Carbon Dioxide and Glaciation
Date: Spring 2013
According to ice cores, levels of CO2 and methane are greater during periods of glaciation. Due to human involvement CO2 levels are now approximating their height during a historically normal period of glaciation. Yet, recent studies are suggesting that anthropogenic CO2 is actually delaying glaciation onset. If this is true, then does this mean that increased CO2 during glaciation is more likely the RESULT of glaciation as opposed to the cause? And do you think that atmospheric CO2 levels may be manipulated by man in the future to permanently delay glaciation?
These are very interesting thoughts. To gain some insight, we have to separate out the different components of your query.
First, do the levels of CO2 found in ice cores allows us to correlate the amount of CO2 in the atmosphere to periods of glaciation (so that we can say that high CO2 atmospheric content coincide with periods of glaciation) or do the increased rates of ice formation simply trap more CO2? For that we have to get corroborating evidence of CO2 content in the atmosphere elsewhere (not from ice cores alone). We might be able to find this in increased plant growth, the ratio of isotopes in the trapped CO2, geological strata effects, etc.
Second (and corollary to the first question), is there a lag between periods of glaciation and the amount of CO2 found in the atmosphere (as found by some other technique than ice core content)? Since the environment tends to respond slowly to changes, lag times might indicate which one controls the other.
Thirdly, if we find that there is indeed a strong correlation as corroborated by other methods, can we think of a mechanism by which glaciation can induce higher CO2 in the atmosphere, or alternatively, the high CO2 content inducing glaciation periods? We can then probe these mechanisms and determine if these events are coincidental, causal, and if causal, which one causes what.
These are questions that need further research. I do not want to try and answer them without looking into the data that's already out there.
Greg (Roberto Gregorius)
Thanks for the question. I am not a climate expert, but I would like to offer some comments. First, I have doubts regarding the accuracy of carbon dioxide levels in ice cores. The diffusion of carbon dioxide (out of the ice core) can result in a lower value than the true value. Second, the effects of acid rain (and nitric acid content) in the snow/ice may affect the ability of carbon dioxide to stay trapped in the ice crystals. The result of these two effects may be to confound the data.
The annual production of carbon dioxide by man is on the order of millions of tons. This production is spread out over most of the globe. Therefore, it will be financially difficult to trap (or sequester) this carbon dioxide and prevent its release to the atmosphere.
I hope this helps. Please let me know if you have more questions.
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