You see headlines like this:
China ratifies Paris climate change agreement ahead of G20
Not so. The National People’s Congress of China has voted to ratify as it was jolly well told to, but that’s not ratification yet. International law is clear on this. The Vienna Convention on the Law of Treaties of 23 May 1969, which codified long-standing practice, says this:
Article 16.
Exchange or deposit of instruments of ratification, acceptance, approval or accessionUnless the treaty otherwise provides, instruments of ratification, acceptance, approval or accession establish the consent of a State to be bound by a treaty upon:
(a) their exchange between the contracting States; (b) their deposit with the depositary; or (c) their notification to the contracting States or to the depositary, if so agreed.
So China or the USA or Vanuatu ratify the treaty when the paperwork is handed over to the Treaty Section of the UN Office of Legal Affairs, and not before. To be helpful to John Kerry, here is the address:
Mr. Santiago Villalpando, Chief of Treaty Section
United Nations Headquarters
Room No. DC2-0520
United Nations Headquarters
New York, NY 10017
I don’t know if he has a bottle of sherry for visitors.
Update, same day: It looks as if both Chinese and American diplomats found Mr. Villalpando without my help. Press release from the UNFCC secretariat:
Both countries have announced they have deposited their instruments of ratification with the UN Secretary-General.
So the Agreement has in one day jumped from 24 parties representing 1% of emissions to 26 parties representing 39% of global emissions. It needs 55 and 55%. Both targets should be hit before the end of the year. November would be nice, as entry into force by the end of the year would lock a hypothetical President Trump into the agreement for his entire first term of office (Article 28). The USA would still stop contributing, but the chair would sit empty.
"So China or the USA or Vanuatu ratify the treaty when the paperwork is handed over to the Treaty Section of the UN Office of Legal Affairs, and not before."
And, to be further helpful, since the President seems to have developed some odd ideas on the topic, the USA ratifies a treaty when the Senate votes to ratify, and not before.*
*We didn't ratify the Vienna convention on the law of treaties, so, no, the President signing it has no legal significance. That the Vienna convention says otherwise is irrelevant, because, again, *we did not ratify it*. Try to understand that: The Constitution sets out the requirements for treaty ratification, and a convention we did not ratify does not amount even to law, let alone constitutional law.
The reason executive agreements don't require Senate ratification, is that they have no legal force. They simply represent a particular President's promise to act in a particular way insofar as domestic law permits. They aren't binding on subsequent Presidents or Congress, they're not even legally binding on the President who enters into them. They're the executive equivalent of a "pinkie promise".
So the Paris accord is utterly lacking in legal significance in the US, whether you regard it as a treaty or Executive agreement.
The Vienna Convention is generally understood to be for the most part declaratory of customary international law, not constitutive. The State Department thinks so.
The Paris Agreement is a "treaty" under international law as explained in Article 2 of the Vienna Convention. It's a matter of domestic US law whether a given international agreement is a "treaty" requiring Senate consent, or an "executive agreement" (the vast majority) that does not. Since a state is represented internationally by its executive, neither Mr. Villalpando nor any other government is going to question Kerry's or Obama's authority to ratify.
Your talking point suggests a domestic legal challenge to Obama's ratification, presumably brought by the Republicans in Congress. Good luck with that. How did the mooted challenges to the Iran nuclear deal - categorised by the State Department as a "political understanding", skating on much thinner ice - work out? It's exactly the sort of case where Roberts' deference to the executive will be at its strongest.
You are misinformed in thinking that signature without ratification has no legal consequences. Article 18 of the Vienna Convention: "A State is obliged to refrain from acts which would defeat the object and purpose of a treaty when: (a) it has signed the treaty …" Not sabotaging a treaty is a low bar, but it is one. This is yet another example of the way in which a Trump presidency, cancelling the Clean Power Plan before withdrawing from the Paris Agreement (which would take four years), would have a broader chilling effect on the international credibility of the United States.