VOA慢速英语2019 如何应对气候变化？再种一万亿棵树（在线收听）

How to Fight Climate Change? Plant a Trillion Trees

Scientists are asking: What is the best way to fight climate change?

科学家们问：应对气候变化最好的途径是什么？  

A new study says: Plant many trees; one trillion trees, maybe more.

一项新的研究回答了这个问题，那就是种树，种一万亿棵树，甚至种更多的树。 

Swiss scientists say there is enough room for that many trees. In their report in the journal Science, they say even with existing cities and farmland, there is enough space for new trees to cover nine million square kilometers. That is about the size of the United States.

瑞士科学家们表示，地球有足够的空间种这么多树。他们在《科学》杂志上发表的报告中称，即使维持现有的城市和农田规模，也有足够空间新种可以覆盖900万平方公里的树，这大致相当于美国的面积。

Trees take carbon dioxide out of the air, and in return, put oxygen back into the air.

树木可以吸收大气中的二氧化碳，然后向大气中释放氧气作为交换。 

The study estimated that over a long period of time, the trees could take in almost 750 billion tons of carbon dioxide from the atmosphere. That is about as much carbon as humans have put into the atmosphere in the past 25 years.

该研究估计，长远来说，这些树木可以从大气中吸收近7500亿吨二氧化碳。这大致相当于人类过去25年中的碳排放。

What is so bad about carbon dioxide? The gas traps heat, causing temperatures to rise.

二氧化碳有什么坏处呢？它会吸收热量，导致气温上升。 

Much of the gain from planting trees will come quickly because trees remove more carbon from the air when they are younger, the researchers said. The place that has the best possibility for removing the most carbon is the tropics— the area close to the equator.

研究人员表示，种植树木很快就能见效，因为幼树可以从空气中清除更多的碳。最有可能除去大部分碳的地方是热带地区——靠近赤道的地区。

This method would also have the lowest cost, says the study co-author Thomas Crowther.

该研究的共同作者托马斯·克劳瑟表示，这种方法的成本也最低。 

This is by far — by thousands of times — the cheapest climate change solution and the most effective, he said. Crowther is a climate change ecologist at the Swiss Federal Institute of Technology in Zurich.

他说：“这是迄今为止最为廉价的气候变化解决方案，也是效果最好的。”克劳瑟是苏黎世瑞士联邦理工学院的气候变化生态学家。

The six nations with the most room for new trees are Russia, the United States, Canada, Australia, Brazil and China.

俄罗斯、美国、加拿大、澳大利亚、巴西和中国是六个新树生长空间最大的国家。 

Before his study, Crowther thought that there were other more effective ways to fight climate change besides cutting emissions. One example could be for people to change their diets by no longer eating meat. But, he said, tree planting is far more effective because trees remove so much carbon dioxide from the air.

克劳瑟在做这项研究之前认为，除了减少碳排放，还有其它更有效应对气候变化的的途径。例如人们可以改变饮食习惯，不再吃肉。但是他说植树更为有效，因为树木可以从空气中去除大量的二氧化碳。

Thomas Lovejoy works as a biologist at George Mason University. He was not part of the study. But, he called the report "a good news story" because planting trees would also help stop the loss of biodiversity.

托马斯·洛维乔伊是乔治梅森大学的生物学家。他并未参与这项研究。但是他称这篇报告是个好消息，因为种树还有助于防止生物多样性的丧失。

Crowther said planting trees is not a substitute for reducing the world’s dependence on oil, coal and natural gas. The carbon dioxide produced by burning these fuels is believed to cause the warming of the atmosphere.

克劳瑟表示，种树并非减少全球对石油、煤炭、天然气依赖的替代方案。据信这些燃料燃烧产生的二氧化碳会引起大气变暖。

None of this works without emissions cuts, he said.

他说：“如果不减少碳排放，这些就都起不到作用。” 

And it is not easy or realistic to think the world will suddenly start planting a lot of trees quickly, although many groups have started, Crowther said.

克劳瑟说，尽管许多组织已经开始植树造林，但认为世界将突然开始迅速地大量植树并不容易，也不现实。

It’s certainly a monumental challenge, which is exactly the scale of the problem of climate change, he said.

他说：“这无疑是一项巨大挑战，也正是气候变化问题的严重性所在。” 

The researchers used Google Earth to see what areas could support more trees, while leaving room for people and crops. Lead writer for the study, Jean-Francois Bastin, estimated there is space for at least 1 trillion more trees, but it could be 1.5 trillion.

研究人员利用谷歌地球来查看哪些区域可以种植更多树木，同时为人类和庄稼留够空间。该研究的主要作者让 - 弗朗索瓦·巴斯汀估计，全球有足够空间可以种植至少1万亿棵树，但是可能会达到1.5万亿棵。

That is in addition to the 3 trillion trees that now live on Earth -- a number Crowther found in earlier research.

这是对目前地球上已有的3万亿棵树的补充，克劳瑟在早期研究中确定了这一数字。