Developing countries seeking international climate and development funding face a significant obstacle: if they borrow to finance climate and development needs, they might not be able to repay or refinance their debt, which could become unsustainable. For years, the International Monetary Fund (IMF) and the World Bank have had a framework for determining when a country’s debt is sustainable, based largely on ratios derived from projections of sovereign debt and macroeconomic performance. Depending on the ratios, a country may be at risk of debt distress. If it has no feasible policy options to avoid debt distress, its debt will be unsustainable and might need to be restructured.