NEW YORK — New York Mayor Bill de Blasio announced a plan Thursday to meet the ‘‘existential threat’’ of climate change by extending a section of the Lower Manhattan coastline as much as 500 feet into the East River.
The mayor said the $10 billion effort to protect Lower Manhattan from flooding by extending the shore between the Brooklyn Bridge and the Battery will be funded partly by private development if federal funds aren’t available.
Officials have been developing schemes to fortify New York City’s waterfront since Hurrican Sandy destroyed thousands of homes and businesses in 2012.
De Blasio said it will cost about $500 million to fortify most of Lower Manhattan from future effects of climate change with grassy berms and removable barriers. But planners determined that protecting the lowest-lying area will require adding more land over several years.
De Blasio, who is contemplating joining the crowded field of 2020 Democratic presidential candidates, said the $10 billion landfill project should be supported by federal funds, but that’s unlikely to happen during the administration of Republican President Trump.
‘‘Lower Manhattan is one of the core centers of the American economy,’’ De Blasio said. ‘‘It’s where the financial capital of the United states is. The security of Lower Manhattan should be a national priority. The fact is it is not. And it’s incomprehensible to me that there’s no sense of urgency from the federal government.’’
The plan to extend the coastline will go through the city’s environmental review process, de Blasio said, but he hopes to avoid ‘‘the endless dragging on that usually accompanies something of this scale.’’