Week 13 - Is human activity contributing to global warming?


I have emphasized that often two separate questions are being confused in arguments about climate change. Actually, there are three questions it may be useful to separate in this debate.

It is the latter question we focus on today.

Discussion questions:

What is the role of water vapor in this debate?

What are sources of water vapor?

What is the variation of water vapor content in the air versus that of CO2, and why is this important?

How would you distinquish between natural and anthropogenic sources of water vapor?

Do we know how global water vapor content has changed in the last centuries, and where might a record of such change be found?

Are water vapor and CO2 concentrations independent of each other?

If water vapor has such a strong effect on warming, why isn't there a runaway hothouse effect?

Monte Hieb's web page states that only .117% of the greenhouse effect is due to atmospheric CO2 from human activity, and well over 90% is from water vapor. Other's calculate the contribution of water vapor at about 60%. Is this the percentage of change due to anthropogenic CO2 or the percentage of the total greenhouse effect?

Why is the debate about timing of warming so important?

For next time: Prepare a policty statement on what should and shouldn't be done in response to global climate change. If you think something should be done, then focus on one or two policy responses, and argue for them. If you think that nothing should be done, then argue why not.