Calculating Historical Contributions To Climate Change – Discussing The ‘Brazilian Proposal’

摘要: This paper discusses methodological issues relevant to the calculation of historical respon- sibility countries for climate change ('The Brazilian Proposal'). Using a simple representation system, compares contributions using different indicators: current radiative forcing, GWP-weighted emissions, forcing from increased concen- trations, cumulative global-average surface-air temperature increase and two new weighted concentrations (analogue emissions) integrated increase. Only last indicators are at same time 'backward looking' (take into account emissions), discounting' (early emissions weigh less, depending on decay in atmosphere) 'forward (future effects considered) comparable all gases. Cumulative calculate but not discounting'. 'Radiative forcing' 'temperature increase' looking'. 'Temperature discounts decade due slow response system. It therefore gives low weight regions that have recently significantly emissions. Results five quite similar large groups (but possibly individual countries): industrialized contributed around 60% today's change, developing 40% (using available data fossil, industrial forestry CO2 ,C H4 N2O). The further argues including non-linearities system or simpli- fied linear is political choice. also notes results need be interpreted with care: Countries developed early benefited economically, high emission, later period can profit developments other likely lower contribution change.