GUY McPHERSON IS RIGHT!

Want to stop extremely dangerous climate change? Try to find a way to turn back time. Otherwise, it's game over; we've already screwed the pooch. Or in this case, Mother Nature.

Climate change may be escalating so fast it could be 'game over', scientists warn - The Independent

It is a vision of a future so apocalyptic that it is hard to even imagine.
But, if leading scientists writing in one of the most respected academic journals are right, planet Earth could be on course for global warming of more than seven degrees Celsius within a lifetime. 

And that, according to one of the world’s most renowned climatologists, could be “game over”... 

Caption: A reconstruction of the Earth's global mean temperature over the last 784,000 years, on the left of the graph, followed by a projection to 2100 based on new calculations of the climate's sensitivity to greenhouse gases (Friedrich, et al. (2016)) Source: The Independent.

In a paper in the journal Science Advances, they said the actual range could be between 4.78C [degrees Celsius] to 7.36C by 2100, based on one set of calculations.

The mean average of the range is 6.07 degrees Celsius. Assuming the long-term sensitivity for a doubling of carbon Dioxide in Earth's atmosphere, or its equivalent, is a rise of 7 deg C above 1880s' levels.  At the present 410 ppm level of CO2, the mean global temperature in several hundred years' time will rise to 3.85 deg C above 1880s levels. At the present level of 490 ppm CO2e, the temp will rise to 5.65 deg C. And we're still adding carbon dioxide and other greenhouse gasses to the atmosphere. And that's the long-term, thousand-year range assuming we stop emitting now, and fail to extract greenhouse gasses from the atmosphere or to geoengineer the planet without using fossil fuels, both very real possibilities.

What's worse, if we keep on emitting as if fossil fuels were are to remain in fashion for the rest of this century, the minimum predicted rise is just shy of 5 deg C.  It is said that a rise of 4 deg C means human extinction

Looks like Guy McPherson is right.