The World's Next Energy Systems

Nearly a year ago, almost 200 countries signed a pledge to limit greenhouse gas emissions, resulting in the Paris agreement of 2015. On the sidelines of the U.N. General Assembly on Sept. 21, there will be a special meeting to encourage the signatory nations to complete the domestic legislation necessary to formally ratify the agreement. If the required 55 countries (accounting for 55 percent of the world's emissions) approve the deal by Oct. 7, it will go into effect before the next global meeting in Marrakech in November. Since the agreement opened for signatures in April, however, only 22 nations have ratified it. Moreover, the Paris agreement, while lauded for its progressiveness and transparency, still has no punitive measures for countries failing to meet their stated targets. Without consequence for failure, countries are less likely to reach their climate change goals. So how will the world actually begin to significantly...