互动科普

The loss of forests worldwide appears to interact synergistically to produce unpredictable effects on the global climate. Christopher Intagliata reports.

全世界范围内林地面积减少似乎会协同地对全球气候造成不可预知的影响。克里斯托弗·因塔利亚塔报道。

Climate change may be partly to blame for the massive die-off of pine trees in the western U.S. But it works the other way, too: forest die-offs can alter the global climate.

美国西部大量松树消失可能是气候变化的一部分原因。但是它还有其他影响：森林相继消失可以改变全球气候。

“I like thinking of this as a parallel to something like EI Nino.” Abigail Swann, an ecological climatologist at the University of Washington. “We think these are also going to have climate impacts far away from where those forests are dying. So it’s going to ricochet in other places around the globe.”

“我们不妨类比厄尔尼诺现象。”华盛顿大学环境气候学家阿比盖尔·斯旺说，“我们认为此处林地减少，也会对森林被砍伐区域之外遥远地方的气候产生影响。所以这一因素会在地球其他某处产生影响。

To model those “ricochet” effects, Swann and her colleagues used climate simulations to wipe out forests and replace them with grasslands, in the western U.S., the Amazon, or both. They found that losing forests in one part of the globe does indeed affect climate very far away. “And that could be negative in a lot of places, it could be bad for the ecosystems, but you could come up with scenarios where it makes the conditions a little bit better.”

为了对这些“反弹“效应建模，斯旺和她的同事们利用气候模拟，将美国西部或亚马逊或两者的森林变换为草地。他们发现，地球某处森林的缺失，对遥远的地方气候造成了确实的影响。”在很多地方，这都会造成负面的影响，它可能会使生态系统变糟，但是你可以通过采取一些措施使情况略微好转。

For example, killing off trees in western North America leads to cooler temps globally. That outcome means lower productivity in Siberian forests-a negative. It also dries up forests in the Carolinas-another negative. But conditions will get wetter in eastern South America-a positive for the forests there. The results are in the journal PLoS ONE. [Elizabeth S. Garcia et al., Synergistic ecoclimate teleconnections from forest loss in 2 different regions structure global ecological responses]

比如，北美西部地区树木被砍伐会导致全球气候变冷，这将导致西伯利亚森林产能降低，这也会使得卡诺莱纳州森林干枯，这两者都是负面影响。但是情况在美国东南部会有不同，那里的森林会变得湿润，这是积极的影响。研究结果发表在《公共科学图书馆：综合》上。

One surprise, though, was that when researchers erased forests in both the Amazon and the western U.S.-it had an unpredictable, synergistic effect on global climate. “It suggests that if we were to think about forest management around the globe, we should manage in a coordinated manner rather than independent entities. Because the climate response to these changes in forest cover is going to be a function of all of them happening at the same time.”

一个意外发现是，当研究者们同时“抹去”了美国西部和亚马逊的森林，这对全球气候造成了不可预知、协同性的影响。“这表明，如果我们考虑全球森林管理，我们需要协调性的管理，而不是各个地区独立。因为全球各处森林覆盖的变化会协同性地对气候产生影响。

We do do that to some extent-like managing tropical deforestation through the U.N. But this study suggests we need to keep it up, and do even better, if we want to see the global forest for the trees.

我们已经实施了一些措施，比如通过联合国管理热带森林砍伐。但是研究表明，我们应该继续保持，并且做得更多，更好，这样我们才能保护全球林地。

-Christopher Intagliata