They agreed / have agreed to reduce their emissions of carbon dioxide

[yuliyaon]

I'm confused about the right choice of a tense from a grammar exercise on Past Simple / Present Perfect. The sentence goes like this: "They agreed / have agreed to reduce their emissions of carbon dioxide and other gases, although so far some countries have not taken any action". The way I see it, it should be Present Perfect, because the countries signed the protocol and the agreement is in force in the present. Or is 'agreeing' just an event from the past which should be expressed in Past Simple? I see a strong connection of this action with 'now', however the book says the correct option is 'agreed'.

 

[Barque]

At first glance the present perfect seemed more likely, but I think both are possible, depending on the surrounding context.

 

[Tarheel]

I wouldn't argue with either one.

 

[5jj]

the book says the correct option is 'agreed'.

It is not the only one.