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Asia
亚洲
Cyclones and climate change
飓风与气候变化
The new normal?
习以为常？
Physics suggests that storms will get worse as the planet warms. But it is too early to tell if it is actually happening
物理学研究表明全球变暖将导致更猛烈的风暴，但一切尚未可知
WAS typhoon Haiyan the strongest recorded storm to make landfall?
台风海燕是有记录以来的最强登陆风暴吗？
Meteorologists will never know. Reliable records go back only a few decades.
气象学家们恐怕永远都不会知道。可靠记录只能回溯几十年。
But it is surely one of them. Besides the devastation and the death toll, one way to assess its potency is to compare it with Katrina, the hurricane that devastated New Orleans in 2005.
不过可以肯定，这是史上最强风暴之一。除了统计摧毁的建筑和死亡的人数，评估该风暴威力的另一个办法，是将它和2005年摧毁新奥良的卡特里娜飓风作比较。
At its most intense, Haiyan's peak wind speeds were probably greater than 300kph.
在高峰期，海燕的最高风速可能超过每小时300公里，
The best estimate for Katrina, when it hit land, is around 200kph.
而卡特里娜登陆时，其风速估计在每小时200公里左右。
Regardless of its precise position in the historical hierarchy, Haiyan—like Katrina—has provoked discussion about the effects of global warming on tropical storms.
且不考虑台风海燕在历史上排行第几，海燕—如同卡特里娜—已激起关于全球变暖对热带风暴影响的讨论。
Naderev Sano, the Philippines' representative at a climate summit in Warsaw, was unequivocal, daring doubters to visit his homeland.
在华沙举行的联合国气候变化大会上，菲律宾代表Naderev Sano态度坚定，他请全球变暖效应的怀疑者们去他的祖国看一看，
The trend we now see is that more destructive storms will be the new norm, he said.
并说：我们从眼下的趋势可以看到，更具破坏性的风暴将成为常态。
In theory, a warmer world should indeed produce more potent cyclones.
理论上，全球变暖确实将引发更具威力的风暴。
Such storms are fuelled by evaporation from the ocean.
这类风暴来自海洋的水气蒸腾。
Warmer water means faster evaporation, which means more energy to power the storm.
水温越高，蒸发越快，这意味着暴风将来得更猛烈。
A warmer atmosphere can hold more moisture, which means more rain.
而温暖的大气将储存更多水分，这将造成更多的降雨。
But other factors complicate things.
不过其他一些因素使事情变得复杂。
Tropical cyclones cannot form when wind speeds in the upper and lower atmosphere differ too much.
当高层和底层大气的风速相差悬殊时，热带气旋便无法形成。
Climate models suggest, in the North Atlantic at least, that such divergent winds may be more common in a warmer world.
气候模型表明，至少在北大西洋，如果气温升高，那这类风速甚异的气流可能会变得更常见。
The Intergovernmental Panel on Climate Change reckons that the frequency of cyclones will stay the same or decrease while their average intensity goes up.
政府间气候变化专门委员会估计，当飓风的平均强度增加时，它的频率或许会保持不变甚至降低。
That is the forecast. But the evidence so far is messy.
这些都只是预测。可迄今为止的证据相当混乱。
Meteorological records are of uneven quality, and tropical storms vary widely in intensity, which makes spotting trends tricky.
气象记录的质量良莠不齐，热带风暴的强度变化不定，这使得认清趋势的任务变得棘手。
One potent storm from 1979, Typhoon Tip, holds the record for the lowest atmospheric pressure recorded, another measure of a storm's intensity.
另一项台风强度的测算显示，1979年的超级强台风泰培保持了最低大气压的记录。
Yet levels of carbon dioxide, the main greenhouse gas, were only 337 parts per million in 1979, compared with 394ppm in 2012.
然而，相比2012年的394ppm，主要温室气体二氧化碳的浓度在1979年仅为337ppm。
The IPCC concludes that, although there is good evidence for more and stronger Atlantic hurricanes over the past 40 years, there is no consensus on the cause of them.
IPCC推断，虽然有充分的证据显示，在过去的40年间，大西洋的飓风正变得更为频繁和猛烈，但IPCC表示，对于此现象的起因，业内并未形成共识。
Worldwide, there is no trend in either the frequency or the intensity of tropical storms.
在世界范围内，关于热带风暴发生的频率或强度的趋势依旧无迹可寻。
And, given the rarity of such storms as Typhoon Haiyan, it will take a long time for any trend to become apparent.
不仅如此，由于像台风海燕这样的罕见风暴的出现，在相当长一段时间内，风暴的趋势将愈加扑朔迷离。
