評論
打印
Science and Technolgy
科技
Climate change
氣候變化
Good news at last?
最終難道是個好消息？
The climate may not be as sensitive to carbon dioxide as previously believed
氣候對二氧化碳的敏感性，可能沒有原來認識的那樣強
CLIMATE science is famouslycomplicated, but one useful number to keep in mind is "climatesensitivity". This measures the amount of warming that can eventually beexpected to follow a doubling in the atmospheric concentration of carbondioxide. The Intergovernmental Panel on Climate Change, in its most recentsummary of the science behind its predictions, published in 2007, estimatedthat, in present conditions, a doubling of CO2would cause warming of about 3°C, with uncertainty of about a degree and a halfin either direction. But it also says there is a small probability that thetrue number is much higher. Some recent studies have suggested that it couldbe as high as 10°C.
氣候科學的復雜是出了名的，但"氣候敏感度"是已知的一個非常實用、必須被謹記的指標。這一指標用于衡量由于大氣中二氧化碳的濃度增長一倍而引起的溫度變化總量。最近一份聯合國政府間氣候變化專門委員會提交的研究預測報告公布于2007年。該報告預測，按照目前的情況，二氧化碳濃度增加一倍將會導致溫度上升3°C，不確定度為±1.5°C。同時報告指出，還存在一種很小可能性，實際的數字也許比這個值要高很多。一些近期的研究認為這個指標高達10°C。
If that were true, disaster beckons. But apaper published in this week's Science,by Andreas Schmittner of Oregon State University, suggests it is not. In DrSchmittner's analysis, the climate is less sensitive to carbon dioxide than wasfeared.
如果這個情況是可靠的，大限將至。但本周，來自Oregon State University的Andreas Schmittner刊登在《科學》雜志上的一篇論文認為，事實并不是這樣的。在Schmittner博士的研究中，氣候對二氧化碳的敏感性并沒有達到大眾所擔心的水平。
Existing studies of climate sensitivitymostly rely on data gathered from weather stations, which go back to roughly1850. Dr Schmittner takes a different approach. His data come from the peak ofthe most recent ice age, between 19,000 and 23,000 years ago. His group is notthe first to use such data (ice cores, fossils, marine sediments and the like)to probe the climate's sensitivity to carbon dioxide. But their paper is themost thorough. Previous attempts had considered only small regions of theglobe. He has compiled enough information to makea credible stab at recreating the climate of the entire planet.
現有的關于氣候敏感性的研究大都依賴于那些回述至19世紀50年代的氣象站檢測數據。Schmittner博士選擇了非傳統的途徑。他的數據來自最近一次冰河期的高峰，一個距今19000年至23000年間的年代。他的團隊并非第一個采用這種類型數據（來自冰核，化石，海洋沉積物或其他類似情形）來研究氣候對于二氧化碳敏感性的團隊。但原先做這種嘗試的研究團隊僅收集全球很小一部分地區的數據。而Schmittner博士編制了足夠多的信息以制作一個可以信賴的模型用于預計整個地球的氣候變化。
The result offers that rarest of things inclimate science-a bit of good news. The group's most likely figure for climatesensitivity is 2.3°C, which is more than half a degree lower than the consensusfigure, with a 66% probability that it lies between 1.7° and 2.6°C. More importantly,these results suggest an upper limit for climate sensitivity of around 3.2°C.
其結果為氣候科學提供一條珍貴的信息，也許是一條好小心。他的團隊傾向于將氣候敏感度標定為2.3°C，相比公認的數值降低了超過半度，其數值在66%的保證率下介于1.7° C至2.6°C間。更重要的是，氣候敏感度的上限應該是3.2°C。
Before you take the SUV out for acelebratory spin, though, it is worth bearing in mind that this is only onestudy, and, like all such, it has its flaws. The computer model used is of only middlingsophistication, Dr Schmittner admits. That may be one reason for the narrowrange of his team's results. And although the study's geographical coverage isthe most comprehensive so far for work of this type, there are still blankareas-notably in Australia, Central Asia, South America and the northernPacific Ocean. Moreover, some sceptics complain about the way ancient data ofthis type were used to construct a different but related piece of climatescience: the so-called hockey-stick model, which suggests that temperatureshave risen suddenly since the beginning of the industrial revolution. It willbe interesting to see if such sceptics are willing to be equally scepticalabout ancient data when they support their point of view.
當你正為此而興奮地沖入你的SUV來一次飚車，或者諸如此類的行為，稍等片刻，你的大腦應該想一想，這個理論固然有它的瑕疵。Schmittner博士承認，計算機模型的精度僅中等水平。這也許是其團隊結果具有的一個局限性。另一個方面，盡管研究的區域覆蓋范圍在這一領域是最全面的，但仍然存在空白，特別是在澳大利亞，中亞，南美和北太平洋。另外，氣候科學界一些對此持懷疑態度的人質疑，所使用的這些年代久遠的數據，是一堆一個本質上不同但貌似有關聯的片段，一個俗稱為的曲棍球模型的現象。他們認為溫度在工業革命初期，溫度徒然升高。如果這些質疑者使用與懷疑那些年代久遠的數據相同眼光審視他們支持的觀點，這將會是一個非常有趣的現象。
