Myths and falsehoods about global warming

Since the release of the film An Inconvenient Truth (Paramount Classics, May 2006) featuring former Vice President Al Gore, the issue of global warming has received increased attention in the popular media. Yet numerous media figures have distorted the scientific studies they cite, frequently drawing criticism from the scientists who produced the studies. And while there is scientific consensus on many issues related to global warming, media figures have advanced several false, misleading, or baseless claims about the causes and seriousness of the crisis:

1. No scientific consensus that humans are the primary cause of global warming

Media figures, including MSNBC host Tucker Carlson, have claimed that "[t]here's no consensus" on "why" the "world is getting warmer." As Media Matters for America has repeatedly documented, scientific organizations such as the National Academy of Sciences (NAS) and the United Nations Intergovernmental Panel on Climate Change (IPCC) share the consensus view that, as stated in a June 2006 NAS report, "human activities are responsible for much of the recent warming" of the planet. An IPCC report released in February found:

Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic [human-produced] greenhouse gas concentrations. This is an advance since the TAR's [Third Assessment Report] conclusion that "most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations". Discernible human influences now extend to other aspects of climate, including ocean warming, continental-average temperatures, temperature extremes and wind patterns. [The report defines "very likely" as a greater than 90 percent probability of occurrence.]

Additionally, despite the overwhelming scientific evidence to the contrary, media figures frequently claim that there is insufficient evidence that humans are contributing to global warming. On the July 29, 2006, edition of Fox News' The Beltway Boys, Weekly Standard executive editor and co-host Fred Barnes denied that humans are a cause of global warming. After co-host Morton M. Kondracke stated that "[g]lobal warming is a fact," Barnes replied, "Yeah, but who caused it? You don't know." When Kondracke replied, "Humans," Barnes retorted: "No. You don't know that."

2. Gore is exaggerating

Reviving a familiar smear during the 2000 presidential campaign of Gore as an "exaggerator," media figures have attacked Gore and the film by accusing him of exaggerating scientific assessments and predictions about rising sea levels, the possible links between global warming and hurricanes, and arctic melting. The attacks take the form of false comparisons and misrepresentations of his claims.

• Sea levels: In a March 13 article, "From a Rapt Audience, a Call to Cool the Hype," New York Times science writer William J. Broad set up a false comparison, suggesting that the IPCC report, which "estimated that the world's seas in this century would rise a maximum of 23 inches," contradicted Gore's claim, "citing no particular time frame," that seas could rise "up to 20 feet." In the book An Inconvenient Truth (Rodale Books, May 2006), Gore wrote that if the West Antarctic ice shelf "melted or slipped off its island mooring into the sea, it would raise sea levels worldwide by 20 feet." He added that "the West Antarctic ice shelf is virtually identical in size and mass to the Greenland ice dome, which also would raise sea levels worldwide by 20 feet if it melted or broke up and slipped into the sea."

But the IPCC projection to which Broad was referring involved rising sea levels as they are affected by "[c]ontinued greenhouse gas emissions at or above current rates" -- not the melting or breakup of the West Antarctic ice shelf or the Greenland ice dome. A chart projecting the rise of sea levels in six different scenarios showed that the "the best estimate for the high scenario," which defined the "likely range" of temperature increases over the next century to be from "2.4°C to 6.4°C," resulting in an increase in sea levels between 0.26 meters and 0.59 meters, which converts to a range of 10.24 to 23.23 inches. The IPCC further claimed that "[c]ontraction of the Greenland ice sheet is projected to continue to contribute to sea level rise after 2100" and that "[i]f a negative surface mass balance were sustained for millennia, that would lead to virtually complete elimination of the Greenland ice sheet and a resulting contribution to sea level rise of about 7 m," which is equivalent to approximately 23 feet. The apple-to-oranges comparison Broad made on sea levels was noted by Bob Somerby on his weblog, The Daily Howler.

The false comparison was repeated in a March 19 Wall Street Journal column by John Fund, who accused Gore of "environmental exaggerations and hypocrisy." Similarly, on the March 21 edition of Fox News' The Big Story, Cato Institute senior fellow Patrick Michaels used this false comparison as the basis for characterizing Gore's position as "beyond shrill" and "thermonuclear."

• Hurricanes: Broad's article also falsely suggested that Gore endorsed the view that global warming affects hurricane frequency. The article claimed that Gore "cites research suggesting that global warming will cause both storm frequency and deadliness to rise," then reported that, in fact, "this past Atlantic season produced fewer hurricanes than forecasters predicted (five versus nine), and none that hit the United States," a fact the article suggests contradicts Gore's claim.

But while Gore attributed the claim "that global warming is even leading to an increased frequency of hurricanes" to "some" scientists in his book, he also acknowledged "[t]here is less agreement among scientists about the relationship between the total number of hurricanes each year and global warming." Similarly, in the update to the film Gore said: "There is no scientific consensus linking the absolute number of hurricanes to global warming." Further, the recent IPCC report appeared to agree with Gore's assessment, concluding that "[b]ased on a range of models, it is likely that future tropical cyclones (typhoons and hurricanes) will become more intense, with larger peak wind speeds and more heavy precipitation associated with ongoing increases of tropical SSTs [sea surface temperatures]." [Emphasis in original.]

• Arctic melting: On the March 21 edition of National Public Radio's (NPR) Morning Edition, science correspondent Richard Harris asserted that in a December 2006 speech, "Gore said that Arctic ice could be gone entirely in 34 years," which, according to Harris, "no one can say" with such "certainty." In fact, in his speech, Gore was apparently citing a research study released three days prior, which found that the "recent retreat of Arctic sea ice is likely to accelerate so rapidly that the Arctic Ocean could become nearly devoid of ice during summertime as early as 2040," or 34 years from when Gore made his remarks. According to a San Francisco Chronicle article on Gore's presentation noted that Gore "said he was surprised to learn this week about new, earlier projections for when the Arctic sea ice will completely melt during the summertime," quoting Gore as saying, "I was shocked that their horizon was 34 years under a business-as-usual scenario."

3. "Rank-and-file" scientists disagree with Gore

In support of his thesis that "[c]riticisms of Mr. Gore have come not only from conservative groups and prominent skeptics of catastrophic warming, but also from rank-and-file scientists," The New York Times' Broad cited numerous scientists who -- far from being "rank-and-file" scientists with "no political ax to grind" -- are well-known global warming skeptics who have made statements questioning global warming that have either been debunked or discredited by the scientific community. Though Broad failed to say so in his article, the scientist he named specifically as his example of a "rank-and-file" scientist who has criticized the film -- Don J. Easterbrook -- has taken a position on global warming that puts him outside of the scientific mainstream and at odds with the IPCC.

Further, while Broad purported to represent the views of mainstream scientists on the accuracy of the film, in May 2006, at the time of the theatrical release of An Inconvenient Truth, the Times published an article by Andrew C. Revkin reporting that mainstream scientists, while taking issue with some details in the film, embraced its premise and subscribed to Gore's "main point":

In interviews and e-mail exchanges, many climate specialists who have seen the film quibbled about details but tended to agree with Eric Steig, a University of Washington geochemist who posted his reactions at the Web log realclimate.org after a recent Seattle screening: ''The small errors don't detract from Gore's main point, which is that we in the United States have the technological and institutional ability to have a significant impact on the future trajectory of climate change.''

A June 2006 Associated Press article reported a similar consensus among scientists.

4. The sun, not human activity, causes global warming

The claim that the sun -- rather than human activity -- is primarily responsible for global warming has been trumpeted by nationally syndicated columnist John McCaslin, who wrote in his March 2 Washington Times column that a February 28 National Geographic News article "cites 2005 data" showing similar warming trends on Earth and Mars as "evidence that the current global warming on Earth is being caused by changes in the sun." In fact, the National Geographic News article, to which conservative Internet gossip Matt Drudge linked, did not itself assert the existence of evidence that "changes in the sun" are largely responsible for global warming -- as McCaslin suggested -- but rather reported on "one scientist's controversial theory." The article first quoted "Colin Wilson, a planetary physicist at England's Oxford University" saying that the claim that the sun is largely responsible for global warming is "completely at odds with the mainstream scientific opinion" and that it "contradict[s] the extensive evidence presented in the most recent IPCC report." The article added that "[t]he conventional theory is that climate changes on Mars can be explained primarily by small alterations in the planet's orbit and tilt, not by changes in the sun" and that "most scientists think it is pure coincidence that both planets are between ice ages right now." The article further reported that "the biggest stumbling block in" the theory is the "dismissal of the greenhouse effect," and quoted Amato Evan, a climate scientist at the University of Wisconsin-Madison, who said that "without the greenhouse effect there would be very little, if any, life on Earth, since our planet would pretty much be a big ball of ice."

Rush Limbaugh made a similar claim in September 2005, selectively reading on his nationally syndicated radio show from a year-old article to falsely suggest that a 2004 study by the Max Planck Institute for Solar System Research found that an increase in solar brightness is the sole cause of global warming. In fact, the article, which appeared in the London Telegraph in July 2004, specifically noted that the study's lead author did not believe increased solar brightness was responsible for the dramatic rise in global temperatures over the past 20 years; according to the parent organization of the group that conducted the study, solar brightness "plays only a minor role in the current global warming."

Two days before Gore testified, Drudge purported to reveal several "[p]roposed questions" that "could lead [sic] Gore scrambling for answers!" One question asked:

How can you continue to claim that global warming on Earth is primarily caused by mankind when other planets (Mars, Jupiter and Pluto) with no confirmed life forms and certainly no man-made industrial greenhouse gas emissions also show signs of global warming? Wouldn't it make more sense that the sun is responsible for warming since it is the common denominator?

5. Carbon dioxide is not bad for the environment

In May 2006, the Competitive Enterprise Institute (CEI) released two 60-second television ads "focusing on the alleged global warming crisis and the calls by some environmental groups and politicians for reduced energy use." One ad titled "Energy" suggests that environmentalists have falsely labeled carbon dioxide as a pollutant when, in fact, it is "essential to life." The ad is misleading because, while carbon dioxide is not inherently harmful, excessive discharges of the gas are indeed harmful to the atmosphere.

Wall Street Journal columnist Pete du Pont echoed the commercial's claim, asserting that carbon dioxide "is not a pollutant -- indeed it is vital for plant growth," But, contrary to du Pont's suggestion, scientists do not argue that carbon dioxide is inherently harmful. Rather, they point to the danger posed to the atmosphere by excessive discharges of C0₂, as the Natural Resources Defense Council noted:

[A] pollutant is a substance that causes harm when present in excessive amounts. CO2 has been in the atmosphere since life on earth began, and in the right amounts CO2 is important for making the earth hospitable for continued life. But when too much CO2 is put into the atmosphere, it becomes harmful. We have long recognized this fact for other pollutants. For example, phosphorus is a valuable fertilizer, but in excess, it can kill lakes and streams by clogging them with a blanket of algae.

6. Greenland and Antarctic ice is increasing, not decreasing

The second CEI ad, "Glaciers," claimed that scientific studies have proven that "Greenland's glaciers are growing" and that the "Antarctic ice sheet is getting thicker, not thinner." But as the weblog Think Progress noted, the Greenland study found increased snow accumulation only on the island's interior, while separate studies conducted during the same period found significant melting among the coastal glaciers. Further, the lead author of the study on Antarctica issued a public statement accusing CEI of a "deliberate effort to confuse and mislead the public about the global warming debate." According to the statement, "Growth of the ice sheet was only noted on the interior of the ice sheet and did not include coastal areas. Coastal areas are known to be losing mass, and these losses could offset or even outweigh the gains in the interior areas. ... The fact that the interior ice sheet is growing is a predicted consequence of global climate warming."

On Fox News' Special Report with Brit Hume, Fred Barnes made a similar claim, asserting that the "hysterical position is to say that sea levels -- based on some glaciers in some places melting -- based on that, sea level is going to rise 20 feet. ... It's getting colder in Greenland." Du Pont's Wall Street Journal column also claimed that "the coastal stations in Greenland had actually experienced a cooling trend." But climate scientist Petr Chylek of the Los Alamos National Laboratory, who found in a 2004 report that "Greenland coastal stations data have undergone predominantly a cooling trend," published a study a year later that attributed this cooling trend to local climate patterns -- specifically, the North Atlantic Oscillations (NAO). Chylek then analyzed the temperature record in the Danmarkshavn region of Greenland -- an area on the northeastern coast apparently unaffected by the NAO -- and found that the rate of warming there was 2.2 times faster than the global average. This corresponds with United Nations climate-change models that show Greenland warming at a faster rate than the rest of the planet and partially explains the rapid deterioration of the Greenland ice sheet in recent years. In addition, recent studies documenting the increased melting in Antarctica and Greenland, as well as studies of past ice-sheet melting, have strengthened the case for accelerated sea-level rise over the course of the next century.

Even when it is accepted that ice is melting, media figures have suggested that scientists don't know why they are melting. In a segment on "the health of our planet" on the September 13, 2006, edition of NBC's Nightly News, host Brian Williams showed recently released NASA images of the Arctic from 2004 and 2005 and said that the difference between the two demonstrated "an abrupt shrinkage ... equal to an area about the size of the state of Texas." Williams stated that the ice is not "shrinking that much every year," adding that "[s]cientists can't say yet whether global warming is the culprit." However, according to the scientist and author of the NASA study on the Arctic ice meltdown to which Williams was presumably referring in citing the Arctic images, new data show "the strongest evidence of global warming in the Arctic so far."

7. Global warming has come and gone

• Most of the global warming in the past 100 years occurred before 1940: During a panel discussion of global warming on a May 2006 edition of Fox News' The Journal Editorial Report, Wall Street Journal editorial board member Rob Pollock falsely claimed that "most" of the global warming that has occurred "over the past century ... happened before 1940." In fact, according to an analysis of "global-mean surface temperature[s]" last revised in January 2006 by NASA's Goddard Institute for Space Studies, "It is no longer correct to say that 'most global warming occurred before 1940' ":

Global warming is now 0.6°C in the past three decades and 0.8°C in the past century. It is no longer correct to say that "most global warming occurred before 1940". More specifically, there was slow global warming, with large fluctuations, over the century up to 1975 and subsequent rapid warming of almost 0.2°C per decade.

• Global warming "stopped in 1998": Fox News host Brit Hume and a Washington Times editorial both cited a misleading statistic to suggest that global warming might have "stopped in 1998" because of a "negligible decrease in temperature" since that year. While 1998 was the hottest year on record, according to the Climatic Research Unit, an examination of temperature data since 1998 undermines the assertion that global warming "stopped" in that year. For example, neither mentioned the fact that five different years since 1998 (2001, 2002, 2003, 2004, and 2005) have seen warmer temperatures than any year preceding 1998, according to Climatic Research Unit figures. Nor did they explain that 2005 was the second-warmest year on record, according to the Climatic Research Unit, and the hottest year on record when analysis of warming in the Arctic is taken into account, according to the Goddard Institute for Space Studies.

8. Alarmism then and now

Media figures have argued that the predictions by scientists now should be put in context because scientists were convinced in the 1970s that global cooling was occurring but have since become similarly convinced that global warming is occurring. In fact, far from suggesting impending doom, one paper frequently cited, "Variations in the Earth's Orbit: Pacemaker of the Ice Ages," addressed only long-term trends "with periods of 20,000 years and longer."

9. Because it's cold outside today, global warming can't be real

Several media figures -- and even weather forecasters -- have looked at weather patterns lasting days, weeks, or months to disprove global warming, which is based on thousands of years of records. For instance, the January 17 edition of Fox News' Your World featured on-screen graphics that read: "Global Warming?" and "Nation in a Deep Freeze: What Global Warming?" Host Neil Cavuto began the segment by noting freezing temperatures in Texas, Arizona, and California and asking if these temperatures were "[p]roof that all this hype over global warming could be just that -- hype?"