The paper presents a comparative summary of previous attempts by the author to assess and map global primary productivity using environmental parameters as predictors. The individual components of the productivity process, net production, gross production, dark respiration as well as their regional rates are computed for 10 degree latitudinal belts. A new version of the Miami Model (Lieth, 1973, 1975) is presented predicting net primary productivity from an increased number of averages of temperature and precipitation. Net primary productivity values in form of dry matter accumulation and caloric energy equivalents are compared.