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The Arctic is a key area for observing and understanding past and future climatic change. During the 20th century, meteorological data demonstrate a more important warming than the global average, but this warming has been neither continuous in time nor homogeneous in space. After a strong surge in the beginning of the 20th century, a trend in decreasing temperatures has been observed from the 40's, which ended more or less rapidly according to the different sectors ; opposite in tendencies have been observed among different sectors, particularly between the European Arctic sector and the West Greenland and Eastern Canadian Arctic's. A strong warming has begun in the 70's to the 90's in the different sectors, it has provoked a noticeable decrease in size and thickness of the ice-sheet in the most recent years. This warming is also related to very important changes in indices of the North-Atlantic Oscillation and Arctic Oscillation, the most prevailing modes of climatic variability in the Arctic area. All climate models foresee a continuation of this warming during the next decades, but seem to fail in simulating the regional differences between the different Arctic sectors, and the variability related to the NAO and AO processes as well. This hinders from a precise anticipation of climate change impacts on natural environments and on human activities in the Arctic.