Ahead of President Trump's expected announcement that the United States was officially withdrawing from the Paris climate change agreement, New York City Mayor Bill de Blasio declared that New Yorkers would "take matters into our own hands" and he would "sign an executive order maintaining New York City’s commitment to the Paris Agreement."

In his final year in office, President Obama took it upon himself to commit the U.S. to cutting greenhouse gas emissions by at least 26% from 2005 levels and handing over billions of dollars to the U.N. President Obama managed to bypass Congress by implementing the agreement via executive order and refusing to call it a formal treaty.

Amid reports that Trump would pull out, De Blasio held a press conference Wednesday to denounce Trump's actions in advance and announce his intention to sign an executive order within the week that would ensure that NYC remains committed to the global warming agreement no matter what the federal government did. The New York Daily News provides some highlights from his grandstanding press conference:

“If cities and towns and counties and states all over the country step up and agree to abide by the Paris agreement, we can forestall the worst,” de Blasio said. “We can stop what President Trump may be about to do from having a devastating effect on our own people.”

“The Paris Accord was the biggest step forward we’ve taken in many many years,” he said. “It’s unconscionable for the President of the United States to step away from it.”

De Blasio cited Hurricane Sandy havoc as an example of climate change’s consequences.

“I want to remind everyone that here in Red Hook we saw the destructive power of nature in the age of climate change,” he said. “We saw this community disrupted so tremendously by something that was directly affected by climate change there’s no question about it.”

De Blasio also issued a series of apocalyptic tweets Thursday warning that withdrawal from the agreement would be "horribly destructive for the planet, the country, and this city." Climate change, he said, would be "a dagger aimed straight at the heart of New York City."

"But we'll take matters into our own hands," he wrote defiantly. "I plan to sign an executive order maintaining New York City’s commitment to the Paris Agreement."

On Thursday, Trump, who has been openly critical of the terms of the deal, fulfilled another campaign promise and announced that the U.S. was withdrawing from the agreement.

"So we are getting out, but we will start to negotiate and we will see if we can make a deal, and if we can, that’s great. And if we can’t, that’s fine," said Trump from the White House Rose Garden.

"In order to fulfill my solemn duty to protect America and its citizens, the United States will withdraw from the Paris climate accord," he said, "but begin negotiations to re-enter either the Paris accord or really an entirely new transaction on terms that are fair to the United States, its businesses, and its taxpayers."

Read more of Trump's statement here.