Waar heb je trouwens dat plaatje vandaan? Ik zie hem wel eens vaker voorbijkomen. Ben benieuwd naar de bron (met nadere info).
Vermoedelijk van de site van Evert Wesker, die het overigens zeer oneens zou zijn met Kimme zijn 'visie'. Hij legt het plaatje wat uitgebreider maar ook iets anders uit:
,,The Gulf Stream has varied considerably. In the figure below the shows the limits of the arctic water on two moments in time: Its position during the climax of the "little ice age" (1695) and during a much warmer period in the north Atlantic Ocean (1920-1950).
The difference between 1920-1950 and 1695 is dramatic. So were the climatic consequences over north-western Europe. In the years 1690 - 1700 the weather in northern Scotland was so cold that in 8 out of 10 years there was a crop failure. The famine which resulted from this took the lives of one to two thirds of the local population. In this region it was a disaster greater than the Bubonic Plague of the 14th century! If one regards the oscillations in temperature over the northern Atlantic Ocean since the last glacial period one can observe maxima at 7000 BC, 4500 BC, 2000 BC and 800 AD. The second of this series was the warmest, about 1 - 2 °C warmer then today. An interesting idea has been proposed to explain this: "The salt conveyor".
"The salt conveyor" has two modes: "On" and "Off".
If the salt conveyor is "On" warm and salty water flows into the north Atlantic where it meets cold and dry arctic air. It will cool and sink away. This water will flow southwards at some depth and flow to the Indian and Pacific ocean. In this way salt is transported away into the depth of the oceans. If at a certain point in time the water becomes too warm or too fresh it will not sink away any more and the salt conveyor switches "off". According to model calculations a fresh water flow equal to one quarter of the flow of the Amazon river appears to be enough to stop "the salt conveyor". In the "off" stage a net ice growth in the north Atlantic is possible.
The late Quaternary record suggests that this process oscillates with a period of about 2000 years, which is almost equal to the periods between little ice ages: every 2500 years. Whether this idea is right is still an open matter. Localised events and the impact of ice sheets on the atmospheric circulation have to be taken into account as well. But it shows a way of linking ocean flow patterns with weather patterns. And to close this point: If the "conveyor belt" hypothesis is (partly) right the present warming of the Earth may well switch the conveyor (partly) "off" due to larger amounts of fresh water (melting of ice, increased rainfall from air masses originating from the Pacific), and the north Atlantic would become colder. Another possibility is a warming of the north Atlantic, but less so than areas at similar latitudes in the northern hemisphere.
In the last IPCC report it is stated that the possibility of a cooling of the North Atlantic due to the mechanism described above is probably remote.''
Gr. Ben
Quote selectie