COP26 updates: Countries officially adopt Glasgow Climate Pact

President Joe Biden apologized to fellow world leaders at COP26 for the decision made by his predecessor to pull out of the Paris Agreement. 

Following his planned remarks at the summit, he made unscripted remarks at a smaller session hosted by U.K. Prime Minister Boris Johnson, where he offered a candid apology for the lack of leadership from the U.S. in the climate fight.

"I guess I shouldn’t apologize, but I do apologize for the fact the United States, the last administration, pulled out of the Paris Accord and put us sort of behind on the eight ball," Biden said. 

Biden was forthcoming with world leaders that he will need to convince Congress to approve additional funding to help nations around the world fight climate change.

In June 2017, then-President Donald Trump announced plans to withdraw from the agreement claiming that could be economically detrimental and cost 2.5 million Americans their jobs by 2025.

The withdrawal became official on Nov. 4, one day after Election Day.

Re-entering the Paris Accord was among the first actions Biden took upon swearing in as president on Inauguration Day on Jan. 20. 

-ABC News’ Molly Nagle and Sarah Kolinovsky

Mike Bloomberg, a member of the UN Special Envoy, and Gina McCarthy, the White House's national climate adviser, were some of the guests that joined the Biden administration on stage for the launch of the U.S. Center, a public diplomacy initiative, at COP26.

Highlighting the goal to cut emissions by 50% in nine years by 2030, Bloomberg said the world can't set goals for 2050, a year "which, I at age 79, am not likely to see."

Bloomberg announced Bloomberg Philanthropies' intention to close a quarter of all the world's existing coal plants and cancel all proposed new coal plants by 2025. He also committed $10 million to the “America is All In” coalition to mobilize climate action.

"Of course, now that we have a strong partner in the White House, we can raise the bar higher, we can do more and we can do it faster," Bloomberg said. "What we can't do is sit back and wait for Congress to act."

President Joe Biden addressed leaders at the COP26 conference, declaring that countries need to act and act now.

"It’s simple," the president said. "Will we act? Will we do what is necessary? Will we seize the enormous opportunity before us? Will we, or will we condemn future generations to suffer?"

The upcoming decade will determine whether collective transformative action around the globe will be enough to curb global warming, Biden said. 

"We only have a brief window left before us to raise our ambitions," Biden said, adding that the time frame is "rapidly narrowing."

The effects of the pandemic made "painfully clear" that "no nation can wall itself from borderless threats," Biden said, adding that no one can escape the worse consequences of climate change.

But it is in the self-interest of every country to create green energy and healthier ecosystems for the planet, he said. 

"We’re standing at an inflection point in world history," Biden said. 

Biden stated that the U.S. will be able to meet its ambitious target to reduce emissions by 50% to 52% by 2030 but called on the rest of the world to do the same. 

"We can do this, so let’s get to work," the president said.

Youth climate activist Greta Thunberg has been making has been making her way around the COP26 summit. 

Thunberg was seen meeting with Scotland's First Minister Nicola Sturgeon and also took part in a student-led climate demonstration, leading the rally near the COP26 venue. 

-ABC News’ Maggie Rulli