Global average CO2 emissions are 4.48 tonnes per person per year. Cutting the world total by 85% means reducing this to 0.672t. Average per capita output in the 38 Annex 1 countries is 9.98 tonnes: to hit this target they must cut their emissions by 93.3% by 2050. If the rich persist in offsetting 50% of this cut, the poorer countries would have to reduce their emissions by 6989mt to absorb our offsets. To meet a global average of 0.672t, they would also need to chop their own output by a further 10838mt. This means a total cut of 17827mt, or 125% of their current emissions. I hope you have spotted the flaw.