During last 10 years investigations on Polar region lakes have been done that allow compare changing in their regimes with previous studying a half century ago. For analysis of lakes vulnerability/stability three mark regions have been chosen: The Lena River delta, Yamal peninsula and East Antarctic oases. Mark parts of Arctic and Antarctic give some very similar information about lacustrine ecosystem but in other processes different. Our investigation of lacustrine sediment cores show quite high self-cleaning of Arctic lakes according to analysis of a cations exchange capacity between near-bottom water and up layer of a core. Intensive natural eutrophication and lake succession stages replacement are available. Against a background stable glacial lakes in Antarctic there are “active” Arctic thermokarst and alas lakes. In Antarctic drying oases areas have been noticed. As a result, reduction of lakes amount as well as increasing of catchments without outflow were observed. In contrast to Antarctic oases deglaciation water system in Arctic become humidity. So, quantity of small lakes rises and lake outflow upwards. Therefore, there are two main reasons of lake ecosystem features non-conformity. One of them is a climate change, in general, and its different evidence, from another side - drying and humidification in Antarctic and Arctic correspondingly, for instance. Sometimes understanding of possibility of lakes features changes is a complicated fact. Furthermore, composition of separate components of ecosystem parts is unequal of a character of a new changed system. Lake vulnerability of both Polar Regions could be the same against the differences of their parts. Using for further ecosystem progress prediction the non-additive parameters like vulnerability/stability is more correct, consequently. The last point of view is Polar lakes is more open to environmental change, mostly to insolation and biogenic elements income, than to anthropogenic impact from Polar stations in these regions.