What is と being used for in these two sentences?

Question

I was reading an article on NHK News Easy, and while I basically understand the two sentences below, I'm having a little trouble deciphering what exactly the particle 「と」 is doing.

So with:

地球の気温が上がらないようにするために二酸化炭素などのガスを減らすと国連で決めた「パリ協定」が、去年１１月から始まりました。

What does the 「減らすと国連で決めた」 part of the sentence mean? What is the purpose of 「と」 here?

And with:

アメリカのトランプ大統領は６月１日、パリ協定から出ると発表しました。

Why does 「出る」 have to be followed by 「と」?

I thought I was familiar with the basic uses of 「と」 (linking nouns, as a conditional, for quoting), but I don't see how it fits here as any of these. Could someone clarify?

Answer 1

That と is the quotative particle and it indicates contents of definition or what's decided when it's not a noun but a clause. i.e "Paris treaty that decided that we would reduce gas including CO2 ...".

In other words, 減らすと決める can be rephrased as 削減を決める or 減らすことを決める. Here, 減らす is a clause while 削減 or 減らすこと are a noun.

An important function of this quotative と is to make adverbs together with onomatopoeia like ダラダラと話し合う (to talk idly) or キラキラと光る (to twinkle). What's really important is that this function is not limited to onomatopoeia but applicable to nouns, clauses or interjections in combination with verbs which other languages don't consider quotable as well.

I understand this idea is difficult for those who are not familiar with Japanese and I appreciate how they think of it as omission of 言う or 思う but that's not how native speakers are conscious of it.

For example, 離すまいと手を伸ばす means "to reach out his/her hand so eloquently as if it never wants to leave it" and the agent is not necessarily thinking that way.

Answer 2

I will start by translating the sentence:

地球の気温が上がらないようにするために二酸化炭素などのガスを減らすと国連で決めた「パリ協定」が、去年１１月から始まりました。 = Paris treaty which has been decided by the united nations to reduce the gas emissions such as carbon dioxide so that the temperature of earth doesn't rise up has started since november of last year.

This is a pretty long sentence, please feel free to correct my english if there is the need to.

Now as for your question, the と basically is the quotative particle. It is very often used in this kind of structure without the verb 言う or any other verb that involve the action of saying something. To help yourself understand it better, you can think of a　「言って」 right after the と particle. As in:

買ってくれと泣いた。 →　買ってくれと(言って)泣いた。 (he cried saying "buy me this!")

ガスを減らすと(言って)国連で決めた。 = we decided with the united nations (saying) that we will reduce gas [...]

This is the same と as in your second sentence:

アメリカのトランプ大統領は６月１日、パリ協定から出ると発表しました。 = They announced that the president of America Trump has "left" Paris treaty on the first of June.

You can imagine 言って between と and 発表する.