U.S. President Joe Biden delivers his inaugural address after he was sworn in as the 46th president of the United States in Washington, D.C., the United States, on Jan. 20, 2021. (Xinhua/Liu Jie)

"We are going to combat climate change in a way we have not done so far," U.S. President Joe Biden said.

WASHINGTON, Jan. 20  -- U.S. President Joe Biden on Wednesday signed an executive order returning the United States to the 2015 Paris Agreement on climate change.

Hours after being sworn in as the 46th President of the United States, Biden signed in the Oval Office an executive order that returns his country back to the Paris Agreement on climate change, reversing his predecessor Donald Trump's decision to abandon the deal.

"We are going to combat climate change in a way we have not done so far," he said before the signing.

UN Secretary-General Antonio Guterres on Wednesday welcomed the new U.S. administration's announcement to re-enter the Paris Agreement on climate change.

"I warmly welcome President (Joe) Biden's steps to re-enter the Paris Agreement on climate change and join the growing coalition of governments, cities, states, businesses and people taking ambitious action to confront the climate crisis," said Guterres in a statement.