◎ 胡立宗

Scientists probed two kilometers through a Greenland glacier to recover the oldest plant DNA on record and discovered that the planet was warmer than believed during the last Ice Age, according to a study.

科學家在格陵蘭冰河下2公里找到現有紀錄最老的植物DNA，發現地球在上次冰河期的溫度比過去認為的還高，一份報告指出。

DNA of trees, plants and insects including butterflies and spiders from beneath the southern Greenland glacier was estimated to date to 450,000 to 900,000 years ago, the remnants of a boreal forest that existed before the Earth cooled.

格陵蘭南部冰河下找到的樹木、植物及蝴蝶、蜘蛛等昆蟲的DNA，年代推估在45萬到90萬年前，是地球進入冰河期前一片北方森林的遺跡。

That sharply altered the previous view that a boreal forest existed in Greenland only as recently as 2.4 million years ago, according to a summary of the study, which is published in the journal Science.

這項發現扭轉了以往的觀點，認為格陵蘭只在240萬年前有北方森林，以後就再也沒有了，刊登在「科學」期刊上的這份研究摘要指出。

The samples suggest the temperature probably reached 10 degrees C in the summer and minus 17 degrees C in the winter.

樣本顯示，夏季溫度可能達到攝氏10度，冬季則在零下17度。

They also indicated that during the last period between ice ages, 116,000-130,000 years ago, when temperatures were on average five degrees C higher than now, the glaciers on Greenland did not completely melt away.

它們也顯示，11萬6000年前到13萬年前的間冰河期期間，即使當時溫度平均比現在高攝氏5度，格陵蘭的冰河都沒有完全融化。

新聞辭典

boreal forest：北方森林，或稱極區森林，環繞北極區呈帶狀分布。

alter：動詞，改變、修改。例句︰Everything altered out of recognition in 10 years. （每件事在10年後都變得完全不一樣了。）

on average：平均、一般而言。例句︰On average, we spent 10 per day at work.（一般而言，我們一天工作10小時。）