For the model in fig. 8.3, the value at = 0.9 yields a temperature t=295 k assuming latex: e_s=235\: \mathrm{w}\: \mathrm{m^{-2}}

(a) calculate the value of at that would increase t by 4latex: ^\circ∘c .

(b) assuming this change in at is driven by increases in atmospheric co2, describe the changes we would see in fig. 7.1b (referring to case ii) and fig. 7.2 referring to wavelengths around 15 latex: \mu m