Cumulative emissions and climate debts: what do we need to do to meet the 2°C target?

All countries have contributed to historical climate changes, but some much more than others. This historical inequality has been a fundamental challenge in the development of an effective and equitable global climate treaty. In this seminar, I will discuss some of the ways that we are able to quantify the climate response to human greenhouse gas emissions, focussing in particular on recent estimates of the climate response to cumulative emissions and the implications of this approach for defining the total allowable emissions for a given climate target.

I will then outline how the total emissions consistent with 2°C of global temperature change could be shared among nations in a manner that respects the principle of international equity. Finally I will discuss how the concepts of carbon and climate debts could be used to quantify historical inequalities among nations, and provide a framework to guide the funding of mitigation and the costs of climate loss and damages in countries that have contributed less to historical climate warming.