A United Nations (U.N.) conference in New York this week seeks to address climate change and the health of the oceans.

“In most probability this conference represents the best opportunity we will ever have to reverse the cycle of decline that human activity has brought upon the Ocean,” said U.N. General Assembly President Peter Thomson in a Monday statement. “If we want a secure future for our species on this planet, we have to act now on the health of the ocean and on climate change.”

Read: Paris Climate Agreement: Companies, Universities, States Sign 'We Are Still In' Statement

The conference is co-hosted by Fiji and Sweden. Frank Bainimarama, prime minister of the island of Fiji and climate conference president, is especially attuned to the health of the world’s oceans.

“Climate change poses the biggest threat the world has ever known.  And the quality of our oceans and seas is also deteriorating at an alarming rate,” said Bainimarama. “They are interlinked, because rising sea levels, as well as ocean acidity and warmer waters have a direct effect on our reefs and fish stocks and the prosperity of our coastal communities.”

The conference calls for countries to voluntarily agree to sustainability goals that would help slow and possibly reverse climate change in the oceans including sea-level rise, decrease in polar ice caps, deoxygenation and extreme weather events.

The U.N. reported it received over 700 individual commitments to help improve the ocean.

The five-day conference, which started on World Environment Day, takes place just a few block away from Trump Towers, the former home of President Donald Trump. On Thursday, Trump decided to pull the United States out of the voluntary Paris climate accords.

The Paris climate accord is landmark global effort to curb climate change through reducing carbon emissions. Trump hinted at the possibility of rejoining the effort if the deal was renegotiated, but European leaders signaled that it would not.

“This agreement is less about the climate and more about other countries gaining an advantage over the United States,” said Trump in a press conference at the White House Rose Garden. “The agreement is a massive re distribution of United States’ wealth to other countries.”

Former President Barack Obama committed to the pledge, agreeing to lower U.S. carbon emissions by over twenty five percent and giving three billion dollars to the U.N. Green Climate Fund.

The decision was widely panned by world leaders.

French President Emmanuel Macron called on scientists and climate change researchers to come to France to continue their studies.

“We will succeed because we are fully committed,” said Macron in a statement Thursday. “Because wherever we live, whoever we are, we all share the same responsibility, make our planet great again.”

Read: Trump On Climate: Pruitt Says Paris Agreement Ineffective; Gore Says Pullout Reckless 

Some American mayors and governors also committed to follow the accord even if the president would not. In his speech Trump indicated that he represented Pittsburgh not Paris, and Pittsburgh’s mayor took offense to that, pledging that his city would follow the agreement.

“I can assure you that we will follow the guidelines of the Paris Agreement for our people, our economy and future,” said Pittsburgh Mayor Bill Peduto Thursday.