Climate-change leaders and campaigners worldwide welcomed US President Joe Biden's move to rejoin the 2015 Paris Agreement but said Washington must also cut emissions and use its influence to encourage other countries to do the same.

In one of his first acts as president, Biden issued an executive order on Wednesday to bring the United States, the world's second-largest greenhouse gas emitter, back into the global treaty committing nearly 200 countries to halt rising temperatures quickly enough to avoid disastrous climate change.

Washington formally left the Paris accord last year but its role as a heavyweight in global climate negotiations had already stalled...