The Earth has been warming and cooling forever, and yet we have few accurate records for more than a hundred years. That alone is reason to say that we have no clue as to whether it will be hotter or colder in fifty years.
There is not enough evidence to conclusively say that we are having any affect that is measurable. Thus the data available is not enough as yet. The conclusions and decisions have to be made by logic, and that isn't something that the nuts in charge know how to do. They rely entirely on fear to pressure others to do what they want done.
Therefore, there is no logical reason right now for the USA to agree to a fine by the United Nations in the way of a tax on the GNP, to give that to the UN, to spend as they want to. That current projection amounted to something like 950 billion dollars back dated through about four years ago. The plan was/is to take it from us, and we will not get any of it back, it then must be spent on non industrialized nations.
That's my big issue, we are more giving to the entire world, and yet there are still people that think that more money should be taken from us. Think about regular charitable contributions. If people give let's say 5% of their income voluntarily to their church etc, what do you think would happen if you the government began to tax them 5% to pay some organization outside of their community? That money is taken and spent outside of their community.
Those people will stop giving to charities, they can't afford it. What is the affect, why of course the communities where the money is taken from will suffer. Those economies will be hurt, productivity will decrease. That is basic economics, and it's also what is wrong with our US Government. We could be doing far better if they would stop taking our money away to spread wastefully among their vote buying programs. If they would leave us alone, there would be much more money that would be spent on the real needs of the community, voluntarily.
The answer is not to steal our assets from us through governmental legislation. That is negative economics, it hurts the entire productivity of the country. The answer is to give incentives to reward the better behavior desired. Don't punish, reward.