The effect of global warming on the Lithosphere: Calculation of the energy release

Category Tectonic & Seismotectonic
Group GSI.IR
Location International Geological Congress,oslo 2008
Author Parubets, Philip; Parubets, Nicolas
Holding Date 02 September 2008

Discussions of global warming have usually focused on its effects on the atmosphere and hydrosphere, but not on its effects on the lithosphere. One of the main outcomes of the presented calculations is the deduction that isostatical/eustatical loading/reloading of the planet’s crust during glaciation/deglaciation leads not only to depression/rebound in corresponding parts of the lithosphere, but also to horizontal displacements in those isostatically/eustatically uncompensated parts of the lithosphere. These displacements occur due to significant changes in those parts’ moments of inertia.
Since the beginning of the Plio-Quaternary glaciation (PQG), a total of up to 90x1015 kg of water was relocated from the ocean to the Eurassian, N. American, and Antarctic tectonic plates in the form of ice sheets during the period of Glacial Maximum.
Such an enormous load redistribution among the tectonic plates leads to correspondingly enormous isostatical/eustatical readjustments in various parts of the planet’s crust. Due to the changing value of the moments of inertia in different parts of the lithosphere, an energy release of up to 165x108 MJ per km2 occurred in some areas during the PQG.
The age of formation of the mid-ocean ridges is Plio-Quarternary as well. They are not relatively uninterrupted formations, as might logically be supposed, but instead the ridge displacements are scattered and situated along the fracture zones. Hence, an important question arises: did the displacements of the ridges’ centers originate at the time of their formation, or were the centers displaced after their formation?
The Euler theorem’s (ET) geometry is the only cause that has been cited for the origin of these displacements. The important point, however, is that the theorem does not and cannot reveal the forces that are moving the crust. Instead, the theorem only points to some abstract mathematical pole. Moreover, if ET is applied to all of the actual ridge displacements on the ocean floor, the theorem surprisingly reveals an unprecedentedly large number of different "poles of rotation," which should somehow co-exist on the same globe during the same geological time. Hence, if ET cannot be applied to explain the origin of the ridge displacements, an assumption can reasonably be made that the PQG/deglaciations could be the very causes of the ridge displacements.
At present, the planet’s ice sheets and glaciers contain up to 34x106 km3 of ice, which, if melted, could add an additional 31x1012 tons of water to the oceans, or 8x104 tons of additional pressure per km2 on the ocean floor, which might intensify the oceanic ridge displacements. Calculations are presented of the energy release resulting from the changing moments of inertia of parts of the lithosphere at the time of PQG. An attempt to calculate the universal energy release from changes in the ice/water mass in any area of the planet affected by isostasy/eustasy is also presented.