James Lawrence Powell

• Welcome
• Case Closed
• Consensus
• Warming Earth
• 1000 years of change
• 20th Century Temperatures
• Global warming: ended in 1998?
• New Hockey Stick
• Climategate; Tempest in Teapot
• CO2 hockey stick
• Earth Breathes
• 800,000 years of history
• Order books
• Talks
• Short Biography
• Resume
• Media

GLOBAL WARMING: Case Closed

For more than four decades, in spite of a raft of scientific studies published in peer-reviewed journals, as well as reams of internal but undisclosed research reports, Big Tobacco companies denied that cigarettes caused cancer and were addictive. In a “Frank Statement to Cigarette Smokers” that appeared in 448 newspapers in 1954, the tobacco industry laid out the themes of denial that it would use into the 1990s: “Medical research...indicates many possible causes of lung cancer. There is no agreement among authorities regarding the cause. There is no proof that cigarette smoking is one of the causes. The validity of the statistics is questioned by numerous scientists.” But as cigarette smokers aged, the connection between smoking and lung cancer became impossible to deny. The WHO estimates that over the 20th Century, tobacco caused 100 million deaths. One billion are estimated to die from tobacco during the 21st century.

Compare the chart above with this one, showing how carbon emissions, atmospheric carbon dioxide concentrations, and global temperatures all began to rise with the Industrial Revolution, as humans burned increasing amounts of coal. (Click on the chart to enlarge.)






One could write a “frank statement on global warming” pointing out that there are natural causes of global temperature change; that a few contrarian scientists disagree about the cause of global warming; that correlation is not “proof”; that “you can prove anything with statistics.” Or one could use our ability to observe effects and reason back to their causes. The simplest explanation of the first chart is that smoking causes cancer; the simplest explanation of the second is that the increase in carbon emissions from fossil fuels and land use changes caused atmospheric carbon dioxide concentrations to increase; through the greenhouse effect--a fact of physics--the extra carbon dioxide caused temperatures to rise. (Carbon isotope studies confirm that the increased carbon dioxide in the atmosphere came from fossil fuel combustion by humans and not from some natural cause.)

To deny that the first chart reveals cause and effect requires one to believe two things for which there is no evidence: first, something prevented the known carcinogens in tobacco smoke from causing lung cancer in smokers; second, something else, something unknown, caused the observed lung cancer pandemic.

Ditto for the second chart: denial requires that something suppressed the greenhouse effect and prevented the known increase in carbon dioxide from causing the known increase in temperature. What that something might have been no one knows. Second, something else--some natural effect--then caused the observed temperature increase. But all natural causes of temperature variations--the Sun’s activity, ozone, volcanic eruptions, sulfur aerosols--have been investigated (see here) and none by itself or in any combination can explain the twentieth century temperature increase.

Those who deny global warming ask us to believe one more thing: carbon emissions and CO2 concentrations can keep on rising into our grandchildren’s future, yet temperature will stop rising of its own accord. That’s the moral and scientific equivalent of assuring smokers that they can continue to smoke without risking lung cancer and the other diseases associated with smoking.

The choice in explaining both charts is to accept simple cause and effect based on known facts--to employ our ability to reason--or to cast reason aside and appeal to unknown processes for which there is no evidence.

(For more detail on global temperatures for the past 2,000 years, see here. To see how temperature, carbon dioxide, and methane have all varied together for 800,000 years, click here. See here for detail on fossil fuel emissions. The movie at Earth Breathes is fascinating. )



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