On page 10 of [wenham, et al. (2007)] it is stated that water vapor in our atmosphere absorbs infrared light strongly in the wavelengths between 4000 and 7000 nm and co2 between 13000 and 19000 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 13000 and 19000 nm emitted by the earth is absorbed by the atmosphere and half is re-emitted towards the earth.