"As chairman of the Intergovernmental Panel on Climate Change, I cannot take a position because we do not make recommendations," . "But as a human being I am fully supportive of that goal. What is happening, and what is likely to happen, convinces me that the world must be really ambitious and very determined at moving toward a 350 target."
Along with Stern and Pachauri, Canadian environmentalist David Suzuki, Nobel Prize winners Desmond Tutu and Al Gore, and NASA climate scientist James Hansen have all the 350 ppm target.
To get there, Hansen recommends phasing out coal for starters.
“If humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted, paleoclimate evidence and ongoing climate change suggest that CO2 will need to be reduced from its current 385 ppm to at most 350 ppm," in a 2008 scientific paper.
“An initial 350 ppm CO2 target may be achievable by phasing out coal use except where CO2 is captured and adopting agricultural and forestry practices that sequester carbon. If the present overshoot of this target CO2 is not brief, there is a possibility of seeding irreversible catastrophic effects.”