Former US Secretary of State John Kerry will act as climate envoy when US President-elect Joe Biden takes office.
Mr Kerry was one of several people named for top positions by the Biden transition team on Monday.
Other key picks included long-time Biden aide Antony Blinken as secretary of state, while reports say former Federal Reserve chair Janet Yellen will be the choice for treasury secretary.
Today, I’m announcing the first members of my national security and foreign policy team. They will rally the world to take on our challenges like no other—challenges that no one nation can face alone.
It’s time to restore American leadership. I trust this group to do just that. pic.twitter.com/uKE5JG45Ts
— Joe Biden (@JoeBiden) November 23, 2020
It comes as calls are growing for Donald Trump to concede the election.
He has made unsubstantiated claims of electoral fraud and is continuing to pursue legal challenges over the result.
Mr Biden is projected to beat President Trump by 306 votes to 232 when the US electoral college meets to formally confirm the winner on 14 December. This is far above the 270 votes he needs.
In a statement following the announcement on Monday, The President-elect said: “I need a team ready on day one to help me reclaim America’s seat at the head of the table, rally the world to meet the biggest challenges we face, and advance our security, prosperity, and values. This is the crux of that team.”
Some of the positions require confirmation in the US Senate.

What about the other roles?
Mr Blinken was nominated as secretary of state – the most important foreign policy position. The 58-year-old was deputy secretary of state and deputy national security adviser during the Obama administration, in which Mr Biden served as vice-president.
He is expected to manage a Biden foreign policy agenda that will emphasise re-engaging with Western allies.

Avril Haines was nominated as the first female director of national intelligence. Ms Haines is a former deputy director of the CIA and deputy national security adviser.
Alejandro Mayorkas was the first Latino nominated to serve as secretary of homeland security. He previously served as deputy secretary of homeland security under President Obama.
Jake Sullivan was named White House national security adviser. Mr Sullivan served as Mr Biden’s national security adviser during Mr Obama’s second term.
Long-time diplomat Linda Thomas-Greenfield was nominated US ambassador to the UN. She also served under President Obama, including as assistant secretary of state for African affairs between 2013 and 2017.