Question

Assume that water vapor in our atmosphere absorbs infrared light strongly in the wavelengths between 4,000 and 7,000 nm and CO₂ between 13,000 and 19,000 nm. Assuming the Earth absorbs and emits radiation as a blackbody and that its rotation results in a uniform surface temperature, develop a planetary energy balance and calculate the mean Earth surface temperature (in K) for the following three cases: 1) zero atmospheric CO₂ and zero H₂O, 2) a sufficiently large amount of H2O such that all radiation between 4000 and 7000 nm emitted from Earth is absorbed by the atmosphere and half is re-emitted towards the Earth, and 3) the same assumption regarding water as in case 2 plus a sufficiently large amount of CO₂ such that all radiation between 13,000 and 19,000 nm emitted by the Earth is absorbed by the atmosphere and half is re-emitted towards the Earth.

Answer 1