If President-elect Donald Trump holds true to his campaign promise on rolling back key climate change agreements and environmental protections, the future may look bleak for his hometown of New York City.

Philip Orton, an oceanography researcher at the Stevens Institute of Technology in New Jersey, told New York City blog Gothamist Monday that abandoning commitments to reduce greenhouse gas emissions as a part of the Paris Climate Change Agreement would lead to as much as half a dozen feet of sea level rise.

“If we abandon those commitments and we don't do anything about climate change, then by 2100 we are going to have three to six feet of sea level rise and there will be doubts about the future viability for the city,” Orton said.

Sea level rise of that magnitude without mitigating efforts would lead to a doubling of the area that is in danger of a storm like Hurricane Sandy, which devastated the city with blackouts and home damages in 2012.

Trump certainly hasn’t been a friendly voice for climate change activists on the campaign trail and it doesn’t appear that his administration will be any different. Soon after winning the election last week, Trump announced that Myron Ebell, a notorious climate change denier, would run his Environmental Protection Agency transition team.

The Paris Climate Agreement is a United Nations effort to curb the emissions of greenhouse gases globally that was spearheaded at least in part by President Barack Obama and his administration. There are more than 100 countries out of 197 that have signed on, including the United States, China and most of Europe, where the majority of emissions come from. The agreement passed over the necessary threshold to go into full force internationally in October.