譯/陳韋廷 A century ago, the flaming fall foliage in Nova Scotia would have long faded by early November. But today, some of the hills are still as nubbly with color as an aunt's embroidered pillow.
Climate change is responsible, scientists say. As the seasonal change creeps later into the year, not only here but all across the northern United States and Canada, the glorious colors will last longer, they predict — a rare instance where global warming is giving us something to look forward to.
一個世紀前，加拿大諾瓦斯科細亞省火紅的秋天樹葉在11月初以前早已凋謝，而當下一些山丘的顏色仍舊一塊塊的，彷彿姨媽的繡花枕頭一般。
科學家說，這都是氣候變遷造成的。他們預測，隨著一年裡的時序變化來得更晚，不僅這個地方，還有在美國北部與加拿大全境，這壯麗的顏色將持續更長的時間，而這是全球暖化讓我們有所期盼的罕見事例。
"If climate change makes eastern North America drier, then autumn colors will be spectacular, as they are on the Canadian Shield in dry summers, especially the red maples," said Root Gorelick, a biology professor at Carleton University in Ottawa. The Canadian Shield is a broad ring of forests and ancient bedrock that extends hundreds of miles from the shores of Hudson Bay.
Over the very long term, the warming planet may have a negative effect on fall foliage, but even then any adverse impact is uncertain. It is not just an aesthetic question, but an economic one as well: The changing colors drive billions of dollars in "leaf peeping" tourism in Canada and the United States.
渥太華卡爾頓大學生物學教授路特．高利克說：「如果氣候變遷讓北美洲東部變得更乾燥，秋天的顏色將會很壯觀，就像加拿大地盾在乾燥夏季時那般，尤其是紅色的楓樹。」加拿大地盾是由廣大的森林與古代基岩所組成，從哈德遜灣海岸向外延伸數百哩。
就極長期而言，地球日益暖化可能會對秋天的樹葉產生負面影響，但即便如此，任何的不利影響都還難以確定。這不僅是個美學問題，還是個經濟問題：這些顏色的變化為加拿大與美國的「賞葉」旅遊業帶來數十億美元的產值。
"From a peeper's point of view, it's good news," said Marco Archetti, the lead author of a 2013 paper at Harvard on predicting climate change impacts on autumn colors in New England.
We only have to read Henry David Thoreau to know that climate change is pushing the changing colors later into the year. He spent a lot of time tramping around his native Concord, Massachusetts, making notes on how plants changed with the seasons.
哈佛大學2013年發表了一篇預測氣候變遷如何影響新英格蘭秋天顏色的論文，論文的主要作者馬可．阿切堤說：「從觀賞者角度來說，這是個好消息。」
我們只消閱讀梭羅的文字就可以知道，氣候變遷正讓一年中這顏色的變化來得更晚。他花了很多時間在他家鄉麻薩諸塞州康科德附近漫遊，記錄植物如何隨季節而變化。
"In general, peak leaf color in Concord and the surrounding Boston area for these maples is now more typically a week or two later" than what Thoreau observed, said Richard Primack, a biology professor at Boston University. He has been using Thoreau's records and satellite images to track the effect of climate change on local plant cycles.
The Harvard study, which looked at the percentage and duration of autumn color in Harvard Forest in central Massachusetts from 1993 to 2010, predicted that with current climate change forecasts, the duration of the fall display would increase about one day for every 10 years.
波士頓大學生物學教授理查．普瑞麥克說，相較於梭羅所觀察到的，「大體而言，康科德跟波士頓周圍地區楓樹顏色最紅的時節，如今通常晚了一、兩周」。他一直在使用梭羅留下的記錄與衛星圖像來追蹤氣候變遷對當地植物周期的影響。
哈佛大學的這項研究觀察1993年至2010年間，麻州中部哈佛森林內秋葉變色部分的百分比及持續期間的長短，他們根據目前對氣候變遷走勢的預測推估，秋葉變色持續的期間，每十年大約會拉長一天。
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文/張佑生
歐陽修〈秋聲賦〉：「夫秋，刑官也」，可視為秋天對（犯）人的影響；「草拂之而色變，木遭之而葉脫」則是對植物的衝擊。紐時介紹全球暖化對秋季「賞葉」（leaf peeping）活動的影響，日文是「紅葉狩」（Momijigari）、中文常說「賞楓」，英語用法不限於賞楓，賞葉人是leaf peeper。
全球暖化延遲且拉長賞葉季的時間，作者稱為「百害一利」。暖化的影響不僅是一片楓葉一片情的美感體驗（aesthetic），更牽涉到數十億美元獲利的實際問題，美國東北的新英格蘭區是賞葉勝地（leaf peeping destination），每年都大發觀光財：Leaf peeping, the pastime of enjoying autumn foliage, brings in $1bn each year to New England.
Foliage指樹葉，一簇葉子、枝葉、葉叢，為不可數名詞。報導舉例的美國大思想家梭羅，在名著《湖濱散記》（Walden）中提到觀察某處著實怪異的草木（a truly grotesque vegetation）時描述，其枝葉形似建築圖案（architectural foliage）的程度比其他樹葉更古老更具代表性。
