Listen to a scientist say very clearly that we have the science and technology to create 100% renewable power in the United States within my lifetime (2050).
We’re only held back by politicians who fail to implement an urgent plan to save us, as they were required to when implementing policy during WWII from another clear threat to the American way of life.
Saskboy's Abandoned Stuff 
The Easter Islanders realized that total deforestation would end their society but that didn’t stop them. Rational, intelligent people can do very self-destructive things out of perceived immediate self-interest.
A few years ago people like James Hansen warned that we had until 2015 to implement massive cuts in our carbon emissions – not proposing it, not studying it, not planning for it but implementing actual, tangible cuts on what to us today would seem a massive scale.
Instead we have America leapfrogging Russia in fossil fuel extraction and the emerging economies burning whatever fossil fuels they can find, all the while assuring us they’re going green.
I too have been using 2015 as the political tipping point for action. The IEA gave this year as the approximate date when enough coal plants would be in production to produce 450ppm of CO2 for our atmosphere before their End Of Life (but I’m having a hard time locating that specific report from about 2010 now).
https://twitter.com/MichaelMicklow/status/535310289257103360