< p >全新世约12000年前开始的原因是因为当时北半球夏天热但是短。炎热的夏季开始熔化过程。< / p > < p >现在,7月是地球离太阳最远的。这使北半球夏季长而温和。这是一个关键的条件,使一个冰期开始。特别是,冰期开始当萨默斯在北半球高纬度如此温和,所有的雪,冬天之前的积累不融化。这触发一个失控的影响通过增加地球的反照率。这意味着明年夏天会更酷,更冰雪会积累。虽然我们对冰期时将名义上开始,还没有发生这次因为的组合低地球轨道的偏心率和相当低的轴向倾斜(倾角)的地球的取向,并可能因为人为的CO 2 <子> < /订阅>大气中浓度。< / p > < p >地球躲避一个冰期的子弹。子弹击中的下一个机会(在6月底或7月初远日点)将23到2.6万年后,和下一个之后,约50名左右的几千年。 From what I've read, eccentricity and obliquity conditions won't be quite conducive to see the onset of a glaciation the next time around, so the Earth will have to wait 50 or so thousand years to see the possibility of another glaciation. While that isn't our problem, we can help our children's children's children's children's ... children (about 2000 generations worth) survive that potential glaciation threat 50 or so thousand years from now by leaving them with lots of carbon-containing resources to burn. They might well need those hydrocarbons to prevent a glaciation. As a double bonus, stopping burning those hydrocarbons now will make for a much better life for our current generation of children, for their children's children, and for their children's children's children (which brings us to about 2100).