A TIME HORIZON FOR COUNTING BIOENERGY EMISSIONS

The paper examines the 'mitigation timing question' for bioenergy, specifically how the time-frame used to calculate carbon payback affects whether bioenergy is seen as a greenhouse gas reduction or increase. The author critiques several existing approaches—including those by O'Hare et al. and Cherubini et al.—for failing to account for emissions trajectories and the disproportionate value of immediate mitigation. The author contends that once a goal of immediate mitigation is adopted, future reductions must be discounted due to the time value of money, technological progress, and the 'option value' of delaying specific commitments. The author suggests a minimum discount rate of 5% per year, which mathematically aligns with a 20-year payback period, similar to the approach used by the European Commission.

• Bioenergy's impact on greenhouse gas emissions depends on the time-frame used; it increases emissions in the year of use due to land management changes but can reduce them over time as biomass production displaces fossil fuels.
• Current regulatory time-frames for liquid biofuels vary, with the European Commission using twenty years and the U.S. Environmental Protection Agency and California Air Resources Board using thirty years.
• The author critiques the 'biogenic Global Warming Potential' approach used by Cherubini et al., arguing it is flawed because it treats all emissions within a 100-year period as equally harmful and ignores emissions after that period.
• The author rejects the theory that only cumulative emissions matter for peak warming, stating that this ignores the fact that early reductions reduce total damages and that delays make it impossible to meet the 2°C target.
• Immediate mitigation is more valuable than future mitigation because it provides more options, avoids the risk of missing climate thresholds, and is often more cost-effective than waiting for more expensive future requirements.
• The author proposes a 5% annual discount rate for bioenergy emissions, composed of the riskless time value of money (2%), declining mitigation costs from technology (1%), risk of alternative technologies (1%), and lost option value (1%).

APA

Searchinger, T. D. (2012). A TIME HORIZON FOR COUNTING BIOENERGY EMISSIONS. Clean Air Task Force. https://cdn.catf.us/wp-content/uploads/2019/10/21093456/20120731-Searchinger-Time-Horizon-for-Counting-Bioenergy-Emissions.pdf

Chicago

Searchinger, Timothy D. A TIME HORIZON FOR COUNTING BIOENERGY EMISSIONS. Clean Air Task Force, 2012. https://cdn.catf.us/wp-content/uploads/2019/10/21093456/20120731-Searchinger-Time-Horizon-for-Counting-Bioenergy-Emissions.pdf.

Wikipedia

{{cite report |last1=Searchinger |first1=Timothy D. |title=A TIME HORIZON FOR COUNTING BIOENERGY EMISSIONS |publisher=Clean Air Task Force |date=31 July 2012 |url=https://cdn.catf.us/wp-content/uploads/2019/10/21093456/20120731-Searchinger-Time-Horizon-for-Counting-Bioenergy-Emissions.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{searchinger2012time, author = {Searchinger, Timothy D.}, title = {{A TIME HORIZON FOR COUNTING BIOENERGY EMISSIONS}}, institution = {Clean Air Task Force}, year = {2012}, month = jul, url = {https://cdn.catf.us/wp-content/uploads/2019/10/21093456/20120731-Searchinger-Time-Horizon-for-Counting-Bioenergy-Emissions.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }