We’re at the halfway point of the United Nations Conference on Climate Change, taking place in Paris. One recurring theme is the lack of enforcement measures against countries that fall short or violate a final agreement. One expert said the only punitive regime they foresee comes down to “naming and shaming.” Mark Hertsgaard, environment correspondent for The Nation magazine, is currently in Paris. He’ll update us on the latest news and what’s been happening at the talks. His most recent book is HOT: Living Through the Next Fifty Years on Earth. (Photo: Flickr/Alisdare Hickson)