The start date of an important element of the Paris Agreement would be set 23 years in the future under a proposal from major emerging economies.

Under the Paris Agreement, all countries are expected to periodically submit national plans to fight climate change. One of the legal specifications was that they would synchronise, beginning at the same time and running for the same term.

These common time frames are intended to allow for comparison and create pressure between countries to do more.

http://www.climatechangenews.com//global-alignment-climat/