The US and China have jointly announced that both countries are ratifying the Paris Agreement on climate change. This has increased, the percentage of greenhouse gas (GHG) emissions covered by countries that have ratified dramatically. The official UNFCCC website now shows 26 Parties having ratified, accounting for 39.08% of emissions. That latter number gets the world closer to the 55% required. And with the political momentum generated, it seems highly likely the Paris Agreement will enter into force soon.
Before the China-US announcement on 3 September 2016, the share of global emissions was less than 1%. Many small countries had ratified, but none of the major emitters. Two triggers must be me for the Agreement to enter into force: 55 countries and 55% of global GHG emissions. The precise text is in Article 21.1 of the Paris Agreement.
The pressure is now on other countries, including South Africa, to follow suit. While there were extensive consultations on SA’s intended nationally determined contribution (INDC) and the position taken to Paris, the Agreement needs to be signed off by Cabinet and presumably also go through a parliamentary process. The US and China have both deposited their instruments of ratification with the UN.
The Paris Agreement is a treaty under the Vienna Convention on the Law of Treaties. While it was agreed in December 2015 and signed by many heads of state earlier this year, formal entry into force requires the two triggers to be met. That point in time now appears to be much sooner than previously expected.
Like many other countries, SA would add around 1% to the global total – the exact percentage depends on gases, sources, sectors, years and other parameters. For the purposes of ratification, a table  was agreed in Paris. The pressure now comes from the political momentum generated by the biggest developed and developing country ratifying. There are several unofficial tools online to examine scenarios when the 55/55 ‘double trigger will be reached – for example this one. The EU would add 12.1%, taking the total to 51.16%; just short of the second trigger; add Brazil and SA and we’re there.
From the first joint US-China announcement in late 2014 onwards, joint announcements by the Presidents, Xi Jinping and Barack Obama, have been influential. The text of the latest joint statement can be found here.
 “This Agreement shall enter into force on the thirtieth day after the date on which at least 55 Parties to the Convention accounting in total for at least an estimated 55 per cent of the total global greenhouse gas emissions have deposited their instruments of ratification, acceptance, approval or accession.” (Paris Agreement, Article 21.1)
 http://unfccc.int/files/ghg_data/application/pdf/table.pdf UNFCCC (United Nations Framework Convention on Climate Change) 2015. Table: Solely for the purposes of Article 21 of the Paris Agreement, information on the most up-to-date total and per cent of greenhouse gas emissions communicated by Parties to the Convention in their national communications, greenhouse gas inventory reports, biennial reports or biennial update reports, as of 12 December 2015. Paris, France, United Nations.