Sinking feeling, or is the Earth moving faster?

If all the world’s glaciers were to melt and engulf the coasts on all continents, would you get a sinking feeling? Here I have to reminisce a little about physics and geology lectures (which I rarely attended) and the fact that buoyancy of continental plates is a factor of the density of the Earth’s mantle and overlying continental material. “Mouthful,” I hear you say and: “Actually, what on Earth does that have to do with me?”

A hell of a lot! We have become obsessed with melting glaciers and ice caps and resultant sea-level rises. What we haven’t given much thought to is the additional pressure that this additional mass of water may be exerting on the sea bed and Earth’s mantle at large. Let me explain …

If all this ice on the planet starts melting and turns to water (not sweet waters of home, unfortunately), besides the partial desalination of the ocean and resultant total upset of the oceanic biosphere, the sea floor will also experience increased pressure as a result of an increased mass of water resting on it.

Continents will seem to “sink” with rising sea levels, but is there some chance of continents rising higher, as a result of more pressure on the ocean floor? Just a thought … think about squeezing a balloon — it pops out somewhere as a result of pressure.

Plate tectonics and the process of building oceanic crust and moving continents around the globe are reasonably well-known. In effect, what happens is that the Earth’s internal heat processes melt “inner-earth” material, which rises to the surface in convective fashion to erupt or extrude at volcanic centres (on land or under sea), cool down and eventually get drawn back into the Earth at subduction zones (thanks, Thailand’s tsunami massacre). The under-sea extrusion zones are called mid-ocean ridges and these are primarily responsible for the movement of plates and building of continents (simplistically speaking).

Now I seem to remember some laws of physics suggesting that increased pressure will lead to increased temperatures, in which case the mid-ocean ridges may be under increased pressure to perform, either resulting in massive undersea explosions or faster sea-floor spreading processes. What would that imply for continental drift and island building?! Is it possible that we, through burning fossil fuels (let’s assume all the global-warming arguments are correct), can actually speed up continental drift and create the United Nations on one continent faster than was anticipated with the initial design of our planet? How powerful we have become if we can influence such large-scale processes through ignorance.

It may be possible that we as humans have missed one of the biggest impacts we may be having on the planet as a result of total oversight. Maybe it’s not all that important in our lifetimes, but it sure as hell will affect Earth’s polar shift rate and man’s ability to survive in a fast-changing environment.

So while continents may end up rising as a result of increase pressure on the ocean floor, there is a chance that they will be moving faster. This is yet another interesting thought added to the climate-change debate, perhaps just the unjustified musings of an eclectic scientist. This scientist will not pretend to know where it may lead the planet and life on it; I’d rather prefer to hear your views on such a scenario.