The 24th Conference of Parties ended on a high note on Dec. 15 by completing a rulebook for the 2015 Paris Agreement on climate change. Though a contingent of nations stayed an extra day at the annual meeting in Poland to finish the instructions -- known as the Katowice Climate Package -- a number of issues remain unresolved. The package provides directions and guidelines for tracking the voluntary targets to limit carbon dioxide and other emissions that were agreed upon three years ago in France. The nearly 200 nations represented at the meeting agreed to set targets on financing and to do a global "stocktake," which involves evaluating progress at midpoints and establishing methods to track emissions as well as the development and transfer of technology. However, the conference delegates failed to establish a voluntary market mechanism, and the agreement was criticized as weak and lacking urgency....