NEW YORK -- United States Secretary of State John Kerry joined other world leaders Friday in New York for the official signing of the Paris climate agreement.
The signing ceremony formalized the agreement member countries reached in Paris last December as part of the United Nations Framework Convention on Climate Change, or UNFCCC. The deal committed world leaders to taking national actions in their countries to reduce emissions by 2020, toward the collective goal of limiting global temperature rise to "well below" 2 degrees Celsius.
Representatives from about 170 countries were expected to participate in the signing ceremony, according to the UNFCCC. Kerry, who came to the stage carrying his toddler granddaughter, signed on behalf of the United States, as President Barack Obama is out of the country.
"When enough people come out and make their voices heard, when they turn their policy into a voting issue, when they work together toward the same real goal, then measurable change is possible," Kerry said in his speech at the United Nations. "Today, as we think of the hard work ahead, I am reminded of Nelson Mandela's very simple words: 'It always seems impossible until it is done.' While it isn't done yet, today we are on the march."
French President François Hollande was the first world leader to sign the document.
Obama and Chinese President Xi Jinping announced last month that both their countries would take part in the signing ceremony, which corresponds with Earth Day. The participation of the U.S. and China is significant, as the two account for more than 40 percent of global greenhouse gas emissions. The agreement goes into force once 55 countries accounting for at least 55 percent of global emissions officially sign.
While significant, the signing ceremony is only another step toward the agreement taking effect. Parties to the agreement will still have to go through the process of joining the agreement, which for most will require processes of approval in their home countries.
A senior State Department official said in a background call with reporters Wednesday that the United States is still going through the process of joining the agreement under executive action, and expects to join "as early as possible this year."
"We’re trying to expedite our internal work to be able to do it quite quickly," he said.
But the signing ceremony is an important step, the official said. "As the drumbeat for climate action continues and more nations join, the agreement moves closer to entering into force," he said.
On Wednesday, a group of businesses, including Google, Ikea, Starbucks and General Mills, lent their support to the signing ceremony.
Climate advocates say that, while largely ceremonial, the signing is consequential. "It's very important every time it's made clear again that governments of the world agreed to aggressive climate goals," May Boeve, executive director of the group 350.org, told HuffPost. "That gives us a chance to push for accountability, to see those commitments followed through."
Watch the signing ceremony here:
This story was updated after the climate agreement was signed.