丹麦气象研究所周三的一项研究显示，受全球变暖削弱的大西洋洋流系统在气候变冷的情况下可能随时间恢复。
An Atlantic Ocean current system weakened by global warming could recover over time if the climate cools, a study by the Danish Meteorological Institute showed on Wednesday.
大西洋经向翻转环流将热带的暖水向北输送至北极，暖水流有助于使欧洲的冬季保持温和。
The Atlantic Meridional Overturning Circulation brings warm water from the tropics northward toward the Arctic, and the flow of warm water helps keep Europe's winters mild.
该研究发表在《科学进展》期刊上，研究发现没有迹象表明存在一些先前研究所暗示的不可逆转的临界点，尽管这些变化的影响可能持续数个世纪。
Published in the journal Science Advances, the study found no sign there was an irreversible tipping point for AMOC, as suggested by some previous studies, although the effects of the changes could last for centuries.
然而，该研究还指出，格陵兰冰盖因向海洋注入冷淡水而导致AMOC减弱，一旦融化就无法恢复 — — 即使变暖趋势被逆转。
However, it also said that the Greenland ice sheet that contributes to weakening the AMOC as it pours cold freshwater into the ocean could not be restored once it had melted — even if the warming trend was reversed.
AMOC的紊乱仍可能导致全球降水模式不稳定，并加速沿海海平面上升。
A disrupted AMOC could still destabilise global rainfall patterns and accelerate coastal sea-level rise.
研究称，在全球变暖达到约7摄氏度时，AMOC的流速可能从大约每秒1700万立方米减慢至约每秒600万立方米。
The study said the AMOC could slow to about 6 million cubic metres of water per second from around 17 million at around 7 degrees Celsius of global warming.
主要作者Chuncheng Guo表示：“在我们的模型中，我们没有看到导致崩溃的临界点。AMOC逐渐减弱，但我们发现，如果全球变暖被逆转，它也会立即恢复其强度。”
"In our model, we do not see a tipping point leading to a collapse. The AMOC gradually weakens, but we find that it also immediately regains its strength if global warming is reversed," lead author Chuncheng Guo said.
然而，他警告说，尽管恢复过程会在气温下降时立即开始，但完成可能需要数个世纪，在此期间，减弱洋流的影响仍将持续。
However, he warned that even though recovery starts as soon as temperatures fall, it could take several centuries to finish, all while the effects of a weakened current would persist.
该建模所使用的7摄氏度升温幅度用于科学研究，远超当前对变暖趋势的预测。
The 7 C rise used in the modelling used for scientific interest is far beyond the current projections for the warming trend.
联合国环境署今年9月表示，全球气温上升将在“几年内”超过1.5摄氏度的关键阈值。各国政府在2015年《巴黎协定》中承诺将气温上升控制在1.5摄氏度以内，以限制极端天气的影响。
The UN's environmental body said in September global temperature rises are set to exceed the key threshold of 1.5 C "within a few years". Governments committed to keeping temperature rises within 1.5 C to limit the impacts of extreme weather under the 2015 Paris Agreement.
郭补充说，逆转大西洋经向翻转环流（AMOC）所需的冷却速率也超过了当前技术所能实现的范围，这也凸显了单一模型研究的局限性。研究还指出，需要进一步用其他模型进行测试。
The cooling rate required to reverse the AMOC also exceeds what is considered realistic with current technology, Guo added, pointing to a limitation of the single-model study. Further testing against other models was also needed, the study said.
未参与该研究的波茨坦气候影响研究所研究员威廉·胡伊斯坎普表示，更稳定的AMOC将是个好消息，但他怀疑现实中的洋流是否真的像一些模型所暗示的那样稳定。
Willem Huiskamp at the Potsdam Institute for Climate Impact Research, who was not involved in the study, said a more stable AMOC would be good news, but said he doubted the real-world current was as stable as some models suggested.
研究人员估计，格陵兰冰盖在升温1.5摄氏度后融化将导致长期海平面上升约20厘米，并呼吁加快行动以遏制排放。
The researchers estimated a long-term sea-level rise of around 20 cm from the melting of the Greenland ice sheet following a 1.5 C rise, and urged faster action to rein in emissions.
郭说：“与其依赖全球降温自然发生，不如一开始就避免变暖，这才是一种远更安全、远更可靠的策略。”
"Instead of relying on the global cooling to happen, it's a much, much safer strategy to not have warming in the first place," Guo said.