研究顯示 美西特大乾旱恐數十年都無解

A megadrought has sapped water supplies, ravaged farms and ranches, and fueled wildfires across the American Southwest for going on 25 years. Not in 12 centuries has the region been so dry for so long.

一場持續近25年的特大乾旱導致美國西南部水源供應枯竭，嚴重破壞農場和牧場，並助長野火蔓延。過去12個世紀以來，這個地區從未遭遇過持續這麼久的乾旱。

Now comes worse news: Relief might still be decades away.

現在傳來更壞消息：從乾旱解脫可能還要等數十年。

According to new findings published in the journal Nature Geoscience, the dry spell is no mere bout of bad luck.

刊登在期刊「自然地球科學」的新發現顯示，乾旱並非僅是偶然運氣不好那麼簡單。

Instead, it seems to be the result of a pattern of Pacific Ocean temperatures that is “stuck” because of global warming, said Victoria Todd, a doctoral student in paleoclimatology at the University of Texas at Austin who led the new research.

領導這項新研究的德州大學奧斯汀分校古氣候學博士生維多莉亞．托德表示，相反地，這似乎是全球暖化導致的太平洋溫度模式「停滯」的結果。

That means the drought could continue through 2050, perhaps even 2100 and beyond — effectively, Todd said, for as long as humans keep heating up the planet.

托德表示，這意味著乾旱可能持續至2050年，甚至2100年以後——實際上，只要人類持續使地球溫度升高，乾旱就會持續。

In their study, Todd and her colleagues set out to understand a different dry period in the region’s deep past. For clues, they looked to mud from the bottoms of two lakes in the Rocky Mountains: Stewart Bog in New Mexico and Hunters Lake in Colorado.

在他們的研究中，托德和她的同事著手去了解該地區遠古時期的另一段乾旱期。為了尋找線索，他們研究洛磯山脈兩個湖泊底部的泥土：新墨西哥州的史都華沼澤和科羅拉多州的杭特斯湖。

The waxy coating on a plant’s leaves preserves a chemical signature of the rain and snow that the plant absorbs. So by analyzing the vegetal remains that had accumulated on the lake beds and become entombed in layers of sediment, Todd and her colleagues reconstructed how wet the Rockies had been over the past 14 millennia. They found that winters were dry for thousands of years in the middle of this period.

植物葉片上的蠟質外層保存植物吸收雨水和雪水的化學特徵。所以，透過分析湖床堆積並被層層沉積物掩埋的植被殘骸，托德和她的同事重現過去1萬4000年間洛磯山脈的濕潤程度。他們發現，在這段期間之中，有數千年的冬季是乾旱的。

Todd and her colleagues ran computer simulations of the prehistoric climate during this warm time to see what might have led to such a severe drought in the Southwest. They found that the extra heat gave rise to something striking in the Pacific: a giant blob of warm water extending east from Japan and surrounded on three sides by cool water, including along the West Coast of the United States. The warm blob shifted the band of winds known as the jet stream and deflected storms away from the Southwest.

托德和她的同事使用電腦模擬這段溫暖時期的史前氣候，觀察導致美國西南部經歷如此嚴重乾旱的可能原因。他們發現，額外的熱量在太平洋引起驚人現象：一團巨大的溫暖海水從日本向東延伸，三面被冷水包圍，包括美國西海岸。這團溫暖海水改變被稱為噴射氣流的風帶，使暴風雨偏離美國西南部。

In the warm world of 6,000 years ago, the blob stayed put, drying out the Southwest for thousands of years.

在6000年前那個溫暖的世界，這團溫暖海水停在原地，導致美國西南部乾旱數千年。

And, when Todd and her colleagues ran simulations of the present-day climate, they found that the blob might be stuck in place again — only this time, it appears to be because humans are changing the atmosphere by burning coal, oil and gas.

而且，托德和她的同事模擬當今氣候時，發現這團溫暖海水可能再次留在原地—只是這次，似乎是因為人類燃燒煤、石油和天然氣改變了大氣層。

FBI準備降低招募門檻 探員憂心

The Trump administration is preparing to lower the recruitment standards for FBI agents, eliciting alarm from many agents who worry that the move will undermine the agency’s primary mission of conducting complex investigations and tracking threats to national security.

川普政府正準備降低聯邦調查局探員招募標準，引發許多探員擔憂。他們憂心，此舉將損害聯邦調查局進行複雜調查，及追蹤國家安全威脅的首要任務。

Under a plan pushed by the director, Kash Patel, and his deputy, Dan Bongino, the FBI will start welcoming new classes of recruits who will receive less training and no longer be required to have a college degree, according to people familiar with the plan who spoke on the condition of anonymity to describe it.

熟悉相關計畫的人士匿名描述，計畫由局長巴特爾和副局長邦吉諾推行，FBI將開始招收一批新成員，他們的受訓時數減少、也不再被要求要具備大學學歷。

The shift comes as the agency anticipates losing more than 5,000 employees by September, largely as a result of agents, analysts and others taking severance or early retirement packages offered by the Trump administration to try to reduce the budget.

這項轉變正值該機構預估至9月將流失逾5000名員工之際，主要原因是探員、分析師及其他人員接受川普政府提供的遣散或提前退休方案，以求縮減預算。

Instead of spending about 18 weeks training at the academy in Quantico, Virginia, the group of agents, tentatively scheduled to start in October, will receive eight weeks, according to the people. And the agents will no longer need to fulfill a long-standing requisite for joining the bureau: a bachelor’s degree.

根據消息人士指出，10月在維吉尼亞州匡提科FBI學院的新訓約18周，將縮減為8周。且新探員將不再需要滿足長久以來加入聯邦調查局的必要條件：學士學位。

Lowering recruiting standards will allow the FBI to draw deeper from the ranks of other federal law enforcement agencies, specifically a category of criminal investigators classified in the federal system as 1811s. Investigators with that designation work at dozens of agencies, including Immigration and Customs Enforcement, inspector general offices and the Bureau of Alcohol, Tobacco, Firearms and Explosives.

降低招募標準將使FBI能更深入從各層級其他聯邦執法機構招募人員，特別是從在聯邦體系中被歸類為1811類別的刑事調查員。擁有該職稱的調查人員在數十個機構工作，包括美國移民和海關執法局、總稽核辦公室，以及美國菸酒槍炮及爆裂物管理局等。

The new plan, current and former agents say, seems to be part of a larger effort by Patel to have the bureau focus more on street crime, rather than on complicated cases touching on financial fraud, public corruption and national security. Doing so, they added, will erode the bureau’s reputation as an elite law enforcement agency, known for its selectiveness about its recruits.

現、前任探員表示，新計畫似乎是巴特爾更大圖謀的一部分，旨在讓聯邦調查局更關注街頭犯罪，而非涉及金融詐欺、公共貪腐和國家安全等複雜案件。他們補充，這麼做將侵蝕聯邦調查局菁英執法機構的名聲，該機構以嚴格篩選新成員聞名。

The FBI declined to comment, leaving its reason for the drastic changes unclear, particularly given that Patel has repeatedly promoted the agency’s record recruiting numbers.

FBI拒回應，導致這些劇烈改變的原因仍不明，特別是考慮到巴特爾過去屢屢強調FBI招募人數創新紀錄。