Permafrost is soil, rock or sediment that is frozen for more than two consecutive years. Mostly located in high latitudes, the permafrost has been diminishing for many years due to global warming and becomes to be highly monitored by the scientific community. When it thaws, this frozen ground releases methane therefore contributing even more to global warming as part of a pernicious feedback loop. Two Essential Climate Variables defined by the Global Climate Observing System (GCOS) are related to permafrost. This visualization depicts the Global Terrestrial Network for Permafrost, which is the worlwide initiative for permafrost essential climate variables monitoring. The blue and red points represent local ground stations where the data is collected whereas the yellow ones are the organizations where the data from stations is aggregated.
You can consult the original visualization here.