After thousands (perhaps millions) of years of completely stable temperatures – suddenly in the year 1880 the world started to heat out of control, due to human generated CO2. The graph below plots CO2 vs year during that period.
At first glance it appears that not much was changing, but we now know from peer reviewed science that there must be something magical about 290.7 ppm. The earth started heating out of control at 290.7, and basically has heated at the same rate for the past 120 years!
There is no physical explanation for why 290.7 ppm CO2 would cause a quantum shift in climate behaviour, so I am going to declare a new climate intrinsic number.
Scribble this in to your textbook.
However … there is a problem here. Hansen claims that 350 ppm is safe, but nothing in the hockey stick supports this number. The world started heating unabated at 290.7 ppm. In order to make the world safe, we need to go back to 290.69.
The hockey stick proves it.