亚马逊雨林可能会开始排放碳而不是吸收碳

亚马逊雨林可能会开始排放碳而不是吸收碳

The amount of planet-warming carbon dioxide that can be sucked up from the atmosphere and stored by tropical forests is falling as the global climate heats up, researchers said on Wednesday.

研究人员周三表示，随着全球气候变暖，从大气中吸收二氧化碳并储存在热带森林中的数量正在下降。

They warned in a study that rainforests could tip from absorbing carbon to becoming a source of emissions faster than scientists had previously expected – a switch that could happen in the Amazon as early as the mid-2030s.

他们在一项研究中警告说，热带雨林从吸收碳转变为排放源的速度，可能比科学家此前预期的要快，这种转变最早可能在本世纪30年代中期就会在亚马逊地区发生。

“The cause of this is climate change impacts – in terms of heat stress and droughts – on these remaining intact forests,” said Simon Lewis, a senior author of the study published in the journal Nature and a professor at Britain’s University of Leeds.

这项研究的资深作者、英国利兹大学教授西蒙·刘易斯(Simon Lewis)在《自然》杂志上发表了这项研究，他说：“造成这一现象的原因，是气候变化对这些保存完好的森林造成的影响——就热应力和干旱而言。”。

The evidence that forests had started the process of turning from a carbon sink into a source was “incredibly worrying”, he told the Thomson Reuters Foundation.

他对汤森路透基金会表示，有证据显示森林已经开始从碳汇转变为碳源，这一过程“令人难以置信地令人担忧”。

“Humanity has been really lucky so far in that these forests have been mopping up our pollution and they might not keep doing that for that much longer,” he added.

他补充道:“到目前为止，人类真的很幸运，因为这些森林一直在清理我们的污染，他们可能不会这么做太久了。”

Large swathes of rainforest, including those in Indonesia, Brazil and Democratic Republic of Congo, help regulate rainfall, prevent flooding, protect biodiversity and limit climate change.

包括印度尼西亚、巴西和刚果民主共和国在内的大片热带雨林有助于调节降雨、预防洪水、保护生物多样性和限制气候变化。

But the 30-year study, led by the University of Leeds and involving almost 100 institutions, showed that the intake of carbon by “intact tropical forests” peaked in the 1990s and had dropped by a third by the 2010s.

但这项由利兹大学(University of Leeds)牵头、涉及近100家机构的30年研究显示，“完整的热带森林”的碳摄入量在20世纪90年代达到顶峰，到2010年代下降了三分之一。

Intact forests are large areas of continuous forest with no signs of intensive human activity like agriculture or logging. They form part of the world’s roughly 5.5 billion hectares of forest.

完整的森林是大面积的连续森林，没有像农业或伐木这样的人类密集活动的迹象。它们是世界上约55亿公顷森林的一部分。

Trees suck carbon dioxide from the air, the main greenhouse gas heating up the Earth’s climate and store carbon, which they release when they are cut down and are burned, or rot.

树木从空气中吸收二氧化碳，而二氧化碳是加热地球气候的主要温室气体，当树木被砍伐、燃烧或腐烂时释放出来。

Tropical forests are huge reservoirs of carbon, storing 250 billion tonnes in their trees alone – an amount equivalent to 90 years of global fossil-fuel emissions at current levels.

热带森林是巨大的碳储存库，仅在其树木中就储存了2500亿吨碳，相当于目前水平下全球90年的化石燃料排放量。

Scientific models have typically predicted that the role of tropical forests in storing carbon would continue for decades.

科学模型通常预测，热带森林在储存碳方面的作用将会持续数十年。

But their ability to offset human emissions is declining faster than thought, Lewis said.

刘易斯说，但它们抵消人类排放的能力下降的速度比想象的要快。

The way to maintain tropical forests as carbon sinks “is to stabilize the climate” by cutting emissions, mainly from fossil-fuel use, to “net zero”, said Lewis.

刘易斯说，保持热带森林作为碳汇的方法是通过减少排放(主要来自化石燃料的使用)来稳定气候”，达到“零排放”。