After seeing many "skeptic" comments claiming undersea volcanoes are causing the warming, I went to a couple of climate science websites and asked about it in comments. Here are some of the replies from scientists.
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Steve Bloom said...
" IMO the easy argument is that the surface above the mid-ocean ridges, which are the where the action really is for ocean volcanism, shows no trace of heat whatsoever. The same applies to individual volcanoes. "
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a_ray_in_dilbert_space said...
"Do the math. How much energy does it take to melt a couple of trillion tonnes of ice? How much energy will an average volcano put out? One of these numbers will be much, much bigger than the other. That ought to give you the answer--namely that anyone who trots out the undersea volcano argument is dumber than owlshit."
EliRabett said...
"Among other things the temperature and pH profiles are wrong. The excess is coming in from the top. "
Jim Eager said...
"Not just melt the ice, a_ray, it first has to heat the entire water column between these undersea volcanoes and the ice, and that's an even larger number.
As you say, dumber than owlshit. "
mitch said...
"Actually there is a trace of heat at about 200 m above the mid ocean ridges that can be traced away-about 0.01 deg. If there were near-human CO2 release at the mid ocean ridges , this would show up as a massive pH anomaly. It isn't there"
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comment by grindupBaker at Skeptical Science
"I compute that a total of ~0.00583 Zettajoules / year heat is added into the deep oceans at the sea bed by the annual 3 cubic kilometers of volcanic lava flow at an assumed average temperature of 1,000 degrees.
Current analysis is that 13.7 Zettajoules / year heat is added into the oceans from the surface down by the residual radiative imbalance
Thus, surface-down heat added = 2,350 times as much as volcano heat.
Also, just to hammer on the utter silliness of this "volcano heat" nonsense, note that the estimate of all geothermal heat is 0.085 w/m**2 (though not known very precisely) which is 1.37 Zettajoules / year. Thus, regular dull geothermal heat seeping up through the land surface and the sea bed is 1.37 / 0.00583 = 235 times as much as volcano heat. I expect that modellers would include this minor but not trivial heat, perhaps somebody else would confirm. The "volcano heat" nonsense is, quite frankly, extremely ignorant and it is beyond lazy not to at least attempt a 1st-order perhaps flawed approximation of the reference quantity for discussion as I have done. It is sadly indicative of a certain group of people that they vastly prefer anecdote and hyperbole to some attempt at analysis."