Three images and one scientific fact: global temperature varies naturally.

(Click image for full size view) 

Click for larger image - December 1979 Time cover w/family huddled around fire in TV
Dec. 1979 Time magazine cover

Click for larger image - Global temp graph-1979-2008

Click for larger image - April 2008 Time cover with penguin
April 2008 Time magazine cover

In 1979, protecting a human family was the imagery. In 2008, animals (usually penguins or polar bears) are often the images found in Time covers, film and other media. The degradation of humans due to unneeded energy rationing or carbon offsets is a secondary concern, if one at all.