Has it occurred to either of you that there is a balance between upwelling and subduction?
For every mile of new (upwelling), hot, barren, underwater magma, there would be a mile of fertile, soil covered, former potential habitat being subducted into the magma.
How does this figure into the big picture?
By the way: Injecting all that magma into the sea is like dropping hot rocks in a pail of water. American Indians used to cook that way. The mineralization and heating of the ocean could not be healthy for sea life, and the separation of the continents would present a huge obstacle to subsequent repopulation of the "earth".
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