glossary and Acronyms-UNEP BRidgiNg thE EmiSSioNS gAP 5 Annex I Countries The industrialized countries (and those in transition to a market economy) which took on obligations to reduce their greenhouse gas emissions under the United Nations Framework Convention on Climate Change. Black Carbon A form of air pollution produced by incomplete combustion of fuels. It is produced especially by diesel-powered vehicles, open biomas burning, cookstoves, and other sources. 'Bottom up' model A model which represents reality by aggregating characteristics of specific activities and processes, considering technological, engineering and cost information. Business-As-Usual A scenario used for projections of future emissions assuming no action, or no new action, is taken to mitigate emissions. Carbon Credits Tradable permits which aim to reduce greenhouse gas emissions by giving them a monetary value. Carbon Dioxide Equivalent A simple way to place emissions of various climate change agents on a common footing to account for their effect on climate. It describes, for a given mixture and amount of greenhouse gas, the amount of carbon dioxide that would have the same global warming ability, when measured over a specified timescale. For the purpose of this report, greenhouse gas emissions (unless otherwise specified) are the sum of the basket of greenhouse gases listed in Annex A of the Kyoto Protocol, expressed as carbon dioxide equivalent. Conditional Pledge Pledges made by some countries that are contingent on the ability of national legislatures to enact the necessary laws, ambitious action from other countries, realization of finance and technical support, or other factors. Double Counting In the context of this report, double counting refers to a situation in which the same emission reductions are counted towards meeting two countries' pledges. Emission Pathway The trajectory of annual global greenhouse gas emissions over time. Greenhouse Gases covered by the Kyoto Protocol Include the six main greenhouse gases, as listed in Annex A of the Kyoto Protocol, namely: Carbon dioxide (CO 2); Methane (CH 4); Nitrous oxide (N 2 O); Hydrofluorocarbons (HFCs); Perfluorocarbons (PFCs); and Sulphur hexafluoride (SF 6). Integrated Assessment Models models of climate change that seek to combine knowledge from multiple disciplines in the form of equations and/or algorithms. As such, they describe the full chain of climate change, including relevant linkages and feedbacks between socioeconomic and biophysical processes. Kyoto Protocol An international environmental treaty intended to reduce greenhouse gas emissions. It builds upon the United Nations Framework Convention on Climate Change. Leakage Carbon leakage is defined as the increase in CO 2 emissions occuring outside of countries taking domestic mitigation action. Lenient Rules Pledge cases with maximum Annex I "lenient LULUCF credits" and surplus emissions units. Likely Chance A greater than 66 per cent likelihood. Used in this report to convey the probabilities of meeting temperature ...