Gregg,
Global warming and CO2 levels are correlated beyond doubt. Here is a chart of CO2 levels and earth's temperature, as recorded in ice cores, tree rings, and ocean sediment over the last 650,000 years. The earth's temperature fluctuations correlate with CO2 levels.
NOTE - link to CO2 diagram deleted for security reasons by LB
(see if you can find an alternate image link that doesn't try to install a cookie)
And here is what the Union of Concerned Scientists of America says about the graph:
from:
www.ucsusa.org/global_warming/science/hockeystickFAQ.html
What is the "hockey stick" graph?
This graph, created by a group of climate researchers in the late 1990s, reflects average Northern Hemisphere temperature changes over the past several centuries. It was the first comprehensive study combining data from many different archives of temperature including tree rings, ice cores, and coral reefs. It demonstrated that Northern Hemisphere temperatures rose sharply during the late 20th century, in marked contrast to the relatively small temperature fluctuations during the previous six centuries. The graph got its name because its shape resembles a hockey stick, with the blade end representing the sharp temperature rise over recent years.
Is there legitimate scientific debate about the accuracy of the hockey stick graph?
Yes, but mainly about the details, not the essential point. Temperature fluctuations that predate written records are preserved in natural archives (e.g., tree rings, ice cores, boreholes) with various time periods (e.g., seasonal, annual, decadal). The scientific discussion has focused on the best statistical method for combining these various records to accurately capture temperature fluctuations for the Northern Hemisphere. As is typical of the scientific process, independent teams of researchers have worked to reproduce the results of the "hockey stick" by using their own approaches and even by using slightly different data. These studies sometimes produce slightly higher temperature fluctuations in the past compared with the initial study. But despite their differences, they still yield the same essential conclusion: the past 10- to 20-year period was likely the warmest of the past millennium.
