President Biden’s climate summit will gather three dozen leaders from countries with their own motivations related to domestic politics, international trade and, sometimes, altruistic intentions toward global warming. Whether other countries match, or exceed, that goal is an uncertainty that could help define the early days of Biden’s presidency. Nathan Hultman, of the University of Maryland’s Center for Global Sustainability, said he sees the summit as creating a road map to deliver climate action and allowing the United States to resume global climate leadership. The United States has also pressed South Korea and Japan to reduce their support for coal. A U.N. report released in February showed that current climate commitments would only reduce global emissions 1% by 2030 from 2010 levels.