Global warming and rising sea levels

[Palfrem]

So how does this pan out then?

BBC News - Undersea mountains march into the abyss

What about "rising sea levels"??

 

[MercFanUk]

Forgive me, but where does the sea level fit into this?

 

[renault12ts]

^ Good question.

 

[Palfrem]

Hmm, as I read this - if a mass the size of "giant volcanoes" is being drawn into a trench and eventually being melted in the earth's mantle, the volume of water displaced by said mountains must be huge. Therefore if the mountain effectively dissappears back into the earth that volume of water must cause some drop in sea level ?

Would this cancel any potential sea level rises out?

 

[WOODYTHEWISE]

So how does this pan out then?

BBC News - Undersea mountains march into the abyss

What about "rising sea levels"??

Surely, as the mountains are already in the sea, their position in it should not alter the sea level.

 

[renault12ts]

Hmm, as I read this - if a mass the size of "giant volcanoes" is being drawn into a trench and eventually being melted in the earth's mantle, the volume of water displaced by said mountains must be huge. Therefore if the mountain effectively dissappears back into the earth that volume of water must cause some drop in sea level ?

Would this cancel any potential sea level rises out?

The mountain is already underwater. If it had been above water, then it would effect sea levels, as it fell into the sea.

 

[MOCAŠ]

The mountain is already underwater. If it had been above water, then it would effect a rise in sea levels, as it fell into the sea.

Fixed that for you.

 

[MercFanUk]

Don't forget it takes a long long time for an entire volcano to get dragged under, plate tectonics is not a speedy process. The actual amount dragged away each year will be tiny compared to the mass of the bergs that break off the ice caps and whatnot. I addition where on one part of the plate it's being sub-ducted under, in the middle of that massive area new mass is being added by the ridge spreading with new material. Then you add on current active volcanoes that are spewing out stuff under water, and it all becomes a mess of new stuff being added, and old being removed.

For example: http://www.bbc.co.uk/news/magazine-15917740

 

[artyman]

On the basis that pebbles being moved about underwater by fish doesn't alter water levels, I don't think I'm going to lose sleep over it. Now if there is a dramatic change over a very short space of time that may cause a ripple.

 

[grober]

Nothing to worry about unless someone pulls out the giant black circular plug thingy in the Marianas Trench-- then we could be in trouble!