演讲MP3+双语文稿:一种从大气中去除二氧化碳的新方法
听力课堂TED音频栏目主要包括TED演讲的音频MP3及中英双语文稿，供各位英语爱好者学习使用。本文主要内容为演讲MP3+双语文稿:一种从大气中去除二氧化碳的新方法，希望你会喜欢！
【演讲者及介绍】Jennifer Wilcox
化学工程师Jennifer Wilcox致力于测试和测量微量金属和碳捕获的方法，以减轻化石燃料对地球的影响。
【演讲主题】一种从大气中去除二氧化碳的新方法
【中英文字幕】
翻译者Annie Zhang 校对者Mark Huang
00:13
Four hundred parts per million: that's theapproximate concentration of CO2 in the air today. What does this even mean?For every 400 molecules of carbon dioxide, we have another million molecules ofoxygen and nitrogen. In this room today, there are about 1,800 of us. Imaginejust one of us was wearing a green shirt, and you're asked to find that singleperson. That's the challenge we're facing when capturing CO2 directly out ofthe air. Sounds pretty easy, pulling CO2 out of the air. It's actually really difficult.
百万分之四百：这就是现在空气里二氧化碳大概的浓度。这意味着什么呢？意味着每四百个二氧化碳分子，都混了另外一百万个氧和氮分子。今天这个房间里大概有1800人。想象一下我们当中只有一个人穿着绿色衬衫，而你被要求找到那个人。这就是我们从空气中直接捕获二氧化碳需要面临的挑战。把二氧化碳从空气中提取出来，听起来很简单，但这实际上是个很复杂的过程。
00:53
But I'll tell you what is easy: avoidingCO2 emissions to begin with. But we're not doing that. So now what we have tothink about is going back; pulling CO2 back out of the air. Even though it'sdifficult, it's actually possible to do this. And I'm going to share with youtoday where this technology is at and where it just may be heading in the nearfuture.
但我要告诉你什么是简单的：在源头减少二氧化碳排放。但是我们并没有真正这样做。所以我们现在得考虑如何逆转现状；将二氧化碳从空气中移除。虽然这个过程很困难，但是依然有可能实现。我今天将与你们分享用来移除二氧化碳的科技，以及在不久的将来，它会朝哪个方向发展。
01:20
Now, the earth naturally removes CO2 fromthe air by seawater, soils, plants and even rocks. And although engineers andscientists are doing the invaluable work to accelerate these natural processes,it simply won't be enough. The good news is, we have more. Thanks to humaningenuity, we have the technology today to remove CO2 out of the air using achemically manufactured approach. I like to think of this as a syntheticforest. There are two basic approaches to growing or building such a forest.One is using CO2-grabbing chemicals dissolved in water. Another is using solidmaterials with CO2-grabbing chemicals.
地球能够自然地通过海水，泥土，草木甚至是石头将二氧化碳从空气中移除。尽管工程师和科学家们为了加快这个自然的过程做了许多宝贵的工作，但还远远不够。好消息是，我们还有别的技术。感谢人类的聪明才智，我们今天才能拥有通过化学制造将二氧化碳从空气中移除的科技。我把它称为人工森林。总的来说，有两种方法可以实现人工森林。一种是使用溶于水的二氧化碳捕集材料。另一种是使用固态的二氧化碳捕集材料。
02:14
This is called an air contactor. You cansee it has to be really, really wide in order to have a high enough surfacearea to process all of the air required, because remember, we're trying tocapture just 400 molecules out of a million. Using the liquid-based approach todo this, you take this high surface area packing material, you fill thecontactor with the packing material, you use pumps to distribute liquid acrossthe packing material, and you can use fans,to bubble the air through the liquid. The CO2 in the air is separated[by] the liquid by reacting with the really strong-binding CO2 molecules insolution. And in order to capture a lot of CO2, you have to make this contactordeeper. But there's an optimization, because the deeper you make thatcontactor, the more energy you're spending on bubbling all that air through. Soair contactors for direct air capture have this unique characteristic design,where they have this huge surface area, but a relatively thin thickness.
它被称为空气接触器。可以看到，它必须设计得非常非常宽，这样才能获得足够大的表面积来处理所有需要的空气，请谨记，我们要尝试在一百万个分子之中捕获仅仅四百个分子。若使用液体材料来捕获二氧化碳，需要选用表面积大的填充材料，将空气接触器装满，再使用泵驱动，并确保液体在填充材料之间充分流动。然后你就可以使用风扇，将空气吹进装置，以气泡的形态穿过液体。空气中的二氧化碳与液体材料发生反应，从而将二氧化碳分子分离出来。为了能捕获更多的二氧化碳，还必须将接触器造得更深。但是这种提升并不是无限的，因为接触器造得越深，制造气泡所消耗的能量也越多。所以直接捕捉空气的空气接触器就具备了这个独一无二的设计，巨大的表面积和相对较薄的厚度。
03:26
And now once you've captured the CO2, youhave to be able to recycle that material that you used to capture it, over andover again. The scale of carbon capture is so enormous that the capture processmust be sustainable, and you can't use a material just once. And so recyclingthe material requires an enormous amount of heat, because think about it: CO2is so dilute in the air, that material is binding it really strong, and so youneed a lot of heat in order to recycle the material. And to recycle thematerial with that heat, what happens is that concentrated CO2 that you gotfrom dilute CO2 in the air is now released, and you produce high-purity CO2.And that's really important, because high-purity CO2 is easier to liquify,easier to transport, whether it's in a pipeline or a truck, or even easier touse directly, say, as a fuel or a chemical.
在二氧化碳被捕获之后，我们还需要能够循环使用用来捕获它的材料，持续不断进行捕获。毕竟，当碳捕获具备了庞大的规模，其捕获方法必须能够满足长远需求并能重复利用材料。另外，重复利用材料的过程需要消耗大量的热量，试想一下：二氧化碳在空气中是如此稀薄，材料对它的约束力就会非常大，你需要消耗很多热量才能回收这个材料。所以你消耗热量回收材料时，从空气中收集的浓缩二氧化碳将被释放出来，你将得到高纯度的二氧化碳。这一点很重要，因为高纯度的二氧化碳更容易液化，无论是利用管道还是卡车，都比气态二氧化碳更容易运输，甚至更容易被直接使用，比如作为燃料或者化学品。
04:25
So I want to talk a little bit more aboutthat energy. The heat required to regenerate or recycle these materialsabsolutely dictates the energy and the subsequent cost of doing this. So I aska question: How much energy do you think it takes to remove a million tons ofCO2 from the air in a given year? The answer is: a power plant. It takes apower plant to capture CO2 directly from the air. Depending on which approachyou choose, the power plant could be on the order of 300 to 500 megawatts. Andyou have to be careful about what kind of power plant you choose. If you choosecoal, you end up emitting more CO2 than you capture.
关于能量，我想再多讲一些。再生或者回收那些材料的热量需求决定了这个过程需要的能量和附随的成本。我想问一个问题：你觉得在一年内 从空气中移除一百万吨的二氧化碳 需要多少能量？ 答案是： 一个发电厂。需要一个发电厂来提供从空气中 捕获二氧化碳所需要的能量。发电厂的发电量，取决于选择的方法，可能在300到500兆瓦之间。还要谨慎选择发电厂的燃料类别。如果选择的是煤，产生的二氧化碳会比捕获的还多。
05:14
Now let's talk about costs. Anenergy-intensive version of this technology could cost you as much as $1,000 aton just to capture it. Let's translate that. If you were to take that veryexpensive CO2 and convert it to a liquid fuel, that comes out to 50 dollars agallon. That's way too expensive; it's not feasible.
现在让我们谈谈成本问题。如果仅仅为了捕获一吨二氧化碳而选择在该技术上投入大量能源，其花费将多达一千美金。让我们解释一下这句话。如果你要把非常昂贵的二氧化碳转化成液体燃料，燃料价格将会高达五十美元一加仑。这太贵了；完全是不可行的。
05:36
So how could we bring these costs down?That's, in part, the work that I do. There's a company today, acommercial-scale company, that can do this as low as 600 dollars a ton. Thereare several other companies that are developing technologies that can do thiseven cheaper than that. I'm going to talk to you a little bit about a few ofthese different companies.
那么我们要怎样降低费用？这就是我所做的部分工作。当前有一个公司，一个商业规模的公司，可以使费用降到每吨六百元。还有其他几个开发技术的公司，还可以进一步降低成本。我要向你们简单介绍一下这些不同的公司。
05:58
One is called Carbon Engineering. They'rebased out of Canada. They use a liquid-based approach for separation combinedwith burning super-abundant, cheap natural gas to supply the heat required.They have a clever approach that allows them to co-capture the CO2 from the airand the CO2 that they generate from burning the natural gas. And so by doingthis, they offset excess pollution and they reduce costs.
其中一个叫做Carbon Engineering，位于加拿大。他们使用基于液体的分离方法结合过剩的，廉价的天然气来提供所需要的热量。他们发明了一个很巧妙的方法，可以从空气中捕获二氧化碳的同时，也捕获燃烧天然气产生的二氧化碳。这样一来，他们就抵消了过度污染的影响，也降低了成本。
06:26
Switzerland-based Climeworks and US-basedGlobal Thermostat use a different approach. They use solid materials forcapture. Climeworks uses heat from the earth, or geothermal, or even excesssteam from other industrial processes to cut down on pollution and costs.Global Thermostat takes a different approach. They focus on the heat requiredand the speed in which it moves through the material so that they're able torelease and produce that CO2 at a really fast rate, which allows them to have amore compact design and overall cheaper costs.
位于瑞士的Climeworks 和位于美国的Global Thermostat 使用的则是不同的方法，固体材料捕获。Climateworks 使用来自地球的热量或者地热能，甚至是来自其他工业过程的过量蒸汽来减少污染和降低费用。Global Thermostat则另辟蹊径，他们专注于所需的热量以及它穿过材料的速度，于是就可以在一个很快的速率下释放和生产二氧化碳，这使得他们采用了更密致的设计，以及整体上更低廉的费用。
07:07
And there's more still. A synthetic foresthas a significant advantage over a real forest: size. The Amazon is capable of capturing 1.6billion tons of CO2 each year. This is the equivalent of roughly 25 percent ofour annual emissions in the US. The land area required for a synthetic forestor a manufactured direct air capture plant to capture the same is 500 timessmaller. In addition, for a synthetic forest, you don't have to build it on arableland, so there's no competition with farmland or food, and there's also noreason to have to cut down any real trees to do this.
还有很多这样的例子。人造森林与天然森林相比有一个显著的优势：规模。亚马逊地区每年能捕获 16亿吨的二氧化碳。大约等于美国每年排放量的百分之二十五。而要捕获等量的二氧化碳所需的人工森林或者人造空气捕获工厂，其占地面积只有天然森林的五百分之一。另外，人工森林不需要在耕地上建造，所以并不会占用畜牧和农耕土地，而且我们也不需要砍去任何自然生长的树木来建造人工森林。
07:59
I want to step back, and I want to bring upthe concept of negative emissions again. Negative emissions require that theCO2 separated be permanently removed from the atmosphere forever, which meansputting it back underground, where it came from in the first place. But let'sface it, nobody gets paid to do that today -- at least not enough. So thecompanies that are developing these technologies are actually interested in takingthe CO2 and making something useful out of it, a marketable product. It couldbe liquid fuels, plastics or even synthetic gravel. And don't get me wrong --these carbon markets are great. But I also don't want you to be disillusioned.These are not large enough to solve our climate crisis, and so what we need todo is we need to actually think about what it could take.
我想退一步，再次提出负排放的概念。负排放，需要被分离的二氧化碳永久性地从大气层中去除，这意味着把它送回地下，也就是它最初所在的地方。但请让我们面对现实吧，至今都没有人以此为生——至少相关从业者数量还远远不够。所以开发这些技术的公司其实是对获取二氧化碳感兴趣，为了从中造出有价值的东西，一个可销售的产品。它可以是液体燃料，塑料，甚至是合成的砾石。别误会我的意思——这些碳源的市场非常好。但是我也不想让你们产生错误的幻想。这些市场还不够大，不足以解决气候危机，所以我们需要认真思考一下还能做些什么来解决危机。
08:55
One thing I'll absolutely say is positiveabout the carbon markets is that they allow for new capture plants to be built,and with every capture plant built, we learn more. And when we learn more, wehave an opportunity to bring costs down. But we also need to be willing toinvest as a global society. We could have all of the clever thinking andtechnology in the world, but it's not going to be enough in order for thistechnology to have a significant impact on climate. We really need regulation,we need subsidies, taxes on carbon. There are a few of us that would absolutelybe willing to pay more, but what will be required is for carbon-neutral,carbon-negative paths to be affordable for the majority of society in order toimpact climate.
关于碳市场的一个绝佳的事实就是，它至少支撑了建造新的捕获工厂，每建造一个捕获工厂，我们都会学到更多；当我们学到更多，我们就能不断地降低成本。但作为一个国际社会，我们还需要愿意去投资。我们有世界上所有的奇妙思想和科技，但是这还远无法让这项技术对气候带来显著的改善。我们还切实地需要法规扶持，我们需要补贴，碳税，我们当中有一部分人绝对愿意为此花更多的钱，但为了走向零碳排放，甚至是碳负排放的道路，我们需要让社会中的大多数人都能够承担得起这部分费用，才能真正影响气候。
09:50
In addition to those kinds of investments,we also need investments in research and development. So what might that look like?In 1966, the US invested about a half a percent of gross domestic product inthe Apollo program. It got people safely to the moon and back to the earth.Half a percent of GDP today is about 100 billion dollars. So knowing thatdirect air capture is one front in our fight against climate change, imaginethat we could invest 20 percent, 20 billion dollars. Further, let's imaginethat we could get the costs down to a 100 dollars a ton. That's going to behard, but it's part of what makes my job fun.
除了这些投资，我们还需要人们在研发项目中投资。这意味着什么呢？ 1966年，美国百分之五十的GDP 被用于投资阿波罗计划。该计划帮助人类安全地登上了月球，并顺利返回地球。而在今天，一半的GDP 大概是一千亿美金。所以当知道直接捕获空气和与气候变化做斗争是同一个战线后，想象一下我们能够投资 20%的GDP，两百亿美元。更进一步，让我们设想一下降低成本到100美金一吨。这很困难，但也正是我工作中的乐趣所在。
10:36
And so what does that look like, 20 billiondollars,100 dollars a ton? That requires us to build 200 synthetic forests,each capable of capturing a million tons of CO2 per year. That adds up to aboutfive percent of US annual emissions. It doesn't sound like much. Turns out,it's actually significant. If you look at the emissions associated withlong-haul trucking and commercial aircraft, they add up to about five percent.Our dependence on liquid fuels makes these emissions really difficult to avoid.So this investment could absolutely be significant.
两百亿美金，一百美金一吨，是个什么概念呢？这需要我们建造二百个人工森林，每个人工森林一年能捕获一百万吨的二氧化碳。这加起来相当于美国每年碳排放量的百分之五。听起来好像不多。实际上，效果已经相当明显了。如果你查看长途运输和商用飞机产生的碳排放，其合计总量就达到了百分之五左右。我们对液体燃料的依赖使这样的碳排放量非常难以避免。所以毋庸置疑，这项研究意义重大。
11:18
Now, what would it take in terms of landarea to do this, 200 plants? It turns out that they would take up about halfthe land area of Vancouver. That's if they were fueled by natural gas. Butremember the downside of natural gas -- it also emits CO2. So if you usenatural gas to do direct air capture, you only end up capturing about a thirdof what's intended, unless you have that clever approach of co-capture thatCarbon Engineering does. And so if we had an alternative approach and used windor solar to do this, the land area would be about 15 times larger, looking atthe state of New Jersey now. One of the things that I think about in my workand my research is optimizing and figuring out where we should put these plantsand think about the local resources available -- whether it's land, water,cheap and clean electricity -- because, for instance, you can use cleanelectricity to split water to produce hydrogen, which is an excellent,carbon-free replacement for natural gas, to supply the heat required.
11:17
那么要建造200个工厂，需要多少土地呢？事实上，它们将占据温哥华大约一半的土地面积。这还是在利用天然气作为燃料的前提下。但是别忘了天然气的缺点——燃烧时也会排放二氧化碳。所以如果你使用天然气直接捕获空气，你最终只会捕获到预期量的三分之一，除非你有像Carbon Engineering一样同时捕获两者的方法。如果我们有一个替代的方法，使用风力发电或者太阳能发电，但随之所需的土地面积可能会扩大十五倍，和现在的新泽西州一样大。我在工作和研究时经常思考的一件事，就是优化和解决两个问题，将这些工厂放在哪里，以及如何就地取材——是否有足够的土地面积，水资源，廉价和无污染的电能——因为，例如无污染的电能可以把水分解成氢气，这是一个极好的，无碳的天然气替代品，可以提供所需的热量。
12:22
But I want us to reflect a little bit againon negative emissions. Negative emissions should not be considered a silverbullet, but they may help us if we continue to stall at cutting down on CO2pollution worldwide. But that's also why we have to be careful. This approachis so alluring that it can even be risky, as some may cling onto it as somekind of total solution to our climate crisis. It may tempt people to continue toburn fossil fuels 24 hours a day, 365 days a year. I argue that we should notsee negative emissions as a replacement for stopping pollution, but rather, asan addition to an existing portfolio that includes everything, from increasedenergy efficiency to low-energy carbon to improved farming -- will allcollectively get us on a path to net-zero emissions one day.
但是我想提醒大家再次对负排放进行反思。负排放不应该被当作是万全之策，但是它们可以在实现真正减少全球二氧化碳排放前帮我们争取一些时间。这也是为什么我们必须小心谨慎。这个方法是如此的诱人，甚至会产生负面效应，有些人过分依赖它，把它看作能彻底解决气候危机的方案。它可以诱使人们每年365天，每天24小时，继续燃烧化石燃料。我认为我们不应该把负排放当成中断污染的替代品，相反的，应该把它当成现有的改善环境措施的一个附加品，从提高能源效率到低碳排放，再到优化农业——总有一天，会让我们走上一条零碳排放的道路。
13:18
A little bit of self-reflection: my husbandis an emergency physician. And I find myself amazed by the lifesaving work thathe and his colleagues do each and every day. Yet when I talk to them about mywork on carbon capture, I find that they're equally amazed, and that's becausecombatting climate change by capturing carbon isn't just about saving a polarbear or a glacier. It's about saving human lives.
我还想谈谈自己的一点反思：我的丈夫是一位急诊医师。他和同事每天从事的救死扶伤的工作令我大为惊叹。然而当我和他们谈起我与碳捕获相关的工作，他们也同样表示了赞叹，因为通过捕获碳来对抗气候变化并不只是关于拯救北极熊或者防止冰川融化，这是为了拯救人类。
13:50
A synthetic forest may not ever be aspretty as a real one, but it could just enable us to preserve not only theAmazon, but all of the people that we love and cherish, as well as all of ourfuture generations and modern civilization.
人工森林可能没有天然森林的美观，但是它不仅仅让我们保护有能力亚马逊，还能保护所有我们所爱的和珍惜的人，以及所有的子孙后代和现代文明。
14:09
Thank you.
谢谢。
14:10
(Applause)
（掌声）
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