Question from a non-scientist

[magic_8ball]

A question just occurred to me, and since the only scientist I know in RL is in a WAY different discipline, I figured I'd post here and see if anyone could give a quick answer. (I read the community guidelines and no, this isn't for homework or anything. Also, I apologize if I shouldn't be posting at, since I'm not a scientist. I'm just a

Comments

[jennaflower]

So, volcanism can have an effect on global warming (or more accurately, global climate change), but not in the way that you've hypothesized (at least as far as I know). Volcanic gases include CO2, which can add to global warming, but in a much lower amount than human activities that produce CO2. On the other hand you have SO2, sulfur dioxide, which can form sulfuric acid aerosols in the stratosphere which can actually cool climate because they absorb solar radiation and scatter it back to space. You also have chlorine from hydrochloric acid, which destroys ozone

[ammonoid]

increase in global ocean temperatures will lead to thermal expansion of water, causing sea level to rise

I was fairly sure this was due to melting of polar ice and glaciers, not from thermal expansion of water. After all, water does not expand or contract much from temperature.

[surferrosa14]

It is from both. It doesn't expand or contract much but it does change slightly. When you look at something as vast as the ocean, this is effect is no longer negligible.

[magic_8ball]

Related question -- melting the polar ice cap would dump countless millions of gallons of fresh water into the ocean, changing the salinity factor and (presumably) raising the freezing temperature of the northern seas. Would that maybe facilitate re-freezing?

[wpenrose]

Many years ago, Lord Kelvin calculated the age of the Earth at 10 million years, based on the increase in temperature with depth in deep mines, and the slow rate of diffusion of heat through rock from the Earth's core to the surface. Of course, he knew nothing about radioactivity, which actually provides considerable additional heat, so the Earth is cooling slower than he calculated. (And is much older.)
http://en.wikipedia.org/wiki/William_Thomson%2C_1st_Baron_Kelvin

But this gives an idea of the time scales involved with heating the crust of the Earth, especially from low temperature sources such as sunlight. It's hard to say that solar heating of the Earth's crust will effect the amount of vulcanism.

Dangerous Bill

[kerouacesque]

I generally agree with the comments already posted, particularly the last. The changes in surface temperature predicted by climate models (at most about 6 deg C) are pretty small relative to the crust's thermal gradient due to heating from below (call it 25 deg C per km), so you're looking at heating maybe the upper 200 m or so of crust (slowly - conduction takes a long time, as wpenrose noted), which is not enough to affect tectonic motion (plates are tens of kilometers thick).

As a geologist, I'm not too worried about global climate change somehow increasing tectonic activity. I'm much more worried about this.

[jennaflower]

I agree.

Although I've always wanted one of these.

[kerouacesque]

Yar.

Of course, this whole thread depends entirely on whether or not you believe in plate tectonics.

[cassiopeia13]

Eh? Don't believe in tectonics? Why not?