DontRunMeOver

Actually, just to point out a slight logical glitch in what might have been the reasoning I saw on the program.

They say that human carbon dioxide emissions have only a small impact on the overall warming of the planet and that sunspots, water vapour and vocanoes have a bigger impact. This is true.

But they don't mention the issue of scale. The earth's average temperature may be about 15 degrees celsius, so it may seem to the ignorant that a 'small change' in the warming capacity would be a fraction of this 15 degrees and that 1 degree would represent a big change.

However, on the ABSOLUTE TEMPERATURE scale (ie, the actual measure of temperature in which 0 means no heat energy) the average temperature of the earth is about 288K. A increase of 1% of the earth's ability to warm up would represent a change of 2.8 K (1 K change = 1 degree change).

Using this scale, it becomes more apparent how the variation of greenhouse gases in the atmosphere can lead to global warming, particularly when you consider that the original slight warming which may happen due to extra carbon dioxide could lead to increased evaporation from the oceans which leads to increased water vapour content in the atmosphere which lead to increased greenhouse effect and so on.

The sun, water vapour and vocanic emissions keep the earth at the liveable temperature it has been for millions of years (ok, ice ages might not be that liveable but you get by), without their warming effects the earth would be somewhere around 0 K and humans wouldn't have existed in the first place. EXTRA emissions of greenhouse gases could add to their combined effects and knock the heat up beyond what humans are used to in terms of air temperature, land quality and land availability. The emphasis here is on COULD, I don't believe the effect is great enough to be noticeable compared to natural fluctuations but it is still theoretically possible... depending on your theory.

Having said that, if the scientific data as they presented it in this documentary is correct then I think that they have a better argument than the anti-CO2 production camp at the moment and that, once again, the pertinent question isn't so much how to stop global temperature changes but rather how to cope with the changes which are going to occur.

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