Reuters: New York City's museum devoted to climate change has no walls, no admission fee and no exhibits. In fact, it doesn't exist yet. It's an idea that its planners, led by Miranda Massie, attorney-turned-museum director, are hoping to make a reality. They are eyeing an opening in 2020, with pop-ups and publicity between now and then to get it off the ground. Yet, despite growing pressure to cut planet-warming emissions and the new historic global accord on climate change reached in Paris last weekend,...