A recent Discovery Channel show on the Permian mass extinction made the following claim:
If the Earth’s oceans heat up by as little as 5 degrees Celsius, this could cause most of the methane hydride on the ocean floor to spontaneously dissociate, releasing lots and lots of methane into the atmosphere.
The theory goes that the Permian mass extinction was triggered by massive volcanic eruptions, which raised global average temperatures by 5 degrees Celsius, which caused the methane hydride in the oceans to release huge amounts of methane into the atmosphere, which (since methane is a greenhouse gas) caused global average temperatures to rise by another 5 degrees Celsius or so, and the cumulative 10 degree C increase in global average temperature was enough to wipe out nearly all species on Earth.
So, here’s my debating position:
If global warming is really happening, and global average temperatures really could rise by as much as 5 degrees Celsius before it’s over with, this global warming could end up releasing all the undersea methane that’s accumulated over the last several million years. This would make global warming that much worse. Therefore, we should mine the methane hydride out of the oceans as fast as we can to use as a fuel source before global warming turns it into atmospheric methane.
I am all for mining the ocean floors, but is such a thing even vaguely possible in the deep ocean? I’m not even talking about the various trenches and whatnot, just plain ol’ mid-ocean floor: Can we mine it, even if we had to?
Easy argument against your proposition, Tracer – removing it from the ocean floor and burning it converts it into two other greenhouse gases – CO[sub]2[/sub] and water vapor, producing much more rapid global warming.
Also, and I’m not sure of the accurate science behind this, one of the early effects of any global warming is to increase tropical-storm forming zones in both size and duration. Net result: more and bigger hurricanes. This is hardly a desirable consequence.
Methane gas has a global warming potential 21 times that of CO[sub]2[/sub]. So if it’s going to be released anyway, you’re better off mining and burning it.
Treating water vapor as a greenhouse gas is problematic because the oceans already provide an inexhaustible supply which permeates the atmosphere at a steady-state level. This tends to limit the effects of anthropogenic water vapor production.
Hmmm … I may have to have a stern word with the Discovery Channel, then.
In any event, if what you say is true and methane is over 20 times as “potent” a greenhouse agent as good old carbon dioxide is, then by golly, we owe it as a duty to this planet to burn as much of this stuff as we can before it’s too late!
The nice thing about methane hydrate (thanks) is that, because it’s so easy to turn into methane, it can be used with all of our existing Natural Gas infrastructure.
Water vapour does indeed have strong greenhousing properties, but the point is that it is in equilibrium, ie. it is not being produced in vast quantities by human activity. The same can be said of several other gases.
Conversely there has been a 30% increase in CO2 since the start of the industrial revolution.
As regards the OP, I believe a 5 degree rise is such a worst-case scenario that other equally calamitous consequences would arise from it (eg. we would surely be talking about the melting of the entire southern ice cap).
