I am going to have to get back to you on some of this, don't have time or energy to answer in full right now. But, briefly, I think that the "bottom line" that you quote here:
The bottom line is that rising temperatures cause carbon levels to rise. Carbon may still influence temperatures, but these ice cores are neutral on that. If both factors caused each other to rise significantly, positive feedback would become exponential. We’d see a runaway greenhouse effect. It hasn’t happened. Some other factor is more important than carbon dioxide, or carbon’s role is minor.
is partly so, but misleading. It isn't that rising rising temperatures don't cause carbon levels to rise in the atmosphere. It does. And it is possible that "positive feedback would become exponential." But there are other factors that can bring carbon levels down as well. Climate is anything but a simple system. Runaway greenhouse effects are possible. The fact that it "hasn't happened" doesn't mean it can't happen. But that doesn't mean that "Some other factor is more important than carbon dioxide, or carbon’s role is minor." It means simply that there are other factors in addition to carbon. Here is another comment on the ocrrelation between carbon rise and temperature:
We all have heard that "correlation does not imply causation." However, with such a high correlation, it's likely safe to assume that one variable likely modulates the other, whether through direct causation or not. On long-term time scales, it does not seem likely that carbon dioxide could modulate temperature in such a dominant manner. Thus, it is likely that temperature would modulate carbon dioxide over time, which makes sense: global temperature, which changes primarily due to solar cycles (see below), modulates biological activity and ocean storage of CO2 (a warmer ocean retains less carbon dioxide, so as temperatures rise (fall), the oceans "exhale" ("inhale") carbon dioxide). However, while carbon dioxide changes as temperature changes, CO2 has a positive feedback (it induces some warming, which causes more water vapor to enter the atmosphere, which further increases the greenhouse effect) that allows the climate system to undergo dramatic temperature swings as the solar cycles and other forcings change the Earth's temperature.
This positive feedback is the primary reason why the current emission of CO2 is such a concern. It appears that our climate past has undergone dramatic climate shifts in short periods of time due at least in some part to atmospheric carbon dioxide. Paleoclimate models have a difficult time reproducing the recent ice age cycles without including this carbon dioxide feedback, implying that carbon dioxide is indeed important in our climate. This is certainly cause for alarm given how much CO2 we are emitting today.
gwfact.rso.wisc.edu
There is more to say about this, but I don't have time to focus on it right now. Reply to this tonight, and I'll try to say more if you want. Or not. |
