Antarctic temperatures over the present century: A study of the early expedition record

Air temperature records for 26 expeditions to Antarctica that have overwintered, for periods of at least 9 months, between 1898 and 1958 have been assembled. Using a map of 1957–75 average annual temperature over Antarctica, the results for the expedition sites were made compatible with modern data. The expedition records are unfortunately confined mainly to two regions, the Antarctic Peninsula and the Ross Sea sectors. It is difficult, therefore, to generalize the results to the entire continental area. The expeditions are also somewhat irregularly spaced in time with relatively few occurring in the 1917–34 period. The best guess that can be made is that Antarctic air temperatures now appear to be warmer, by at least 1°C, than those prevailing during the first decade of the twentieth century. The result is broadly consistent with temperature changes that have been reported for both land and marine regions over the rest of the Southern Hemisphere. This result is, however, in contrast with the course of temperature change over the Arctic region, where temperatures are now only 0.35°C warmer than in 1901.