Suppose that the surface temperature of the Sun were to increase by 3% from the current value, assuming for simplicity that the radius of the Sun stays fixed. By how much would the solar constant on Earth increase? If, at present, Earth radiates away an amount of energy equal to the current incoming energy flux from the Sun by radiating as a black body at an effective temperature of T_b ≅ 5 ^◦C, by what amount would the temperature T_b have to increase to offset the increase in incident solar energy?