蒸腾的太平洋：海水升温成因复杂

Hurricane Patricia was a surprise. The eastern Pacific hurricane strengthened explosively before hitting the coast of Mexico, far exceeding projections¹ of scientists who study such storms.

飓风“帕特里夏”(Patricia)让人比较意外。在袭击墨西哥海岸之前，这场出现在东太平洋海域的飓风势头骤然增强，远超出了研究此类风暴的科学家们的预料。

And while the storm’s strength dissipated quickly when it struck land, a question remained. What made it such a monster?

虽然登陆之后，它的力量迅速消散，但有一个疑问依然存在，即这场势如怪兽的飓风是由什么引起的？

Explanations were all over the map, with theories that included climate change (or not), and El Ni漀.

相关解释五花八门，其中包括气候变化（或气候不变）和厄尔尼诺现象等各种理论。

But the answer is more complicated. The interplay of all the different kinds of warming going on in the Pacific at the moment can be difficult to sort out and, as with the recent hurricane, attributing a weather event to a single cause is unrealistic.

但答案却更为复杂。目前太平洋上有各种不同的变暖现象在相互作用，难以厘清。就最近这场飓风而言，将一个气象事件归于某个单独的因素是不现实的。

Gabriel Vecchi, head of the climate variations and predictability group at the geophysical fluid dynamics² laboratory of the National Oceanic and Atmospheric³ Administration in Princeton, N.J., likened the challenge to the board game Clue.

布里埃尔·韦基(Gabriel Vecchi)将这项挑战比作桌游“妙探寻凶”(Clue)，他是位于新泽西州普林斯顿市的美国国家海洋与大气管理局（National Oceanic and Atmospheric Administration，简称NOAA）地球物理流体动力学实验室气候变化和可预测性小组的负责人。

“There’s all these suspects, and we have them all in the room right now,” he said. “The key is to go and systematically⁴ figure out who was where and when, so we can exclude people or phenomena⁵.” Extending the metaphor⁶, he noted⁷ that criminal suspects could work together as accomplices⁹, and there could be a character not yet known. And, as in all mysteries, “You can have a twist ending.”

“有各种各样的疑犯，目前都在这个屋子里，”他说。“关键在于系统地搞清楚每个人什么时候都出现在什么地方，这样我们才能排除不是凶手的人，或说排除不是影响因素的现象。”他还表示，拿这个比喻继续推演，几名疑犯可能会联合作案，可能还有你不了解的角色存在。而且，就像在所有的迷案中一样，“结尾有可能出现剧情大逆转。”

At the moment, the world’s largest ocean is a troublesome place, creating storms and causing problems for people and marine¹⁰ life across the Pacific Rim⁸ and beyond. A partial list includes the strong El Ni漀 system that has formed along the Equator, and another unusually persistent¹¹ zone of warm water that has been sitting off the North American coast, wryly¹² called “the Blob.”

全世界最大的海洋目前成了一个比较棘手的地方，它制造多场风暴，给居住在环太平洋区域的人们带来各种问题，也影响了这一区域的海洋生物。这些问题包括沿赤道形成的强厄尔尼诺气候，和在北美沿岸海域持续存在的异常暖水区域，后者被人戏称为“温水区”(the Blob)。

And a longer-term cycle of heating and cooling known as the Pacific Decadal Oscillation may be switching from a cooling phase to a warming phase. On top of all that is the grinding progress of climate change, caused by accumulation of greenhouse gases generated by human activity.

还有一种被称为“太平洋十年涛动”(Pacific decadal oscillation)、周期更长的海水冷热更替现象，现在可能正从寒冷期转入温暖期。除了这些，还有一个最重要的因素，那就是由人类活动产生的温室气体不断累积而引发的、无休无止的气候变化。

Each of these phenomena operates on a different time scale, but for now they appear to be synchronized¹³, a little like the way the second hand, minute hand and hour hand line up at the stroke of midnight. And the collective effects could be very powerful.

这些现象各有自己的运转节奏，但目前它们似乎实现了同步，有点像秒针、分针和时针在午夜重合。而且由此形成的集体效应非常强大。

Although they interact with one another, each of these warming events is being blamed for specific problems.

尽管他们相互作用，但每个变暖事件都被归为某些特定问题的起因。

“The Blob” has been associated, among other effects, with the unusually dry and warm weather in the western United States. Out in the ocean, the nutrient-poor warmer waters of the Blob — about four degrees Fahrenheit¹⁴ higher than average — are disrupting the food web of marine life. Some species of fish are showing up where they are not expected, including tropical sunfish off the Alaska coast, and an unusual number of emaciated¹⁵ sea lion pups and Guadalupe fur seals are being found stranded¹⁶ on California shores.

温水区被认为与许多问题有关，其中之一是美国西部出现的不寻常的干燥温暖天气。它所在的海域营养贫乏、温度高于正常的海水——大概比平均温度高4华氏度——正在扰乱海洋生物的食物链。有些鱼类出现了它们本不会出现的地方，比如阿拉斯加海岸附近出现了热带太阳鱼，加州海岸上则有数目异乎寻常的赢弱海狮幼崽和瓜达卢普海豹搁浅岸边。

The warm water has also been linked to unprecedented¹⁷ harmful algal blooms along the coasts that have rendered shellfish toxic¹⁸ and shut down shellfish fisheries in Washington, Oregon and California. “A single clam¹⁹ can have enough toxins²⁰ to kill a person,” said Vera L. Trainer, the manager of the marine biotoxin program at NOAA’s Northwest Fisheries Science Center in Seattle. Officials also ordered the largest closure of the state’s Dungeness crab²¹ fishing.

海水变暖还被认为与海岸线出现的前所未有的有害藻类大量繁殖现象有关，它导致甲壳类水生动物中毒，使华盛顿州、俄勒冈州和加州关停了贝类水产养殖场。“一个蛤蜊所含的毒素就足以致人死亡，”位于西雅图的NOAA西北渔业科学中心的海洋生物毒素项目负责人薇拉·L·特雷纳(Vera L. Trainer)说。官员还下达了该州规模最大的一次邓杰内斯蟹禁捕令。

“It’s really worrisome,” Dr. Trainer added. “If this is a single event that then goes away and we can forget about it down the road, it’s O.K. If it’s a window into the future, it’s not a good future.”

“这真的很让人担忧，”特雷纳博士接着说。“如果这是一个单一事件，之后就会消失，人们可以忘记它，倒也还好。但如果它是面向未来的一扇窗，那就不妙了。”

The unusually strong El Ni漀 weather pattern, in which the ocean’s surface warms and releases immense amounts of heat into the atmosphere, has drawn²² more attention — in part because it tends to bring heavy rain to Southern California, which is amid an intense drought, and cooler temperatures and rain across the southern United States during the winter and potentially into the spring. (The northern band of the country tends to have somewhat warmer and drier conditions.) But El Ni漀’s effects are felt across the planet, and this one has been linked to drought in Australia and enormous peat fires in Indonesia.

厄尔尼诺气候异常强大，它会使海洋表面变暖，并向大气中释放巨大的热量，这种气候现象已经引起更多的关注，部分原因在于，它会在冬季，甚至一直到春天，给正处于剧烈干旱之中南加州带来强降雨，并使整个美国南部都有持续降雨和更低的气温。（美国北部地区则可能会更温暖和更干燥。）但是，厄尔尼诺气候的影响遍及全球，这一次它已经被与澳大利亚的干旱和印尼的泥炭土丛林大火灾联系了起来。

The other large force at work, the Pacific decadal oscillation, is a long period — sometimes, as the name implies, spanning decades — of relatively²⁴ cooler or warmer water. Since about the year 2000, the oscillation has been in a cool state, which many climate scientists say has allowed the ocean to soak up a great deal of the heat generated by greenhouse gases as part of climate change.

另一种正在产生影响的巨大力量是太平洋十年际涛动，它是相对更冷或更热的海水期交替出现的现象，周期比较长，有时候如它的名字所显示的，会延续数十年。大约从2000年开始，它一直处于寒冷周期，许多气候科学家认为这使得海洋吸收了很多由温室气体产生的热量，而温室气体是气候变化的一部分。

This, in turn, may have kept global average surface temperatures from rising. Climate scientists have called that condition the warming hiatus, and those who deny the overwhelming scientific consensus²⁵ on warming have used the hiatus to raise doubts about whether climate change exists.

这反过来可能避免了全球地表平均温度的上升。气候科学家们称这种情况是“变暖间歇”(warming hiatus)，而那些否认气候变暖这个压倒性科学共识的人，则利用这种间歇来质疑气候变化是否存在。

Now, however, the oscillation appears to be entering a warming phase, said Gerald A. Meehl, a senior scientist at the National Center for Atmospheric Research, and strong El Ni漀猀 tend to nudge the cycle into a new phase. So the oscillation and El Ni漀 “can all add together to give you a really big shift” toward warming over all.

然而，国家大气研究中心(National Center for Atmospheric Research)资深科学家杰拉德·A·米尔(Gerald A. Meehl)表示，现在波动似乎正在进入变暖期，而且强大的厄尔尼诺现象也可能会推动相关循环进入新阶段。于是，波动和厄尔尼诺“可能共同发挥作用，带来真正的大转折”，全面转向升温变暖。

“That’s going to provide a bigger boost to a global warming system,” he said. “These things will add together.” Already, 2015 is on track to be the hottest year in the historical record.

“这将进一步推动全球变暖的系统，”他说。“这些因素将叠加在一起。”目前，2015年有望成为有历史记录以来最热的一年。

Climate change could nudge all of the interacting cycles of ocean heat and cold. Scientists are still trying to determine its effect on hurricanes, though it is widely believed that because warm ocean water provides the energy for hurricanes, the more powerful storms will grow even more potent²³ over time.

气候变化可能会推动海洋中所有的热冷互动循环。科学家仍在试图确定其对飓风的影响，但人们普遍认为，由于温暖的海水会为飓风提供能量，已然加强的风暴还会随着时间的推移而愈发强烈。

Whether there is a clear and detectable²⁶ human-caused component²⁷ to today’s cyclone²⁸ activity is harder to prove, said Thomas R. Knutson, a research meteorologist with NOAA’s geophysical fluid dynamics laboratory at Princeton. “We don’t expect to necessarily be able to detect these changes at this time,” he said.

气象学家托马斯·R·纽森(Thomas R. Knutson)表示，难以证明如今的气旋活动，是否有明确且能察觉到的人为因素。纽森供职于NOAA在普林斯顿大学的地球物理流体动力学实验室。他说，“我们并不指望一定能在这个时候观察到这些变化。”

While no individual weather event can be linked to climate change, the continued warming already appears to be increasing the potential strength of storms, said Kerry Emanuel, a hurricane expert at the Massachusetts Institute of Technology. Whether the storms reach their full potential depends on other factors, he said. Statistically²⁹, however, there are too few storms to show that the stronger hurricanes are being caused by climate change yet.

麻省理工学院(Massachusetts Institute of Technology)研究飓风的专家克里·伊曼纽尔(Kerry Emanuel)表示，虽然无法将任何一个单独的天气事件和气候变化联系在一起，但持续变暖似乎增强了风暴的潜在强度。他说，风暴能否达到最大强度取决于其他因素。但从统计数据看，现有的风暴次数还太少，不足以显示飓风强度的提高是由气候变化引起的。

One phenomenon³⁰ appears to be the result of a combination of El Ni漀, the Blob and climate change. NOAA this year announced that the world was in the midst of only the third global coral bleaching³¹ event ever recorded. Severe bleaching can lead to the death of reefs, and the loss of habitat for marine life and shoreline protection from storms. The current event began in 2014 in the Pacific and has persisted into this year, with the Blob’s effects being felt most keenly near Hawaii, where the western tail of that large patch of warmed water extends.

有一种现象似乎是厄尔尼诺、太平洋“温水区”和气候变化综合作用的结果。NOAA今年宣布，世界目前处在史上第三次全球珊瑚白化潮之中，严重的白化会导致珊瑚礁死亡，让海洋生物由此失去栖息地，也使海岸线失去阻挡风暴的防护墙。发生在太平洋里的这次白化潮始于2014年，一直延续到今年，而受“温水区”影响最大正是靠近夏威夷群岛的区域，那里是“温水区”带来的大片温暖海水延伸的西部边缘地带。

“This is absolutely the worst that they have ever seen,” said C. Mark Eakin, the coordinator³² of NOAA’s Coral Reef Watch. “It’s only the third time they’ve seen mass coral bleaching in Hawaii; the last time was last year.” And because El Ni漀 events stretch from one year’s winter into the next spring, “we’re very likely to see the bleaching that’s going on this year go on into 2016 and even be worse in 2016,” he said.

“这绝对是我见过的最糟糕的情况，”NOAA全球珊瑚礁观测网络(Coral Reef Watch)的协调员C·马克·埃金(C. Mark Eakin)说。“夏威夷区域出现大规模珊瑚白化，这还只是第三次，上一次是在去年。”而且，因为厄尔尼诺现象通常会从一年的冬季延续到下一年的春季，“我们很可能会看到这次白化潮持续到2016年，甚至在2016年变得更加严重，”他说。

A warmer Pacific also means higher seas at the United States coastline, because warm water expands and the general winds that flow from west to east will push water against the shore. That can add to an increase in what William Sweet, a NOAA oceanographer based in Maryland, calls nuisance flooding in low-lying coastal³³ areas.

太平洋变暖，也意味着美国海岸线的海平面会升高，因为水温升高体积就会膨胀，自西向东的整体风向会把海水吹向海岸。那会提高低海平面区域发生威廉·斯威特(William Sweet)所说的“海水漫溢灾害”的几率。斯威特是NOAA驻马里兰州海洋学家。

Even a general increase of a half a foot from El Ni漀 can, when combined with storms, cause a pronounced increase in such flooding, he said, adding that San Francisco could go from an average 12 days of nuisance flooding to 21 this year, and La Jolla, Calif., from six to 10.

他表示，即便海平面只因厄尔尼诺现象总体升高半英尺，当同时受到风暴因素影响时，也会显著增加发生此类海水漫溢灾害的几率。他还指出，旧金山过去每年平均遭遇12天的海水漫溢，今年有可能增加到21天，加州的拉霍亚市区则可能从过去的6天增加到10天。

Nicholas A. Bond, a research meteorologist at NOAA’s cooperative institute at the University of Washington who gave the Blob its name, said that climate change could make El Ni漀 conditions more common. “That would just have monstrous³⁴ implications,” he said. And though developed-world nations like the United States could take measures to adapt to the changing conditions, “It is going to be a different place,” he said.

供职于NOAA在华盛顿大学(University of Washington)的合作机构的气象学家尼古拉斯·A·邦德(Nicholas A. Bond)表示，气候变化可能会让厄尔尼诺现象变得更加常见。“温水区”这一现象就是邦德命名的。“那会带来各种可怕的后果，”他说。尽管美国等发达国家可以采取措施适应变化的气候情况，“但这里将成为另外一种样子，”他说。

Despite all the current dark clouds over the Pacific, literal and metaphorical³⁵, Dr. Bond managed to spot a silver lining³⁶.

虽然目前太平洋上布满了阴云——这既是现实，也是比喻——邦德博士设法为我们带来了一丝希望。

The confluence³⁷ of problems can serve as a “wake-up call,” and a harbinger of climate change, he said. “We have a real chance with this kind of event to see what’s going to happen, and show folks, ‘Hey, this is the consequence³⁸ of messing around with the climate.’ ”

他说，这些问题合在一起，可以看做一种“警示”，是气候变化的前兆。“有了这类事件，我们得以真正有机会了解未来会发生些什么，可以跟人们说，‘看吧，这就是破坏气候带来的后果。’”