James Lawrence Powell

• Welcome
• Case Closed
• There is a Consensus
• The Earth is Warming
• 1000 years of change
• 20th C temperatures
• Global warming: ended in 1998?
• The Hockey Stick
• Climategate; Tempest in Teapot
• The Rise of Carbon Emissions
• 800,000 years of earth history
• Order books
• Talks
• Short Biography
• Resume
• Media

GLOBAL WARMING: Case Closed

From the year 1,000 until the early 1800s, carbon emissions, atmospheric carbon dioxide concentrations, and global temperatures stayed within relatively narrow limits. Then as the Industrial Revolution began and humans burned larger amounts of coal, all three began rising. They have been rising together ever since, the farther the faster, with no end in sight. Click on the chart for a larger version.

One of the attributes that sets Homo sapiens apart is that we are endowed with the ability to reason: we observe effects and reason back to their causes. The chart above shows such a cause and effect: 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 chart illustrates cause and effect requires one to believe two things for which there is no evidence: first, during the twentieth century, 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.

The choice is whether to accept simple cause and effect based on known facts--whether to employ our ability to reason--or to cast reason to the winds and appeal to two unknown processes for which there is no evidence. Does the chart below show cause and effect? Or is smoking perfectly safe?

Some deniers claim that global warming is a hoax. If so, it is the greatest conspiracy in human history, for there is more outspoken consensus on global warming than on any other topic in science. For the evidence, see here.

(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)



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