Sporadic observations of sea ice thickness in the Arctic have revealed a drastic thinning of about 43% between the period 1951-1975 and 1993-1997. However, as those measurements have been performed only in a few regions of the Arctic Ocean, their interpretation in terms of climatic change is difficult. The presentation will review our currentknowledge about ice thickness changes and ice thickness measurement techniques and will demonstrate the need for additional new technologies. The two main candidates for more systematic future thickness surveying are airborne electromagnetic sounding and in particular satellite altimeters. The presentation will also address logistic issues which can be complicated for airborne campaigns in the Arctic and Antarctic.