Tyson Slams Deniers!

[Jehanne]

As promised, here is my regression analysis.  It is a simple regression equation, the first with temperature versus CO2 levels, the second identical to the first, except I had a categorical variable for heavy volcanism:

Regression Analysis: Temp versus CO2 level
Analysis of Variance
Source          DF  Adj SS  Adj MS  F-Value  P-Value
Regression       1  494525  494525  2500.71    0.000
  CO2 level      1  494525  494525  2500.71    0.000
Error          704  139219     198
  Lack-of-Fit  679  136978     202     2.25    0.008
  Pure Error    25    2241      90
Total          705  633744

Model Summary
      S    R-sq  R-sq(adj)  R-sq(pred)
14.0625  78.03%     78.00%      77.90%

Coefficients
Term          Coef  SE Coef  T-Value  P-Value   VIF
Constant   -326.42     7.14   -45.74    0.000
CO2 level   1.0109   0.0202    50.01    0.000  1.00

Regression Equation
Temp = -326.42 + 1.0109 CO2 level

Regression Analysis: Temp versus CO2 level, Volcanic
Method
Categorical predictor coding  (1, 0)

Analysis of Variance
Source          DF  Adj SS  Adj MS  F-Value  P-Value
Regression       2  495729  247865  1262.54    0.000
  CO2 level      1  494629  494629  2519.47    0.000
  Volcanic       1    1204    1204     6.13    0.014
Error          703  138015     196
  Lack-of-Fit  679  136352     201     2.90    0.001
  Pure Error    24    1663      69
Total          705  633744

Model Summary
      S    R-sq  R-sq(adj)  R-sq(pred)
14.0115  78.22%     78.16%      78.01%

Coefficients
Term          Coef  SE Coef  T-Value  P-Value   VIF
Constant   -326.26     7.11   -45.88    0.000
CO2 level   1.0111   0.0201    50.19    0.000  1.00
Volcanic
  1          -9.06     3.66    -2.48    0.014  1.00

Regression Equation
Volcanic
0         Temp = -326.26 + 1.0111 CO2 level
1         Temp = -335.32 + 1.0111 CO2 level

While both models are kind of "back of the envelope," the second is clearly to be preferred as major volcanic activity does have a very short-term and minor impact on the Earth's climate, but by far, the dominant impact on global temperatures is the rising CO2 levels.