You want me to not skim over your posts and go through everything you say? Fine.
First point. Chinese officials are already working towards taking action against their own country's carbon emissions and
investing heavily in renewable power. YOUR assumption that countries like China and India will never do anything is inherently flawed. It's not like they're immune to the effects of climate change. Parts of China and MUCH of India is going to get drier if this continues. So you think they wouldn't be concerned about it at all? They know it's happening, and that it's a big problem. Since climate change is an issue that affects everyone, it DOES threaten to tank the world economy as well. Yet, it is possible to have an economy that doesn't rely almost exclusively on fossil fuels. You're also forgetting about European countries and their contributions to GHG emissions, which is greater than that of the United States. And THEY are doing things about it too. And of course, the power that the United Nations has to make emissions treaties like the Montreal Protocol (which was a runaway success that halted the destruction of the ozone layer, it is now expected to make a full recovery by 2070). And as Funkthulhu pointed out, carbon tariffs, which countries may resort too if the situation gets particularly bad.
Your statement that the US is the only country that has ever listened to environmentalists is erroneous too. Brazil listened to environmentalists who were protesting deforestation, so they implemented a new satellite monitoring program to track illegal deforestation that ended up cutting deforestation rates in half over the course of a few years. Costa Rica, which is set to become the one of the wealthiest nations (per capita) in the Western Hemisphere, has strict environmental laws and a national park system that allows it to both have a robust, rapidly growing economy and pristine natural beauty and biodiversity. And as I stated above, the European Union is genuinely concerned about climate change and many European countries (notably Germany) are already transitioning their energy economies away from fossil fuels. Maybe you should do your research before saying things like that.
Why is it you think that attempting to transition our economy to something that is better for both the environment and the health of the populace will destroy the country? It calls for investing in new, state of the art technologies and new companies that comprise one of the most rapidly growing industries in the world. I thought investment in something that has so much promise is a good thing? Even if there are economic hardships along the way, the benefit in the end will FAR exceed the cost. It would be great to have no more smog in Los Angeles, but I doubt you've ever had to experience something like that on a daily basis, or have not experienced it in a while, since you live in Hawaii where the biggest problem is exotic species rather than rampant air pollution. And how about being able to generate your own electricity for pennies on the dollar with solar? That would be great too, wouldn't it? No more water pollution from coal mining (see what just happened in West Virginia) or fracking? And no more oil spills? Count me in! I'd love to see what happens to our economy once we make that transition. Cancer rates would probably plummet due to less exposure to toxic chemicals from fossil fuels and air pollution, easing the strain on our healthcare system and making healthcare cheaper. People spend less on medical bills, meaning they have more money to put into consumption. More consumption creates more jobs, on top of the jobs that were created in the new clean energy industry. Those are probably just a few of the effects it would have, on top of less severe climate change, which would have had the potential to cripple the ENTIRE WORLD'S economy. In the end, it would probably end up providing a massive economic stimulus.
Next point. Yes, we have had warming and cooling periods in the past. But these periods have been very strongly correlated with variances in greenhouse gas concentrations. GHG levels go down, average temperature goes down. GHG levels go up, average temperature goes up. You know why? Because greenhouse gases trap heat in the atmosphere. This is not rocket science. I don't need to explain this simple concept, the graph will for me.
Now, your last point. You are right. My last assumption was wrong. We CAN know it is happening. And we DO, with 99% certainty. The fact that people like you continue to stick your fingers into your ears and scream "LALALALALA I CANT HEAR YOU!" doesn't change anything. It didn't change anything about the reality of the hole in the ozone layer, it didn't change anything about the reality of the fact that smoking cigarettes causes cancer, it didn't change anything about the reality of Darwinian evolution or the age of the universe. You are not a scientist. You can't prove that it's not happening, but you can believe that it's not happening. You have every right to. Beliefs are just that -- beliefs. I could very well say that I believe the Earth is 6,000 years old, or that injecting heroin cures cancer, or that the world's governments are secretly controlled by alien space leprechauns from Alpha Centauri. That doesn't make any of it true.
It's clear to me that you did a thorough analysis of the logic game I had prepared for you. I'm going to assume for a moment that you are a rational human being, regardless of what you believe. That may or may not be true, but for the purpose of this, I will assume that it is true. If you, a rational human being, decided to play the game, and assess the potential risks and rewards of each situation, your rationale would lead you to only one conclusion. That the best course of action would be to do something about climate change. But it seems to me that you are so closed-minded and dead set on your own belief that it isn't happening that you aren't even willing to ponder it. Either that, or you simply refused to take the challenge because you knew you would have been proven wrong in the end.