Skepticism abounds as to whether the UN Framework Convention on Climate Change (UNFCCC) being held in Copenhagen in December 2009 will result in a new climate change agreement. This policy brief asserts that the North-South divide is perhaps the most important hindrance to reaching an agreement. The divide stems from two factors: differences between the North and South with regard to incomes per capita and economic growth; and disagreement over responsibility for damage and whether to measure emissions on an annual basis or on a historical or cumulative basis. According to the authors, movement across this divide will be necessary to reach a deal; however, the likelihood of a significant agreement, even post-Copenhagen, is unclear despite the current political momentum. China’s recent emissions-reduction commitment offers an opportunity to lessen the divide, but how the parties will respond remains to be seen.