Recession of the southern part of Barnes ice cap, Baffin island, Canada, between 1961 and 1993, determined from digital mapping of Landsat TM

Changes along the margin of the southern half of the 5900 km(2) Barnes Ice Cap have been assessed using 1993 Landsat TM imagery in comparison with digitized 1:50 000 NTS maps based on 1961 photogrammetry. The average recession over the 183 km long southern perimeter was found to be at least 4 m a(-1), with no significant difference between the southeast and southwest sectors. Viewed in conjunction with the sustained retreat previously reported for the northwest margin, these results indicate that a general reduction in the size of Barnes Ice Cap is occurring. The present pretreat phase began under a regional climate warming in the late 19th to early 20th century period and continues, while the record of the ablation-season temperature since the midcentury, has not shown any significant trend.