2016年考研英语阅读材料:Curbing climate change

　　ON SEPTEMBER 23rd 120-odd presidents and prime ministers will gather in New York for a UN meeting on climate change. It is the first time the subject has brought so many leaders together since the ill-fated Copenhagen summit of 2009. Now, as then, they will assert that reining in global warming is a political priority. Some may #mit their governments to policies aimed at reducing greenhouse-gas emissions. What few will say is how many tonnes of carbon dioxide these will save―because they almost never do.

　　According to scientists, cutting carbon-dioxide emissions is an essential part of reducing catastrophic risks from climate change. Yet governments are persistently averse to providing estimates of how much carbon a policy saves. That may be because, in countries where climate change is controversial, it makes more sense to talk about the other benefits a scheme offers rather than its effect on carbon. Or it may be that, in countries which are enthusiastic about renewable energy, pointing out that it may not save that much carbon is seen as unhelpful. Or perhaps governments think climate change is so serious that all measures must be taken, regardless of cost (though their overall lacklustre record suggests this is not the case).

　　Whatever the reason, the end result is that while the world's governments have hundreds of policies for tackling climate change, some of them very expensive―China, America and the European Union spend $140 billion a year on subsidising renewable energy―it is hard to say which policies are having the greatest effect.

　　So The Economist has made a stab at a global #parison of carbon-mitigation efforts. Chart 1 is the result. It ranks 20 policies and courses of action according to how much they have done to reduce the atmosphere's stock of greenhouse gases. We have used figures from governments, the EU and UN agencies. As far as we know, this exercise has not been carried out before.

　　First, a health warning: the policies and actions on our list are not strictly #parable. Some are global, some regional and some national. Some are long-standing; some new. A couple are not policies at all, such as the collapse of the Soviet Union, which led to the closure of polluting factories and to inefficient state farms reverting to grassland, locking up carbon.

　　And the numbers almost all #e with caveats. It is fairly easy to estimate how much carbon a new field full of solar cells or a nuclear-power plant saves by looking at the amount of electricity it produces in a year and how much carbon would have been emitted if fossil fuels had been used instead, based on the local mix of coal, gas and oil. But as Paul Joskow of the Massachusetts Institute of Technology has pointed out, the standard “levelised” calculations, which divide the total amount of power a plant will produce over its lifetime by its total lifetime cost, are a poor way to #pare fossil fuels and renewable energy.

　　Other measures have problems, too. Take the effects of fuel-efficiency standards. Would #panies have curtailed their cars' emissions anyway to sell more of them to cost- and mileage-conscious drivers? And how much has better fuel efficiency encouraged drivers to drive farther?

　　A further #plication is that many policies have benefits beyond―or indeed closer to hand than―those they offer in terms of climate. Burning less coal saves lives in the near future as well as reducing climate risks in decades to #e. Saving forests preserves wildlife, not just carbon.

　　So our table should be treated with caution. It is only safe to say that one policy is better than another in climate terms if it beats it by a wide margin.

　　参考译文:

　　9月23日，120多位国家总统和首相将会汇聚纽约联合国总部，就气候变化议题举行会议。这是自2009年一无所获的哥本哈根气候大会之后，国家元首们第一次为了此项议题聚会。就像当时一样，他们如今也一致认为控制全球变暖是政治的头等大事。一些元首们也许会承诺实行以削减温室气体排放为目标的相关政策。但很少人能明确说出这些政策最终将减少多少吨二氧化碳排放量―因为根本没效果。

　　科学家表示，减少二氧化碳排放量是缓解由气候变化导致的灾难性后果的重要一步。但政府自始至终都不愿意预估他们的政策到底能少排多少碳。这也许是因为，在那些对气候变化仍存争议的国家，政府更愿意显示他们实行的其他福利政策是多么有效，而非低碳减排。或者在那些热衷于再生能源的国家，指出政府政策并没有减少那么多碳排放也于事无补。或者政府认为气候变化太重要了，可以不惜一切代价来完成(不过总的来看，根据他们拖拖拉拉的表现，这是不可能的)。

　　不管什么原因，结果就是尽管世界各个政府出台了几百条治理气候变化的政策，有的还代价高昂―中国、美国和欧盟每年花费1400亿补贴再生能源――很难说哪些政策是最有效的。

　　因此，《经济学家》尝试制作了一张全球各国碳减排成果的比较图。图表1是结果，列出了前20个政策和行动方案以及每个政策方案的大气层温室气体的减少量。我们使用了政府、欧盟和联合国各机构公布的数据。据我们所知，以前还没有人做过这样的比较。

　　首先有个温馨提示：本次列出的政策和行动方案严格来说是不可比较的。一些是全球范围的，一些是区域性或国家层面的。一些是长期执行的，另一些是新政。有几条并不能算是政策，比如由苏联解体导致的污染工厂关门、效率底下的国有农场复归草原，锁住了碳。

　　这些数据都显示出了警告信号。很容易估算出一片新铺满太阳能板或盖满核能工厂的旷野减少了多少碳排放，只要看看它每年发了多少电就可以了;另外，根据当地煤、气、油的混合状况也能很简单地估计出如果以化石燃料替代之，将多排放多少碳。然而，正如麻省理工学院的Paul Joskow指出的那样，标准的“水平化计算”――即用一座工厂整个使用年限所耗费的成本除以其产生的全部功率值，并不是一种比较化石燃料和再生能源的好方法。

　　其他的测量方法也有问题。以燃料效率标准为例。司机对成本和公里数很敏感，公司会为了向他们销售更多汽车而减少汽车排量么?更高的燃料利用率又在多大程度上鼓励了司机多开车?

　　更加复杂的是，很多政策所带来的好处不仅仅是治理气候。燃烧更少的煤炭可以在不远的将来挽救很多生命，也能减少未来几十年内气候变化带来的各种危机。拯救森林不止是控制碳排放，也能保护野生动物。

　　所以这次谈判应该谨慎对待。只有当某个政策提供了更多的回旋余地，才能说它是更好的。