The global economy [ needs to cut its carbon intensity by 6% per year from now till 2100 ]( http://pwc.co.uk/assets/pdf/low-carbon-economy-index-2014.pdf ) to avoid more than 2 degrees of heating. And that's assuming good luck, that we don't hit an unexpected positive feedback that sends heating shootin ahead.
Ссылка: https://stallman.org/archives/2014-jul-oct.html#24_September_2014_%28Global_economy_needs_to_cut_its_carbon_intensity%29