Glossary .vAcronyms . viiForeword . viiiExecutive Summary .1Chapter 1: Introduction .8Chapter 2: Current and Projected Greenhouse Gas Emissions .9 2.1 Introduction .9 2.2 Current and projected global emissions .10 2.3 National emission reduction pledges and expected global emissions in 2020 as a result of the pledges .10 2.4 Current and projected national emissions .13 2.5 Comparison of current and expected emissions and emission intensities in 2020 for G20 countries with a pledge .18 2.6 Summary .18Chapter 3: The Emissions Gap An Update .21 3.1 Introduction .21 3.2 Which scenarios are analysed? .21 3.3 Emission levels in 2020, 2030 and 2050 for the 2C target .23 3.4 The emissions gap for the 2C target .24 3.5 Results for a 1.5C target .24 3.6 Other findings from the least cost scenarios .26 3.7 Results of later action scenarios .28 3.8 Present UNFCCC policy options to bridge the gap .29 3.9 The implications of current emissions levels and the emissions gap .29Chapter 4 Bridging the Emissions Gap.30 4.1 Introduction .30 4.2 Emission reduction potentials by sector in 2020 summary and update .30 4.3 Best practice policies .32 4.4 Conclusions .43References .45ContentsAnnex I Countries the industrialised 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.Aerosols are collections of airborne solid or liquid particles, with a typical size between 0.01 and 10