Funny, most rights scholars disagree! If you're unfamiliar:

https://blog.libertasbella.com/negative-vs-positive-rights/

Can the U.S. government act to restrict your speech in Saudi Arabia, even with the Saudi government's support? Answer is no, Constitutionally, because the government is bound to refrain from doing so. Me posting to a Canadian forum from Saudi Arabia (outside the U.S. jurisdiction entirely) is still protected speech from the perspective of the U.S. government.

Enforceability has nothing to do with the existence or non-existence of a right. Whether the government can hale a copyright violator into court for violating your copyright is immaterial... your right still exists. Similarly, if you kill someone and flee to a country with no extradition treaty, the rights of your victim do not cease to exist.

To be clear, I see no support for the right to a stable climate. But if one existed, it would not hinge on enforceability.