Center for the Study of Carbon Dioxide and Global Change
Are observed changes in the concentration of carbon dioxide in the atmosphere really dangerous?
This is the title-question of a major review article by C.R. de Freitas of the School of Geography and Environmental Science at the University of Auckland in New Zealand, which was published in the June 2002 issue of the Bulletin of Canadian Petroleum Geology. Its focus is the ongoing rise in the air's CO2 content and what the consequences of that phenomenon might be for earth's climate and biosphere.
In broaching this subject, de Freitas focuses on certain key questions: Is global climate warming? If so, what part of that warming is due to human activities? How good is the evidence? What are the risks? Finding answers to these questions, he says, "is hindered by widespread confusion regarding key facets of global warming science," and it is these several fallacies or misconceptions that he addresses.
Fallacy 1: Carbon dioxide in the atmosphere is increasing at alarming rates. It just ain't so, according to de Freitas, who notes that annual CO2 concentration increases appear to be leveling off in recent years. He also wonders what is alarming about the aerial fertilization effect of atmospheric CO2 enrichment, which dramatically stimulates the growth rates and enhances the water use efficiencies of essentially all of earth's plants.
Fallacy 2: Humans are big players in the global carbon cycle. In reality, says de Freitas, "anthropogenic CO2 emissions are only about 3% of the natural carbon cycle and less than 1% of the atmospheric reservoir of carbon." He also notes that the increase in the air's CO2 content over the past few centuries could well have been the result of earth's oceans giving off the gas in response to the planet's recovery from the Little Ice Age.
Fallacy 3: There is a close relationship between changes in atmospheric carbon dioxide and global temperature. De Freitas debunks the implied message of this myth, i.e., that it is changes in CO2 that drive changes in temperature, by citing many well-documented cases where just the opposite occurred, over periods ranging from months to millennia, reminding us that correlation does not prove causation and that cause must precede effect.
Fallacy 4: Global temperature has increased over the past two decades. Although data gathered by various types of thermometers do indeed indicate warming in many places over this time period, the concurrent growth of cities and towns, according to numerous scientific studies cited by de Freitas, has increased so dramatically that much - if not all - of that warming may be due to an intensifying of the urban heat island phenomenon.
Fallacy 5: Satellite data support IPCC claims on observed and projected global warming. No way, says de Freitas; climate models predict significant warming of the lower atmosphere, which is not evident in the satellite temperature record. Hence, the only data set that provides a truly global perspective of atmospheric temperature actually provides "direct evidence against the IPCC global warming hypothesis."
Fallacy 6: Global climate trends during the past century are very unlike those of the past. This highly-heralded falsehood is soundly refuted by de Freitas, who cites the results of a host of scientific studies that demonstrate the warming of the past century is but the most recent phase of a natural climatic oscillation that over the past millennium brought the world the Medieval Warm Period, the Little Ice Age, and now the Modern Warm Period.
Fallacy 7: There are reliable forecasts of future climate. No credence can be given to this claim, says de Freitas, until the models making the forecasts have been verified, which likely will not happen anytime soon. In fact, he notes that "earth's atmosphere has warmed only about 10 per cent as much as climate models forecast, averaged over the last 30 years." The reason? "Large uncertainties associated with most model parameters."
Fallacy 8: Significant anthropogenic global warming is underway. First of all, as de Freitas has noted, there may not be any warming currently occurring. Second, as he has demonstrated, much of what may be occurring may be natural. Third, much of what little man-induced warming may exist may not be due to CO2 emissions, but rather to urbanization, changes in land use, and various other greenhouse gases and particulates.
Fallacy 9: Global warming will produce a rise in sea level. Again, not so, according to de Freitas. For one thing, he notes there has been no acceleration in long-term sea level rise over the past century. Plus, he cites the work of many scientists who suggest that warming could result in greater snowfall over the polar ice caps, transferring large amounts of water from the oceans to the ice sheets and possibly halting sea level rise.
Fallacy 10: Global warming will result in more extreme weather events. Nothing could be further from the truth, as de Freitas demonstrates. Whether it be extremes of heat and cold, droughts, floods, hail, tornadoes or hurricanes, there is absolutely no evidence that these phenomena have increased globally over the twentieth century. In fact, there is much empirical evidence to suggest that more warmth leads to a more stable climate.
Fallacy 11: IPCC's predictions are reasonable. In addition to the many problems associated with current climate models, IPCC warming predictions are based on future greenhouse gas scenarios that are patently unreasonable. Over half of their predictions, according to de Freitas, assume that atmospheric CO2 is increasing twice as fast as it actually is, while methane concentrations have fallen steadily for the past seventeen years.
Fallacy 12: Observed temperature trends are those predicted by climate models. It is difficult to see how this statement can be believed when, as noted by de Freitas, (1) "observed global warming is so much less than predicted by conventional climate models," (2) so fantastically less than the high-end warming that is used to leverage political action, (3) possibly due to other causes than CO2, or (4) even non-existent.
Fallacy 13: There is a consensus that greenhouse induced climate change is a major threat. Quoting de Freitas, "scientists are a well-educated, diverse and ill-disciplined assortment of freethinkers." To believe such a group would reach a consensus on so complex an issue is ludicrous in the extreme. Indeed, de Freitas' own paper, with its many references, is ample proof that true science is alive and well ... and dissenting.
Fallacy Fourteen: The threat of human-caused climate change justifies taking the action proposed in the UNFCCC and Kyoto Protocol. If there is a consensus on anything related to this issue, it is that Kyoto's effect on temperature "would be imperceptible," writes de Freitas. "So," he continues, "in addition to being ineffective, costly, and unfair to industrialized nations, the Kyoto Protocol is also unnecessary." To which we say ... Amen!
Sherwood, Keith and Craig Idso
de Freitas, C.R. 2002. Are observed changes in the concentration of carbon dioxide in the atmosphere really dangerous? Bulletin of Canadian Petroleum Geology 50: 297-327.
25 December 2002
28 dec 2002