I do not think so. To select a man that represents a party is never a good idea. Al Gore, some may say, defends an environmentalist agenda, not a party.
First that agenda is not based on rock but on sand. It may turn out to be solid sand or friable rock, but we do not really know for sure.
Second, Gore is still eligible to run for the US presidency. This may not be realistic, but a small window remains open. I find it less than desirable to openly support someone who may still have big personal/political interests.
Finally, it is unclear what are the real merits of Al Gore. Is he a good movie director/actor? Well then, he already got an Oscar for that. Is he making ground-breaking scientific discoveries? No we can set this aside. Is he communiticating efficaciously an important political message? Yes! And so what? That is the bread and butter of all good politicians. It does not follow that they deserve a Nobel prize for that reason