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热刺和ac米兰哪个强: 加州野火為什么越燒越猛?與氣候有關系,但原因并不簡單

热刺贝尔 www.gyplwd.com.cn 巴益明(Eamon Barrett) 2019年11月05日

盡管我們很容易將火災的爆發與氣候變化聯系在一起,但二者的關聯并不總是那么簡單。

森林大火正在摧毀加利福尼亞州。

多場大火正在加利福尼亞州肆虐,其中索諾瑪縣的金卡德大火(Kincade Fire)波及的范圍達到了兩個舊金山的面積。大約18萬人被要求撤離,9萬棟建筑遭到威脅,而加州最大的能源供應商太平洋煤氣電力公司(Pacific Gas & Electric)近幾周來第三次燈火管制,切斷了超過94萬用戶的供電。

加利福尼亞州每年大火的嚴重程度似乎有上揚態勢,盡管我們很容易將火災的爆發與氣候變化聯系在一起,就像加利福尼亞州的前州長杰里·布朗所做的那樣,但二者的關聯并不總是那么簡單。

哥倫比亞大學(Columbia University)的大氣科學家和極端天氣與氣候倡議(Initiative on Extreme Weather and Climate)項目負責人亞當·索貝爾在《紐約時報》(New York Times)上寫道,近年來大多數登上頭條的火災都發生在秋季,因此氣溫并非重要因素。索貝爾還指出,隨著全球變暖的繼續,加劇火災的迪亞波羅和圣塔安娜的風力現象未來會越來越不常見。

然而,卻有證據顯示氣候變化加劇了加利福尼亞州的干旱狀況,盡管問題的矛頭也可以指向規模高達500億美元的農業市場,它們消耗了干旱州40%至80%的水資源。

無論如何,干旱導致了樹木枯死,又抽干了落葉的水分,森林也就變成了干燥的易燃物。我們需要盡量縮小這些危險區域,然而根據美國林務局(U.S. Forest Service)的報告,聯邦對于伐木的限制導致加利福尼亞州的林木采伐量從20世紀80年代至2012年減少了超過70%,密集的死亡森林面積在不斷增長。

去年致命的加利福尼亞州大火發生之后,總統特朗普在推特上表示,火災的原因是“森林的嚴重管理不善”。自然,這條推文引發了爭議。州長布朗和州里的消防員很快表示特朗普的理論是“無知的”。不過布朗承認,森林管理由聯邦政府而非州政府負責,是問題的“一大因素”。

基礎設施管理是另一大因素:過去三年里,州能源供應商太平洋煤氣電力公司的落地電線已經引發了多起火災,而目前的金卡德大火可能也是因為類似事故導致。不過至少據我所知,更有趣的一點在于,人類的居住范圍距離著火區域之近也是前所未有,這導致自然火災成為了致命的威脅。

據Vox報道,隨著城市開始向鄉間擴張,加利福尼亞州有1,130萬的居民住在“林野-城區交界”區域,占全州人口的30%。令人震驚的是,超過270萬的加利福尼亞人住在“火災隱患極高的區域”,這個數字預計還會增長。

波莫納學院(Pomona College)環境分析教授、森林火災政策專家查爾·米勒去年對《太平洋標準》(Pacific Standard)表示:“加利福尼亞州是火災常發地,這很正常。現在的困境不在于火災,也不在于它燒毀的東西,而在于人類如今大量居住在火災隱患區,將自己陷于危險之中?!保ú聘恢形耐?/p>

譯者:嚴匡正

Wildfires are devastating California.

Multiple infernos are blazing across the state and one, the Kincade Fire in Sonoma County, has consumed an area twice the size of San Francisco. Some 180,000 people are under evacuation order, roughly 90,000 buildings are at risk and the state’s largest energy supplier, Pacific Gas & Electric (PG&E) has implemented blackouts for the third time in as many weeks, cutting power to over 940,000 customers.

The severity of California’s annual blazes appears to be on the rise and while it’s tempting to draw a line connecting the fire outbreaks with climate change—as former California Governor Jerry Brown does—the correlation is not always so simple.

Adam Sobel, an atmospheric scientist and director of the Initiative on Extreme Weather and Climate at Columbia University, writes in the New York Times that the most headline-catching blazes of recent years have come in fall when temperature is less of a factor. Sobel also notes that the Diablo and Santa Ana wind phenomena that have fanned those wildfires are expected to grow less common as global warming continues.

There is evidence, however, that climate change has increased drought in California—although the finger of blame could also be pointed at the $50 billion agricultural industry that consumes between 40% and 80% of the arid states water supply.

Either way, drought causes tree death and dries out the fallen, turning patches of forest into dried-out kindling. Those hotspots need to be thinned but, according to a U.S. Forest Service report, federal restrictions on logging caused timber harvesting in California to reduce over 70% between the 1980s and 2012, allowing dense, dead forest patches to grow.

After deadly wildfires in California last year President Trump took to Twitter and asserted that “gross mismanagement of the forests” was the cause of the blaze. Naturally, that was a controversial tweet. Governor Brown and state firefighters were quick to dismiss Trump’s theory as “uninformed” but Brown admitted forest management—a large swathe of which is handled by federal, not state, government—is “one element” of the problem.

Infrastructure management is another: fallen power lines managed by state energy provider PG&E have caused numerous fires in the past three years and the ongoing Kincade fire is suspected to have been caused by a similar mishap. But one of the more interesting issues, at least to my ears, is that humans are simply living closer to fire zones than ever before—turning natural fires into fatal threats.

According to reporting by Vox, some 11.3 million Californians, or 30% of the state population, live in “wildland-urban interface” areas where the city sprawls into the countryside. Shockingly, over 2.7 million Californians live in “very high fire hazard severity zones” and that number is expected to rise.

Char Miller, a professor of environmental analysis at Pomona College and an expert on wildfire policy told Pacific Standard last year, “California is one of those places where fire is normal and it should happen. The dilemma is not the fire, and it isn’t the stuff it burns—it’s the fact that human beings are now living in fire zones at an unhealthy rate and putting themselves in danger.”

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