A central commitment of action on climate is the promise of “developed countries” to jointly mobilize $100 billion of climate finance per year by 2020 (and through to 2025), formalised at the UN climate change conference in 2010 (COP16). Five years later, the Paris Agreement reaffirmed this commitment and promised a new goal after 2025 “from a floor of USD 100 billion per year.”
We propose an approach for calculating financial climate liabilities for each country based on their historical CO2 emissions, using the idea of an externality: a social cost that has not been borne by the agent whose actions produced it. The paper follows earlier work on calculating carbon debts (e.g., Kunnas, 2014) which we update with recent and authoritative research on carbon pricing methods. We also adjust for awareness, calculating the accruing of liabilities only from the time that countries knew that their emissions were harmful. We present several scenarios adjusting this and other assumptions. The main scenario produces a clearly quantified liability for each country and a total carbon liability to the world of $34 trillion, or $4,500 per capita. If this liability was used to set climate finance goals, it would suggest OECD countries would need to contribute $190 billion a year to 2100. The analysis also highlights that other industrialised countries, notably China and Russia, have also built-up substantial liabilities and should therefore also contribute to future climate finance goals.
