 Mantle thermal budget

An energy balance for heat stored in the mantle. Here $C_m$ is its effective heat capacity, $H_m$ internally generated radioactive power, $Q_{\mathrm{cmb}}$ power entering across the core-mantle boundary and $Q_m$ power leaving the mantle. The sign of the right-hand side determines warming or secular cooling in this reduced model. Different reservoirs and latent heat may require additional terms. Surface heat loss includes crustal contributions and should not be substituted for $Q_m$ without specifying the partition.