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Early this week in the Brooklyn neighborhood of Red Hook, New York City Mayor Bill de Blasio championed what officials in his administration are calling a "modern, efficient, state-of-the-art" transit link along the waterfront of Brooklyn and Queens.

Since de Blasio signaled his intention to support the Brooklyn-Queens Connector (BQX) project earlier this month, neighborhood activists and climate experts have raised questions about its feasibility, price tag (currently $2.5 billion), and necessity, with many critics arguing that express busses (into Manhattan) would better serve the low-income communities along the waterfront.

The question of whether the project — which would traverse several low-lying waterfront areas — makes sense from a climate change perspective has not yet been fully scrutinized.

Instead, most news accounts have presented the BQX as a restoration of one leg of the trolley lines that used to be common throughout the boroughs, giving rise to the name of the Brooklyn (trolley) Dodgers. But at the Red Hook press conference, Polly Trachtenberg, the city's transportation commissioner, explained that the project would actually combine both trolleys and light rail.

Promoted by a variety of transportation advocates, the BQX would extend from Sunset Park, Brooklyn to Astoria, Queens along a 16-mile route connecting what the city calls "innovation clusters. The __New York Times' architecture critic Michael Kimmelman and the longtime traffic expert "Gridlock Sam" Schwartz, among others, have come out in support of the project.

At the Red Hook launch, Ydanis Rodriguez, chair of the city council's transportation committee, called the project "sustainable" and "the type of infrastructure investment the city needs in the 21st century."

But some leading climate change specialists are cautioning otherwise. Columbia University geologist Klaus Jacob says that while the proposed BQX project "solves desperate transportation needs, the problem is that it runs along current and future flood zones."

According to the latest report from the New York City Panel on Climate Change (NPCC), which consists of both de Blasio administration officials and leading scientists and urban planners, sea levels are projected to rise 11-21 inches by mid-century, 18-39 inches by the 2080s, and as high as 6 feet by 2100.

Jacob has been a member of the NPCC since it was created by the Bloomberg administration. He cautions against building up low-lying areas of the city until a variety of basic issues are resolved. "The resiliency of all transportation and infrastructure — electric and gas, sewage, etc.— in vulnerable areas needs to be established before large development projects should proceed," he said.

De Blasio, for his part, vows to connect the project to his administration's larger climate change initiatives. Amy Spitalnick, a de Blasio spokeswoman, said, "The BQX, like any new development along the waterfront, will be made climate resilient, and will be fully integrated into the $20 billion resiliency plan underway in Brooklyn, Queens, and across the city."

Councilman Carlos Menchaca, who represents Sunset Park and Red Hook, explained that those communities are engaged in "extensive flood protection, resilience, and environmental justice work that can serve as a model for the BQX plan." However, UPROSE, a leading environmental justice organization based in Sunset Park, cautioned that the project requires a "serious environmental impact analysis" led by the waterfront communities themselves.

The town of Wuppertal, Germany has been operating a monorail since 1901. (Image via Klaus Jacob)

Absent the creation of sea walls along the waterfront (which are not part of the administration's plans), areas like Red Hook will remain particularly vulnerable to flooding. And so one climate-ready solution would be to convert the BQX into a monorail.

Jacob points to many "elegant" examples of elevated rail in low-lying cities such as Kuala Lumpur and Tokyo. Though located on higher ground, the town of Wuppertal, Germany, which is nearby Dusseldorf, offers a particularly handsome monorail, one that's been running since 1901.

Closer to home, elevated tracks in New York City have yielded mixed results. The streets below tend to be dark, cramped, and noisy. And the great urban planner Jane Jacobs argued that areas under expressways and railroads became "border vacuums," walling off neighborhoods from one another.

But the successful renovation of the High Line on Manhattan's West Side recently showed that a repurposed overhead railway passage can help ignite a development boom. One trick for the BQX could be to merge some elements of the High Line's pedestrian-friendly benefits into a functioning railway project.

Spitalnick said there are plenty of design issues to be resolved, making it "incredibly premature to judge" the BQX project at this point.

Jacob offered two related suggestions. One is for the city to conduct a complete technical study, fully estimating the cost of the elevated option. The other is for it to show how the entire project corresponds with the comprehensive planning of the waterfront.

And should it proceed on the ground or in the air, Jacob said, if the BQX is detached from a full blueprint that maps out the waterfront's long-term sustainability, it risks becoming "one more example of short-sighted, short-term planning."