xion skrev:Nytt köldrekord på Jorden.
Nästan -100 grader på Antarktis.
Då får man klä på sig ordentligt.
Jasså?
Hur var kölden på Antarktis under istiden då? Högre eller lägre?
Det är ju alltid lätt att påstå saker som inte det finns evidens för - bara för att "jag tycker så, tror så" - det är ju typiskt utanför vetenskapen att man har ett tyckande och troende som nästintill aldrig är befäst i sanna uttalanden om verkligheten.
Här kan man läsa lite mer kring klimatet:The last 3 million years have been characterized by cycles of glacials and interglacials within a gradually deepening ice age. Currently, the Earth is in an interglacial period, beginning about 20,000 years ago (20 kya).
The cycles of glaciation involve the growth and retreat of continental ice sheets in the Northern Hemisphere and involve fluctuations on a number of time scales, notably on the 21 ky, 41 ky and 100 ky scales. Such cycles are usually interpreted as being driven by predictable changes in the Earth orbit known as Milankovitch cycles. At the beginning of the Middle Pleistocene (0.8 million years ago, close to the Brunhes–Matuyama geomagnetic reversal) there has been a largely unexplained switch in the dominant periodicity of glaciations from the 41 ky to the 100 ky cycle.
The gradual intensification of this ice age over the last 3 million years has been associated with declining concentrations of the greenhouse gas carbon dioxide, though it remains unclear if this change is sufficiently large to have caused the changes in temperatures. Decreased temperatures can cause a decrease in carbon dioxide as, by Henry's Law, carbon dioxide is more soluble in colder waters, which may account for 30ppmv of the 100ppmv decrease in carbon dioxide concentration during the last glacial maximum. [1]
Similarly, the initiation of this deepening phase also corresponds roughly to the closure of the Isthmus of Panama by the action of plate tectonics. This prevented direct ocean flow between the Pacific and Atlantic, which would have had significant effects on ocean circulation and the distribution of heat. However, modeling studies have been ambiguous as to whether this could be the direct cause of the intensification of the present ice age.
This recent period of cycling climate is part of the more extended ice age that began about 40 million years ago with the glaciation of Antarctica.
https://en.wikipedia.org/wiki/Geologic_ ... ure_record