气候变化致亚马逊热带雨林面临更大的风险

困难

高中三年级

说明文

世界与环境

气候变化给亚马逊热带雨林带来严重后果，亚马逊雨林应对干旱以及恶劣天气的能力正在快速下降，其恢复能力也在衰退，全球气候新常态正在形成。

In the Amazon rainforest, for every three trees that die due to drought, a fourth tree dies as well, even if it is not directly impacted. That’s what recent research discovered.

在亚马逊雨林中，每三棵树因干旱而死亡，第四棵树也会死亡，即使它没有受到直接影响。这是最近的研究发现的。

As climate change causes increasingly frequent and severe dry periods in the Amazon Basin, the rainforest in South America may lose its rain and, with it, its moisture(水分) supply. The forest is threatened by a lack of rain because it breathes water: when it rains, the soil absorbs as much as the plants, and both release a large quantity back via evaporation and transpiration. The forest creates most of its own weather through this atmospheric(大气的) moisture recycling, generating up to half of the rainfall in the Amazon Basin. And, although it is incredibly effective, the moisture recycling system ultimately depends on how much water is initially put into the system. A lack of rain reduces the amount of water recycled, and there will be less rainfall in neighboring areas, placing even more sections of the forest under serious stress.

由于气候变化导致亚马逊河流域日益频繁和严重的干旱时期，南美洲的雨林可能会失去雨水，并因此失去水分供应。森林因为呼吸水分而受到缺乏雨水的威胁: 下雨时，土壤吸收的和植物一样多，并且通过蒸发和蒸腾释放大量水分。森林通过这种大气水分回收创造了自己的大部分天气，产生了亚马逊盆地高达一半的降雨量。而且，尽管它非常有效，但水分回收系统最终取决于最初向系统中注入了多少水。少雨减少了循环水的量，邻近地区的降雨量也会减少，使更多的森林处于严重的压力之下。

Climate science predicts that what used to be extraordinarily dry years may well become the new normal. These frequent droughts are already producing quantifiable(可量化的) changes to the Amazon’s moisture network. Scientists use these observations to understand and model the consequences of a future climate. But droughts have different effects on forest systems within the Amazon. Trees and forest systems there differently adapted to water availability, as some regions commonly exhibit a distinct dry season while others have rain all year round. Even the dry season-adapted parts of the Amazon forest won’t necessarily survive a new climate normal, and the risk of becoming savannah(稀树草原) or no trees at all is high. The consequences for biodiversity would be disastrous, but the same goes for the local, regional, and global climate.

气候科学预测，过去异常干燥的年份很可能成为新的常态。这些频繁的干旱已经对亚马逊的水分网络产生了可量化的变化。科学家利用这些观察结果来理解和模拟未来气候的后果。但是干旱对亚马逊的森林系统有不同的影响。那里的树木和森林系统对水的可用性有不同的适应，因为一些地区通常表现出明显的旱季，而其他地区全年都有雨。即使是适应旱季的亚马逊森林也不一定能在新的气候常态下存活下来，而且成为大草原或根本没有树木的风险也很高。生物多样性的后果将是灾难性的，但地方、区域和全球气候也是如此。