COP21 Glossary of Terms Guiding the Long-term Emissions-Reduction Goal

The document defines key climate terminology used in COP21 negotiations, such as decarbonization, carbon neutrality, and carbon budgets, while explaining how these terms influence the global emissions trajectory. It argues that for long-term goals to be effective, they must be consistent with climate science, limit both long-term and cumulative emissions, and provide clear dates and plausible reduction pathways.

• The document distinguishes between various 'neutrality' and 'zero' terms: 'Net zero carbon emissions' and 'carbon neutrality' are often used as synonyms, though carbon neutrality can be achieved via offsets from other jurisdictions. 'Net zero GHG emissions' and 'climate neutrality' extend these concepts to include all greenhouse gases beyond just carbon dioxide.
• Carbon neutrality is sometimes misinterpreted by countries as stabilizing emissions at a specific level rather than aiming for zero net emissions. For example, Ethiopia's goal is to achieve 'carbon-neutral middle-income status before 2025' while limiting net GHG emissions in 2030 to 145 Mt CO2e or lower, and Costa Rica's INDC aims for carbon neutrality by 2021 with net emissions comparable to 2005 levels.
• Peaking emissions is described as a critical factor for the global emissions trajectory; any delay in the peak date necessitates more aggressive future reductions and increases the risk of failing to meet the 2°C goal.
• The carbon budget is the total amount of CO2 the world can emit to likely limit warming to 2°C. Based on the IPCC's Fifth Assessment Report (2014), two-thirds of this budget has already been used, and the WRI estimates it could be entirely exhausted within two decades if emissions are not reduced.
• To provide clarity for the private sector, cities, and countries, complementary long-term goals must include specific dates, emissions levels, and covered gases, and must be consistent with recent climate science.

APA

Levin, K. (2015). COP21 Glossary of Terms Guiding the Long-term Emissions-Reduction Goal. World Resources Institute. https://www.wri.org/insights/cop21-glossary-terms-guiding-long-term-emissions-reduction-goal

Chicago

Levin, Kelly. COP21 Glossary of Terms Guiding the Long-term Emissions-Reduction Goal. World Resources Institute, 2015. https://www.wri.org/insights/cop21-glossary-terms-guiding-long-term-emissions-reduction-goal.

Wikipedia

{{cite report |last1=Levin |first1=Kelly |title=COP21 Glossary of Terms Guiding the Long-term Emissions-Reduction Goal |publisher=World Resources Institute |date=2 December 2015 |url=https://www.wri.org/insights/cop21-glossary-terms-guiding-long-term-emissions-reduction-goal |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{levin2015cop21, author = {Levin, Kelly}, title = {{COP21 Glossary of Terms Guiding the Long-term Emissions-Reduction Goal}}, institution = {World Resources Institute}, year = {2015}, month = dec, url = {https://www.wri.org/insights/cop21-glossary-terms-guiding-long-term-emissions-reduction-goal}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }