12-10-2008, 01:43 PM
To break down anthropomorphic global warming into its component parts:
1) human activity has caused a rise in CO2;
2) CO2 is a greenhouse gas, therefore increases in CO2 will cause temps to rise;
3) As a result of the increase in temp from increased CO2, the earth will actually warm.
#1 is probably clearly true and there may very well be something approaching "consensus" on that point.
#2 is also probably true, although the actual mechanism by which a rise in CO2 will drive an increase in temperature is poorly understood, and the significance of CO2 as a greenhouse gas on earth is also disputed (Mars for example has a higher concentration of CO2 in its atmosphere).
#3 is the area of significant uncertainty. But #3 does not follow logically from 1 and 2. We lack adequate historical data on global temperatures to model this, and predictions for the models are within the margin of error for measuring global temp. Other factors, like solar activity, may outweigh the positive impact of increased CO2.
1) human activity has caused a rise in CO2;
2) CO2 is a greenhouse gas, therefore increases in CO2 will cause temps to rise;
3) As a result of the increase in temp from increased CO2, the earth will actually warm.
#1 is probably clearly true and there may very well be something approaching "consensus" on that point.
#2 is also probably true, although the actual mechanism by which a rise in CO2 will drive an increase in temperature is poorly understood, and the significance of CO2 as a greenhouse gas on earth is also disputed (Mars for example has a higher concentration of CO2 in its atmosphere).
#3 is the area of significant uncertainty. But #3 does not follow logically from 1 and 2. We lack adequate historical data on global temperatures to model this, and predictions for the models are within the margin of error for measuring global temp. Other factors, like solar activity, may outweigh the positive impact of increased CO2.