The world's oceans have warmed 50 percent faster over the last 4

The world's oceans have warmed 50 percent faster over the last 40 years than previously thought due to climate change,Australian and US climate researchers reported Wednesday．Higher ocean temperatures expand the volume of water,contributing to a rise in sea levels that is covering small island nations and threatening to destroy the low-lying,densely-populated low regions around the globe. The study,published in the British journal Nature,adds to a growing scientific chorus of warnings about the pace and consequences rising oceans．It also serves as a corrective to a massive report issued last year by the Nobel-winning UN Intergovernmental Panel on Climate Change(IPC C),according to the authors. Rising sea levels are driven by two things:the thermal expansion of sea water,and additional water from melting sources of ice．Both processes are caused by global warming．The ice sheet that sits atop Greenland,for example,contains enough water to raise world ocean levels by seven meters,which would bury sea-level cities from Dhaka to Shanghai. Trying to figure out how much each of these factors contributes to rising sea levels is critically important to understanding climate change,and forecasting future temperature rises,scientists say．But up to now,there has been a puzzling gap between the projections of computer-based climate models,and the observations of scientists gathering data from the oceans. The new study,led by Catia Domingues of the Centre for Australian Weather and Climate Research,is the first to reunite the models with observed data．Using new techniques to assess ocean temperatures to a depth of 700 meters from 1961 to 2003,it shows that thermal warming contributed to a 0.53 millimeter-per-year rise in sea levels rather than the 0.32 mm rise reported by the IPC C. What was the main finding of the study?
A、The warming of the world's oceans is not a threa
B、That not enough is being done about global warmin
C、There is a puzzling gap between the model and observation
D、Ocean waters have warmed faster than scientists had previously though
【正确答案】：C
【题目解析】：经过仔细阅读给出的文章，我们可以看到文章首先提到了一个重要发现：“在过去的40年里，由于气候变化，世界海洋变暖的速度比以前认为的快了50%”。这是一个重要的发现，但我们需要确定这是否是文章的主要发现。 接下来，文章详细描述了这一发现的影响，如海水温度的上升导致海水体积膨胀，从而导致海平面上升，进而覆盖小岛屿国家并威胁全球低洼、人口稠密的地区。这些描述是对主要发现影响的解释，而不是主要发现本身。 文章还提到了IPCC（联合国政府间气候变化专门委员会）去年发布的一份报告，并指出新的研究是对该报告的修正。这也说明了新研究的重要性，但并非主要发现。 然后，文章讨论了海平面上升的两个主要原因：海水热膨胀和融化水源的额外水分，并强调了全球变暖是这两个过程的原因。但同样，这只是对海平面上升原因的描述，而不是文章的主要发现。 文章进一步提到，科学家们试图弄清楚每个因素对海平面上升的贡献量对于理解气候变化和预测未来气温上升至关重要。但这里的关键是“但到目前为止，基于计算机的气候模型的预测与科学家从海洋中收集数据的观测之间存在一个令人困惑的差距”。这一点是对主要发现的具体阐述，并且后面的新研究正是为了弥补这一差距。 最后，文章描述了新研究是如何首次将模型与观测数据结合起来的，并给出了新的评估结果。但这仍然是对主要发现的详细解释和进一步支持，而不是主要发现本身。 综合以上分析，我们可以看出，文章的主要发现是：“但到目前为止，基于计算机的气候模型的预测与科学家从海洋中收集数据的观测之间存在一个令人困惑的差距”。因此，正确答案是C：“模型与观测之间存在令人困惑的差距”。而D选项“海洋水温上升的速度比科学家以前认为的要快”虽然是一个重要发现，但并非文章的主要发现。