　　The government’s top Great Barrier Reef scientist says a third mass bleaching

游客2025-02-03 12

问题　　The government’s top Great Barrier Reef scientist says a third mass bleaching event in five years is a clear signal the marine wonder is "calling for urgent help" on climate change.
　　One quarter of the Great Barrier Reef suffered severe bleaching this summer in the most widespread outbreak ever witnessed, according to analysis of aerial surveys of more than 1,000 individual reefs released on Tuesday.
　　Dr David Wachenfeld, chief scientist at the Great Barrier Reef Marine Park Authority, told Guardian Australia: "My greatest fear is that people will lose hope for the reef. Without hope there’s no action.
　　"People need to see these [bleaching] events. They are clear signals the Great Barrier Reef is calling for urgent help and for us to do everything we can."
　　Prof Terry Hughes, director of the Centre of Excellence for Coral Reef Studies at James Cook University, surveyed 1,036 reefs from a plane over nine days in late March. The marine park authority also had an observer on the flights. Hughes has released maps showing severe levels of bleaching occurred in 2020 in all three sections of the reef - northern, central and southern - the first time this has happened since mass bleaching was first seen in 1998. Some 25% of the reefs were severely bleached - meaning that more than 60% of the corals on each reef had bleached.
　　The Great Barrier Reef has experienced five mass bleaching events - 1998, 2002, 2016, 2017 and 2020-all caused by rising ocean temperatures driven by global heating. Hughes said there probably would not be the same level of coral death in the north and central regions in 2020 as in previous years, but this was partly because previous bleaching outbreaks had killed off the less heat-tolerant species. The 2020 bleaching was second only to 2016 for severity, Hughes said.
　　Corals can recover from mild bleaching, but scientists say those corals are more susceptible to disease. Severe bleaching can kill corals. "It’s not too late to turn this around with rapid action on emissions," he said.
　　In February the reef was subjected to its hottest sea surface temperatures since records began in 1900. Some scientists fear that rising levels of heat being taken up by the ocean have pushed tropical reefs to a tipping point at which many locations bleach almost annually.
　　Wachenfeld said the reef’s sheer size - it comprises about 3,000 individual reefs - made it resilient, "but climate change brings a new scale of impact unlike anything we have seen before". "No one climate event will kill the Great Barrier Reef, but each successive event creates more damage. Its resilience is not limitless and we need the strongest possible action on climate change."
　　The globe has already warmed by about 11 above pre-industrial levels, caused primarily by rising levels of greenhouse gases in the atmosphere from burning fossil fuels. Measures to improve the resilience of the reef include improving water quality, controlling outbreaks of coral-eating starfish, and research and development to improve the heat tolerance of corals.
　　"None of that is a substitute for strong action on emissions," Wachenfeld said. "Dealing with the climate problem is the underpinning for everything else to work."

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答案    澳大利亚研究大堡礁的权威科学家表示，五年内发生第三次大规模白化现象，是大堡礁这一海洋奇迹在气候变化的影响下“紧急求救”的明确信号。
   根据周二发布的一项对1000多个独立珊瑚礁的航测分析，今年夏天，大堡礁四分之一的区域出现了严重白化，这是迄今爆发的最大规模的白化现象。
   大堡礁海洋公园管理局(the Great Barrier Reef Marine Park Authority)首席科学家大卫·瓦肯菲尔德博士(Dr．David Wachenfeld)告诉《卫报》澳大利亚版：“我最担心的是人们会对大堡礁丧失希望。没有希望，又何谈行动。
   “人们应该来看一看这些白化现象。这是大堡礁在紧急求救、请求我们竭力救助的明确信号。”
   3月下旬，詹姆斯库克大学(James Cook University)珊瑚礁卓越研究中心(Centre of Excellence for Coral Reef Studies)主任特里·休斯教授(Prof．Terry Hughes)，乘飞机在高空对1036个珊瑚礁进行了历时9天的调查。海岸公园管理局派出了一名观察员随行。休斯公开的图像显示，就在今年，大堡礁北部、中部和南部三个区域全部都出现了严重的白化现象，这是自1998年首次发现大规模白化现象以来第一次出现这种情况。大约有25％的珊瑚礁严重白化，这意味着每个岛礁有超过60％的珊瑚发生了白化。
   1998年、2002年、2016年、2017年和2020年，大堡礁共经历了五次大规模白化现象，且均由全球变暖而导致的海洋温度上升造成。休斯说，今年大堡礁北部和中部区域的珊瑚死亡率可能不会像往年那么高，但其一部分原因是之前爆发的白化现象己然导致耐热性较差的珊瑚死亡。休斯表示，2020年的白化严重程度仅次于2016年。
   轻微白化的珊瑚可以自我恢复，但科学家们表示，这些珊瑚更容易得病。而严重的白化则会杀死珊瑚。休斯说：“现在马上采取行动控制污染排放，扭转局面尚为时不晚。”
   今年2月，大堡礁遭遇了自1900年有记录以来的最高海面温度。一些科学家担心，海洋吸收的热量不断攀升己将热带珊瑚礁推至生存极限，这样的话，很多区域几乎年年都会发生白化。
   瓦肯菲尔德说，大堡礁由大约3000个独立岛礁组成，其庞大的体积使其恢复能力很强。“但气候变化带来的影响是前所未有的。”“一次气候变化事件不会‘杀死’大堡礁，但持续的气候变化则会对其造成更多的破坏。大堡礁的恢复能力并不是无限的，所以我们需要采取最强有力的行动来应对气候变化。”
   全球气温已经比工业化前上升了约1摄氏度，这主要是由于燃烧化石燃料导致大气中的温室气体含量升高所致。改善珊瑚礁复原力有很多措施，包括改善水质、控制以珊瑚为食的海星数量的疯长，以及研究改善珊瑚的耐热性等。
   瓦肯菲尔德说：“所有这些都不能替代强有力的减排行动。解决气候问题是推行其他一切措施的基础。”

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