The big climatic disasters
of the geologic history
Throughout its immense geologic history, the globe was marked by innumerable climatic upheavals as a consequence of solar activity variations, the eccentricity of the global orbit, the migration of the magnetic poles and, less importantly the volcanic activity.
Naturally, these temperature variations affected the whole globe.
The two last great glaciations, that of RISS and that of WURM refreshed the Sahara which covered itself with vegetation on several occasions.
For the last time, for 35 thousand years, all the Swiss plain is totally covered under thicknesses of ice of 1000 to 1700 meters.
After this great glaciations, a first very hot period corresponds to the Roman empire. It ends in a great cooling.
One second hot period corresponds to the Middle Ages. It is also ended by a great cooling.
The temperature variations, more or less full, extend until the nineteenth century.
Starting from 1820, well before the industrial time, the warming is general. The glaciers move back everywhere and harvests are abundant.