Three weeks before the start of the Paris climate talks, negotiators working to craft an international agreement to curb global greenhouse gas emissions are staring into a wide gulf between what countries are willing to do and what they need to do. Most countries have stepped up with pledges to meaningfully cut carbon emissions or to at least slow the growth of emission totals between 2020 and 2030. However, national commitments fall short of what’s needed to prevent the average global temperature in 2100 from being any more than 2 degrees Celsius warmer than at the start of this century—the international community’s consensus benchmark for climate impact. Worse still, national pledges employ a hodgepodge of accounting methods that include some significant loopholes that ignore important emissions such as leaking methane from U.S. oil and gas production and underreported coal emissions from China. How promised reductions will be verified post-Paris is “a big debate right now and it makes a massive difference in the numbers,” says Jennifer Morgan, global director for the climate program at the World Resources Institute, a Washington, D.C.-based non-governmental organization.