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Repository of Articles on Offset Quality

Repository of Articles on Offset Quality

Last updated: February 18, 2024

This webpage hosts a repository of peer-reviewed articles and independent research institute reports that analyze the quality of offset projects and protocols (also called methodologies). Quality has been a critical challenge for carbon offsetting from its inception. Studies of carbon offsets from the first major carbon offset program, the UN Clean Development Mechanism (CDM), through compliance offset programs like California's, and growing voluntary offset programs have documented significant quality issues. 

Cames et al. (2016) found that 85% of CDM offset projects are likely to be non-additional (the reductions would likely have occurred regardless of the incentive from the offset program) or otherwise over-credited, and so the reductions should not have been claimed by other countries to meet their UN emission reduction targets. This is supported by an earlier study that found that the "large majority" of CDM projects are likely to be non-additional (Haya 2010). Studies of California’s second generation offset program, designed to remedy problems with the CDM, document similar levels of overcrediting from by its Forest protocol, which generates over 80% of the program's offset credits. Currently, four offset registries generate most of the offset credits on the voluntary offset market (see all projects and credits in our Voluntary Registry Offsets Database). These credits are available to companies, universities, individuals, and others who wish to meet voluntary emissions targets or otherwise "offset" their emissions of greenhouse gases. Articles on a range of protocols find many of the same quality challenges.

We define offset quality as credits that accurately represent their actual climate benefit, taking into account: 

  • additionality - would the projects have occurred without the offset program?
  • baselines - what would likely have occurred without the offset program?
  • leakage - do projects displace emitting activities to elsewhere?
  • perverse incentives - do projects otherwise create incentives that increase emissions outside of project accounting boundaries?
  • durability - is the risk that any stored carbon will be released back into the atmosphere managed and fully accounted for?
  • emissions factors - otherwise are the methods used to estimate project impacts conservative and aligned with the latest science?
  • do no harm - do projects have low risk of social or environmental harm?
  • scalable - if scaled, can the project type contribute to meeting the Paris Agreement goal of limiting increases in global temperatures to no more than 1.5 Celsius?

Credit quality can be assessed at the project or project type level. At the project type level, credits are considered to have environmental integrity if the total credits generated over the set of projects is unlikely to exceed their actual climate benefit, taking into account that overcrediting such as from the participation of non-additional projects can be counterbalanced by undercrediting such as from conservative methodological choices across the portfolio of participating projects. 

In addition to the academic analyses listed below, some excellent investigative reports by media outlets and non-profit organizations have covered offset project outcomes. Some of these articles can be found on our media page as well as Carbon Market Watch's carbon project case study tracker and Carbon Plan's media page. 

Protocols with the most credits for each project type are designated with an *.

Please let us know about any peer reviewed or independent research institute publications that we missed and if new publications come out by emailing bhaya@berkeley.edu. 

Please cite as Barbara Haya & Emily Clayton. (2024) Repository of Articles on Offset Quality, Berkeley Carbon Trading Project, University of California, Berkeley

Project types covered |

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Clean Water & Community Boreholes 

 

 

Articles:

  • Pickering, A. J., Arnold, B. F., Dentz, H. N., Colford, J. M., & Null, C. (2017). Climate and Health Co-Benefits in Low-Income Countries: A Case Study of Carbon Financed Water Filters in Kenya and a Call for Independent Monitoring. Environmental Health Perspectives, 125(3), 278–283. https://doi.org/10.1289/EHP342

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Cookstoves

 

⇒ Download the Voluntary Carbon Market Cookstove Baseline and Project Fuel/Stove Database, v2 
     (v2 has data through Nov 9, 2022. Archive of v1 with data through the end of 2021 is here)

Protocols:

Cookstove offset projects reduce carbon dioxide (CO2) and non-CO2 emissions from the combustion of solid fuel used for cooking in low- and middle-income countries. These projects either reduce the amount of biomass needed through more efficient stove design or replace a traditional stove (i.e., a three-stone fire) with a fuel with a smaller carbon footprint (e.g., ethanol, biogas, liquified petroleum gas (LPG)). The non-CO2 emissions from traditional stoves include methane (CH4), nitrous oxide (N2O), black carbon (BC), organic carbon (OC), elemental carbon (EC), and other products of incomplete combustion (PICs). 

Clean Development Mechanism (CDM) and Gold Standard (GS) methodologies take different approaches to quantifying abated carbon from improved cookstoves. GS credits reductions in CO2 emissions from the combustion of non-renewable biomass and reductions in CH4 and N2O gases from all biomass combustion (renewable and non-renewable). For projects that switch cooking fuels from fuelwood or charcoal to another fuel like ethanol or LPG, the protocol also accounts for CO2 and non-CO2 gases from the new replacement fuel. In contrast, the CDM only credits reductions in CO2 from non-renewable biomass, ignoring non-CO2 gases. Also, instead of using traditional fuels as the baseline, the CDM applies an emissions factor of a fossil fuel that is projected to substitute non-renewable biomass. This avoids crediting avoided deforestation, which is not permitted under the CDM. This method, in theory, provides a conservative estimate of emissions reductions, given that emissions from non-renewable biomass is typically greater than fossil fuels per unit of heat energy provided to the pot. It also is simpler, since it avoids directly measuring the baseline technology’s emission profile. But it does not reflect actual emission reductions. Further, for projects that switch fuels, the CDM only credits the increased efficiency of the new stove in delivering heat to a pot, and ignores any reduced emissions from the switch of the fuel. CDM includes a deduction to account for any continued use of baseline stoves. 

In our study, Gill-Wiehl et al. (2024), we comprehensively assess the quality of the credits from five efficient cookstove methodologies. We perform a quantitative over/under-crediting analysis, analyzing the full set of assumptions and methods prescribed by the methodologies and used by projects. We do this by comparing the credits generated by the projects, with our own independent assessment of their emissions benefits based on a review of the scientific literature and our own additional analysis. We estimate that our project sample is over-credited 9.2 times. This article and its supplemental material contact a complete review of the literature. Below we summarize some of the most important articles. A summary of this study can be found on our cookstoves webpage. 

Quite a few other studies have looked closely at the effectiveness of improved and clean cookstoves projects at reducing GHGs, improving health and well-being, and measuring those impacts as offset projects. These studies identify several important sources of over-crediting by CDM and GS protocols including default values for the fraction of biomass used for cooking that is non-renewable biomass, incorrect stoichiometry that ignores how reductions in non-CO2 gases lead to increased CO2 emissions, and inadequate monitoring of stove adoption and use. Additionality, studies identify a smaller source of under-crediting by CDM protocols—ignoring non-CO2 gases—and slight under-crediting by both protocols from using default CO2 emissions factors that are on average lower than those found in the literature. Uncertainties remain regarding leakage and black carbon. All improved cookstoves have significant co-benefits from reducing the need to collect fuelwood or purchase charcoal, but only tier 4 and 5 stoves (solar, electric, biogas, natural gas (NG), LPG, ethanol, or an emerging class of advanced biomass gasifiers (e.g., Mimi Motto)) reduce cookstove smoke enough to meaningfully reduce the respiratory and related health impacts from breathing wood smoke. 

These studies are described in more detail below. 

Sources of Under-Crediting 

Sanford & Burney (2015) find systematic under-crediting from the choice of default CO2 emissions factors for CDM and GS protocols. They compile and compare protocol and literature-derived emission factors for stove types including traditional firewood, charcoal, natural draft, gasifier, and forced draft stoves. They find that the protocols’ medium CO2 emission factor values are often very different from those found in the literature. The default CO2 emission factors that CDM uses underestimate the CO2 emissions for all stove types except gasifiers, leading to under-crediting. The default CO2 emission factors that GS uses underestimate the CO2 emissions from traditional firewood and charcoal stoves, leading to under-crediting. Beyond CO2, the authors point out that the CDM under-credits by ignoring reductions in CH4 and N2O gases. 

Sanford & Burney (2015) also argue that all methodologies except GS are under-crediting by not accounting for emission reductions of renewable biomass. GS accounts for the emission reductions of renewable biomass for CH4 and N2O gases, but not BC, OC, EC, or other PICs. They argue that all protocols should include the reductions of PICs released from the combustion of renewable biomass. Sanford & Burney include BC, OC, and EC in their PICS; however, subsequent research makes the results for these PICs less certain, which we discuss below. That being said, the accounting for CH4 and N2O gases from the combustion of renewable biomass still stands as a source of under-crediting.

Sources of Over-Crediting 

Fraction of Non-Renewable Biomass (fNRB)

Projects that reduce CO2 emissions from fuelwood or charcoal use can only be credited for the proportion that is from non-renewable sources. Bailis et al. (2015) developed the WISDOM model to calculate refined fNRB estimates that account for geographical, ecological, and land use heterogeneity. The WISDOM model can be implemented at a minimum administrative unit of analysis (i.e, villages, counties, states) and has been used to estimate fNRB for 25 countries. Using their more refined fNRB values at the regional level, Bailis et al. (2017) found 41-59% lower estimates of abated carbon than the CDM and Gold Standard protocols. Johnson, Edwards & Masera (2010) and Bailis et al. (2017) advocate for the use of community-level fNRB values in emission reduction calculations. 

Stove Adoption and Use Monitoring

Lee et al. (2013) in their review of GS and CDM interview experts in the clean cooking field who question if the improved stove (funded by the GS/CDM) meets all the household’s cooking needs, and thus assume that there is an overestimation of improved stove use. Lee et al. (2013) advocate for data loggers connected to the improved stove to fully and accurately capture actual usage. GS has implemented a new metered protocol for electricity, LPG, biogas, and ethanol metered stoves.

Stoichiometry

Whitman & Lehmann (2011) explain that Gold Standard protocols over-credit due to an error in the way they account for reductions in methane emissions from renewable biomass. Instead of claiming a reduction in methane using its full GWP value, the protocol should use a lower GWP value that accounts for the renewability of the carbon which would enter the atmosphere as CO2. This correction would lower the calculated climate benefits of reducing methane by 12%. 

Stove production

While neither protocol accounts for the production and transport of improved cookstoves to households, one study indicates that this oversight has a negligible impact on the program. Wilson et al. (2016) find that replacing one three-stone fire with a Berkeley-Darfur Stove in Sudan saves 440 times more carbon dioxide equivalent than the stove’s materials, manufacturing, transportation, and end-of-life. 

Unknowns 

Leakage

Another source of uncertainty is unquantified leakage (Simon, Bumpus & Mann, 2012). It is largely unknown whether the introduction of an improved stove program increases the consumption of biomass of non-project households. The methodologies allow projects to either thoroughly evaluate five potential sources of leakage (e.g., non-participant households using more wood due to increased supply as the project has reduced overall community demand) or rely on an unjustified default value of 5% (Simon, Bumpus & Mann, 2012). 

Black Carbon

Freeman & Zerrifi (2014) and Sanford & Burney (2015) argue that the CDM and GS protocols both result in substantial under-crediting by ignoring reductions in BC emissions which has 600 times the GWP of CO2. (Freeman and Zerriffi 2014; Sanford and Burney 2015). Subsequent research, however, has found the climate benefits of reducing BC from improved cookstoves to be ambiguous (Kodros et al., 2015; Huang et al., 2018). This ambiguity is partly due to the simultaneous reduction of co-pollutants, some of which have climate cooling effects. Improved stoves shrink the ratio of EC (a climate cooler) to OC (a climate warmer), an effect which reduces and possibly negates the climate benefits of lowering BC emissions (Johnson et al., 2008). Grieshop et al. (2009) note that accounting for benefits over shorter time periods could counter-balance these complicating factors, as BC’s short lifespan may offer immediate climate relief, while the imbalance of EC to OC has implications over longer time spans. 

Other Considerations 

Additionality 

Highlighting the dearth of systematic, empirical study of the additionality of carbon financing projects, only Purdon (2015) evaluates the additionality of numerous bioenergy carbon finance projects including a CDM cookstove project in Tanzania. Through multiple field visits, Purdon verified the stated fuelwood reductions, observed no improved cookstove use in the control village, and found the project suspended when the carbon financing fell through. Purdon highlights potential issues with the additionality of cookstove projects, although only one case is examined. 

Co-benefits

CDM and GS project documents have highlighted the co-benefits of cookstove projects with regard to family livelihoods, income generation, and female empowerment; however, Lehmann (2019) found that the co-benefits are often less transformational than presented. Although overstated, other research supports the co-benefits in terms of reducing time spent collecting firewood (Wang & Bailis, 2015; Gebreegziabher et al., 2018), time spent cooking (Gebreegziabher et al. 2018), and exposure to indoor air pollution (Smith-Sivertsen et al., 2009; Smith et al., 2010). However, due to concentration curves, the health benefits from an improved stove are only realized if the emissions (and resulting exposure to indoor air pollution) are drastically reduced. The World Health Organization (WHO) quantifies the level of reduction needed and then categorizes stoves and fuels as meeting a Tier 1-5 with 5 being the best health improvement, according to the International Standardization Organization’s Voluntary Performance Targets (VPTs) for PM2.5 and CO. Solar, electric, biogas, natural gas, LPG, and ethanol fuels all meet the Tier 5 criteria for both PM2.5 and CO. Currently, only one improved biomass stove, the Mimi Motto, meets Tier 4 of the WHO’s VPTs (WHO, 2021). 

Articles:

  • Bailis, R., Wang, Y., Drigo, R., Ghilardi, A. & Masera, O. (2017). Getting the numbers right: Revisiting woodfuel sustainability in the developing world. Environmental Research Letters, 12(11). https://doi.org/10.1088/1748-9326/aa83ed
  • Bailis, R., Drigo, R., Ghilardi, A. & Masera, O. (2015). The carbon footprint of traditional woodfuels. Nature Climate Change, 5(3), 266–272. https://doi.org/10.1038/nclimate2491
  • Beltramo, T. & Levine, D. I. (2013). The effect of solar ovens on fuel use, emissions and health: Results from a randomised controlled trial. Journal of Development Effectiveness, 5(2), 178–207. https://doi.org/10.1080/19439342.2013.775177
  • Champion, W. M. & Grieshop, A. P. (2019). Pellet-Fed Gasifier Stoves Approach Gas-Stove Like Performance during in-Home Use in Rwanda. Environmental Science and Technology, 53(11), 6570–6579. https://doi.org/10.1021/acs.est.9b00009
  • Freeman, O. E. & Zerriffi, H. (2014). How you count carbon matters: Implications of differing cookstove carbon credit methodologies for climate and development cobenefits. Environmental Science and Technology, 48(24), 14112–14120. https://doi.org/10.1021/es503941u
  • Gebreegziabher, Z., Beyene, A. D., Bluffstone, R., Martinsson, P., Mekonnen, A. & Toman, M. A. (2018). Fuel savings, cooking time and user satisfaction with improved biomass cookstoves: Evidence from controlled cooking tests in Ethiopia. Resource and Energy Economics, 52, 173–185. https://doi.org/https://doi.org/10.1016/j.reseneeco.2018.01.006
  • Gill-Wiehl, A., Kammen, D. M., & Haya, B. K. (2024). Pervasive over-crediting from cookstove offset methodologies. Nature Sustainability. https://doi.org/10.1038/s41893-023-01259-6
  • Grieshop, A. P., Reynolds, C. C. O., Kandlikar, M. & Dowlatabadi, H. (2009). A black-carbon mitigation wedge. Nature Geoscience, 2(8), 533–534. https://doi.org/10.1038/ngeo595
  • Hanna, R., Duflo, E. & Greenstone, M. (2016). Up in smoke: The influence of household behavior on the long-run impact of improved cooking stoves. American Economic Journal: Economic Policy, 8(1), 80–114. https://doi.org/10.1257/pol.20140008
  • Huang, Y., Unger, N., Storelvmo, T., Harper, K., Zheng, Y. & Heyes, C. (2018). Global radiative effects of solid fuel cookstove aerosol emissions. Atmospheric Chemistry and Physics, 18, 5219–5233. https://doi.org/10.5194/acp-18-5219-2018. 
  • Johnson, M., Edwards, R., Alatorre Frenk, C. & Masera, O. (2008). In-field greenhouse gas emissions from cookstoves in rural Mexican households. Atmospheric Environment, 42(6), 1206–1222. https://doi.org/10.1016/j.atmosenv.2007.10.034
  • Johnson, M., Edwards, R. & Masera, O. (2010). Improved stove programs need robust methods to estimate carbon offsets. Climatic Change, 102(3), 641–649. https://doi.org/10.1007/s10584-010-9802-0
  • Kodros, J. K., Scott, C. E., Farina, S. C., Lee, Y. , L’Orange, C., Volckens, J. & Pierce, J. R. (2015). Uncertainties in global aerosols and climate effect due to biofuel emissions. Atmospheric Chemistry and Physics, 15, 8577-8596. https://doi.org/10.5194/acp-15-8577-2015.  
  • Lee, C. M., Chandler, C., Lazarus, M. & Johnson, F. X. (2013). Assessing the Climate Impacts of Cookstove Projects: Issues in Emissions Accounting. Challenges in Sustainability, 1(2), 53–71. https://doi.org/10.12924/cis2013.01020053
  • Lehmann, I. (2019). When cultural political economy meets ‘charismatic carbon’ marketing: A gender-sensitive view on the limitations of Gold Standard cookstove offset projects. Energy Research and Social Science, 55(April), 146-154. https://doi.org/10.1016/j.erss.2019.05.001
  • Levine, D. I., Beltramo, T., Blalock, G. & Cotterman, C. (2012). What Impedes Efficient Adoption of Products? Evidence from Randomized Variation in Sales Offers for Improved Cookstoves in Uganda. https://escholarship.org/uc/item/7qk8m53w
  • Purdon, M. (2015). Opening the Black Box of Carbon Finance “Additionality”: The Political Economy of Carbon Finance Effectiveness across Tanzania, Uganda, and Moldova. World Development, 74, 462–478. https://doi.org/10.1016/j.worlddev.2015.05.024
  • Sanford, L. & Burney, J. (2015). Cookstoves illustrate the need for a comprehensive carbon market. Environmental Research Letters, 10(8). https://doi.org/10.1088/1748-9326/10/8/084026
  • Simon, G. L., Bumpus, A. G. & Mann, P. (2012). Win-win scenarios at the climate-development interface: Challenges and opportunities for stove replacement programs through carbon finance. Global Environmental Change, 22(1), 275–287. https://doi.org/10.1016/j.gloenvcha.2011.08.007
  • Smith-Sivertsen, T., Díaz, E., Pope, D., Lie, R. T., Díaz, A., McCracken, J., Bakke, P., Arana, B., Smith, K. R. & Bruce, N. (2009). Effect of Reducing Indoor Air Pollution on Women’s Respiratory Symptoms and Lung Function: The RESPIRE Randomized Trial, Guatemala. American Journal of Epidemiology, 170(2), 211–220. https://doi.org/10.1093/aje/kwp100
  • Smith, K. R., McCracken, J. P., Thompson, L., Edwards, R., Shields, K. N., Canuz, E. & Bruce, N. (2010). Personal child and mother carbon monoxide exposures and kitchen levels: Methods and results from a randomized trial of woodfired chimney cookstoves in Guatemala (RESPIRE). Journal of Exposure Science and Environmental Epidemiology, 20(5), 406–416. https://doi.org/10.1038/jes.2009.30
  • Wang, Y. & Bailis, R. (2015). The revolution from the kitchen: Social processes of the removal of traditional cookstoves in Himachal Pradesh, India. Energy for Sustainable Development, 27, 127–136. https://doi.org/10.1016/j.esd.2015.05.001
  • Whitman, T. L. & Lehmann, C. J. (2011). Systematic under and overestimation of GHG reductions in renewable biomass systems. Climatic Change, 104(2), 415–422. https://doi.org/10.1007/s10584-010-9984-5
  • WHO. (2021). Clean Cooking Webinar: Defining and Achieving Clean Cooking. World Health Organization. https://www.youtube.com/watch?v=Q2jt03x5JpA. 
  • Wilson, D. L., Talancon, D. R., Winslow, R. L., Linares, X. & Gadgil, A. J. (2016). Avoided emissions of a fuel-efficient biomass cookstove dwarf embodied emissions. Development Engineering, 1, 45–52. https://doi.org/10.1016/j.deveng.2016.01.001.

Written by Annelise Gill-Wiehl

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Improved Forest Management (IFM)

 

Protocols:

  • American Carbon Registry (ACR):
    • Improved Forest Management (IFM) on Canadian Forestlands 
    • Improved Forest Management (IFM) on Non-Federal U.S. Forestlands 
    • Improved Forest Management (IFM) on Small Non-Industrial Private Forestlands 
  • California Air Resources Board (ARB):
    • U.S. Forest Projects
  • Climate Action Reserve (CAR):
    • Forest Protocol- Version 5.0
    • Mexico Forest Protocol- Version 2.0
  • Verified Carbon Standard (Verra):
    • VM0003 Methodology for Improved Forest Management through Extension of Rotation Age- Version 1.2 
    • VM0005 Methodology for Conversion of Low-productive Forest to High-productive Forest- Version 1.2 
    • VM0010 Methodology for Improved Forest Management: Conversion from Logged to Protected Forest - Version 1.3 
    • VM0012 Improved Forest Management in Temperate and Boreal Forests (LtPF)- Version 1.2
    • VM0034 Canadian Forest Carbon Offset Methodology- Version 2.0

Improved Forest Management (IFM) offset projects credit reductions in carbon loss and increases in carbon sequestration in existing forests. Most IFM projects are in the United States and involve conservation practices which reduce timber harvesting compared to the baseline scenarios used. Other types of IFM activities include increasing the average age of trees on managed forestlands through extended harvest rotations, increasing forest productivity through changes forest management like thinning, and low impact logging practices. Credits are generated as the difference in on site carbon stocks compared to the baseline scenario, adjusted to account for carbon held long-term in harvest wood products, leakage effects (when reductions in timber harvesting on project lands displace harvesting and associated forest carbon loss to other lands to meet timber demand), and an uncertainty deduction. A portion of credits are held in a buffer insurance pool to cover the estimated risk of reversal including from fire and drought. Forestland owners commit to not deplete carbon stocks for a pre-specified number of years (100 for the CAR U.S. protocol and ARB, 40 for ACR, and varied figures for other protocols).

Haya et al. (2023) comprehensively assesses the quality of all IFM offset methodologies that generated credits as of March 2022. We compare the methods used by the methodologies to research literature related to baselines, leakage, durability, and forest carbon accounting. Below is a short summary of key articles cited in this assessment.

Most articles on IFM protocols focus on the California Air Resources Board’s (ARB’s) offset protocol. This protocol has the greatest share of IFM offset credits globally and is based on the Climate Action Reserve’s U.S. Forest protocol. Published articles find that ARB projects over-credit substantially in its methods for establishing project additionality, baselines, leakage impacts, and reversal risks, and also create incentives that increase fire risk. Most ARB IFM projects define their baseline (what would likely have happened without the offset income) at or slightly above common practice for the forest type, which is the minimum allowable baseline for most projects. Stapp et al. (2023) use remote sensing to assess the baselines and additionality of 90 ARB IFM projects across the United States that had issued credits and made spacial coordinates publicly available. The study found that participating lands had high initial carbon stocks and low historical harvesting compared to the regional averages used to set the baselines, and detected little effect of the offset project on forest management compared to other non-offset lands with similar characteristics. Similarly, Coffield et al. (2022) use remote sensing-based datasets to compare the outcomes of 37 California-based ARB IFM offset projects with similar control lands and found no evidence that the offset program influenced land management practice. Also on additionality, Anderson et al. (2017a and 2017b) find that in a small survey of participating landowners, 31% of respondents reported that they were not confident of the additionality of their own projects. Badgley et al. (2022b) find that inaccurate methods for determining common practice which is used in establishing project baselines has on its own led to over-crediting by around 29%. They propose an alternative method for assessing common practice that more accurately represents common practice for participating forestlands. Haya (2019) finds that ARB IFM projects have over-credited by 51–82% by applying lenient methods for accounting for leakage (when offset-induced reductions in timber harvesting displaces logging, and the associated forest carbon loss, to elsewhere to meet demand). Anderegg et al. (2020) find that ARB’s offset protocol underestimates reversal risk, and therefore project contributions into the buffer insurance pool, from wildfire given climate change. If recent wildfire trends continue or increase, the entirety of the buffer pool will be consumed well before the 100-year project lifetimes (Badgley et al. 2022a). Herbert et al. (2022) find that ARB's IFM offset protocol creates incentives counter to long term carbon stability and the goals of other California programs focused on reducing fire risk. 

On Darkwoods VCS IFM project in British Columbia, Canada, Van Kooten et al. (2014) argue that the baseline –timber liquidation – is implausible, leading to high levels of over-crediting. They also argue that the true baseline is highly uncertain.  

Last updated May 24, 2023

Articles:

  • Anderegg, W. R., Trugman, A. T., Badgley, G., Anderson, C. M., Bartuska, A., Ciais, P., Cullenward, D., Field, C. B., Freeman, J., & Goetz, S. J. (2020). Climate-driven risks to the climate mitigation potential of forests. Science, 368(6497). https://www.science.org/doi/10.1126/science.aaz7005
  • Anderson, C. M., Field, C. B., & Mach, K. J. (2017). Forest offsets partner climate-change mitigation with conservation. Frontiers in Ecology and the Environment, 15(7), 359–365. https://doi.org/10.1002/fee.1515
  • Anderson, C., & Perkins, J. (2017). Counting California Forest Carbon Offsets: Greenhouse Gas Mitigation Lessons from California’s Cap-and-Trade U.S. Forest Compliance Offset Program (Report submitted as public comment to the California Air Resources Board on the 2017 Scoping Plan Update). https://www.arb.ca.gov/lispub/comm/iframe_bccomdisp.php?listname=scopingplan2030&comment_num=89&virt_num=70
  • Badgley, G., Chay, F., Chegwidden, O. S., Hamman, J. J., Freeman, J., and Cullenward, D. (2022a). California’s forest carbon offsets buffer pool is severely undercapitalized. Frontiers in Forests and Global Change (5). https://doi.org/10.3389/ffgc.2022.930426 
  • Badgley, G., Freeman, J., Hamman, J. J., Haya, B., Trugman, A. T., Anderegg, W. R. L., & Cullenward, D. (2022b). Systematic over‐crediting in California’s forest carbon offsets program. Global Change Biology, gcb.15943. https://doi.org/10.1111/gcb.15943
  • Coffield, S. R., Vo, C. D., Wang, J. A., Badgley, G., Goulden, M. L., Cullenward, D., et al. (2022). Using remote sensing to quantify the additional climate benefits of California forest carbon offset projects. Global Change Biology, gcb.16380. https://doi.org/10.1111/gcb.16380.
  • Haya, B. (2019). The California Air Resources Board’s U.S. Forest offset protocol underestimates leakage. University of California, Berkeley. https://gspp.berkeley.edu/assets/uploads/research/pdf/Policy_Brief-US_Forest_Projects-Leakage-Haya_4.pdf
  • Haya, B. K., Evans, S., Brown, L., Bukoski, J., Butsic, V., Cabiyo, B., Jacobsom, R., Kerr, A., Potts, M., & Sanchez, D. L. (2023). Comprehensive review of carbon quantification by improved forest management offset protocols.Frontiers in Forests and Global Change (6), https://doi.org/10.3389/ffgc.2023.958879
  • Herbert, C., Haya, B. K., Stephens, S. L., and Butsic, V. (2022). Managing nature-based solutions in fire-prone ecosystems: Competing management objectives in California forests evaluated at a landscape scale. Frontiers in Forests and Global Change. https://doi.org/10.3389/ffgc.2022.957189 
  • Ruseva, T., Hedrick, J., Marland, G., Tovar, H., Sabou, C., & Besombes, E. (2020). Rethinking standards of permanence for terrestrial and coastal carbon: Implications for governance and sustainability. Current Opinion in Environmental Sustainability, 45, 69–77. https://doi.org/10.1016/j.cosust.2020.09.009
  • Stapp, J., Nolte, C., Potts, M., Baumann, M., Haya, B. K., Butsic, V. (2023). Little evidence of management change in California’s forest offset program. Communications Earth & Environment, 4, 331. https://www.nature.com/articles/s43247-023-00984-2
  • Van Kooten, G. C., Bogle, T. N., & de Vries, F. P. (2014). Forest Carbon Offsets Revisited: Shedding Light on Darkwoods. Forest Science, 61(6), 370–380. https://doi.org/10.5849/forsci.13-183

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Landfill Methane


 

Protocols: 

Landfill gas capture offset projects capture and destroy methane generated by landfills. Landfills produce methane when organic materials decompose in the absence of oxygen. Landfill gas capture offset projects convert methane into carbon dioxide, a less potent greenhouse gas, through flaring or through use by injection into a natural gas pipeline, sale as vehicle fuel, or direct use to generate electricity or heat. 

Most articles on landfill gas capture offsets focus on CDM projects. These articles raise several environmental integrity issues.

Cames et al. (2016) review the Clean Development Mechanism large-scale protocol ACM0001 “Flaring or Use of Landfill Gas” and small-scale protocol AMS-III-G “Landfill Methane Recovery” based on literature review and their own desk analysis. They find that most projects are likely to be additional because they are rarely implemented in CDM countries without offsets and the significant improvement on project internal rate of return from offset income. Over-crediting is likely occurring for some projects. Baseline assumptions are likely to over-credit specifically for landfills where capture is required or that had existing capture systems before the start of the offset project but had little data about capture rates from those systems. Early versions of ACM0001 (v11 and earlier) and AMS-III.G (v7 and earlier) also over-estimate baseline emissions by ignoring the greater soil methane oxidation that would likely have occurred without a capture system; this was partially fixed in later versions of both protocols. 

The authors also identify several potential perverse incentives. The protocols create the incentive for landfill managers to manage waste to generate more methane, for example, by stacking waste rather than extending it across a larger area. To avoid over-crediting because of such practices, updated CDM protocols exclude projects where management practices are changed in order to increase methane generation, although the authors indicate that verifying this condition is met may prove challenging in practice. Second, by increasing income from landfills, the protocol creates a perverse incentive for governments and waste managers not to handle waste more sustainably by recycling or composting. The protocols also create a perverse incentive for governments not to require waste separation or methane capture. Landfill gas capture projects can also restrict waste picker access to landfill sites, reducing the amount of reuse and recycling of materials and the emissions savings from these activities, and impacting livelihoods (cite GAIA). 

Docena (2010) describes how the perverse incentives Cames et al (2016) identify played out in practice in the Philippines. Though waste separation and landfill methane capture are both federally required, landfill gas capture was still allowed as CDM offset projects if those regulations are not enforced. Docena describes how this created a perverse incentive for governments not to enforce these regulations, and locked in an approach to waste management that is unsustainable and higher emitting (even with gas capture) than other alternatives.

Mollersten & Gronkvist (2007) find that the CDM exaggerates emissions reductions from landfill gas capture projects by treating the captured methane as completely eliminated, rather than accounting for the release of CO2 from methane combustion. This results in over-crediting of 13% from CDM landfill gas capture projects. 

Lee et al. (2013) document discrepancies in credits issued under various landfill gas capture protocols. They find that the CDM generates more credits than Climate Action Reserve Version 4.0 for one sample project because it assumes higher methane destruction efficiency and ignores soil oxidation factors. 

Baxter & Gilligan (2017) raise additionality concerns in the context of Australia’s Emissions Reduction Fund (ERF), finding that many of the projects issuing credits had already been capturing methane or lacked regulatory additionality due to state-level requirements for methane capture.

Articles:

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Project types on page 2 of the Repository:

⇒ Mine Methane Capture

⇒ N2O Destruction in Adipic Acid Production

⇒ N2O Destruction in Nitric Acid Production

⇒ REDD+ (reducing emissions from deforestation and forest degradation)

⇒ Renewable Energy & Hydropower (Grid-Connected)

⇒ Soil Carbon

⇒ Solar Lighting