English: This image, acquired by one of the Copernicus Sentinel-2 satellites on 24 September 2020, shows the status of the Arctic tundra in the Yamalsky District (Russia) in the beginning of the 2020 autumn. Arctic tundra is a unique ecosystem composed mainly of permafrost. Permafrost, according to current estimates, is the main source (45%) of all Arctic methane emissions, one of the most dangerous GHG. Due to climate change, Arctic regions have been warming faster than other global regions over the last century: warmer temperatures accelerate the decomposition of organic carbon in permafrost soils, resulting in higher net methane emissions. According a new research published in Global Change Biology, most of the methane emissions from thawing permafrost occurs in Autumn and climate change can contribute to further increasing emissions in the future. The Copernicus Sentinel-2 satellites, with a maximum revisit time of five days, are very useful for monitoring the impact of climate change in such an important and delicate environment as the Arctic Circle.