Ocean Heat
海洋热量
Ya?l: I hear a lot about global warming, but how do scientists take the Earth’s temperature?
Don: Great question. Most of the excess heat trapped by greenhouse gasses like carbon dioxide ends up in the oceans.That’s because the earth’s oceans are kind of like a giant sponge that can hold a lot of heat for a long time.
Y: The oceans are also huge–in fact, they cover most of the planet, and some parts of the oceans are warmer and some are colder. So it’s not like you can just stick a thermometer in somewhere and say, “OK, that’s the ocean’s temperature.”
D: Of course not. Scientists take thousands of temperature readings from different parts of the oceans. They use a combination of heat sensitive satellites and thousands of floats that directly measure the temperature of ocean water at various depths. Together, these instruments allow scientists to calculate an average ocean temperature.
Y: It’s an ongoing process, and scientists are always trying to get more accurate measurements. But they’ve found that the oceans have in fact been warming at a rate that corresponds with how much heat scientists think has been trapped by greenhouse gasses.
D: This may not sound too bad; as long as the oceans are absorbing most of the extra heat, why worry? But higher ocean temperatures cause icebergs and ice shelves to melt, which raises sea level. And warmer oceans could affect weather patterns in ways that scientists don’t fully understand.
Y:So, warming of the oceans affects us all.
Ya?l: 我听到很多关于与全球变暖的事情，但科学家们是怎么测量地球温度呢？
Don: 问得好。温室里的大多余热象二氧化碳之类气体的都被海洋吸收了。这是因为地球就象一块巨大的海绵，可以长时间容纳大量的热量。
Y: 实际上海洋是很大的，它占据了地球大部分的面积。海洋有的地方比较暖和，而有的地方比较寒冷。所以并不是那样，你拿个温度计随便测量某个地方的温度，然后说，“好了，这就是海洋的温度”。
D: 当然不是那样。科学家们会在海洋的不同区域测量无数次温度。他们把热敏感卫星和许多直接测量不同深度的海水温度的漂浮物结合起来。这些工具让科学家们计算出一个平均海温。
Y: 这是一个持续的过程，科学家们一直试图做更精确的测量。但他们发现，海洋变暖的速度其实与科学家们认为被温室所困住的气体的多少成比例的。
D: 这听起来也许不是太糟糕，只要是海洋吸收掉大部分多余的热量，为什么要担心呢？但较高的海洋温度会造成冰山和冰架融化，这引起了海平面上升。变暖的海洋可能会以一种科学家不理解的方式影响天气。
Y: 因此，海洋变暖影响着我们每一个人。 |