromentin, O. Hoegh-Guldberg, and F. Bairlein, 2002, "Ecological responses to recent climate change", Nature, 416:389-395.
• Walther, G.-R., 2002, "Weakening of climatic constraints with global warming and its consequences for evergreen broad-leaved species," Folia Geobotanica, 37:129-139.
• Webster, P. J., G. J. Holland, J. A. Curry, and H.-R. Chang, 2005, "Changes in tropical cyclone number, duration, and intensity in a warming environment,"Science, 309:1844-1846.
• World Resources Institute, 2004, "Taking the high (fuel economy) road," World Resources Institute, on line [http://pdf.wri.org/china_the_high_road.pdf].
• Young, J. A. T., and S. Hastenrath, 1991, "Glaciers of the Middle East and Africa--Glaciers of Africa," USGS, on line [http://pubs.usgs.gov/prof/p1386g/africa.pdf].
• Zhao, H., and G. W. K. Moore, 2006, "Reduction in Himalayan snow accumulation and weakening of the trade winds over the Pacific since the 1840s,"Geophysical Research Letters, 33:L17709.
• Zwally, H. J., W. Abdalati, T. Herring, K. Larson, J. Saba, and K. Steffen, 2002, "Surface melt-induced acceleration of Greenland ice-sheet flow," Science, 297:218-222.