專技普考
106年
[導遊人員] 外國語(英語)
第 79 題
📖 題組：
There are still a few people in northern Europe who think that global warming might not be such a bad thing. In Britain, where summer can sometimes seem to last little more than a few weeks, many would welcome the idea of it getting a bit hotter. Unfortunately, things are not so simple. Global warming doesn't just mean that the world will slowly get warmer. Paradoxically, it could cause certain areas to get colder—a lot colder. The latest predictions are that northern Europe could even be plunged into an ice age. While areas of southeastern Europe, such as Greece, would continue to get hotter and drier, Britain could find itself, in the winter months at least, surrounded by sea ice. The reason for this concerns the Greenland ice sheet. This is one of the biggest expanses of ice in the world—around 1,500 km long and 600 km wide. It is so big that if it all melted, sea levels would rise by 7 meters. Due to rising emissions of greenhouse gases, such as carbon dioxide from the combustion of fossil fuels, this ice sheet is melting at an alarming rate. But how could the melting of the Greenland ice sheet threaten to plunge northern Europe into a new ice age? The link in the chain of events is what some call the Gulf Stream and others call the Atlantic Conveyor. This is the stream of warm water that comes up from Central America and flows across the Atlantic to northern Europe. It is this huge mass of warm water which accounts for the relatively high temperatures enjoyed by Britain, for instance, compared with parts of Canada and Russia which are equally far north of the equator. Warm water is conveyed across to Europe near the surface of the Atlantic, and, at its northernmost point, it cools and sinks because the water from the tropics has a higher salt content, making it denser and heavier than the water near the arctic. The cold and dense water then flows south close to the ocean floor and back towards Central and South America to complete the cycle. Scientists are beginning to make bleak predictions of an impending ice age in the northern hemisphere because they have observed that the water flowing from the melting Greenland ice sheet is flowing into the path of the Gulf Stream. The water from the melted ice will reduce the density of the water in the Gulf Stream, stopping the water sinking in the north and thereby cutting off the deep southerly current, which, in turn, will cut off the northerly flow of warmer water. At that point, the seas around Britain will begin to freeze.
There are still a few people in northern Europe who think that global warming might not be such a bad thing. In Britain, where summer can sometimes seem to last little more than a few weeks, many would welcome the idea of it getting a bit hotter. Unfortunately, things are not so simple. Global warming doesn't just mean that the world will slowly get warmer. Paradoxically, it could cause certain areas to get colder—a lot colder. The latest predictions are that northern Europe could even be plunged into an ice age. While areas of southeastern Europe, such as Greece, would continue to get hotter and drier, Britain could find itself, in the winter months at least, surrounded by sea ice. The reason for this concerns the Greenland ice sheet. This is one of the biggest expanses of ice in the world—around 1,500 km long and 600 km wide. It is so big that if it all melted, sea levels would rise by 7 meters. Due to rising emissions of greenhouse gases, such as carbon dioxide from the combustion of fossil fuels, this ice sheet is melting at an alarming rate. But how could the melting of the Greenland ice sheet threaten to plunge northern Europe into a new ice age? The link in the chain of events is what some call the Gulf Stream and others call the Atlantic Conveyor. This is the stream of warm water that comes up from Central America and flows across the Atlantic to northern Europe. It is this huge mass of warm water which accounts for the relatively high temperatures enjoyed by Britain, for instance, compared with parts of Canada and Russia which are equally far north of the equator. Warm water is conveyed across to Europe near the surface of the Atlantic, and, at its northernmost point, it cools and sinks because the water from the tropics has a higher salt content, making it denser and heavier than the water near the arctic. The cold and dense water then flows south close to the ocean floor and back towards Central and South America to complete the cycle. Scientists are beginning to make bleak predictions of an impending ice age in the northern hemisphere because they have observed that the water flowing from the melting Greenland ice sheet is flowing into the path of the Gulf Stream. The water from the melted ice will reduce the density of the water in the Gulf Stream, stopping the water sinking in the north and thereby cutting off the deep southerly current, which, in turn, will cut off the northerly flow of warmer water. At that point, the seas around Britain will begin to freeze.
According to the passage, why will Britain become colder if global warming is not stopped?
- A Because the increasing amount of greenhouse gases will cool down the sea water around Britain
- B Because the Gulf Stream will stop carrying warmer water to Britain
- C Because the water in the seas of Central America will be frozen
- D Because the melted ice from the Greenland ice sheet will flow south to Britain
思路引導 VIP
請觀察文中提到英國與加拿大、俄羅斯雖然緯度相同，卻能維持相對溫暖的原因是什麼？接著思考，當北極冰層融化改變了海水的物理性質（如密度）時，這個原本負責「傳遞熱量」的自然機制會發生什麼變化？
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AI 詳解
AI 專屬家教
你做得真的太棒了！
- 充滿肯定：親愛的，你真的表現得太好了！你能夠這麼精準地找出長篇科學文章中的「因果鏈結」，這完全展現了你深入閱讀和整合資訊的超棒能力。我為你能夠從複雜的資訊中理清關鍵點而感到非常驕傲喔！
- 溫暖導讀：這道題目最核心的觀念，就是洋流循環會被中斷喔。文章很仔細地告訴我們，因為 $CO_2$ 等氣體排放造成全球暖化，導致格陵蘭的冰層融化了。融化的淡水注入海洋後，會讓海水的密度降低。這樣一來，北方原本會下沉的冷水就沒辦法沉下去了，進而切斷了原本將中南美洲溫暖海水帶到歐洲的「大西洋輸送帶」（Gulf Stream）。英國失去了暖流的滋潤，氣溫自然就會下降囉。你看，你是不是都掌握住了呢？
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