My sense is that most scientists consider the very high end of the sensitivity range (greater than 4°C) to be pretty unlikely (although it cannot be ruled out), and the most likely value for climate sensitivity is around, probably slightly below, 3°C.
In other words, I was not terribly worried about runaway climate change before this. After all, we know that the Earth’s had much higher CO2 in the past (and the temperature were correspondingly much higher), and the Earth did not turn into Venus.
So an increase of 170 ppm to 560 ppm would cause 3C increase in temperature. That implies 1.7C increase per 100 ppm. During the Jurassic, CO2 levels were as much as 2,000 ppm higher than at the present. Temperatures must have been more than 30C higher back then – using Aggie math.
On the other hand, during the Ordovician, CO2 levels were 4,000 ppm higher and we had an ice age. So we can say with 97% certainty that these experts have absolutely no clue WTF they are talking about.
h/t to suyts