温哥华因洪水而被气候变化所包围

上周在不列颠哥伦比亚省（以其山区，海岸线和雄伟的森林而闻名的不列颠哥伦比亚省）下降的巨大降雨和大风，迫使17,000人离开家中，清空整个城镇和淹没农场。

Vancouver, Canada’s third-largest city, lost its road and rail links to the rest of the country, cut off by washed-out bridges and landslides.

这是该省六个月来第二次遭受与天气有关的紧急情况，专家说，这两种灾难可能与气候变化有关。

British Columbia has been besieged this year by record-breaking heat, wildfires and floods. The disasters have killed hundreds — including three people in the recent rains — and caused hundreds of millions of dollars in damage. The impact has rippled across Canada after hobbling the province and the port of Vancouver, which is vital to the country’s economy.

“在过去六个月,公元前燃烧和drowned,” said Merran Smith, the executive director of Clean Energy Canada, a climate program at Simon Fraser University in Vancouver. “So there’s really no greater evidence of climate change right now than here in British Columbia.”

In July,记录温度高达121度华氏度带来了干旱和无法控制的野火。高温集中在该省的内部，从6月到八月杀死了595人，开火consumed an entire town.

The floods last week have spared more lives but have destroyed vital infrastructure and left freight to pile up at Vancouver’s port, Canada’s gateway to Asia. The country’s supply lines have been disrupted as well at a time when American ports are too backed up to offer much help.

Experts said that events in this sequence — heat, fire, drought, flood — could produce so-called compound effects.

A drought can dry out vegetation, which in turn can fuel and intensify fires. Fire itself can weaken or kill plants and make the soil less permeable, meaning that rain is more likely to run off rather than soak in, causing flash floods and landslides.

Rachel White, a professor at the University of British Columbia who studies how large-scale atmospheric patterns contribute to extreme weather, said it was impossible to say for sure whether the extraordinary heat and the devastating rains resulted directly from climate change.

她说：“我们需要做更多的研究，以真正尝试了解这里发生了什么。”“这也是气候变化的迹象，还是不列颠哥伦比亚省今年变得非常不幸？”

However, she said, one thing is certain: “These events were made worse because of climate change.”

一个被称为“大气河”的普通天气事件导致该省毁灭性的洪水，并在几个社区创造了降雨记录。一条水分传送带，也许是菠萝快递，是一条相对较窄但非常长的快速移动，充满水分的空气，在夏威夷附近的太平洋中形成。

Normally, such systems release that moisture as intense rain once they reach British Columbia’s coastal mountains and peter out before they enter the dry interior region on the other side. But this atmospheric river was different, said Armel Castellan, a meteorologist with the weather service at Environment and Climate Change Canada.

他说：“这具有太大的效力，以至于它能够骑上那些山脉并真正释放到否则干皮带上。”

U.C.L.A.大气科学教授亚历克斯·霍尔（Alex Hall）补充说，这种现象以其规模而闻名。例如，霍普的内政城镇在52小时内被降雨11.6英寸，比11月整个11月通常收到的降雨量高出三分之一。

“What’s not normal is to have atmospheric river events that are this large,” he said, adding that in terms of rainfall, these events “are nearly equaling the historic record.”

Because the interior region had already had an usually wet fall, the ground was saturated before the storm hit, Mr. Castellan said. Compounding the situation, there was relatively little snow at higher altitudes to soak up water. In addition, the summer of extreme heat, drought and wildfires had left little vegetation to slow or prevent mudslides.

霍尔博士说：“当您设置正确的序列时，您会产生更加极端的条件。”

Human meddling with geography has also made things worse. Much of the fertile farmland near Abbotsford was created 100 years ago by draining the Sumas Lake, a process that forced Indigenous people onto other land. While pumps and levees held back some of the water, the storm last week allowed the lake to reassert itself after a century.

当雨水倒下并关闭道路时，惊慌失措的购物者重新定下了大流行的早期，并清理了几家杂货店，尤其是在温哥华地区。

Rebuilding lost bridges, roadways and railways could take months. But Greg Wilson, the director of government relations in British Columbia for the Retail Council of Canada, said that widespread shortages were not likely in the province. Fresh produce can still arrive on the highway from Seattle, the route much of it usually follows to supply Vancouver this time of year.

周末，温哥华的一条高速公路重新开放到轻型汽车和卡车上，另一条高速公路恢复了一条车道，以进行基本旅行。但是，来自加拿大其他地方的卡车主要是通过绕过美国来到达温哥华。不列颠哥伦比亚省的大部分地区是受击中最严重的地区，仍然通过火车和卡车向加拿大其他地区开放。

威尔逊说：“温哥华地区没有食物的危险。”“会有挑战，但供应很多。”

曼尼托巴大学教授，前运输学院的前主任巴里·普伦蒂斯（Barry Prentice）说，不列颠哥伦比亚省一直是试图减轻气候变化影响的领导者。2008年，它介绍了North America’s first carbon tax.它也采取了身体措施。他说，温哥华的港口已被大约三英尺高，以适应海平面上升的水平。

But province’s mountainous nature, he said, limits what is possible and will make rebuilding a difficult and prolonged process.

“To try and make everything resilient is very hard,” he said. “We don’t have many options for routes coming through the mountains.”

自从温哥华港口将该国与亚洲联系起来以来，重新开放的延误很可能会显着影响整个加拿大，这是用于进口消费品的进口和经济上至关重要的资源出口，例如谷物和钾肥。尽管不列颠哥伦比亚省北部的鲁珀特亲王港口的铁路线仍然向东方开放，但普伦蒂斯教授说，该港口无法在正常行动的基础上实际处理温哥华的所有交通。

While it may be possible to beef up the transportation network during rebuilding, Professor Prentice said that the only long-term solution remained dealing effectively with climate change.

Ms. Smith of Clean Energy Canada said that Prime Minister Justin Trudeau’s government had a credible and ambitious climate plan but that the country had yet to rein in its oil and gas industry, particularly oil sands operations based largely in neighboring Alberta.

“We need to reduce the emissions from the oil and gas sector; it is one of Canada’s biggest challenges,” she said. “All of these other good policies, we need to see them implemented without delays. There’s a lot of inaction that gets disguised as flexibility, and we’re past that time.”

While the water has started to recede in most flood zones, it is unclear when evacuees will return home or abandoned cars will be returned to their owners. And more danger may be ahead for British Columbia. Forecasts predict another batch of heavy rain this week.

Winston Choi-Schagrincontributed reporting.