With their extinct cast of characters, the popular animated Ice Age films give the false impression that ice ages have only occurred in the distant past. By definition, an ice age is any cold period with glaciers or ice sheets present. Because you can find glaciers on every continent all year long, we're technically in an ice age. When most people refer to "the Ice Age," they imagine the time around 20,000 years ago when much of Earth was covered with ice. However, scientists specifically call that time a glacial period. In fact, ice ages involve alternating glacial periods (cooling) and interglacial periods (warming). These changes can be gradual or relatively rapid. Because past "warm periods" have lasted about 10,000 years (and Earth has been in one for that long), could we be on the brink of a new "Ice Age"? Perhaps. Some scientists believe that because Greenland is melting into the ocean, higher levels of fresh water may affect normal currents that keep Europe's climate mild. Without the movement of these currents, Europe could begin to freeze. Now, before we start imagining scenes from the Ice Age movies, we must remember that climate change is normal. Earth has experienced numerous cycles of cooling and warming throughout its history. Scientists do agree Earth is seeing higher levels of greenhouse gases than ever before, meaning human activity may be partially esponsible for global warming. However, Greenland could be melting for other reasons: ocean currents, snowfall levels, or Earth's current "warming period." The bottom line is we can't be certain of what will happen to Earth's temperatures next. We'll just have to wait and "feel."
賣座動畫電影《冰河歷險記》裡的絕種動物角色，讓人誤以為冰河時期只發生在久遠的過去。就字面上意義來說，冰河時期指的是地球上被冰河或冰原覆蓋的寒冷時期。由於一整年都能在每塊陸地上發現冰河，所以技術上來說我們是處在冰河時期。 當大多數人提到冰河時期，他們想到的是約兩萬年前地球被冰河覆蓋的那段期間，但其實科學家把那段時期特指為「冰河期」。事實上，冰河時期包含冰河期（冷）和間冰期（暖）兩個階段的冷暖交替，這些改變可以是緩慢，也可以是相當快速的。 由於過去的暖期（warm period）持續了近一萬年（地球也同樣經歷了等長時間的暖期）。我們是 否正進入冰河時期的邊緣呢？也許吧。一些科學家相信，由於格林蘭島（Greenland）冰原融化，大量進入海洋的淡水可能會影響正常的洋流，這些洋流讓歐洲的氣候保持溫暖，如果沒有這些洋流，歐洲也許會開始結冰。 現在，在我們開始想像冰河時期的電影畫面前，我們必須記住氣候變化是正常的，地球已經經歷過很多次冷暖循環的過程。科學家認為地球已累積了比過去多的溫室氣體，這代表著人類活動是導致溫室效應的部分原因。然而格陵蘭的融化也許有其他因素，像是洋流影響、積雪量多寡，或是地球目前遭遇的暖期，都可能是格陵蘭冰原融化的成因。 總之，我們無法預測地球的氣溫下一步會發生什麼變化，只能等待時間過去慢慢體會了。 | 
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