GREENHOUSE STATISTICS - TIME-SERIES ANALYSIS .2.

The analysis of part I (Tol and de Vos, 1993) is supplemented, updated and refined, and the resolution bound of simple statistical analysis is tentatively explored. The main conclusion of part I, the hypothesis that the anthropogenically enhanced greenhouse effect is not responsi ble for the observed global warming during the last century is rejecte d with a 99% confidence, is reconfirmed for the updated sample period 1870-1991. The slight decrease in the global mean temperature between 1940 and 1975 is attributed to the influence of El Nino and the volcan ic activity. The influence of sunspots, or the length of the solar cyc le, is found to be small and unlikely to have caused the observed glob al temperature rise. The analysis of a number of alternative records l owers the significance of the influence of the enhanced greenhouse eff ect to 95%. The temperatures on the northern hemisphere rise a little faster than the southern hemisphere temperatures; this distinction is not significant but in line with the larger amount of land at the nort hern hemisphere. Some indications are found of an unexplained four yea r cycle in the temperatures of the northern hemisphere. Winter tempera tures rise fastest, summer temperatures slowest; this is more profound on the northern than at the southern hemisphere. The difference is no t significant; it could be due to the influence of anthropogenic aeros ols. The analysis of monthly temperatures confirms the conclusions abo ve, and shows that the models used here are close to being too simple to be used at this resolution.