Neither Katrina or any other hurricane or cyclone can be attributed to anthropogenic global warming

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Criticisms of Al Gore's "An Inconvenient Truth"

The high court of London found that An Inconvenient Truth "uses emotive images of Hurricane Katrina and suggests that this has been caused by global warming" which is simply not provable.

The deadliest cyclone in recorded history was Cyclone Bhola, which struck Bangladesh (then part of Pakistan) in 1970. Estimates for the number killed range from 200,000 to 1,000,000 people. Like Katrina, this storm was classified as a category 3 when it made landfall. But unlike Katrina it did not have minute by minute satellite tracking. What was its maximum wind speed while it was over the ocean? It was reported to be 185 mph the day it made landfall, but nobody knows for sure. I'd like to show some large high resolution color pictures of the devastation and the suffering of the people, just like Al Gore did for Katrina, but there are few to be found. You can see several grainy low resolution black and white pictures here.

There were no cell phone cameras, few personal cameras and few, if any, television cameras in Bhola at that time. Although there were at least a hundred times the number of casualties due to the Bhola cyclone than due to Hurricane Katrina, most people today have never heard of the Bhola cyclone. Those in the United States that do remember Cyclone Bhola are probably fans of George Harrison's "The Concert for Bangladesh." (A great concert. by the way, featuring Harrison, Ringo Starr, Bob Dylan, Eric Clapton and more.)

Figure 1. Movie poster for "The Concert for Bangladesh

If you google "Katrina" and "hurricane" you will get 34 million hits. If you google "Bhola" and "cyclone" you will get 10 thousand hits. 3,400 hits on Katrina for every one hit on Bhola. Shortly after Cyclone Bhola the Bulletin of the American Meteorological Society published a paper by Neil Frank of the National Hurricane Center in Florida and S.A. Husain of the Pakistan Meteorological Department entitled "The Deadliest Tropical Cyclone in History?" They list five other hurricanes where the loss of life is believed to be more than 100,000 people. Four of the five are all prior to the 20th century. But the numbers are highly speculative. Before the days of mass communication its was hard to tell how many people died due to a storm in a neighboring village, let alone on the other side of the Earth.

The same effect holds for judging the meteorological parameters of storms. Since the 1970s tropical cyclones have been tracked from space with continuously improving technology. Aircraft have been used to study and track hurricanes starting in the mid 1940s. Prior to that, tracking relied of data from ships and islands while the storms were at sea, and from land side observations once a storm hit shore. So, as technology has advanced, the quality of data has advanced.

J.P. Kossin of the Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin-Madison, wrote in the Journal Geophysical Research Letters (2007) that "The variability of the available data combined with long time-scale changes in the availability and quality of observing systems, reporting policies, and the methods utilized to analyze the data make the best track records inhomogeneous by construction" Even in the short satellite era the quality of the data has continuously improved so that Kossin says "the known lack of homogeneity in both the data and techniques applied in the post-analyses has resulted in skepticism regarding the consistency of the best track intensity estimates." Kossin, et. al., re-analysed the satellite data used in the frequently cited paper by Webster that purported to show an increasing trend in tropical cyclones in the six major cyclone basins (West Pacific, East Pacific, South Pacific, Northern Indian, Southern Indian and North Atlantic). But first they made the data quality consistent by reducing the spatial and temporal resolution of the newer data to match the resolution of the older data (8 kilometers and 3 hours).

Kossin, et. al., found that the global increasing hurricane trend reported by Webster disappeared when data of consistent quality were used. While Webster found increasing trends in 5 of the six basins, Kossin found a significantly increasing trend in only one basin (the North Atlantic). In fact Kossin found a small decreasing global trend.

Christopher Landsea (of the NOAA National Hurricane Center) et. al., drew similar conclusions in the Journal Science in 2006. He points out that in 1975 there were only two geostationary satellites with 9 km resolution used to monitor tropical storms. Today there are eight geostationary satellites with 4 km resolution to do the same monitoring. More important than the number of satellites is the fact that with only two satellites much of the imagery is from oblique angles. Consequently, "The resulting higher resolution images and more direct overhead views of tropical cyclones result in greater and more accurate intensity estimates in recent years." Lansea explains that the satellite image pattern recognition method, called the "Dvorak Technique," which is relied on to make storm intensity estimates is highly subjective and tends to give different results when applied by different analysts. Originally the Dvorak Technique was applied only to visible light images (that is daylight images), but was later (1984) applied to infrared images as well.

As an example, Landsea shows satellite images of five North Indian Ocean cyclones taken between 1978 and 1989. Each of these cyclones were listed as reaching category 3 at the time. But reanalysis of the these images using current procedures would result in the storms being classified as category 4 or category 5 today. The implication is that even during the satellite era storm intensity was underestimated in the past compared to the present.

Is the satellite era long enough to judge whether current level of tropical cyclone activity falls outside the natural range?

The only way to answer this question is through paleoclimatological studies. A variety of such studies relating to this question have been done. The paleoclimatological evidence is quite clear: Current hurricane and cyclone activity is NOT unusual from a long term perspective. Several examples of such studies follow:

1. In Low Atlantic hurricane activity in the 1970s and1980s compared to the past 270 years, Nyberg, et. al., point out that "reliable observations of hurricane activity in the North Atlantic only cover the past few decades." It is not possible to say, based on this short set of data, if the variation that has been seen during these few decades is greater than should be expected over longer time scales. However, they developed a proxy for both sea surface temperature and vertical wind shear covering 270 years. (Vertical wind shear is inversely related to hurricane formation). The result shows that "the average frequency of major hurricanes decreased gradually from the 1760s until the early 1990s, reaching anomalously low values during the 1970s and 1980s." It seems clear that the upswing in hurricane activity seen from the beginning of the satellite era to the present is largely a consequence of the beginning of the satellite era being at the low point of hurricane activity for the last 270 years.

2. The article in Nature, "Intense hurricane activity over the past 5,000 years controlled by El Nin˜o and the West African monsoon," by Donnelly and Woodruff of the Woods Hole Oceanographic Institution in Massachusetts echos the concern that "the instrumental record is too short and unreliable to reveal trends in intense tropical cyclone activity." To overcome these limitations they used sediment deposits in coastal lagoons of the Caribbean to gauge hurricane activity on the century and millennial time scales over a 5000 year period. They found the frequency of intense hurricanes varied widely on these time scales during the past 5,000 years and that the frequency appears to be governed by the El Nin˜o/Southern Oscillation and the strength of the West African monsoon." Additionally, " sea surface temperatures as high as at present are not necessary to support intervals of frequent intense hurricanes."

3. The short instrumental record of hurricane activity was a motivation for Miller, et. al. in their 2006 Proceedings of the National Academy of Sciences paper, "Tree-ring isotope records of tropical cyclone activity." As trees grow, the oxygen isotope ratios of the water at that place and time are locked into their rings. It is also known that the precipitation of tropical cyclones and hurricanes have oxygen isotope ratios that are greatly different that more common causes of precipitation. Miller, et. al., examined long leaf pines (pinus pulustris) in Georgia because they have shallow roots and a distinct early season growth and late season growth in their rings. these combine to give a precise temporal fix on isotope ratio variation. Their study covered 1770 to 1990. Their analysis of the tree ring oxygen isotope data shows very close agreement with the instrumental data for the southeastern United States after 1940, verifying the efficacy of their method for earlier times. The overall results indicate "systematic, decadal- to multidecadal-scale variations" in the isotope ratios, and consequently variations in the number of hurricanes. Hurricane activity appears to have peaked in the 1770s, 1800s to 1820s, 1840s and 1850s, 1865 to 1880, and the 1940s to 1950s. The quietest decades are the 1780s through 1790s, and the 1970s. The 1970s saw the beginning of satellite tracking of hurricanes. The fact that there has been an upswing in hurricanes in the satellite record is much less alarming when you consider that the 1970s was one of the least active decades (at least for the southeastern United States) in over 200 years.

It is quite clear, based on the best analysis of satellite data and paleoclimatological data, that the high court of London ruled correctly when saying that Al Gore had not proved his case when implying that Hurricane Katrina could be attributed to anthropogenic global warming.

Jeffrey P. Donnelly & Jonathan D. Woodruff, "Intense hurricane activity over the past 5,000 years controlled by El Nin˜o and the West African monsoon," Nature, Vol 447, 24 May 2007 (Get copy here)

Neil L. Frank and S.A. Husain, "The Deadliest Tropical Cyclone in History?," Bulletin of the American Meteorological Society, Vol 52 No. 6, June 1971 (Get copy here)

J. P. Kossin, "A globally consistent reanalysis of hurricane variability and trends," Geophysical Research Letters, Vol. 34, 2007 (Get copy here)

Christopher Landsea, et. al., "Can We Detect Trends in Extreme Tropical Cyclones?," Science, Vol 313, July 2007 (Get copy here)

Dana L. Miller, et. al., "Tree-ring isotope records of tropical cyclone activity," Proceedings of the National Academy of Sciences, PNAS, Vol. 103, no. 39, September 26, 2006 (Get copy here.)

Johan Nyberg, et. al., "Low Atlantic hurricane activity in the 1970s and 1980s compared to the past 270 years," Science, Vol 447, 2007. (Get copy here.)

P.J. Webster,, "Changes in Tropical Cyclone Number, Duration, and Intensity in a Warming Environment," Science 309, 1844 (2005) (Get copy here)

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Criticisms of Al Gore's "An Inconvenient Truth"

Gore implies ice cores proves that rising CO2 causes temperature increases over 650,000 years

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In the very compelling graph from "An Inconvenient Truth" shown below in figure 1, Al Gore shows the close correlation between CO2 and temperature. The implication is clear: the temperature increase is controlled by the CO2 level. His simple model is illustrated in the block diagram in figure 2, but one is left wondering what controlled the level of CO2 before humans started burning fossil fuels.

Figure 1. Al Gore showing temperature and CO2. The present is on the right near his head and the past is on the left.

Figure 2. Gore's simple model is: CO2 controls temperature. Nothing more need be said. But what controlled the CO2 before humans burned fossil fuels?

Gore is an advocate for a certain point of view, not an objective scientist, so perhaps he can be forgiven for leaving out a fundamental point concerning this relationship. That point is illustrated below in figure 3, which shows part of page 431 from the journal Nature, 3 June, 1999. The article is "Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica" by J. R. Petit, et. al., (scientists from France, Russia, and the United States). The graph in figure 3 shows the same data that Gore is standing in front of in figure 1, plus several other things that Gore doesn't show. Please note that Gore's graph shows the present at the right and the Petit paper shows the present at the left. On Petit's graph CO2 level is circled on top, temperature is circled in the middle of the graph, and the insolation at 65 degrees latitude is circled at the bottom.

Figure 3. Graph from Petit paper showing CO2 and temperature (same as Gore is showing in figure 1) and insolation (which Gore apparently forgot to show). Note that the time direction is reverse between Gore's graph and Petit's graph.

The most important thing that Gore does not show is the changing insolation pattern. Insolation is the amount of light from the sun that shines on a particular place. It is important to understand that neither the temperature nor CO2 level can influence the insolation. According to Andre Berger, in the Journal of Atmospheric Sciences, the source for Petit's insolation data, the insolation is primarily governed by "the eccentricity, the longitude of the perihelion, the precessional parameter and the obliquity" of the Earth's orbit. If there is any correlation between the insolation and the temperature, or the insolation and the CO2 level, then the insolation must be driving the correlation, not the temperature or CO2.

Figure 4, below shows my digitized version of the temperature and CO2 level over the last 150,000 years from the Petit (1999) paper. This time period covers the current interglacial (warm)period, the previous ice age, and the interglacial prior to the ice age. Compare the data in figure 3 with Gore's data in figure 1. They are, in fact, the same (although I show the unsmoothed and smoothed temperature, while Gore shows only his smoothed temperature). Figures 5 through 7 show the temperature, CO2 level, and relative ice volume each compared with the insolation for the last 150,000 years.

Figure 4. Digitized version of data from figure 3 or Petit, et. al. (1999). I have included the unsmoothed version of temperature data overlaid by a smoothed version. Gore shows only a smoothed version. See text below for explanation of relationship between deuterium isotope ratio and temperature.

Figure 5. Temperature at Vostok, Antarctica and insolation at 65 degrees north over the last glacial - interglacial cycle. Insolation, the magnitude of solar radiation, shown here as a deviation from an average. Both sets of data are digitized from figure 3 of Petit's (1999) paper.

Figure 6. CO2 at Vostok, Antarctica and insolation at 65 degrees north over the last glacial - interglacial cycle. Both sets of data are digitized from figure 3 of Petit's(1999) paper.

Figure 7. Ice Volume and insolation at 65 degrees north over the last glacial-interglacial cycle. Ice volume is digitized from figure 2 of Petit's(1999) paper.

Early in Gore's movie and book he relates an anecdote about his sixth grade classmate who, upon seeing a map of the Earth, wondered whether or not South America and Africa once fit together. The teacher responded "Of course not! That's the most ridiculous thing I've ever heard!" Gore says "That sixth-grade teacher had an assumption in his mind that he didn't bother to question: Continents are so big, obviously they don't move." The moral of the story being, of course, that the CO2 and temperature graphs do fit together and an unprejudiced child can see it. I wonder what Gore's classmate would say if he saw the two side by side graphs of figure 8, below.

Figure 8. Would Gore's sixth grade classmate only see the relationship between CO2 and temperature in the graph on the left? Or would he also see the relationship between insolation and temperature in the graph on the right? Was Gore talking about himself when he quoted Mark Twain: "It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so."

It is clear that in the relationship between CO2, temperature, and insolation only insolation can be the primary driver. According to Andre Berger, in the Journal of the Atmospheric Sciences, Insolation is controlled by the "eccentricity, the longitude of the perihelion, the processional parameter and the obliquity" of the Earth's orbit.

Hubertus Fischer (1999)(Scripps Institution of Oceanography) wrote about Ice core records of Atmospheric CO2 Around the Last Three Glacial Terminations, in the Journal Science and concluded "High resolution records from Antarctic ice cores sow that carbon dioxide concentrations increased... 600 ± 400 years after the warming..." That is, as the last three ice ages ended and temperatures started rising, the CO2 lagged behind the temperature rise, indicating that CO2 was not the primary driver of temperature rise.

The timing between CO2 and temperature rise for climate transitions was also studied by Manfred Mudelsee of the Institute of Meteorology at the University of Leipzig. He reported his findings in the Quaternary Science Reviews in 2001. He used a "lagged, generalized least-squares regression" technique to conclude that the Vostok ice records show "CO2 variations lag behind atmospheric temperature changes in the Southern Hemisphere by 1.3 ± 1.0 ka."

More recently Lowell Stott (2007) from the department of Earth Sciences at the University of Southern California wrote about the end of the last ice age in the Journal Science. He points out that temperature led "the rise of in atmospheric CO2 and tropical surface ocean warming by ~1000 years." He explains the following sequence of events: 1. "The trigger for the initial deglacial warming around Antarctica was the change in solar insolation over the Southern Ocean during austral spring that influenced the retreat of sea ice." 2. "Retreating sea-ice would have led to enhanced Ekman transport in the Southern Ocean and decreased stratification due to stronger air-sea fluxes. 3. "These forcings promoted enhanced ventilation of the deep sea and subsequent rise in atmospheric CO2."

My interpretation of the papers by Fischer, Mudelsee, and Stott, as well as the correlation between insolaton, temperature and CO2 suggest that Gore's simple model is better replaced by the more realistic model shown in figure 9, below.

Figure 9. This model is more realistic than Gore's. It does not start with a mystery about what controlled CO2 levels before humans started burning fossil fuels. Insolation is the primary controller of temperature. Temperature controls CO2 with a small feedback.

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Melting snows on Mt. Kilimanjaro are not evidence of global warming.

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What is the extent of Al Gore's argument that Mount Kilimanjaro, in Tanzania, is an indicator of the effects of global warming? In his book he simple shows a series of three pictures: one taken in 1970, one taken in 2000, and one taken in 2005. The two pictures from 1970 and 2000 are taken from the same angle and thus allow the reader to see a large change in the glacial cover. The entire text consists of 109 words and can be seen in my reproductions of pages 42 through 45 in figures 1 and 2 below.

Figure 1. Reproductions of pages 42 and 43 of An Inconvenient Truth. I have "photoshopped" the images from these pages to make the snow and glaciers stand out more clearly. The obvious point that the reader is supposed to be impressed with is the dramatic decline in snow and glaciers on Kilimanjaro between 1970 and 2000.

Figure 2. Reproductions of pages 44 and 45 of An Inconvenient Truth. I have "photoshopped" the images from these pages to make the snow and glaciers stand out more clearly. The reader is supposed to note the further decline in the glaciers up to 2005. But note that the picture is taken form a different angle than those on pages 42 and 43.

In the movie version of An Inconvenient Truth these same pictures are shown with Al Gore speaking over them saying essentially the same thing seen in the text of the above images. That's all there is. There are no references to any scientific studies done concerning these glaciers and the possible causes for their retreats. We are simply shown these compelling photographs and the clear impression is left that this shrinkage is caused by CO2 induced global warming.

What does the best science say concerning the glaciers on Kilimanjaro?

Georg Kaser (Tropical Glaciology Group, Department of Geography, University of Innsbruck). et. al., concluded in the International Journal of Climatology in 2004 that since the end of the ice age Kilimanjaro's glacial extensions and recessions reached their maximum in the Little Ice Age. That is, the glaciers on Kilimanjaro were smaller one or two or three thousand years ago than they were 150 years ago. Then around 1880, long before the atmospheric CO2 concentration showed a significant increase, a climate shift caused them to start receding from their Little Ice Age maximum. On page 336 of the journal article they said that temperature increases "have not contributed to the recession process on the summit so far."

Philip Mote (Department of Atmospheric Sciences, University of Washington Climate Impacts Group) et. al. said in a recent article in American Scientist, "The observations ... point to a combination of factors other than warming air—chiefly a drying of the surrounding air that reduced accumulation and increased ablation—as responsible for the decline of the ice on Kilimanjaro since the first observations in the 1880s." They continue, "If human-induced global warming has played any role in the shrinkage of Kilimanjaro's ice, it could only have joined the game quite late, after the result was already clearly decided, acting at most as an accessory..."

Thomas Molg (Innsbruck University Network of Climate and Cryospheric Research) and Douglas Hardy (Climate System Research Center, Department of Geosciences, University of Massachusetts) pointed out in the Journal of Geophysical Research that "it has been speculated that general global warming is directly driving the retreat of Kilimanjaro’s glaciers [e.g., Irion, 2001]. However, detailed analyses of glacier retreat in the global tropics uniformly reveal that changes in climate variables related to air humidity prevail in controlling the modern retreat..."

Gore refers to his "friend, Dr. Lonnie Thompson" and said "He predicts that within 10 years there will be no more 'Snows of Kilimanjaro.'" But Thompson's paper Kilimanjaro Ice Core Records: Evidence of Holocene Climate Change in Tropical Africa in the journal Science in 2002 is clearly not a ringing endorsement for Gore's claim that the recession of Kilimanjaro's glaciers is due to anthropogenic CO2. In fact, nowhere in the article is the term "CO2" ever mentioned. Thompson acquired and studied six ice cores from the oldest glaciers near the summit. In the Northern Ice Field (NIF), which supplied the oldest three ice cores (NIF1, NIF2, and NIF3), only one of the cores (NIF3) indicates that its position was covered with ice at the end of the ice age. Thompson's analysis of the ice core data "suggests that, at ~4 ka [4 thousand years ago], the NIF was smaller than it is today and that the crater-side ice wall likely retreated past the present-day sites of NIF1 and NIF2." (emphasis added by Moriarty).

Thompsom provides abundant evidence that the climate in tropical Africa has undergone huge and rapid changes multiple times since the end of the ice age (12,000 years ago). For example, 11,000 to 4,000 years ago lakes in the area were up to 100 meters higher than today. Lake Chad in sub-Saharan Africa expanded "from 17,000 km2 to cover an area between 330,000 and 438,000 km2, comparable to that of the Caspian Sea today." Then it receded back to its present size (17,000 km2) 4,000 years ago when "conditions became cooler and drier." In fact Thompson states "The Kilimanjaro record documents three abrupt climate changes in this region: at 8.3, 5.2, and 4 ka." ("ka" means "thousand years ago").

It is true that Thompson says "if climatological conditions of the past 88 years continue, the ice on Kilimanjaro will likely disappear between 2015 and 2020." But nowhere in this paper does he even attempt to link the principle drivers of this ice loss to anthropogenic CO2.

Brief look at CO2, temperature and ice extent at Kilimanjaro

Figure 3. Atmospheric CO2 concentration vs. Kilimanjaro ice extent. CO2 data up to 1953 is from the Siple ice core. CO2 data after 1953 is from Mauna Loa, Hawaii. Ice extent for 1880 is from Osmaston, H. 1989. Glaciers, glaciation and equilibrium line altitudes on Kilimanjaro. In Quaternary and Environmental Research on East African Mountains, ed. W. C. Mahaney. Rotterdam: Brookfield, pp. 7-30. Ice extent from 1912 to present is from "Kilimanjaro Glaciers: Recent areal extent from satellite data and new interpretation of observed 20th century retreat rates" Cullen, et. al., GRL 33, 2006

Figure 4. Kilimanjaro summit temperature and ice extent. Ice extent data is the same as figure 3 and the temperature dat is from the National Centers for Environmental Prediction/National Center for Atmospheric Research; compiled by Doug Hardy, University of Massachusetts, Amherst. I have digitized the data from a graph adapted by Tom Dunne.

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Criticisms of Al Gore's "An Inconvenient Truth"

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Al Gore's An Inconvenient Truth became a big part of the British secondary educational landscape when it was made part of the official curriculum. This was big victory for those who feel the world is in imminent danger because of anthropogenic global warming. However, the High Court of London recently said "not so fast." Steward Dimmock sued under Section 406(1)(b) of the Education Act 1996, claiming that the movie is a form or political indoctrination. That law says that school governing bodies and head teachers "shall forbid... the promotion of partisan political views in the teaching of any subject in the school".

The court ruled that 1.) in order to show this movie to the children teachers must make clear that the film is a political work and promotes only one side of the argument. 2.) If teachers present the film without making this plain they may be in breach of section 406 of the Education Act 1996 and guilty of political indoctrination. 3.) Nine inaccuracies have to be specifically drawn to the attention of school children.

I will use these nine cited inaccuracies as a jumping off point for my criticisms of An Inconvenient Truth, both the book and film. These nine inaccuracies are:

  • The film claims that melting snows on Mount Kilimanjaro evidence global warming. The Government’s expert was forced to concede that this is not correct. more...

  • The film suggests that evidence from ice cores proves that rising CO2 causes temperature increases over 650,000 years. The Court found that the film was misleading: over that period the rises in CO2 lagged behind the temperature rises by 800-2000 years. more...

  • The film uses emotive images of Hurricane Katrina and suggests that this has been caused by global warming. The Government’s expert had to accept that it was “not possible” to attribute one-off events to global warming. more...

  • The film shows the drying up of Lake Chad and claims that this was caused by global warming. The Government’s expert had to accept that this was not the case. more...

  • The film claims that a study showed that polar bears had drowned due to disappearing arctic ice. It turned out that Mr Gore had misread the study: in fact four polar bears drowned and this was because of a particularly violent storm. more...

  • The film threatens that global warming could stop the Gulf Stream throwing Europe into an ice age: the Claimant’s evidence was that this was a scientific impossibility.

  • The film blames global warming for species losses including coral reef bleaching. The Government could not find any evidence to support this claim.

  • The film suggests that sea levels could rise by 7m causing the displacement of millions of people. In fact the evidence is that sea levels are expected to rise by about 40cm over the next hundred years and that there is no such threat of massive migration.

  • The film claims that rising sea levels has caused the evacuation of certain Pacific islands to New Zealand. The Government are unable to substantiate this and the Court observed that this appears to be a false claim.

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A Semi-Empirical Approach to Projecting Future Sea-Level Rise," Rahmstorf, Science, Vol 315, 2007

Rahmstorf's sea level rise rate vs.T does not fit a line
Time for sea level to reach equilibrium is not millennia
Rahmstorf extrapolates out more than five times the measured temperature domain