PARIS—President Barack Obama and Microsoft co-founder Bill Gates will launch a multi-billion-dollar initiative Monday to accelerate clean-energy research and development as part of a global effort to fight climate change. The announcement is timed to provide a jolt of momentum as world leaders gather in Paris for the start of a two-week summit focused on forging an international agreement to cut greenhouse-gas emissions . The president and Mr. Gates will join with other heads of state and investors to detail complementary public and private commitments to clean-energy innovation. The goal, Obama administration officials said, is to speed the pace of progress on new technologies that will help curb emissions and limit the rise of global temperatures. Brian Deese, a senior White House adviser who specializes in climate issues, said the initiative “should help to send a strong signal that the world is committed to helping to try to mobilize […]