We are constantly harangued that Global Warming and melting ice will cause the oceans to rise.
But what really controls ocean depth? Is it really ice? Or does the ocean floor vs continental mass depend on something bigger?
Mantle convective flow determines the depth of the ocean
Mireia Altimira March 6, 2013
The depth of the ocean is directly related to the behavior of the tectonic plates. Studies conducted so far have assumed that the sea floor depth depends solely on its age. However, these results do not match the experimental measurements.
The work developed by Adam and Vidal 1 shows that the convective flow of the underlying viscous mantle plays a strong role on the plates’ movement and, therefore, on the sea-floor depth.
Flow lines were computed using several kinematic models, which gave very similar trajectories. Figure 3 (right) clearly shows the differences between trajectories following the age-gradient compared to the flow lines derived from mantle convection. Along the flow lines, a linear relation between the sea-floor depth and the square root of the distance from the ridge is observed, which is in turn proportional to the sinking rate. This relation holds all along the plate, so a more accurate fit to the actual sea-floor depth is obtained. Local geophysical processes such as volcanoes, swells or fracture zones explain local discrepancies observed in Figure 3 (left).
In short, the authors propose a more simple and accurate way to reproduce the sea-floor depth by relating it to the mantle convective flow. Instead of introducing new variables in the existing model, they questioned the basis of the model itself, setting a good example of Occam’s razor.
I’ve often complained that sediments flowing into the oceans will cause them to rise while both the ocean floor and continental crust are rising / falling in different places and with a whole lot of motion going on, the ocean depth is dependent on geology much more than on ice melting.
This article looks to have the same idea, but looked at data to confirm it, and modeled the process.
So tell me again why sea level rises and falls? And what role CO2 does or doesn’t play in it…