National Geographic: If the world waits until 2020 to take action on global climate change, it will undoubtedly be too late, the International Energy Agency (IEA) warns in a new report. However, the Paris-based agency, which is tasked with maintaining global energy security, identified four proven policies, each relying on current technology, that could be implemented immediately. (See quiz: "What You Don't Know About World Energy.") These efforts could keep the world on track while nations work toward a more comprehensive...