Continental heat gain in the global climate system

Recent estimates have shown the heat gained by the ocean, atmosphere, and cryosphere as 18.2 · 10 22 J, 6.6 · 10 21 J, and 8.1 · 10 21 J, respectively over the past half‐century. However, the heat gain of the lithosphere via a heat flux across the solid surface of the continents (29% of the Earth's surface) has not been addressed. Here we calculate that component of Earth's changing energy budget, using ground‐surface temperature reconstructions for the continents. In the last half‐century there was an average flux of 39.1 mW m −2 across the land surface into the subsurface, leading to 9.1 · 10 21 J absorbed by the ground. The heat inputs during the last half‐century into all the major components of the climate system — atmosphere, ocean, cryosphere, lithosphere‐reinforce the conclusion that the warming during the interval has been global.