Global temperatures have been rising since the turn of the twentieth century, most notably during the past 30 years, but la Nina is part of a regular cycle that is simply overlaid onto that pattern.

进入20世纪以来，全球气温骤然升高，这在近30年尤其显著。拉尼娜现象不过是基于这种模式下，正常循环的一部分。

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La Nina is a natural 3-6-year cycle, and the cold stretch of a periodic thermal oscillation in ocean surface temperatures that occurs throughout the tropical Pacific.

拉尼娜每隔3到6年发生一次，太平洋热带地区海水温度会随之发生周期性的异常变冷。

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The best hope lies in trying to identify the broader changes under way - for example with the retreat of the Arctic sea-ice or the cycle of warming in the Pacific Ocean with El Nino and La Nina.

BBC: Predicting the next big flood