If it doesn't get any warmer, how else could an increase of CO2 possibly cause "catastrophic weather"?

Question

If it doesn't get any warmer, how else could an increase of CO2 possibly cause "catastrophic weather"?

Answer 1

I don't know for sure, but doesn't CO2 cause warmer temperatures in the atmosphere?

Answer 2

1.  The radiative balance of the atmosphere is affected by the CO2 concentration.  The key effect is that more energy, dQ available in the troposphere.  The increased energy can be manifest as higher temperatures as dT = CpdQ, where Cp is the heat capacity at constant pressure.  Alternately, for an isothermal process dS = dQ/T, where S is the entropy and T is the absolute temperature.  This says that the entropy of the earth must increase because dQ is positive (CO2 traps energy).  Entropy is a measure of disorder.  An intact city is more ordered than a pile of rubble.  A mountain is more ordered than a pile of sand.  The main prediction for the isothermal case is an increased rate of weathering i.e. more violent storms.  Some of the storms would increase entropy in densely inhabited areas and would hence be considered catastrophic.  

2.  Plants actively trap CO2, and lose water in the process (transpiration).  Plants are able to absorb CO2 with less transpiration as the partial pressure of CO2 increases.  Although the relative humidity of the atmosphere at equilibrium is a function of temperature alone, an atmosphere at equilibrium would be rather boring. The presence of weather indicates that the atmosphere is not at equilibrium. Hence, even at constant temperature the CO2 concentration can alter the rate at which water vapour is added to the atmosphere.  This will affect the rate at which latent heat is delivered to the atmosphere and hence the weather.

3.  There can be a feedback effect on the biospehere from in increase in carbonic acid in water.  As noted above, transpiration can affect the weather, so any change in plant growth positive or negative from the acidification effect can also indirectly affect the weather.

Edit Bob236: Transpiration is a major source of water vapour and perhaps dominant in the amazon basin.  The perturbations on transpiration in the isothermal case with rising CO2 may well be small. An expert in that field can give a better order of magnitude estimate than I can. If the plausible effects 2 and 3 are small as you suggest, then other factors such as global warming that are explicitly excluded in the question posed may be dominant.

Answer 3

Acidification of water. The CO2 get dissolved in water and turns into carbonic acid H2CO3. So more CO2 more acidic water and oceans so maybe kill fish etc...

Answer 4

I am not sure how the acidification of the oceans could lead to "catastrophic weather".

Anyhow, obviously this was a response to randall's question. The answer: it can't.

"3. There can be a feedback effect on the biospehere from in increase in carbonic acid in water. As noted above, transpiration can affect the weather, so any change in plant growth positive or negative from the acidification effect can also indirectly affect the weather."

Both your 2 and 3 are on a small scale. If you attempt to quantify the effect, you certainly will not see catastrophic weather.

Answer 5

Bob the rise of Co2 is because of deforestation in the tropical third world that removes the biomass that used to consume it before the forests were clear-cut. Replant these forests and the Co2 levels will decrease naturally fail to do this and the levels will increase.