A handful of major states resisted pressure on Dec. 15 to ramp up efforts to combat global warming as a U.N. climate summit came to a delayed close. The summit talks in Madrid, dubbed COP25, were viewed as a test of governments’ collective will for more aggressive cuts to greenhouse gas emissions. But the conference, in its concluding draft, endorsed only a modest declaration on the “urgent need” to close the gap between existing emissions pledges and the temperature goals of the 2015 Paris climate pact. Brazil, China, Australia, Saudi Arabia, and the United States had led resistance to bolder...