Who's Responsible for Climate Change? New Evidence Based on Country-level Estimates of Climate Debt

Persistent increases in average global temperatures, in the absence of mitigation policies, risk catastrophic climate change as well as reduced world GDP per capita. In the absence of policy changes, fossil fuel consumption and global CO2 emissions are projected to continue to rise, with an increase in global CO2 emissions of 4 percent by 2030 relative to 2019. Over the longer term, even scenarios that maintain global emissions at present levels, before dropping after 2050, are troubling. For example, the intermediate scenario of the Intergovernmental Panel on Climate Change predicts an increase in average global temperatures from the present 1.2 degrees Celsius above the pre-industrial average (1850–1900) to an average of 2 degrees in 2041–60 and 2.7 degrees in 2081–2100. In order to avoid the adverse consequences of this scenario of increasing global temperatures, a number of countries have pledged to reduce emissions beyond their initial commitments in the 2015 Paris Agreement (COP21). under which countries agreed to limit global warming to well below 2 degrees relative to pre-industrial levels and aim for 1.5 degrees. Under the present framework, mitigation pledges in countries’ nationally developed contributions (NDCs) are voluntary. However, pledges would only cut global emissions by 1/3–2/3 of the reductions consistent with Paris warming targets. As such, there is a large gap between what countries have committed to do and what needs to be done. In this context, a key issue in deciding which countries should do more is an assessment of which countries have contributed the most to climate change (through their CO2 emissions) and its associated economic damages. The total sum of these damages can be conceptualized as a “climate debt” in the sense that these costs have been imposed on the globe without any compensation. This paper seeks to contribute to this debate by providing an assessment of the climate debt of each country, based not only on historical emissions, but emissions that are likely in the near future. These estimates could be used to address the appropriate size of climate finance assistance, where countries with large climate debt may be seen as needing to contribute proportionately more to these efforts.