But the technology has been rapidly getting more economical, and in some ways is now actually cheaper than fossil fuels (which also has many negative externalities of its own). And this has been happening only because there has been an enormous investment in renewable energy. The idea that the scientists all on their own will work for decades and come up with fully-ready technologies that then will be put into full production is just not how these things actually work.
Do you understand the difference between average and 15-40%? How about the difference between average and median, non-normal distributions, etc.?
There's no changing of definitions from anyone except yourself in your misleading "quote".
Here's a more accessible article: http://www.nature.com/climate/2008/0812/full/climate.2008.12...
This is true, but the people who are, in fact, deniers likely won't change their minds anyway and likely will not be alive long enough to see any undeniable evidence that could.
It's the same thing with discussing religion, I learned long ago to keep my mouth shut about it when talking to anyone who didn't express even a touch of an open mind about it.
I agree that the magnitude of the effect has not been demonstrably measured by anyone yet, but I don't see that as any reason to not take action to at least try to reduce whatever damage we might have done, are currently doing, and might do in the future.