Energetics of the Solid Earth: An integrated perspective

Abstract

The internal energy of the Solid Earth is mainly transferred through thermal convection of the mantle. Here, we discuss the 1020-J-scale energy relating to the dynamics of the Solid Earth’s interior. The energy released from the interior of the present-day Earth to outer space per year is estimated as Eearth = 1.4 × 1021 J yr−1 based on the recent dataset of globally observed crustal heat flow, which is a factor of two or three times larger than the annual energy consumption of the total population of the world, 5.7 × 1020 J yr−1. Of the energy from global crustal heat flow, the energy released by all of the major hotspot plumes in volcanic vents per year is estimated as Eplume = 7.2 × 1019 J yr−1, which is approximately only 6% of the Eearth. We propose that a large number of mantle plumes have not emerged as hotspots on the Earth’s surface, with the possibility that Eplume is larger than expected if the energy released from small seamounts of the Earth is considered. Considering the heat (energy) budget of the Earth, the heat production by the decay of radioactive isotopes in the mantle and crust is nearly comparable to the heat released by the secular cooling of the Earth. Of Eearth, the annual energy released by the secular cooling of the Earth is estimated as 6.6 × 1020 J yr−1. This energy is closely related to the geothermal energy from our planet.