Övrigt > Historia
Verkningar av Lakis utbrott i Sverige?
tty:
Benjamin Franklin som var amerikansk ambassadör i Paris observerade också fenomenet och skrev året därpå:
"During several of the summer months of the year 1783, when the effect of the sun's rays to heat the earth in these northern regions should have been greater, there existed a constant fog over all Europe, and a great part of North America. This fog was of a permanent nature; it was dry, and the rays of the sun seemed to have little effect towards dissipating it, as they easily do a moist fog, arising from water. They were indeed rendered so faint in passing through it, that when collected in the focus of a burning glass they would scarce kindle brown paper. Of course, their summer effect in heating the Earth was exceedingly diminished. Hence the surface was early frozen. Hence the first snows remained on it unmelted, and received continual additions. Hence the air was more chilled, and the winds more severely cold. Hence perhaps the winter of 1783-4 was more severe than any that had happened for many years.
The cause of this universal fog is not yet ascertained [...] or whether it was the vast quantity of smoke, long continuing, to issue during the summer from Hecla in Iceland, and that other volcano which arose out of the sea near that island, which smoke might be spread by various winds, over the northern part of the world, is yet uncertain"
Vilket innebär att han sannolikt var den förste som direkt visade på att vulkanutbrott påverkade klimatet.
Jerrark:
Nu upplever vi än en gång verkningarna av ett vulkanutbrott på Island. Idag stängde Sverige, Norge och flera andra europeiska länder sitt luftrum på grund av askmolnet från vulkanen vid Eyjafjallajökull. På Island tar man in sina djur för att de inte skall andas in stoft och gaser från vulkanen.
Vi får väl se hur länge vulkanen forsätter att spy ut stoft och aska och hur det kommer att påverka oss.
Jerrark:
Någon som vet hur väl denna händelse återspeglas i årsringarna från träd? Forskning i Amerika har ju t ex tydligt visat att klimatvariationer, även kortvariga sådan syns väl i årsringarna.
Lite om årsringsforskning i Amerika:
Tree-Ring Data Show History, Pattern to Droughts
http://www.sciencedaily.com/releases/2013/02/130217083054.htm
New Drought Record from Long-Lived Mexican Trees May Illuminate Fates of Past Civilizations
http://www.sciencedaily.com/releases/2011/02/110203124816.htm
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