My comrade-in-arms muriel sent me a link to NYT’s article about rising temperature of Lake Baikal.

It is an issue that concerns me: my native town was on the eastern shore of the lake, in the Selenga river delta. Actually, from an ecological point of view, Baikal is not a lake, it is a freshwater ocean. It is kept fresh and clean by a pattern of circulation of water caused by the annual cycle of change of ambient temperature. Crucially, mean temperature of air is below 4 degrees of Celsius,  the point of maximum density of water (the zero degrees mean isoterm crosses or at least touches the lake, its nothern tip lies in the permafrost area). A similarly deep Tanganyika Lake is dead below certain depth because of lack of water circulation.

Raising mean temperature by 4 degrees (possible in the worst case scenario of global warming) will kill Baikal — the surface water will stop to sink into the depth of the lake. However, this will happen pretty slowly: the water circulation cycle is 400 or 600 years, and the water mass is huge.

One of the principal lessons of my life was the degradation of environment: I grew up in a rustic place where hawks were stealing chicks from the barnyard, where flocks of migrating geese and ducks were literally darkening the sky — and the whistling sound of hundreds of thousands of wings was heard long before the dark cloud covered the sun. For a Russian reader, the Selenga delta was where Zilov from Vampilov‘s Duck Hunt went from Irkutsk (where the action of the play took place) to shoot ducks. Indeed, duck shoot was fabulous — in a nearby settlement of istomino, I had once seen a man who was shooting ducks while drinking tea from a samovar on a terrrace of his house.  As a boy, I angled for baby sturgeon (fish so oily that my mother was using it in place of frying oil, to fry eggs and potatoes). All that has gone.

On a more technical note – I am looking for a good map of the Earth with isoterms of mean temperature shown in steps of 1 degree. By default, permafrost is formed in areas of below zero mean temperature. Such a map will show the area of permafrost which will melt after mean temperature rising by 1 degree (of coures, with all the simplifying assumption that warming is uniform, etc.). Still, it is something that would give some food for thought.