Atmospheric Science, the weather, and global warming

[Alex]

Originally Posted by scaeagles

I am merely saying that climate change happens, and it has happened long before man pumped one spec of CO2 into the atmosphere (or any other gas).

This is the contral point of An Inconvenient Truth. Global climate has always changed over time. And looking at those changes there is a strong correlation between average global temperature and levels of atmospheric CO2. Here's a chart showing how well they correlate for the last 400,000 years (the period over which temperature and CO2 information is readily available from ice cores).



So, the real question is what should we expect to happen with that big spike in the green line right at the end of the graph. There is no question that current levels of CO2 are much higher than at any time in the past 400,000 years. There is no question that this is mostly anthrogenic.

Where therre is a question is what will happen in response. Perhaps there is some holistic breaking system that will prevent temperature from snapping as far as CO2 levels otherwise indicate. Perhaps while CO2 and temperature are correlated there is not a causal relationship (though the theory on the causal relationship is pretty well grounded).

But if there is a causal relationship between CO2 levels and mean global temperature and there is not systemic breaking mechanism on temperature are we willing to experience the consequences?

That is the fundamental question of the anti-global warming crowd. The outcome is not certain, but are we really willing to risk it?

Considering that we've essentially deforested continents, we've killed off global fisheries, we've drained bodies of water almost as big as the Great Lakes, I have no problem with the idea that we've altered the global atmosphere. It really isn't all that big.