譯/江昱蓁
極端氣候惹禍 全美橋梁崩塌風險增
On a 35°C day this summer, New York City's Third Avenue Bridge, connecting the Bronx and Manhattan, got stuck in the open position for hours. As heat and flooding scorched and scoured the Midwest, a steel railroad bridge connecting Iowa with South Dakota collapsed under surging waters. In Lewiston, Maine, a bridge closed after the pavement buckled from fluctuating temperatures.
紐約市連結布朗克斯與曼哈頓的第三大道橋，在今夏氣溫達攝氏35度的某天卡在開啟狀態數小時。隨著高溫與洪水席捲中西部，連結愛荷華州與南達科他州的一座火車鐵橋因河水暴漲而坍塌。在緬因州路厄斯頓市，氣溫起伏導致路面變形，一座橋梁被迫封閉。
America's bridges, a quarter of which were built before 1960, were already in need of repair. But now, extreme heat and increased flooding linked to climate change are accelerating the disintegration of the nation's bridges, engineers say, essentially causing them to age prematurely.
四分之一美國橋梁建於1960年以前，原已需要整修。但如今有關氣候變遷的極端高溫與更頻繁洪水正加速該國橋梁解體，工程師說，實質上造成它們提前老化。
The result is a quiet but growing threat to the safe movement of people and goods around the country, and another example of how climate change is reshaping daily life in ways Americans may not realize.
結果是對全美民眾和貨物的安全運輸帶來寂靜但與日俱增的威脅，也再次顯示氣候變遷正以美國人可能沒有發覺的方式重塑日常生活。
"We have a bridge crisis that is specifically tied to extreme weather events," said Paul Chinowsky, a professor of civil engineering at the University of Colorado Boulder who researches the effects of climate change on infrastructure. "These are not things that would happen under normal climate circumstances. These are not things that we've ever seen at this rate."
研究氣候變遷對基礎設施影響的美國波爾德科羅拉多大學土木工程教授奇諾斯基說，「我們正面臨一場與極端氣候事件緊密相連的橋梁危機。這不是正常氣候條件下會發生的事情，這不是我們曾見過以這種速度發生的事情」。
Bridges designed and built decades ago with materials not intended to withstand sharp temperature swings are now rapidly swelling and contracting, leaving them weakened.
幾十年前設計與建造的橋梁，使用的建材並未預期須承受氣溫劇烈變化，如今快速熱漲冷縮讓其變得脆弱。
"It's getting so hot that the pieces that hold the concrete and steel, those bridges can literally fall apart like Tinkertoys," Chinowsky said.
奇諾斯基表示，「氣溫變得這麼熱，支撐混凝土與鋼材的組件和那些橋梁可能像積木一樣解體」。
As temperatures reached the highest in recorded history this year, much of the nation's infrastructure, from highways to runways, has suffered. But bridges face particular risks.
隨著今年氣溫創歷史新高，從高速公路到機場跑道，全美許多基礎設施受到影響，但橋梁面臨特別的風險。
A study in the journal PLOS ONE found that extreme temperatures resulting from climate change could cause 1 in 4 steel bridges in the United States to collapse by 2050. By 2040, failures caused by extreme heat could require widespread bridge repairs and closures, researchers found.
刊載於PLOS ONE期刊的一項研究發現，到2050年，氣候變遷導致的極端氣溫恐讓美國四分之一鋼橋坍塌。研究人員發現，到2040年，極端高溫造成的故障，可能導致廣泛的橋梁維修與封閉。
Studies show that climate change has caused more rapid shifts between extreme heat and cold, said Royce Floyd, a professor of engineering at the University of Oklahoma. Those seesawing temperatures can cause pavement to squeeze from both sides onto a span, forcing the road and steel to buckle or crack, or even pushing steel beams out of alignment, Floyd found.
奧克拉荷馬大學工程教授佛洛伊德表示，研究顯示，氣候變遷導致極端熱與冷之間更加迅速轉變。佛洛伊德發現，那些氣溫來回變化，可能造成路面由兩端擠壓橋梁，迫使道路與鋼材彎曲或龜裂，甚至導致鋼梁錯位。
