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联合国表示,臭氧空洞有望在50年内修复

联合国表示,臭氧空洞有望在50年内修复

Seth Borenstein, 美联社 2023-01-12
长期以来,全球各地的科学家和环保人士一直认为,各国为修复臭氧空洞于1987年签订的《蒙特利尔议定书》是人类在维护生态方面最大的胜利之一。

联合国(United Nations)的一份新报告称,地球的臭氧层正在缓慢“愈合”,按照当前速度,南极洲上方的空洞有望在43年内完全消失。

该修复进程由四年一次的科学评估发现,此时距全球各国一致同意停止生产会侵蚀大气中臭氧层的化学物质已经过去35年。臭氧层能够为地球防护有害辐射,避免人们罹患皮肤癌、白内障等疾病以及农作物损失。

“在平流层上层和臭氧空洞中,我们看到情况正在好转。”科学评估联合主席保罗·纽曼表示。

今年1月9日在丹佛举行的美国气象学会(American Meteorological Society)大会上发表的报告显示,臭氧空洞缩小进展缓慢。报告称,离地球表面18英里(约28.97千米)的臭氧平均含量要到2040年左右才可以恢复到1980年变稀薄之前的水平。北极地区到2045年才会恢复正常。

报告称,南极洲的臭氧层已经极为稀薄,每年都会出现巨大的空洞,要到2066年才能够完全恢复正常。

长期以来,全球各地的科学家和环保人士一直认为,各国为修复臭氧空洞于1987年签订《蒙特利尔议定书》(Montreal Protocol),约定禁止生产常用于制冷剂和喷雾剂的化学物质,这是人类在维护生态方面最大的胜利之一。

“臭氧治理为气候行动树立了先例。逐步淘汰破坏臭氧的化学品方面获得的成功充分显示了,情况紧迫时可以做些什么以及怎样做,才能够逐渐淘汰化石燃料,降低温室气体排放,限制气温上升。”世界气象组织(World Meteorological Organization)的秘书长彼得里·塔拉斯教授在一份声明中表示。

四年前就已经出现修复的迹象,但当时迹象尚不明显且偏初步阶段。“如今证明臭氧恢复的数据稳定了很多。”纽曼说。

纽曼也是美国国家航空航天局戈达德太空飞行中心(NASA’s Goddard Space Flight Center)的首席地球科学家,他表示,大气中破坏臭氧的两种主要化学物质含量有所降低。报告称,氯含量自1993年达到峰值以来下降了11.5%,而破坏臭氧更严重的溴比1999年峰值减少了14.5%。

大气中溴和氯含量“停止增长并逐步下降,充分证明了《蒙特利尔议定书》的作用。”纽曼表示。

“全社会处理破坏臭氧物质的方式发生了巨大变化。”美国国家海洋和大气管理局(U.S. National Oceanic and Atmospheric Administration)化学科学实验室主任、科学小组联合主席大卫·W·费伊说。

费伊称,几十年前人们随便去商店就可以买到会破坏臭氧的制冷剂,导致臭氧空洞还污染大气。现在,相关物质不仅禁止销售,人们家里或汽车上也几无留存,取而代之的是更清洁的化学制剂。

南极的自然气候模式也会影响臭氧空洞状况,一般秋季空洞规模最大。纽曼指出,过去几年受自然气候影响空洞规模还有所扩大,但总体仍然保持缩小趋势。

这一趋势“每年能够避免200万人罹患皮肤癌。”今年早些时候,联合国环境规划署(United Nations Environment Programme)的署长英格·安德森在一封电子邮件里对美联社(The Associated Press)表示。

几年前,被禁的化学物质之一——氯氟烃-11(CFC-11)排放量停止降低并转为增加。纽曼说,因为中国部分地区发现了排放,现在已经降回预期水平。

几年前,第三代化学物质含氢氟烃被禁止使用,原因并不是会破坏臭氧层,而是因为含氟氯烃是吸热的温室气体。新研究报告称,该禁令可以避免温度再升高0.5度至0.9度(0.3摄氏度至0.5摄氏度)。

报告还警告道,如果向大气中加入喷雾剂反射阳光从而人为冷却地球,就将导致南极洲的臭氧层减少20%。(财富中文网)

美联社的气候和环境报道获得了几家私人基金会的支持。美联社对所有内容负责。

译者:梁宇

审校:夏林

联合国(United Nations)的一份新报告称,地球的臭氧层正在缓慢“愈合”,按照当前速度,南极洲上方的空洞有望在43年内完全消失。

该修复进程由四年一次的科学评估发现,此时距全球各国一致同意停止生产会侵蚀大气中臭氧层的化学物质已经过去35年。臭氧层能够为地球防护有害辐射,避免人们罹患皮肤癌、白内障等疾病以及农作物损失。

“在平流层上层和臭氧空洞中,我们看到情况正在好转。”科学评估联合主席保罗·纽曼表示。

今年1月9日在丹佛举行的美国气象学会(American Meteorological Society)大会上发表的报告显示,臭氧空洞缩小进展缓慢。报告称,离地球表面18英里(约28.97千米)的臭氧平均含量要到2040年左右才可以恢复到1980年变稀薄之前的水平。北极地区到2045年才会恢复正常。

报告称,南极洲的臭氧层已经极为稀薄,每年都会出现巨大的空洞,要到2066年才能够完全恢复正常。

长期以来,全球各地的科学家和环保人士一直认为,各国为修复臭氧空洞于1987年签订《蒙特利尔议定书》(Montreal Protocol),约定禁止生产常用于制冷剂和喷雾剂的化学物质,这是人类在维护生态方面最大的胜利之一。

“臭氧治理为气候行动树立了先例。逐步淘汰破坏臭氧的化学品方面获得的成功充分显示了,情况紧迫时可以做些什么以及怎样做,才能够逐渐淘汰化石燃料,降低温室气体排放,限制气温上升。”世界气象组织(World Meteorological Organization)的秘书长彼得里·塔拉斯教授在一份声明中表示。

四年前就已经出现修复的迹象,但当时迹象尚不明显且偏初步阶段。“如今证明臭氧恢复的数据稳定了很多。”纽曼说。

纽曼也是美国国家航空航天局戈达德太空飞行中心(NASA’s Goddard Space Flight Center)的首席地球科学家,他表示,大气中破坏臭氧的两种主要化学物质含量有所降低。报告称,氯含量自1993年达到峰值以来下降了11.5%,而破坏臭氧更严重的溴比1999年峰值减少了14.5%。

大气中溴和氯含量“停止增长并逐步下降,充分证明了《蒙特利尔议定书》的作用。”纽曼表示。

“全社会处理破坏臭氧物质的方式发生了巨大变化。”美国国家海洋和大气管理局(U.S. National Oceanic and Atmospheric Administration)化学科学实验室主任、科学小组联合主席大卫·W·费伊说。

费伊称,几十年前人们随便去商店就可以买到会破坏臭氧的制冷剂,导致臭氧空洞还污染大气。现在,相关物质不仅禁止销售,人们家里或汽车上也几无留存,取而代之的是更清洁的化学制剂。

南极的自然气候模式也会影响臭氧空洞状况,一般秋季空洞规模最大。纽曼指出,过去几年受自然气候影响空洞规模还有所扩大,但总体仍然保持缩小趋势。

这一趋势“每年能够避免200万人罹患皮肤癌。”今年早些时候,联合国环境规划署(United Nations Environment Programme)的署长英格·安德森在一封电子邮件里对美联社(The Associated Press)表示。

几年前,被禁的化学物质之一——氯氟烃-11(CFC-11)排放量停止降低并转为增加。纽曼说,因为中国部分地区发现了排放,现在已经降回预期水平。

几年前,第三代化学物质含氢氟烃被禁止使用,原因并不是会破坏臭氧层,而是因为含氟氯烃是吸热的温室气体。新研究报告称,该禁令可以避免温度再升高0.5度至0.9度(0.3摄氏度至0.5摄氏度)。

报告还警告道,如果向大气中加入喷雾剂反射阳光从而人为冷却地球,就将导致南极洲的臭氧层减少20%。(财富中文网)

美联社的气候和环境报道获得了几家私人基金会的支持。美联社对所有内容负责。

译者:梁宇

审校:夏林

Earth’s protective ozone layer is slowly but noticeably healing at a pace that would fully mend the hole over Antarctica in about 43 years, a new United Nations report says.

A once-every-four-years scientific assessment found recovery in progress, more than 35 years after every nation in the world agreed to stop producing chemicals that chomp on the layer of ozone in Earth’s atmosphere that shields the planet from harmful radiation linked to skin cancer, cataracts and crop damage.

“In the upper stratosphere and in the ozone hole we see things getting better,” said Paul Newman, co-chair of the scientific assessment.

The progress is slow, according to the report presented on January9 at the American Meteorological Society convention in Denver. The global average amount of ozone 18 miles (30 kilometers) high in the atmosphere won’t be back to 1980 pre-thinning levels until about 2040, the report said. And it won’t be back to normal in the Arctic until 2045.

Antarctica, where it’s so thin there’s an annual giant gaping hole in the layer, won’t be fully fixed until 2066, the report said.

Scientists and environmental advocates across the world have long hailed the efforts to heal the ozone hole — springing out of a 1987 agreement called the Montreal Protocol that banned a class of chemicals often used in refrigerants and aerosols — as one of the biggest ecological victories for humanity.

“Ozone action sets a precedent for climate action. Our success in phasing out ozone-eating chemicals shows us what can and must be done – as a matter of urgency — to transition away from fossil fuels, reduce greenhouse gases and so limit temperature increase,” World Meteorological Organization Secretary-General Prof. Petteri Taalas said in a statement.

Signs of healing were reported four years ago but were slight and more preliminary. “Those numbers of recovery have solidified a lot,” Newman said.

The two chief chemicals that munch away at ozone are in lower levels in the atmosphere, said Newman, chief Earth scientist at NASA’s Goddard Space Flight Center. Chlorine levels are down 11.5% since they peaked in 1993 and bromine, which is more efficient at eating ozone but is at lower levels in the air, dropped 14.5% since its 1999 peak, the report said.

That bromine and chlorine levels “stopped growing and is coming down is a real testament to the effectiveness of the Montreal Protocol,” Newman said.

“There has been a sea change in the way our society deals with ozone depleting substances,” said scientific panel co-chair David W. Fahey, director of the U.S. National Oceanic and Atmospheric Administration’s chemical sciences lab.

Decades ago, people could go into a store and buy a can of refrigerants that eat away at the ozone, punch a hole in it and pollute the atmosphere, Fahey said. Now, not only are the substances banned but they are no longer much in people’s homes or cars, replaced by cleaner chemicals.

Natural weather patterns in the Antarctic also affect ozone hole levels, which peak in the fall. And the past couple years, the holes have been a bit bigger because of that but the overall trend is one of healing, Newman said.

This is “saving 2 million people every year from skin cancer,” United Nations Environment Programme Director Inger Andersen told The Associated Press earlier this year in an email.

A few years ago emissions of one of the banned chemicals, chlorofluorocarbon-11 (CFC-11), stopped shrinking and was rising. Rogue emissions were spotted in part of China but now have gone back down to where they are expected, Newman said.

A third generation of those chemicals, called HFC, was banned a few years ago not because it would eat at the ozone layer but because it is a heat-trapping greenhouse gas. The new report says that the ban would avoid 0.5 to 0.9 degrees (0.3 to 0.5 degrees Celsius) of additional warming.

The report also warned that efforts to artificially cool the planet by putting aerosols into the atmosphere to reflect the sunlight would thin the ozone layer by as much as 20% in Antarctica.

Associated Press climate and environmental coverage receives support from several private foundations. The AP is solely responsible for all content.

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