The Sun is the primary forcing of Earth's climate system. Sunlight warms our world. Sunlight drives atmospheric and oceanic circulation patterns. Sunlight powers the process of photosynthesis that plants need to grow. Sunlight causes convection which carries warmth and water vapor up into the sky where clouds form and bring rain. In short, the Sun drives almost every aspect of our world's climate system and makes possible life as we know it.
Earth's orbit around and orientation toward the Sun change over spans of many thousands of years. In turn, these changing "orbital mechanics" force climate to change because they change where and how much sunlight reaches Earth. (Please see for more details.) Thus, changing Earth's exposure to sunlight forces climate to change. According to scientists' models of Earth's orbit and orientation toward the Sun indicate that our world should be just beginning to enter a new period of cooling -- perhaps the next ice age.
However, a new force for change has arisen: humans. After the industrial revolution, humans introduced increasing amounts of greenhouse gases into the atmosphere, and changed the surface of the landscape to an extent great enough to influence climate on local and global scales. By driving up carbon dioxide levels in the atmosphere (by about 30 percent), humans have increased its capacity to trap warmth near the surface.
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Read more here/Leia mais aqui: NASA
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NOTA CAUSTICANTE DESTE BLOGGER:
Ué, mas não era o aquecimento global que era antropogenicamente provocado? Agora é uma Nova Era do Gelo? Caracas, mano, me ensinaram que a ciência é o único meio de se conhecer a verdade sobre a natureza, e agora eles ficam sem saber dizer cientificamente se é o aquecimento global ou uma nova era do gelo que é antropogenicamente provocado: uma hora é aquecimento global, outra hora é um congelamento global?
Fui, nem sei por que, pensando com os meus botões -- aquela pequeníssima população humana foi quem provocou a última Idade do Gelo? Ué, mas eles nem tinham carros, casas com geladeira e ar condicionado, nem sequer tinham indústrias poluentes, e provocaram aquela catástrofe?
Ora, vão caçar sapos de botas, e procurar fazer ciência com mais rigor baconiano!!!
