A model describing the evolution of the present atmosphere and hydrosphere has been developed. The model is based on the following experimental parameters: a) the abundance of mantle fluid occluded in Arkansas diamonds, b) the 3.1 b.y. age of crystallization for an Arkansas (USA) diamond, c) the depth range for diamond formation, about 100 to 400 km and d) the age for the Earth of 4.67 b.y. The data for all occluded fluids except H2O and CO2 are in terpreted interms of a first order mechanism for degassing of the Earth. A rate constant of 6.5¿10-10yr-1 is obtained which gives good agreement for experimental values of atmospheric N2 and 36Ar. The constant is slightly higher than that for decay of 40K(&lgr; = 5.5¿10-10yr-1) and suggests that the decay of 40K might be the maindriving force for all processes occurring in this region of the mantle. Evidence indicates that CO2 and H2o exist in two phases in the low seismic velcoity region of the upper mantle. If true, this requires a transformation of the first order rate law to a zero order rate law for these fluids. This was done and with &lgr;H2O-3.4¿108 tons yr-1 and &lgr;CO2 = 0.5¿108 tons yr-1 the experimental and calculated values agree. Good agreement between the calculated and experimental abundance of all fluids in the atmosphere and hydrosphere gives strong support for the validity of the theoretical model. To preclude possible fortuitous agreement, four additional tests over different time spans were made; one with N2, two with Ar and one with H2O. The experimental results and theoretical values agree to within 20% for these additional tests, further supporting the model.