Over the past four years the "emissions gap" series published by the United Nations Environment Programme has analysed the size of the gap and has provided insights on options to close it. This fifth report provides an updated measure of the emissions gap. In addition, this year’s update of the analysis calculates an emissions gap relative to expected emission levels in 2030, in recognition of the growing focus that action beyond 2020 is gaining in international climate change negotiations. Not least, the report provides an assessment of the carbon budget that is consistent with the 2° Celsius temperature target. Chapter 1. Introduction -- Chapter 2. What emission levels will comply with temperature limits? -- Chapter 3. Emissions pledges and the emissions gap -- Chapter 4. Improving energy efficiency and reaping development and climate benefits.