Report Predicts Drastic Rise in New York City's Sea Levels

The need for the Climate Mobilization Act — and other measures to combat climate change — became clear on the sunny morning of Jan. 13, 2024. As the high tide rolled in to Lower Manhattan around 9 a.m., the water kept rising until seawalls were breached and sidewalks were submerged. Ferries to the Statue of Liberty were halted because the boarding area was underwater. Parts of Hudson River Park were also shut down.

This so-called "sunny-day flooding" or "high-tide flooding" is triggered by the gravitational pull of new and full moons that results in exceptionally high tides, and it's exacerbated by rising sea levels. Those levels are expected to rise drastically in the near future — with drastic implications for Lower Manhattan and other low-lying areas of New York City.

A new report from the New York State Climate Impacts Assessment, a science-based investigation into how global warming is affecting New York, predicts that in the next decade, water levels at the southern tip of Manhattan could rise nearly as much as they did in the previous century, increasing by as much as 11 inches by the mid-2030s, The Broadsheet reports.

The report, called "Understanding and Preparing for Our Changing Climate," predicts that by mid-century, sea levels surrounding Lower Manhattan could rise by as much as 19 inches, by as much as 50 inches by the end of this century, and by as much as seven feet by the middle of the next century. The projections factor in multiple drivers of climate change, such as glacial melt and the ensuing rise in sea levels.

The city's Climate Mobilization Act seeks to address these drivers of climate change by forcing building owners, including co-op and condo boards, to reduce their buildings' carbon emissions, which now account for about two-thirds of the city's greenhouse gas emissions.

“While New York City currently experiences approximately 10 high-tide floods per year as measured at the Battery, that number could rise to 60–85 days by the 2040s,” the report notes. “This projection means chronic flooding could affect low-lying coastal neighborhoods once a week or more.” 

The $169-million Battery Coastal Resilience project, which completed its design process last year and is expected to break ground shortly, aims to address these concerns. But if the worst-case predictions contained in the Climate Impacts Assessment prove accurate, the five feet of additional elevation envisioned by the Battery Coastal Resilience designs may offer only a limited reprieve. The seven feet-plus of additional water predicted by this report for the mid-22nd century would overtop these barriers by more than two feet several times each week.