气候变化与地质工程学

　　Fears of a bright planet

　　地球发光，令人担心

　　Experiments designed to learn more about ways of geoengineering the climate should be allowed to proceed

　　为更好地利用工程学手段研究气候问题所设计的实验应该获准进行下去。

　　SHINY things absorb less heat when left in the sun. This means that if the Earth could be made a little shinier it would be less susceptible to global warming. Ways to brighten it, such as adding nanoscale specks of salt to low clouds, making them whiter, or putting a thin haze of particles into the stratosphere, are the province of “geoengineering”. The small band of scientists which have been studying this subject over the past decade or so have mostly been using computer models. Some of them are now proposing outdoor experiments—using seawater-fed sprayers to churn out particles of the exact size needed to brighten clouds, or spewing sulphur particles from underneath a large balloon 20km up in the sky.

　　发光的物体放在太阳下面会吸收较少的热量。这就意味着如果让地球发一点光的话，受到全球变暖的影响就会小一些。让地球发光的方式，比方说在低空云层上添加纳米级的盐微粒，让云变得更白，或者是将一层薄的雾状物洒向平流层，这些都属于地质工程学的范畴。过去十年左右研究这一领域的一小批科学家主要使用计算机模型，其中一些人现在提出要做室外实验――就是用装有海水的喷雾器射出大量使云彩发光所需的相同大小的粒子，或者从升到距地面20公里处的大型气球下喷洒硫粒子。

　　气候变化.jpg

　　The aims are modest. The scientists hope to understand some of the processes on which these technologies depend, as a way of both gauging their feasibility (can you reliably make tiny puffs of sea salt brighten clouds?) and assessing their risks (how much damage to the ozone layer might a stratospheric haze do, and how might such damage be minimized?). The experiments would be far too small to have any climatic effects. The amount of sulphur put into the stratosphere by the experimental balloon would be 2% of what a passenger jet crossing the Atlantic emits in an hour.

　　这样做的目标并不宏伟。科学家们希望能够了解这些技术所依托的一些过程，也是作为衡量其可行性（能否可靠使用微小的海盐粒子让云彩发光？）和评估其风险（附着在平流层的雾状物会给臭氧层造成多大危害，如何把危害降到最低？）的方式。这些实验对气候变化的影响微乎其微。实验所用的气球投入平流层的硫总量相当于横越大西洋的喷气式客机一小时喷射气体总量的2%。

　　Nonetheless, these experiments—and this whole line of research—are hugely controversial. Many scientists are skeptical about geoengineering and most greens are outraged. Opponents object to them for a range of reasons. Some are against the very idea of geoengineering and any experiments in the area, even those which pose no immediate risk to the environment. They abhor the hubris involved in trying to affect the mechanics of the climate and despair at the potential diversion of attention from controlling carbon emissions as the route to countering climate change. They find the idea of some–possibly many—countries having the power to change the climate for the whole planet a geopolitical nightmare. Even modest experiments in geoengineering, according to this logic, are the beginnings of a slippery slope, one that will engender a false sense of security and domesticate an idea that should have always remained outrageous.

　　尽管如此，这些实验以及整个研究领域存在巨大争议。许多科学家怀疑地质工程学，多数绿党成员感到很气愤。反对的原因很多。一些人反对地质工程学这一学科和涉及该领域的实验，甚至对环境不会立即造成风险的实验也遭到了反对。他们讨厌尽力影响气候机制而产生的傲慢行为，并对应对气候变化过程中可能将注意力远离控制碳排放的行为感到绝望。他们发现，一些（也可能是许多）国家有能力改变全球气候的想法是一个地缘政治的梦魇。根据这一逻辑，即使是很小的地质工程实验也是大灾难的开端，会产生不真实的安全感，并滋生一种永远都令人气愤的想法。

　　Yet caving in to this opposition would raise, rather than reduce, the dangers to the planet. Geoengineering is not an alternative to mitigating climate change by cutting carbon emissions, but it may be needed as a complement to it. Although pressure for cuts in carbon emissions through negotiations such as those currently taking place in Lima is yielding results—witness the recent agreement by China and America on new reduction targets—it has so far been insufficient to the task, and emissions look set to rise for decades yet.

　　然而，向这种反对声音投降会增加而非减少对地球造成的危险。通过减少碳排放来缓解气候变化，地质工程学并不是其备用方案，但可能是一种补充方案。尽管通过协商来解决减少碳排放问题的压力会带来好的结果（例如目前在利马召开的气候变化峰会见证了中美两国制定新的减排目标）,但是到目前为止，这么做是远远不够的，而且排放量还会在几十年里有所增加。

　　Even if emissions do eventually start to fall, the cuts will take decades to have any effect so temperatures are likely to go on going up for some time. Although they have not soared in the past couple of decades as they did in the 1980s and 1990s, there is a fair chance that this year will tie with the hottest on record. The planet is not getting cooler and the pressures on the climate are unlikely to go away. It is therefore not too hard to imagine a world, decades hence, in which emissions are falling but temperatures are rising steeply and the ability to adapt to them has been stretched too far. An additional way to stabilize temperatures might then seem in order. Geoengineering offers that possibility.

　　即使排放量最终真的会开始减少，也要在几十年之后才会见到成效，所以在一段时间内温度还是可能会上升的。尽管过去几十年温度不像上世纪八九十年代那样上升得那么厉害，但是今年很有可能追平过往的最高温度纪录。地球不会降温，气候带来的压力也不可能消失。所以不难想象，几十年后的世界，排放量减少，但是温度陡升，适应这样的环境无法做到。到那时，让温度稳定下来的额外方式似乎可能成形，而地质工程学就会实现这一目标提供可能。

　　Knowledge can be dangerous; ignorance can be worse

　　知识有危险，无知更危险。

　　Research on a question of such gravity will have implications beyond its scientific results. But that is a reason to hold the scientists to high standards, not to duck the experiment entirely. If the research consists of safe, well-conceived experiments designed to improve scientific understanding of the processes involved; if it is conducted by people who openly discuss with the public the implications of their research; if it is funded by bodies that take the need for transparency and debate about the risks inherent in such research seriously: then it deserves to be approved.

　　关于这一严重性问题的研究可能会带来科学以外的结果。但是这是让科学家保持高标准要求而不是完全回避实验的一个原因。如果研究是由安全的，构思缜密的，旨在增强对操作过程的科学理解的实验组成，如果做研究的人公开讨论过研究的意义，如果为实验提供资金的机构能够认真对待研究本身的透明度和所造成风险的讨论，那样的话实验才能获得批准。

　　There are all sorts of reasons why geoengineering may prove impossible, either politically or scientifically. It may be too dangerous to countenance, and the circumstances which might make it an appealing complement to cutting emissions may never arise. But to treat research into the subject as taboo on the basis that ignorance is a viable defense against folly would be a dangerous mistake.

　　地质工程学不可能实现有各种各样的原因，有政治上的原因或者科学上的原因。地质工程的做法太危险，无法获得批准，而将其作为减少碳排放的补充方案也无法实现。但是如果忌讳这一研究领域，原因是无知可以切实地捍卫愚蠢的话，那这就是一个很危险的错误了。