Foi a peste que alterou o clima ?

Num artigo acabado de ser publicado na revista NEWSCIENTIST é exposta uma teoria que demonstra que as diferentes eras de gelo, períodos de forte arrefecimento climático, que atravessaram os milénios mais próximos da civilização humana, poderão ter sido causados por fortes movimentos demográficos, ocasionados por pestes, que levando a uma forte redução da actividade agrícola, conduzem a alterações do clima.

Caso os factos o provem, teriamos que a peste negra ao reduzir drásticamente a actividade agrícola conduziria a uma alteração climática importante, a pequena idade do gelo, ao invés da actual teoria que atribui aos efeitos da alteração do clima o aparecimento da peste.

Tratar-se-ia de uma inversão total dos acontecimentos.

Mais desenvolvimento em: www.newscientist.com

A Chilling Tale

Did ancient plagues and pestilence that killed millions of people also alter the planet's climate ?

Slight dips in the level of carbon dioxide in the atmosphere over the past 2000 years are usually put down to natural causes, such as lower emissions from vulcanoes. But when human populations were decimated by disease, large areas of farmland would have been abandoned to nature. As florests reclaimed the land, huge quantities of CO2 would have been sucked out of the atmosphere.

Ruddiman has shown that the timing of one of the larger dips in CO2 matches a series of plagues that peaked around AD 540. Another coincides with the "black death" of the 14th century. In both cases Europe's population may have fallen by a third or more. Worse still was the effect of European settlers bringing smallpox and other diseases to the Americas, causing populations to fall by as much as 90 per cent. This coincides with a relative cool period known as the "little ice age".

Historians have suggested that the little ice age caused famine, disease and depopulation - but was disease the trigger for the little ice age, rather than the upshot?