美国国家航空航天局与国家海洋和大气管理局牵头进行的一项研究发现，加利福尼亚州的一些地区正在下沉。洛杉矶和旧金山部分地区海平面上升的高度可能比之前预计的高出了一倍。

Parts of California's coastline around Los Angeles and San Francisco are sinking, which means sea levels could rise more than twice as much as previously predicted in those areas.

Scientists at NASA and the National Oceanic and Atmospheric Administration (NOAA) came to that conclusion after using satellite radar to study ground elevation along the coast of California.

科学家绘制了加利福尼亚沿海城市和中央谷地区的陆地下沉情况（蓝色表示），这些地区的陆地下沉因土壤压实、侵蚀和地下水抽取等因素导致。图源：美国航空航天局地球观测站

在旧金山湾区的圣拉斐尔和福斯特城等下沉热点地区，地面正在以每年超过0.4英寸（1.02厘米）的速度下降。

In sinking hotspots like San Rafael and Foster City in the San Francisco Bay Area, the ground is dropping by more than 0.4 inches per year.

这意味着未来25年，当地海平面可能上升超过17英寸（45厘米），比此前估计的7.4英寸（19厘米）高出一倍多。这两个热点地区都有一部分建在垃圾填埋场上。

That sinking means local sea levels could rise by more than 17 inches in the next 25 years, which would more than double a previous regional estimate of 7.4 inches. Both of these hotspots were partially built on landfill.

研究人员1月29日发表在《科学进展》杂志上的这份研究报告显示，洛杉矶附近类似的填海区域，比如纽波特比奇，下沉速度也有所增长，可能在2050年预计的海平面上升6.7英寸（17厘米）的基础上再增加6英寸（15厘米）。

Near Los Angeles, similar reclaimed areas like Newport Beach are sinking at a rate that is likely to add up to 6 inches to the 6.7 inches of sea level rise predicted for 2050, according to the researchers' study, which was published Jan 29 in the journal Science Advances.

reclaimed /rɪˈkleɪmd/：回收的，再生的；翻造的

研究报告第一作者、美国航空航天局喷气推进实验室的遥感科学家马林·戈沃尔钦在一份声明中说：“在世界许多地方，就像旧金山的填海地区一样，陆地的下沉速度比海洋本身上升的速度还要快。”

"In many parts of the world, like the reclaimed ground beneath San Francisco, the land is moving down faster than the sea itself is going up," study lead author Marin Govorcin, a remote sensing scientist at NASA's Jet Propulsion Laboratory, said in a statement.

研究报告称，陆地的上升和下沉——研究人员称其为“垂直运动”——由板块运动这类自然过程和抽取地下水等人为因素推动。

The rising and sinking of land, which the researchers called "vertical land motion," are driven by natural processes, such as the movement of tectonic plates, and human factors, like the pumping of groundwater, according to the study.

全球范围内，海平面都在随气候变化上升。全球变暖带来的额外热量使冰川和冰盖融化，海洋中的水因此增多，最终把海岸线进一步推向内陆。不断上升的海平面威胁着世界各地的城市和沿海地区。

Globally, sea levels are rising along with climate change. The extra heat from the warming planet melts glaciers and ice sheets and expands the water in the oceans, ultimately pushing coastlines farther inland. These rising seas threaten cities and coastal communities around the world.

垂直运动可能很难预测，但这项研究强调，要预测未来几十年将有多少海洋蔓延至陆地，这是一个需要纳入考量的重要因素。

Vertical land motion can be difficult to predict, but the study highlights that it's an important factor to include in predictions of how much of the ocean will rise onto land in the coming decades.

编辑：左卓

实习生：汪钰宁

来源：参考消息 Live Science 美国国家航空航天局