Palaeoclimates from 18 kyr BP on and the anthropogenic climate change due to the present CO2 increase have been computed using the Adem thermodynamic model. Temperature results for 18 kyr BP are lower than at present for almost all the Northern Hemisphere, with extreme anomalies in the north of the continents. The main cause is the snow-ice cover, the insolation delays the annual cycle by about one season, and the CO2 reinforces the anomaly. From 18 to 14 kyr BP, the continental climate was colder than at present due to the extended snow-ice, then it became wanner from May to November, following the insolation pattern. Over the oceans this anomaly was smoother and delayed by about one season. For 4 kyr BP, the surface and tropospheric average annual temperatures were almost the same as at present, but the seasonal variability was larger, with winter and spring colder, and summer and autumn warmer. Over continents this effect is stronger at the surface than above, and the opposite is true over oceans. These results agree well with those from other authors. For the CO2 doubling, the temperature increases by a few degrees centigrade, and a relative drought appears in most continents.