文勇的新托福黄金&ccedil

apparently the most obvious reason for

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Unformatted text preview: 在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在 在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在 (在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在 ),在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在 17 在在在在在在在在在在在在在在在在在在在在在在在在在在在 在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在 在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在 20 在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在 在在在在在在在在在在在在在在在在在在在在在在 在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在 only 在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在 在在在在在 在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在在 311 Mail@liuwenyong.com 在在在在在在 www.liuwenyong.com 在在在在在在在在在在在在在在在,在在在在在在在在在在 Variations in the Climate One of the most difficult aspects of deciding whether current climatic events reveal evidence of the impact of human activities is that it is hard to get a measure of what constitutes the natural variability of the climate. We know that over the past millennia the climate has undergone major changes without any significant human intervention. We also know that the global climate system is immensely complicated and that everything is in some way connected, and so the system is capable of fluctuating in unexpected ways. We need therefore to know how much the climate can vary of its own accord in order to interpret with confidence the extent to which recent changes are natural as opposed to being the result of human activities. Instrumental records do not go back far enough to provide us with reliable measurements of global climatic variability on timescales longer than a century. What we do know is that as we include longer time intervals, the record shows increasing evidence of slow swings in climate between different regimes. To build up a better picture of fluctuations appreciabl...
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