http://www.ac.wwu.edu/~dbunny/research/global/co2_glochng.pdf
Is Global Warming Caused by Rising CO2?
No tangible, physical evidence exists that proves a cause–and–effect relationship between global
climate changes and atmospheric CO2. The fact that CO2 is a greenhouse gas and that CO2 has increased
doesn’t prove that CO2 has caused global warming. As shown by isotope measurements from ice cores in
Greenland and Antarctica and by measurements of atmospheric CO2 during El Nino warming oceans emit
more CO2 into the atmosphere during climatic warming. The ice core records indicate that after the last
Ice Age, temperatures rose for about 800 years before atmospheric CO2 rose, showing that climatic
warming causes CO2 to rise, not vice versa. No doubt exists that the present high levels of atmospheric
CO2 are the result of human input, but the contribution that it makes to global warming remains to be
proven.
Assertions by the ICPP and other CO2 proponents
As seen in the previous discussion, no correlation exists between atmospheric CO2 and the many
global climate changes that have occurred over the past several centuries and the past 15,000 years. In a
Newsweek article (August 13, 2007), author Sharon Begley states “Current warming is 10 times greater
than ever before seen in the geologic record. The chance that warming is natural is less than 10
percent.” Every competent geologist knows that this statement is totally false and contrary to vast
amounts of well-established data. Global climates have warmed about 4-7° F in a series of ~30 year
cycles since the Little Ice Age 400 years ago, all with no correlation with atmospheric CO2, yet the author
claims that “the pattern of warming has a human fingerprint.” What is needed to bring clarity to the
issue is not rhetoric like this, but a hard look at the huge amount of geologic data that shows we’ve had
climate changes 20 times greater than the past century in a fourth of the time.
In February 2007, The International Panel on Climate Change (IPCC) released a summary report for
policymakers by 33 authors. The panel conducted no research of its own but relied on previously
published material. Neither the summary report nor the earlier full report contains any tangible, physical,
cause-and-effect evidence that global warming is caused by anthropogenic CO2 emissions. The IPCC
conclusions are based on the empirical observation that global temperatures have risen during the past
century and CO2 has also risen and on computer model simulations that assume global temperatures will
rise with increasing atmospheric CO2. Because the coincidence of increase in global temperature and
atmospheric CO2 is an empirical relationship, that does not in itself prove that rising CO2 is causing
global warming. Nonetheless, the IPCC summary report for policymakers concludes that “Most of the
observed increases in globally averaged temperatures since the mid-20th century is very likely due to the
observed increase in anthropogenic greenhouse gas concentrations.” They also concluded that “The
widespread warming of the atmosphere and ocean, together with ice mass loss, support the conclusion
that it is extremely unlikely that global climate change of the past fifty years can be explained without
external forcing, and very likely that it is not due to known natural causes alone.” Curiously, they later
state the “It is very unlikely that climate changes of a least the seven centuries prior to 1950 were due to
variability generated within the climate system alone. A significant fraction of the reconstructed
Northern Hemisphere interdecadal temperature variability over those centuries is very likely attributed to
volcanic eruptions and changes in solar irradiance, and it is likely that anthropogenic forcing contributed
to the early 20th century warming evident in these records.” The report does not elaborate on why, if
solar irradiance or volcanic eruptions were responsible for earlier climate changes, they could not also be
the cause of changes since 1950, nor how anthropogenic emissions could be responsible for early 20th
century warming before CO2 emissions began to soar after 1945.
