1.It’s a bit funny to be at a conference dedicated to things not seen, and present my proposal to build a 6,000-kilometer-long wall across the entire African continent.
能够来参加这次大会是件很有趣的事， 因为这是一个致力于还未出现的事物的会议， 而且我将呈现一个创意， 一个将可在非洲大陆上筑起全长 6000公里的城墙的建议。
2.About the size of the Great Wall of China, this would hardly be an invisible structure.
这就形同中国长城的规模， 因此它将成为令人难以忽视的建筑。
3.And yet it’s made from parts that are invisible, or near-invisible to the naked eye, bacteria and grains of sand.
然而构成它的部件却是不显眼的，或者说对肉眼几乎是不可见的， 那就是细菌和沙粒。
4.Now, as architects we’re trained to solve problems.
如今，作为建筑师我们被教以解决问题。
5.But I don’t really believe in architectural problems; I only believe in opportunities.
但是我不太相信建筑学上的问题， 我只相信机遇。
6.Which is why I’ll show you a threat, and an architectural response.
这就是为什么我要向你们展现一个恶兆， 和一个建筑学上的回答。
7.The threat is desertification.
这个恶兆就是沙漠化。
8.My response is a sandstone wall made from bacteria and solidified sand, stretching across the desert.
而我的回答 是一条由细菌和固化沙粒建筑而成的城墙， 它将横穿整个沙漠。
9.Now, sand is a magical material of beautiful contradictions.
在如今，沙子是一种不可思议的材料， 它充满着各种美丽的矛盾。
10.It is simple and complex.
它简单却又复杂。
11.It is peaceful and violent.
和平却也暴力。
12.It is always the same, never the same, endlessly fascinating.
它虽为永恒却也无常， 它有着无穷尽的迷人魅力。
13.One billion grains of sand come into existence in the world each second.
这个世界，时时刻刻都有 成千上万的沙粒在产生。
14.That’s a cyclical process.
那是一个循环过程。
15.As rocks and mountains die, grains of sand are born.
岩石和山脉消逝之时， 沙粒于焉诞生。
16.Some of those grains may then cement naturally into sandstone.
一些沙粒随后又自然粘结形成岩石。
17.And as the sandstone weathers, new grains break free.
随着岩石风化，新的沙粒形成。
18.Some of those grains may then accumulate on a massive scale, into a sand dune.
其中一些沙粒 会大规模积聚， 形成沙丘。
19.In a way, the static, stone mountain becomes a moving mountain of sand.
从某种程度上来说，静态的岩石山脉 变成了移动的沙粒山脉。
20.But, moving mountains can be dangerous. Let me try and explain why.
但是，移动的山脉是危险的。我来试着解释一下原因。
21.Dry areas cover more than one third of the Earth’s land surfaces.
地球表面超过三分之一的陆地处于干旱地区。
22.Some are already deserts; others are being seriously degraded by the sand.
其中一些是荒漠， 其它的则被沙完全覆盖。
23.Just south of the Sahara we find the Sahel.
就在撒哈拉沙漠的南边我们发现了沙赫尔。
24.The name means “edge of the desert.”
这个名字的意思是“沙漠的边缘”。
25.And this is the region most closely associated with desertification.
这是和沙漠化联系最紧密的地区。
26.It was here in the late ’60s and early ’70s that major droughts brought three million people to become dependent upon emergency food aid,
也就是在这，在六十年代晚期和七十年代早期， 干旱让三百万人民 只能依靠应急救援食品来生存，
27.with about up to 250,000 dying.
并夺去了总计大约250000人的生命。
28.This is a catastrophe waiting to happen again.
这样的大灾难正伺机卷土重来。
29.And it’s one that gets very little attention.
但它却很少受到人们的注意。
30.In our accelerated media culture, desertification is simply too slow to reach the headlines.
在我们日益加速的媒体文化中， 沙漠化是如此缓慢 而难以登上头版头条。
31.It’s nothing like a tsunami or a Katrina: too few crying children and smashed up houses.
它一点也不像海啸或卡特里娜（飓风）： 很少有哭泣的孩子和被摧毁的房屋。
32.And yet desertification is a major threat on all continents, affecting some 110 countries and about 70 percent of the world’s agricultural drylands.
然而，沙漠化 对所有国家都是一个主要的威胁。 大约110个国家 和全球70%左右的农用旱地都受其影响。
33.It seriously threatens the livelihoods of millions of people, and especially in Africa and China.
它严重地威胁了数以万计的人 的生计问题， 尤其是在非洲和中国。
34.And it is largely an issue that we’ve created for ourselves through unsustainable use of scarce resources.
很大程度上这个问题是我们人类自找的， 源于我们对稀有资源的滥用。
35.So, we get climate change.
为此，我们得到了气候变化。
36.We get droughts, increased desertification, crashing food systems, water scarcity, famine, forced migration, political instability, warfare, crisis.
我们得到了干旱， 日益严重的沙漠化、 食物系统崩溃、水资源短缺、 饥荒、被迫的移民、 政治动荡、战争和危机。
37.That’s a potential scenario if we fail to take this seriously.
如果我们不严肃对待， 那一切的不幸将在现实上演。
38.But, how far away is it?
那么，它现在离我们有多远呢？
39.I went to Sokoto in northern Nigeria to try and find out how far away it is.
我试着去尼日利亚南部的索科托州 寻找答案。
40.The dunes here move southward at a pace of around 600 meters a year.
这的沙丘以每年大约600米的速度向南移动。
41.That’s the Sahara eating up almost one meter a day of the arable land, physically pushing people away from their homes.
撒哈拉沙漠每天几乎要吞噬掉一米的可耕地， 把人赶出他们的房屋。
42.Here I am — I’m the second person on the left — (Laughter) with the elders in Gidan-Kara, a tiny village outside of Sokoto.
我在这——左边第二个—— （笑声） 和Gidan-Kara的长老一起。 那是索科托州外的一个小村庄。
43.They had to move this village in 1987 as a huge dune threatened to swallow it.
1987年他们不得不搬离了这个村子， 因为一座巨大的沙丘正威胁着将它吞没。
44.So, they moved the entire village, hut by hut.
所以，他们一间屋子一间屋子地搬走了整个村庄。
45.This is where the village used to be.
这是他们村子曾经所在的地方。
46.It took us about 10 minutes to climb up to the top of that dune.
爬到那座沙丘的顶部大约花掉了我们10分钟时间。
47.Which goes to show why they had to move to a safer location.
这说明了他们为什么不得不搬到一个更安全的地方。
48.That’s the kind of forced migration that desertification can lead to.
那就是沙漠化所导致的 被迫的迁移。
49.If you happen to live close to the desert border, you can pretty much calculate how long it will be before you have to carry your kids away,
如果你碰巧住在离沙漠边界很近的地方， 你几乎能计算还有多久 你就得带着你的孩子离开，
50.and abandon your home, and your life as you know it.
遗弃你的房屋和生活，正如你所知道的。
51.Now, sand dunes cover only about one fifth of our deserts.
现在，沙丘只覆盖了我们大约五分之一的荒漠。
52.And still, those extreme environments are very good places if we want to stop the shifting sands.
但是，如果我们想要阻止流沙的话 那些极端的环境会是很好的地方。
53.Four years ago, 23 African countries came together to create the Great Green Wall Sahara.
四年前，23个非洲国家 联合起来建造撒哈拉沙漠长城。
54.A fantastic project, the initial plan called for a shelter belt of trees to be planted right across the African continent, from Mauritania in the west, all the way to Djibouti in the east.
一个项不可思议的工程，它最初的计划 是种植一条西起毛里塔尼亚东至吉布提 贯穿非洲大陆的 防护林带。
55.If you want to stop a sand dune from moving what you need to make sure to do is to stop the grains from avalanching over its crest.
如果你想要停止沙丘移动 你就必须确保能够阻止沙粒 从沙丘顶部崩塌下来。
56.And a good way of doing that, the most efficient way, is to use some kind of sand catcher.
有一个很好的也是最有效的方法 就是用某种沙子捕手。
57.Trees or cacti are good for this.
树或者仙人掌就不错。
58.But, one of the problems with planting trees is that the people in these regions are so poor that they chop them down for firewood.
但是种树面临着一个问题， 那个地区的人太穷， 他们把树砍倒当柴火了。
59.Now there is an alternative to just planting trees and hoping that they won’t get chopped down.
现在，除了种树然后指望着它们别被砍掉 我们有了另一种选择。
60.This sandstone wall that I’m proposing essentially does three things.
我所提倡的岩石长城从本质上做了三件事。
61.It adds roughness to the dune’s surface, to the texture of the dune’s surface, binding the grains.
它增加了沙丘表面纹理的粗糙度， 把沙粒粘结在一起。
62.It provides a physical support structure for the trees, and it creates physical spaces, habitable spaces inside of the sand dunes.
它为树木的生存提供了物理支撑结构， 它还在沙丘的内部创造了 可供居住的空间。
63.If people live inside of the green barrier they can help support the trees, protect them from humans, and from some of the forces of nature.
如果人们居住在这道绿色的屏障内， 他们就能帮着照料这些树，保护它们免受人类 和一些自然力量的破坏。
64.Inside of the dunes we find shade.
在沙丘里我们能找到阴凉的地方。
65.We can start harvesting condensation, and start greening the desert from within.
我们开始收获（沙粒的）凝结， 并开始从内部将沙漠绿化。
66.Sand dunes are almost like ready-made buildings in a way.
沙丘已经差不多有点像现成的建筑了，
67.All we need to do is solidify the parts that we need to be solid, and then excavate the sand, and we have our architecture.
我们需要做的只是固化所需的部分， 然后挖掘沙子， 构筑我们的建筑。
68.We can either excavate it by hand or we can have the wind excavate it for us.
我们既可以用手挖掘 也能让风来帮我们。
69.So, the wind carries the sand onto the site and then it carries the redundant sand away from the structure for us.
风把沙粒搬运上来 再把多余的沙从我们的建筑上搬走。
70.But, by now, you’re probably asking how am I planning to solidify a sand dune?
但是，到现在，你们或许会问 我打算怎样把一座沙丘固化呢？
71.How do we glue those grains of sand together?
我们又怎样把沙粒粘合在一起？
72.And the answer is, perhaps, that you use these guys, Bacillus pasteurii, a micro-organism that is readily available in wetlands and marshes, and does precisely that.
答案就是，或许，你可以用这些家伙， 巴氏芽孢杆菌， 一种能从湿地和沼泽中 轻松获取的微生物。
73.It takes a pile of loose sand and it creates sandstone out of it.
它带着一堆疏松砂岩 并能用它们制造砂岩。
74.These images from the American Society for Microbiology show us the process.
这些来自美国微生物学会的照片向我们展示了这一过程。
75.What happens is, you pour Bacillus pasteurii onto a pile of sand, and it starts filling up the voids in between the grains.
所发生的是，你把巴氏芽孢杆菌倒在一堆沙上， 它开始填充沙粒间的间隙。
76.A chemical process produces calcite, which is a kind of natural cement that binds the grains together.
由一个化学过程产生方解石， 方解石是一种天然的水泥， 能把沙粒粘结在一起。
77.The whole cementation process takes about 24 hours.
整个粘结过程大概需要24个小时。
78.I learned about this from a professor at U.C. Davis called Jason DeJong.
我从加州大学一个叫Jason DeJong的教授那里学到了这些。
79.He managed to do it in a mere 1,400 minutes.
他成功地在1400分钟里完成了这个实验。
80.Here I am, playing the part of the mad scientist, working with the bugs at UCL in London, trying to solidify them.
在这，我扮演起了这位疯狂的科学家的角色， 和这个疯子一起在伦敦的伦敦大学学院工作， 尝试着固化它们。
81.So, how much would this cost?
那么，这个项目要花费多少呢？
82.I’m not an economist, very much not, but I did, quite literally, a back of the envelope calculation — (Laughter) — and it seems that for a cubic meter of concrete
我一点也不像个经济学家， 但是，我做了一个——照字面来说的——封底运算…… （笑声） 看起来一立方米粘结物
83.we would have to pay in the region of 90 dollars.
要耗费我们90美元左右。
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