It is essential to trace back and explain long-term climate variations in order to understand current global warming and predict its impact for the coming centuries.
This is especially true for the countries of the South.
Indications of variations in sea level and therefore in the polar ice caps, measured from corals off Tahiti, enabled the research team to refute the classical hypothesis according to which solely the insolation at high Northern latitudes influence the various glacial/interglacial changes.
They showed that the end of the penultimate glacial period, 137 000 years ago, brought into play processes that operate in both hemispheres.
This suggested that the Earth’s orbital parameters regulate its climate by modulating the seasonal and latitudinal variations in solar energy received at the Earth’s surface.
Hot summers favour progressive melting of the ice caps.
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They require large quantities of light in order to develop, therefore they inhabit areas of shallow water, at between 0 and 10 m depth.The processes that trigger deglaciation episodes appear to be more complex than the long accepted idea that the main factor behind the build-up (or regression) of ice caps is the summer insolation on the higher latitudes of the Northern Hemisphere.To explain the climatic cycles, aspects other than just the relation between the Earth and the Sun must be considered: this is the astronomical theory of climate, developed by the Serbian geophysicist Milutin Milankovitch in the early XXth Century.Failing a sufficient understanding of the processes involved, the 2007 report of the Intergovernmental Panel on Climate Change (IPCC) does not take account of the ice caps’ dynamic response to current global warming.It recognizes that this is the major uncertainty holding back efforts for forecasting sea levels that might be reached by 2100.