Single-year mitigation targets: Uncharted territory for emissions trading and unit transfers

The paper argues that single-year emissions targets are fundamentally flawed compared to continuous multi-year targets because they create uncertainty regarding cumulative emissions, are more susceptible to annual variability, and are incompatible with domestic emissions trading schemes. The authors highlight that the use of tradable units can further reduce the ambition of single-year targets, potentially allowing countries to meet goals without domestic mitigation. They recommend that future international agreements mandate continuous multi-year targets to ensure comparability and align with global carbon budgets.

• Single-year emissions targets create significant uncertainty regarding cumulative global emissions and are less ambitious than multi-year targets. Because they lack accountability for years leading up to the target date, emissions may increase during the goal period and only be reduced shortly before the target year, resulting in higher cumulative emissions.
• The use of transferable emission-reduction units can further undermine the ambition of single-year targets. It is theoretically possible for a country to meet a single-year target entirely through the purchase of units without implementing any domestic emission reductions, a scenario that would be far more difficult and costly under a multi-year target.
• Single-year targets are fundamentally incompatible with the functioning of domestic emissions trading schemes (ETS). Multi-year targets allow for the banking of unused allowances and create long-term price signals, whereas single-year targets lack this temporal flexibility and leave countries more vulnerable to annual variability in weather, trade, or economic conditions.
• The issuance and transfer of units by countries with single-year targets complicate accounting and comparability. Unlike multi-year targets, where selling a unit requires a corresponding reduction in the seller's allowance to avoid double-counting, there are no clear accounting requirements for units transferred by single-year target countries in years not covered by their target.
• The paper evaluates four options to address the shortcomings of single-year targets: 1) restricting unit vintage to the target year, 2) limiting the fraction of the target met by units, 3) requiring the translation of single-year targets into continuous multi-year paths, and 4) requiring a multi-year path specifically for the portion of the target met by units. The authors conclude that Option 3 is the most robust from an accounting perspective.
• The authors recommend that any international climate agreement established in 2015 require targets to be continuous and multi-year. This approach aligns with the concept of carbon budgets, as highlighted in the IPCC Fifth Assessment Report, by focusing on limiting cumulative emissions rather than specific annual levels.

APA

Lazarus, M., Kollmuss, A., & Schneider, L. (2014). Single-year mitigation targets: Uncharted territory for emissions trading and unit transfers. Stockholm Environment Institute. https://www.sei.org/mediamanager/documents/Publications/Climate/SEI-WP-2014-01-Single-year-pledges.pdf

Chicago

Lazarus, Michael, Anja Kollmuss, and Lambert Schneider. Single-year mitigation targets: Uncharted territory for emissions trading and unit transfers. Stockholm Environment Institute, 2014. https://www.sei.org/mediamanager/documents/Publications/Climate/SEI-WP-2014-01-Single-year-pledges.pdf.

Wikipedia

{{cite report |last1=Lazarus |first1=Michael |last2=Kollmuss |first2=Anja |last3=Schneider |first3=Lambert |title=Single-year mitigation targets: Uncharted territory for emissions trading and unit transfers |publisher=Stockholm Environment Institute |date=March 2014 |url=https://www.sei.org/mediamanager/documents/Publications/Climate/SEI-WP-2014-01-Single-year-pledges.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{lazarus2014singleyear, author = {Lazarus, Michael and Kollmuss, Anja and Schneider, Lambert}, title = {{Single-year mitigation targets: Uncharted territory for emissions trading and unit transfers}}, institution = {Stockholm Environment Institute}, year = {2014}, month = mar, url = {https://www.sei.org/mediamanager/documents/Publications/Climate/SEI-WP-2014-01-Single-year-pledges.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }