Trump became the 47th president of the United States in a rare indoor inauguration ceremony. Trump became the 47th president of the United States in a rare indoor inauguration ceremony. Equally important is the need to promote multilateralism as the foundation for addressing climate change and other global challenges. It's critical for the international community to know that climate action will continue in the US Climate Alliance will bring this message to the United Nations Climate Change Conference in Brazil (COP30) later this year." Sitting on the sidelines also means the United States will have fewer levers to hold other major economies accountable for living up to their commitments.