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Imagine you're on a beach.
想象你正在一片海滩上。
It's flat, it's wide.
一片平滑而宽阔的海滩。
With pristine sand.
脚下的沙石晶莹剔透。
Looks nice, right?
听着就很舒服，对吧？
Unfortunately, many beaches don't look this way.
不幸的是，很多海滩都并不是这幅模样。
They’re narrow, with steep cliffs, and waves breaking close to the property line.
它们不仅很窄，还有陡峭的悬崖，海浪只差一点就能打到沿岸的房屋。
This is a beach that’s experiencing erosion.
这就是一个正在被侵蚀的海滩。
In America, about 80 to 90 percent of sandy coastlines have this problem.
在美国，有大约80%~90%的沙质海滩都有这个问题。
So the government spends billions to expand some of the most rapidly eroding beaches in an effort to defend the coast.
为了保护海岸，政府拨出了数十亿美元的资金扩建那些正在被严重侵蚀的海滩。
But this effort, while effective in the short term, can actually hurt beaches in the long run.
问题是，这一做法虽然从短期来看是很有效，但从长远来看其实是有害的。
It's because every shoreline on the planet is subject to erosion.
这是因为地球上的所有海岸线都很容易受到侵蚀。
Beach erosion occurs when waves and currents remove sand from the shoreline.
海滩侵蚀就是海岸线上的沙子被海浪或水流冲走的现象。
The loss of sand makes the beach narrower and lowers its elevation.
沙子的流失会使海滩变窄，还会降低海拔高度。
This erosion becomes a problem when it reaches structures built by humans along the coast.
侵蚀蔓延到人类在海岸边修建的建筑时，问题就严重了。
Especially for beaches that generate tourism.
尤其是对能带来旅游业的海滩而言。
The visitors enjoy the sandy coasts while the cities and towns nearby enjoy the revenue gained.
游客享受海滩，海滩附近的城镇则享受游客带来的收入。
But the driving factor there is the beach—a place like Miami Beach wouldn’t have the same draw if there weren't lots of sand.
但这一模式背后的驱动因素是那片海滩——没有了大量的沙子，迈阿密那样的海滩就会失去其现有的魅力。
In fact there was a time when it didn’t look this way at all.
事实上，曾经有段时间，迈阿密海滩还真就不是现在这个样子。
In the 1970s, a seawall turned the beach in Miami into a narrow strip.
20世纪70年代，一座海堤将迈阿密的海滩变成了一条狭长的细线。
But by the '80s, the beach in Miami re-emerged nice and wide.
但到了80年代，迈阿密的海滩又回归了。
How? Well, coastal engineers rebuilt it through a process called "beach nourishment."
怎么回归的？原来，海岸工程师通过一种叫作“海滩养护”的办法把迈阿密的海滩给填回来了。
"Beach nourishment is a shore protection strategy to try to counter the loss, the natural loss of sand."
“海滩养护是一种意在抵御流失，抵御沙子的自然流失的海岸保护策略。”
The typical way to do this is with dredging.
典型的海滩养护方法就是疏浚。
Boats will dig up sand from a borrow site and move it onto the beach.
挖沙船从借料点挖出沙子然后将其运到海滩上。
"You'll have a big pipe pump and you'll suck up the sand.
“就用一个很大的管道泵把沙子吸上来。
Then it's transferred to the coastline.
再把那些沙子转移到海岸上去。
Where it's dumped or pumped out onto the beach and then bulldozers move it around to try to mimic what the natural beach was like before the project took place."
把沙子倒在海滩或抽到海滩上后，就让推土机把沙子推到各个位置，为的就是模拟实施这个项目之前，天然的迈阿密海滩的样子。”
The result is a nice wide beach.
一个漂亮而开阔的海滩就铺好了。
The new profile will better defend the property line from damage during more intense weather like storm surge and flood.
新铺的海滩还能帮助岸上的居民更好地抵御风暴潮、洪灾等恶劣天气。
In the United States, beach nourishment is the main strategy used to protect coastal properties from risky erosion.
在美国，海滩养护是保护海岸财产免受危险侵蚀的主要策略。
But there’s a problem. The protection doesn’t last.
问题是，这么做有一个问题——这种保护并不能持久。
As the constant beating of waves and wind takes the sand away from the shore,
随着持续不断的海浪和风将沙子从海滩上刮走，
and soon it looks like it did before the nourishment occurred.
很快，养护后的海滩就会被打回原形。
Every 2 to 8 years, on average, the nourishments need to be repeated.
养护过的海滩平均每2~8年就需要重新养护一次。
Like this beach in Florida.
就比如佛罗里达的这片海滩。
"Well this morning, Lido Beach is under a local state of emergency..."
“今天早晨，丽都海滩已经升级为当地的紧急状态。”
"Just look at how powerful the wind was earlier today..."
“看看今天早上的风有多大……”
"Problem getting worse by the hour."
“形势每时每刻都在恶化。”
Lido Beach, on the Gulf Coast of Florida, got an emergency nourishment in 2018 after damage from storms reduced the beach to a narrow strip.
2018年时，丽都海滩，位于佛罗里达海湾，就因为暴风雨将其变成了一个窄条而进行了紧急养护。
But the beach had already gotten new sand 15 times since 1964.
事实上，自1964年以来，该海滩的沙子已经换了15次了。
And Lido Key isn’t an outlier.
而且，丽都并不是个例。
More than 200 of the 400 miles of critically eroding coastlines in Florida have received one or more nourishments.
佛罗里达州被严重侵蚀的海岸线足有400英里长，其中有200多英里的海岸线都已经进行过至少一次养护。
And across the United States, there have been nearly 3000 known-nourishment events since 1923.
自1923年以来，美国各地已知的海滩养护工程就已经有近3000起了。
The funding for these projects gets a little wonky, but here's what's important:
这些项目的资金还没有那么稳定，但重要的是：
The federal government pays for a lot of these nourishments.
这些项目联邦政府也没少出力。
Up to 65% of the cost.
一个项目甚至就出了65%的资金。
State and local funds will make up the rest.
剩下的费用则由州政府和当地政府补上。
But not all beaches that want or need nourishment will get it.
问题是，并不是所有想要或需要养护的海滩都能得到养护。
The Army Corps of Engineers — the group that approves and designs nourishments —
陆军工兵部队——负责批准及设计养护的单位——
prioritizes defending some beaches over others, based on the potential loss of value.
会根据潜在的价值损失优先养护个别海滩。
According to ProPublica, the Corps only funds nourishments where the expected benefit is 2 and a half times as high as the cost.
ProPublica的数据显示，工兵部队只会拨款给预计收益能达到成本的2.5倍的养护项目。
Poorer communities won’t often meet that criteria.
相对贫困的社区往往都达不到这一标准。
So places like Miami Beach, Florida, and Ocean City, Maryland, are more likely to get a lot of nourishment.
所以，佛罗里达州的迈阿密海滩，马里兰州的海洋城这样的地方才更有可能经常得到养护。
They have the expensive shorefront developments that make the investment worthwhile.
因为他们拥有豪华的海滨开发项目，有能力把投进去的钱赚回来。
And for beaches that don’t make the cut for nourishment, continued erosion can lead to damaged or destroyed property.
那些达不到养护效益门槛的海滩就只能继续忍受侵蚀，继续承担侵蚀可能带来的财产损失或破坏等风险。
Nourishments aren't just about protecting buildings, but also protecting the economies tied to them and the beach.
养护海滩不仅仅是为了保护沿岸的建筑，也是为了保护系于海滩及沿岸建筑的经济。
Consider the 200 million dollars spent on nourishments in Florida from 1995-2001.
从1995年到2001年，佛罗里达州在海滩养护上花了足足2亿美元。
That might seem like a lot of money, until you see the revenue from coastal tourism — it was $21.6 billion in just one year — 2001.
听上去好像很多，但当你发现海滨旅游收益之高——仅2001你那一年就带来了216亿美元的收益——你就不会觉得多了。
On average, the State of Florida generates more than 5 dollars of revenue for every dollar invested in beach nourishment.
平均下来，佛罗里达州在海滩养护上每投资1美元，就能赚到5美元以上的收益。
Which is why nourishment is so appealing.
这就是海滩养护如此令人着迷的地方。
It make economic sense.
因为从经济的角度来讲，这么做是合情合理的。
But they do present one major problem.
不过，海滩养护的确也有一个比较大的问题。
According to research published by the American Geophysical Union, there is a feedback loop.
美国地球物理联盟发表的研究显示，海滩养护存在一个反馈循环。
Nourishment tends to happen along beaches that generally have expansive properties
养护往往都是那些比较具有扩张性质的海滩在养护，
and they also seem to drive development along the same shores, despite the risk of future erosion.
而且，这些地方似乎也在将发展朝着同样的海滩推进，丝毫不顾未来被侵蚀的风险。
"If you were in a place that had nourished its beach,
“如果你去过做过海滩养护的地方你就会发现，
the houses behind that nourishment project were significantly larger, in every case, than in a place that had never nourished its shoreline at all."
那些地方的建筑都要比从来没做过海滩养护的地方的建筑大得多，而且每个地方都是这样。”
Research found that areas with nourished beaches had homes that were about three times bigger than non-nourished ones.
研究发现，做过海滩养护的地区的房屋面积是没有做过养护的地区的房屋的三倍左右。
And this excessive development is a real problem, because it's based on false security.
这种过度开发其实是一个很大的问题，因为它是建立在虚假的安全感的基础上的。
According to the researchers, "beach nourishment may actually mask or reduce the apparent impact of coastal hazards
按照研究人员的说法，“事实上，海滩养护可能会掩盖或缩小海岸灾害的表面影响，
without changing the natural processes that drive them."
实际上却并没有改变造成那些灾害的自然机制。”
In fact, building more property in these areas only increases the potential damage from future erosion.
事实上，在这些地区建造更多的房产只会增加未来侵蚀造成的潜在损失。
So, while beach nourishments protect property and local economies in the short run,
综上所述，虽然海滩养护能够在短期内保护财产和当地经济，
they also trick us into thinking it’s safe to build in places that aren't.
它也会让我们误以为在那些地方修建房屋是安全的，尽管实际并不安全。
Which sets up coastal communities for an ugly reckoning at the shore...sooner or later.
这就等于给沿海社区设了一个圈套……迟早让他们还账。
