U.S. President Joe Biden convened world leaders for a two-day virtual climate summit on Thursday to send a message that the U.S. is back and ready to lead. Many of the 40 heads of state who participated had their own message: America needs to do more to convince everyone else that it’s both up to the task and reliable over the long haul.

Biden opened the event by promising to cut U.S. greenhouse gas emissions by at least 50% below 2005 levels by 2030, a clear demonstration that climate is at the center of his agenda. That he did so in front of presidents, prime ministers and a king shows the White House has the influence to draw world leaders together.

The summit was also meant to demonstrate a vast difference with former President Donald Trump, who pulled the U.S. out of the Paris Agreement and systematically rejected the threat of climate change. Perhaps the biggest departure came when Biden reappeared to promise a doubling of the U.S. spending toward international climate goals. Annual spending will rise to $5.7 billion by 2024-assuming he can get Congress to go along. Even that, however, may not have been enough to change minds.