Energy budget of the earth

Abstract

The Earth loses energy as heat flows out through its surface. The total energy loss of the Earth has been estimated at 46 ± 2 TW, of which 14 TW comes through the continents and 32 TW comes from the seafloor. After removing the heat production of radioactive elements in the continental lithosphere, the energy loss from the convecting mantle is 39 TW. Three main sources balance the mantle energy loss: Heat flow from the core, radiogenic heat production in the mantle, and the secular cooling of the mantle. The uncertainty on the exact contribution of each component is much larger than that on the total heat loss. The best estimate of the present cooling rate of the mantle (110 K Gy1) is higher than the secular cooling rate estimated from petrology. The present cooling rate may be different from its long-term average because of variations in seafloor spreading rates and higher mantle heat production in the past.