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[2012.06.16] 边界条件

2012-6-18 08:18| 发布者: migmig| 查看: 7723| 评论: 20|原作者: dqzxf

摘要: 地球环境边界条件的概念正在为人们所普遍接受。超过这个边界,人类将面临生存危机
地球环境

边界条件

地球环境边界条件的概念正在为人们所普遍接受。超过这个边界,人类将面临生存危机

Jun 16th 2012 | from the print edition
《经济学人》杂志2012年6月16日文章

当您拉开一根弹簧,然后松开时,弹簧就会啪地一声复归原来的形状。下一次将弹簧拉得更长一些,它会照样弹回。依此而行,每次都拉得更长一点,弹簧每次也都依然弹回;但直到您拉伸到某一次时,弹簧会突然就失去了弹性。这根昔日的弹簧变成了一根卷曲的废铁丝。简而言之,许多科学家担心的就是,如果地球的各个环境系统就像这根弹簧一样承受了超过限度的拉伸,则地球的命运就会如这根弹簧一样。

正是出于这种担心,在2009年秋,诞生了地球环境边界条件的概念。在那年的哥本哈根全球气候大会期间,一组对此感到不安的科学家在瑞典的斯德哥尔摩应变中心的资助下,在《自然》杂志上发表一篇文章,对他们认为是人类发展的安全运作空间进行了界定。这个界定由一组共9项极限条件所组成。超过了这些极限值,人类就将失去他们的地球家园。

这9项边界条件涉及的领域有:气候变化;海洋酸化;臭氧层变薄;对植物生长至关重要的氮与磷酸盐循环的妨碍;荒野变为农田与城市的转化率;物种的灭绝;化学污染物的积聚以及大气颗粒污染物的浓度。这篇文章的作者们认为,在这些领域中有7个可以设置具体的边界值。对此他们有足够的自信。而对于化学污染物积聚与大气颗粒污染物浓度这两项指标,他们稍后将提出具体的边界值。

自那以后,地球环境边界条件的概念就扎下了根。在“联合国全球环境展望”第5版中(GEO-5),这个概念被多次提及,颇为出人意外。“全球可持续发展高级别小组”(High-level Panel on Global Sustainability)最近向联合国秘书长潘基文提交了一份报告。报告中这个概念被置于醒目的位置。最近在伦敦召开了一个规模庞大的科学大会:重负下的星球(Planet Under Pressure)。大会将地球环境边界条件的概念作为会议的核心信息传达给“里约+20”。“里约+20”是定于6月20日在巴西召开的联合国环境高峰会议。

不要将“我”禁锢住

地球环境边界条件的概念为人类思考环境变化问题提供了一种有效的手段。在许多情况下,人们都可以借助这种手段预先觉察到地球环境尚未出现的变化。这是一个很少考虑环境问题的朋友们可以接受的概念;同时这又是一个能与对环境保护持敌意的人达成妥协的概念。但这个概念尚有众多的缺陷。正如这个概念的倡议者们所知,给出的边界值有些武断。其部分原因是人类目前的知识水平所限,但人们不知道这种状况还要持续多长的时间。也许有些边界值被突破却不会引发不可逆转的灾难;也许有些边界值的设定完全错误。一些学术观点认为,即使这些边界条件全都没有被突破,地球环境也很可能发生巨变。

最近的批评声来自突破研究所(Breakthrough Institute)。这是一家持坚定的非主流观点的研究机构,专注于研究能源与环境问题。在这家机构于6月11日发表的报告中,有两个观点非常引人注目。第一个观点是,地球环境边界条件的概念并没有在真正造成全球影响的事物与那些基本上只是造成了局部或地区性影响事物的区分上给予足够的关注。第二个观点是,大多数地球环境边界条件值是依据对全新世地球状况的考察而得出。这个地质年代始自最近一场冰川期的结束,而人类文明正是在这一时期发展起来的。这两个批评观点都值得我们深思。

一根弹簧如果拉伸(或压缩)过度就会产生不可逆的变化。对于那些明显具有弹簧这样特性的事物,如冰架的崩塌或永久冻土带的融化等,地球环境边界条件就像安装在女儿墙上的安全栏杆一样非常有益,可以让人类不要过于逼近危险的临界点。人们有充分的理由相信,部分气候现象已经在向这个临界点逼近,因而有必要设置安全栏杆。但在这9项边界条件中,设置者们相信真正具有全球性临界点的环境系统只有气候、海洋的酸化程度与臭氧层这3项。其他6项中,一些可能有区域性临界点,但大多数系统的全球性影响都只不过是区域性影响的集合而已。

突破研究所的报告指出,混淆了这两者的区别,将会导致错误政策的出笼。例如,由于中国过度使用氮肥而带来危害,就对全球范围内氮元素的使用进行限制,其结果将导致人们放弃使用氮肥。这样一来,非洲贫瘠的土地也就无法受益于这种肥料了。

突破研究所在这份报告提出的其他批评意见中含蓄地认为,由于现代人类是在全新世进化成熟的,因此全新世的环境状况对现今的物种而言是最适宜的。人们确实有理由相信,在某些方面全新世的环境状况是最佳选择。在这段地质年代里,气候相对稳定。在地球的温带地区,气候温暖宜人。突破研究所的批评者们也同意气候稳定是件好事。然而该研究所的报告指出,并没有证据证明,全新世的氮圈或磷酸盐圈的作用方式等特别适合人类生存。人类利用化工生产的方法来缩短氮循环的周期,利用空气中的氮来生产氮肥,其速率远远超过了大自然的运作规律,对环境产生了实实在在的影响。例如,富含硝酸盐的地表径流能够破坏湖泊的生态平衡。但如果人类能够控制这些影响,则无法断定从空气中提取氮的数量达到多少时才会成为问题。

这实际上是在争论人类世(人类地质年代)的性质。许多科学家感到人类对地球的影响巨大,全新世已经成为过去,一个真正独立的地质年代——人类世已经开始。而地球边界条件的概念是想将人类世禁锢于全新世的范畴之内。与之对照,突破研究所认为,应该根据人类福祉的需要通过计算来确定规范,而不应西颦东效地模仿地球史上已经出现过的状态。这两种方法中哪一种更为谨慎,对此人们没有疑义。而谨慎行事的方法总是能得到大多数人的支持。但哪种方法更有道理,或更实际可行,则尚需人们通过大量的争论来得出结论。

独立宣言

地球环境边界条件这个概念的另一个问题就是假定所有的边界条件都是相互独立的。这一点似乎不大可能成立。若果真如此,则可能出现任何单一边界条件的极值都没有被突破,但却爆发了一场全球性环境危机的情况。在6月7日出版的《自然》杂志上刊登了一份证据审查报告,其结论是这种情况很有可能出现。在如哥本哈根世界气候大会与“里约+20”这类声势浩大的国际会议召开之前,这份报告就像一颗投入水中的石子,激起了阵阵涟漪。这份报告认为,地球可能正在接近一个“临界点”。越过这个临界点,就会出现土地使用、气候等方面同时出现的变化。人口数量的不断增长与人类生活的不断富足都在推动着这种变化,将地球的环境系统推入到一个与现今非常不同的状态。气候带会持续改变;生态系统功能也会不断变化。各方面的变化不胜枚举。

(地球环境)很可能出现突然的变化。既然如湖泊一类较小生态系统的状态经常出现这样的突然变化,那么如地球一类大型生态系统自然也会如此。没有什么明显的理由能说明它们为什么不会产生这样的变化。根据加州大学的安东尼•巴诺斯基(Anthony Barnosky)和《自然》杂志上报告的作者之一伯克利(Berkeley)的看法,即使地球生态系统的所有单项指标没有突破地球环境边界条件的极限值,多项系统的变化叠加后依然可以触发这样的状态改变。

这可能是一个坏消息。即使这种状态改变的最终结果是地球上仍然适合人类居住,状态改变的过程就可能是人类的一场巨大灾难。但环境指标没有超出边界值仍然可能出现灾难性后果的可能性又导出了一个反向问题:超出了边界值后人类是否还能有光明的未来?特别是,对于控制温室气体预警与气候变化最重要的边界条件而言,能否灵活设置其边界值?

提出地球环境边界条件这个概念的科学家们用两种不同的方法定义了环境边界条件,这有点令人困惑不解。一种方法是限定二氧化碳这种长久以来对引发温室效应的起主要作用的气体的数值。其限定极值为:大气中每百万个气体颗粒中有350个二氧化碳颗粒(ppm)。另一种方法是限定“辐射强迫”(radiative forcing)的数值。“辐射强迫”是指一段时间内射入到地球表面的能量增值,大体上是温室气体增加带来的结果。相对于工业化前的水平,辐射强迫的极值定为每平方米1瓦特。无论采用哪一种方法,气候边界条件都正好直接面对人类的后视镜。这是提出地球边界条件这个概念的科学家中部分人的观点。如戈达德太空研究所(Goddard Institute for Space Studies)的詹姆士•汉森(James Hansen)就持这种看法。他们认为现在的气候已经超出了临界点,但很多事物却长久地存活了下来。格陵兰的冰川就是如此。如果这个冰川消融了,则地球的海平面将上升7米。

如果提出了地球环境边界条件这个概念的科学家们计算的正确,则温室气体的状况看起来令人绝望。目前大气中的二氧化碳高达近400ppm,而且还在以每年2ppm的速度增长。如果要想将大气中的二氧化碳降到350ppm的水平,就必须在漫长的时间内做到二氧化碳零排放,这一过程很有可能需要数百年时间。而且要采用所有可能的方法将二氧化碳从大气中分离出来,将它们重新埋入地下。

不可抗力

然而,由于温室气体对辐射强迫的影响,它与辐射强迫是同一个问题。如果借助其他手段能将辐射强迫控制在限定值内,则对二氧化碳的限定就不再起作用了。而在高层大气中喷洒反光颗粒,将阳光反射回太空的方法就可能实现对辐射强迫的控制。

这样一个激进的方案很可能产生各式各样令人烦恼的副作用。对各种政治问题的考量很可能会超过环境问题。虽然目前还无法断定这个方案确实正确可行,但并不能排除其可行性。能够肯定的是,这样一个方案说明,尽管地球也许有各种不能超越的边界,但思考如何来帮助她却可能没有止境。
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引用 vlidges 2012-6-18 10:40
好贴,学习了啊!!
引用 yannanchen 2012-6-18 10:47
planet-wide environmental boundaries, 地球环境边界条件
这个-wide 没有翻译出来

地球全球性的环境边界
引用 yannanchen 2012-6-18 10:55
In the run-up to that year’s climate conference in Copenhagen 在那年的哥本哈根全球气候大会期间,

in the run-up to the conference 不等于 in the course of the conference
指的是 从开会前的某一时间算起,一直到大会开始为止。

n run-up
1. (Individual Sports & Recreations / Athletics (Track & Field)) an approach run by an athlete for a long jump, pole vault, etc.
2. a preliminary or preparatory period
the run-up to the election
引用 yannanchen 2012-6-18 10:57
a set of nine limits beyond which people should not push their planet.超过了这些极限值,人类就将失去他们的地球家园。

失去?过分诠释。
引用 yannanchen 2012-6-18 10:59
The nine areas of concern were: 这9项边界条件涉及的领域有

参考上一段的 One result of this worry, in the autumn of 2009, was the idea of planetary boundaries

这里的concern = worry , 不是 涉及。
引用 yannanchen 2012-6-18 11:01
intervention in the nitrogen and phosphate cycles (crucial to plant growth);对植物生长至关重要的氮与磷酸盐循环的妨碍;

intervention = interference , 干扰, 不是 妨碍。
引用 yannanchen 2012-6-18 11:04
the conversion of wilderness to farms and cities; 荒野变为农田与城市的转化率

哪有 转化率?
引用 yannanchen 2012-6-18 11:09
For chemicals and particulates, they deferred judgment.他们稍后将提出具体的边界值。

稍后?这暗示着后来给出了边界值, 不一定吧?
他们不愿马上给出具体的边界值。

引用 szseat 2012-6-18 11:32
yannanchen: planet-wide environmental boundaries, 地球环境边界条件这个-wide 没有翻译出来地球全球性的环境边界

这样是否更简洁:全球地表环境边界  
引用 yannanchen 2012-6-18 12:14
本帖最后由 yannanchen 于 2012-6-20 01:03 编辑

Planetary boundaries provide a useful way of thinking about environmental change, because in many cases they give scope for further change that has not already happened. That has brought the concept friends who are not normally persuaded by environmental thinking, as well as green enemies who will brook no compromise. But the concept has numerous drawbacks. The actual location of the boundaries is, as their proponents acknowledge, somewhat arbitrary. That is partly because of the incomplete state of current knowledge, but it may remain so however much anyone knows. Some boundaries might be transgressed without irreversible harm occurring. Some may have been drawn around the wrong things altogether. And some academic opinion holds that spectacular global change could come about without breaking through any of them.地球环境边界条件的概念为人类思考环境变化问题提供了一种有效的手段。在许多情况下,人们都可以借助这种手段预先觉察到地球环境尚未出现的变化。这是一个很少考虑环境问题的朋友们可以接受的概念;同时这又是一个能与对环境保护持敌意的人达成妥协的概念。但这个概念尚有众多的缺陷。正如这个概念的倡议者们所知,给出的边界值有些武断。其部分原因是人类目前的知识水平所限,但人们不知道这种状况还要持续多长的时间。也许有些边界值被突破却不会引发不可逆转的灾难;也许有些边界值的设定完全错误。一些学术观点认为,即使这些边界条件全都没有被突破,地球环境也很可能发生巨变。

评论:That has brought the concept friends = that has brought friends to the concept
这里的concept = the concept of  planetary boundaries
这里的 that = scope (for further change that has not already happened 。)
That is partly because of the incomplete state of current knowledge, but it may remain so however much anyone knows其部分原因是人类目前的知识水平所限,但人们不知道这种状况还要持续多长的时间。
这个理解 不对。这里的it=the incomplete state of current knowledge

My translation:

地球环境边界条件的观念为思考环境变化问题提供了一种有用的手段, 因为,在许多情况下,这个观念可以为那些尚未发生但是仍可发生的进一步变化给出许可的余地。这就为环境边界条件的观念赢得了一些在正常的情况下不为环保观念所动的朋友,尽管这也制造了一些致力环保的敌人,这些人在环保问题上绝不妥协半分。可是这个概念尚有众多的缺陷。正如这个概念的提倡者都承认的那样,实际给出的边界值多少有些武断。其部分原因是人类目前的知识水平所限,不管哪个人知道了多少, 这种知识水平有限的状况还可能要长期持续下去。
引用 yannanchen 2012-6-18 12:40
green enemies 很费斟酌。
是环保的敌人(反对环保的),还是 为了环保而成为敌人? 这里我觉得是后者。 欢迎批评。
引用 dqzxf 2012-6-18 18:10
本帖最后由 dqzxf 于 2012-6-18 18:18 编辑
yannanchen 发表于 2012-6-18 11:09
For chemicals and particulates, they deferred judgment.他们稍后将提出具体的边界值。

稍后?这暗示着 ...

defer:put off (an action or event) to a later time; postpone. 推迟,延迟

1) they deferred the decision until February.
2) The decision has been deferred by the board until next week.

依我的理解,前7项指标他们有自信现在就给出极限值。而这两项指标他们还要研究一段时间之后才能给出。如果他们都认为无法给出具体的边界值,那提出这9项指标也就没有意义了。
引用 yannanchen 2012-6-18 19:06
Some boundaries might be transgressed without irreversible harm occurring. Some may have been drawn around the wrong things altogether. And some academic opinion holds that spectacular global change could come about without breaking through any of them.也许有些边界值被突破却不会引发不可逆转的灾难;也许有些边界值的设定完全错误。一些学术观点认为,即使这些边界条件全都没有被突破,地球环境也很可能发生巨变。
评论:Some may have been drawn around the wrong things altogether也许有些边界值的设定完全错误------这里存在理解错误。
前文提到nine areas of concern, 所谓设限, 是对这9大人类所关心的范畴设限。 但是, 有人提出不同的看法,这9大范畴中的个别,恐怕是完全选定错误。
Some may have been drawn around the wrong things altogether = some boundaries may have been drawn around the wrong areas of concern altogether.

引用 yannanchen 2012-6-18 19:13

The second is that the planetary-boundaries group derives most of its limits by looking at conditions during the Holocene。第二个观点是,大多数地球环境边界条件值是依据对全新世地球状况的考察而得出。

The planetary-boundaries group-------what is this? Please refer back to

In the run-up to that year’s climate conference in Copenhagen a group of concerned scientists working under the auspices of the Stockholm Resilience Centre, in Sweden,
引用 yannanchen 2012-6-18 19:35
Nitrate-rich run-off, for example, can wreck the ecology of lakes.

这里指的是类似中国太湖那种蓝藻疯长的情况。周围农田施用氮肥, 水土流失, 或田水溢流之后, 进入太湖, 亚硝酸盐刺激藻类疯长,直到掩盖了整个湖面。
引用 yannanchen 2012-6-18 19:43
get/put/stick your oar in  (British & Australian informal)
to involve yourself in a discussion or a situation when other people do not want you to I don't want Janet coming to the meeting and sticking her oar in - she knows nothing about the situation.


这份报告就像一颗投入水中的石子,激起了阵阵涟漪??????
引用 yannanchen 2012-6-18 19:53
carbon-dioxide levels pushing 400ppm

不是高达,而是接近
引用 yannanchen 2012-6-18 19:57
Either way, the climate boundary is one that already lies squarely in humanity’s rear-view mirror.

在后视镜里,意思是气候的边界条件已经被侵越,
引用 dqzxf 2012-6-18 20:54
yannanchen 发表于 2012-6-18 12:40
green enemies 很费斟酌。
是环保的敌人(反对环保的),还是 为了环保而成为敌人? 这里我觉得是后者。 欢 ...

刚才看了一篇文章,应该代表了美国极右翼的观点。但透彻了解了这个单词的意思。

We are witnessing an environmental attack on American energy and, ultimately, on America
America’s Green Enemies
        - Alan Caruba Saturday, February 11, 2012

It was good news that the Nuclear Regulatory Commission approved the nation’s first nuclear power plants on February 9th, clearing the way for the construction of two reactors by Southern Company at its Plant Vogtle site near Atlanta, Georgia. The bad news is that these are the first new nuclear plants since 1978!
In a nation with a growing population and increasing need for electricity to power homes and businesses, it is nothing less than insane to not include nuclear energy in the mix of providers. Environmentalists immediately attacked the announcement using the usual scare campaigns.
Equally insane is the failure to provide the means to safely store the radioactive materials that result. Highly contested by environmentalists, the Nevada-based Yucca Mountain deep geological repository storage facility for spent reactor fuel was cancelled in 2009. Nevada’s Senator Harry Reid, Majority Leader in the Senate, played a major role in this disgraceful decision. The Obama administration terminated funding for the development of the site in 2011, leaving the nation with no long-term storage site.
In a similar fashion, the U.S. Environmental Protection Agency has waged a long war on the provision of energy; most recently with the imposition of its Utility MACT rule on plant carbon dioxide (CO2) and mercury emissions, neither of which pose any threat. Sen. James Inhofe (R-OK), ranking member of the Senate Committee on Environment and Public Works, decried the rule as one “intended to undermine the viability of coal, one of our country’s most abundant and reliable energy sources.”
Despite having spent billions to meet the demand for upgrades of the technology to trap such emissions, coal-fired plants all over the nation are in the process of being closed as a result of the MACT rule. These “greenhouse gas” rules are baseless insofar as CO2 is not a pollutant and is vital to the growth of all vegetation on the planet. There is no proof that minor mercury emissions represent any threat to public health.
The EPA use of bogus “computer models” to support wild health claims argues for an end to this agency and the return of its responsibilities to state environmental agencies.
In January, the American Electric Reliability Corporation (NERC), the leading authority, warned that “environmental regulations are shown to be the number one risk to reliability over the next one to five years.”
The Institute for Energy Research has stated that “Beyond the 38 gigawatts of electricity capacity that has already been announced to retire, NERC estimates that another 36 to 59 gigawatts of capacity will come off-line by 2018, depending on the ‘scope and timing’ of EPA regulations. Together, nearly a quarter of our coal-fired capacity could be off-line by 2018, marking the first time in energy history that installed coal-fired capacity has declined.”
This is a threat to the viability and security of a nation that sits atop the largest deposits of coal in the world! It is a nation in which coal provides 50% of its electricity.
In a similar fashion, environmentalists, after a long propaganda war against coal, have launched an equally massive campaign against natural gas, attacking the use of “fracking”, a technology that has been safely used for the last fifty years or more to access equally vast reserves of natural gas.
Likewise the cost of automobiles has been systematically driven up by the wholly false EPA assertion that their CO2 emissions represent a threat to clean air. The imposition of a mandate to mix gasoline with ethanol has resulted in greater CO2 emissions while, at the same time, reducing the mileage of cars. In addition, the use of food crops like corn for the production of ethanol, have driven up food prices.
Anyone who has lost electricity due to a blizzard or a hurricane knows how totally dependent the nation is on reliable and affordable electricity, and knows how totally dependent they are on is provision.
The simple fact is that the present and prior administration’s EPA, the Department of Transportation, and others have been lying to Congress and the American public for years regarding their claims about air pollution and energy provision. The Interior Department just put uranium-rich acres of land off-limits to mining.
Environmental organizations and special interest groups like the American lung Association are a fifth column of enemies within the nation.
The global warming hoax—now called climate change—is on its last legs. Nations around the world that have wasted billions on the claims made for “renewable” energy, solar and wind, are pulling back from further support. The “science” behind these claims has been totally and utterly refuted.
Even the United Nations, the source of the global warming hoax, is now switching its debased claims to a new hoax based on so-called endangered species.
The loss of tens of thousands of jobs in the energy and transportation sectors, as well as energy-intensive industries, is incalculable. EPA demands and mandates are deliberately undermining the nation’s economy.
The lives and safety of Americans are under attack by environmental organizations and, if they are successful, the only outcome would be the deaths of millions here and around the world from hunger and the lack of power to turn on the lights, heat and cool homes, and power industries.
The planet is not running out of oil, coal, or natural gas. It can use more nuclear power, not less.
We are witnessing an environmental attack on American energy and, ultimately, on America.

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