The historical responsibility of countries listed in the Annex I of the Convention on Climate Change has been used extensively as a justification for the lack of action of countries not included in Annex I to reduce their greenhouse gas emissions. We analyzed the contribution of non-Annex I countries to the CO2 emissions in the period 1850 - 2006 to assess their relative contribution to total CO2 emissions. In the period 1980 - 2006 non-Annex I countries represented 44% of the total but this contribution increased in the period 1990 - 2006 to 48%. If we extrapolate present trends to 2020 they will represent 56% in the period 1990 - 2020. The "historical responsibility" of Annex I countries is therefore decreasing. If we take 1990 as the starting year in which the Climate Convention recognized clearly that greenhouse gases are interfering dangerously with the climate system, it becomes very difficult to attribute "blame" and "guilt" to Annex I for their historical contributions. It becomes also quite clear the need of non-Annex I countries to engage with Annex I countries in the effort to reduce emissions. The Copenhagen Accord has no mention of "historical responsibilities".