The concept of constraining cumulative greenhouse gas (GHG) emissions globally until, e.g., 2050 influences climate policy-making since the 2009 UN Climate Change Conference in Copenhagen. Cumulative emissions allow specifying the risk of exceeding a global warming target (e.g., 2 degrees C) by 2050 and beyond better than any other concept. Cumulative emission constraints must be expected to receive increasing attention in the future both scientifically and politically. However, the treatment of emissions from land use / land-use change (LUC) under this concept falls short.