The strategy the president plans to outline Monday is at odds with his often-warm relations with the leaders of China and Russia.
Nikki R. Haley, the American ambassador to the United Nations, presented what she said was evidence that Iran was violating one of its international agreements. John Ismay, a Times reporter, said the evidence fell short of proving her claims.
Island states that are least responsible for global emissions but most vulnerable to storms and rising seas are looking outside the United Nations process for aid.
In midday remarks from the White House, President Trump is expected to declare that “America is Back” as he sums up a year of action on the world stage.
After President Trump’s announced withdrawal from the Paris accord, a number of national and local leaders have emerged as climate change champions.
At a panel discussion, former secretaries of state Condoleezza Rice and Madeleine K. Albright coached President Trump’s ambassador to the United Nations.