In a press release, the mayor's office said it would also be setting a goal to divest city funds from fossil fuel reserve owners within five years.
The lawsuit follows the city's announcement that it plans to divest its pension funds from fossil fuel companies.
The lawsuit was filed in the Southern District of NY. Adding to the urgency of this problem, it is estimated that the sea level is rising 50 percent faster around NY than the global average. It said resiliency projects will cost billions of dollars - money the city doesn't have.
Later on Twitter, de Blasio added, "We are fighting for our lives and we will not wait for anyone else to do it for us".
The mayor blamed the oil industry for helping to cause extreme weather events, including deadly Hurricane Sandy. "The companies knew the harm their products were causing but crafted a carefully coordinated strategy to lie to the public so they could continue to profit from their activities". Exxon has rejected the claims.
"I think we're at the point where we need to get over the conversation of who believes and who doesn't, and move to a conversation about solutions", Gerard said, referring to climate change.
ACCF also finds three of the 10 worst performing NYCERS private equity funds this year were focused on supporting Environment, Social and Governance (ESG) ventures. The mayor said oil companies intentionally misled the public about the links between their industry and climate change to protect their bottom lines.
The suit alleges that ExxonMobil, Chevron, Shell, BP and ConocoPhillips bear responsibility for the costs of climate damages due to their outsized contributions to global warming emissions and decades of sowing doubt about the risks of their products. Linda Kelly, senior vice president and general counsel of the National Association of Manufacturers (NAM) called the litigation "misguided" and "politically motivated" and said that it undermined the U.S. manufacturing industry.
New York City has previously announced its intention to honor the Paris climate accord even though President Trump has pledged to withdraw the U.S., the largest historical emitter, from the historic agreement.
San Francisco and Oakland filed similar suits in September against the same five companies. The claim is that ExxonMobil and its peers had a sophisticated understanding of climate change but denied it to the public. Exxon said it's the victim of a vast "conspiracy" and "abuse of government power".
"The bar for being a climate leader has just been dramatically raised", author and Nation contributor Naomi Klein told the conference.
The money is seen as necessary to make NY more resilient against extreme weather events.
"This is what climate leadership looks like", said Michael Brune, Executive Director of the Sierra Club.
Plans by the City of NY to sue and divest $5 billion worth of pension funds from oil companies accused of harming the environment have been heralded as a major step by environmentalists. City officials plan to submit a joint resolution instructing pension fund trustees to begin analyzing how it can be done in a responsible way.
The legal action and the divestment draw perhaps the starkest dividing line yet between NY and the Trump administration on climate change.