A 35 year record of production and respiration in the Northern Hemisphere bas been derived from monthly records of atmospheric concentration, fossil fuel combustion, and oceanic absorption of carbon dioxide using a method developed by Hall et al. The original conclusion of Hall et al. that there was no significant change in biotic metabolism, is confirmed by measuring both production and respiration from 1958 to 1972. But the analysis of the subsequent record shows that both production and respiration have been enhanced since the early 1970s by some large scale global change, probably of human origin. Our results also show that high-latitude regions in the Northern Hemisphere are changing more than regions further south. Nevertheless, the ratio of production to respiration (P/R) remains unchanged during the time period examined. Thus, no argument can be made for net carbon storage of or release from the biosphere from this analysis, although the turnover rate of the biosphere appears to be enhanced.