National Academies Press: OpenBook

Modeling the Economics of Greenhouse Gas Mitigation: Summary of a Workshop (2011)

Chapter: Measurement and Monitoring of Forests in Climate Policy Design--Molly K. Macauley

« Previous: Carbon Offsets in Forest and Land Use--Brent Sohngen
Suggested Citation:"Measurement and Monitoring of Forests in Climate Policy Design--Molly K. Macauley." National Research Council. 2011. Modeling the Economics of Greenhouse Gas Mitigation: Summary of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/13023.


Molly K. Macauley61

Improved data are required for quantitative assessment of the role of forests in climate policy. The attraction of including forests in the shaping of climate policy is twofold. Managing trees to store carbon by reducing deforestation and maintaining forest health can physically counterbalance, or offset, greenhouse gas emissions (GHG).62 Carbon dioxide is taken in by trees and other plants during respiration and sequestered in plant tissue and the surrounding soil.63 Estimates of emissions released in deforestation vary widely, ranging from 7 to possibly 30 percent of all sources of GHG emissions (Denman et al 2007, Houghton and Goetz, 2008). The lack of good data severely limits the capacity to refine these estimates. The data gap also limits the design of cost-effective greenhouse gas abatement regimes, including, for example, the use and monitoring of forest sequestration offsets.

For an individual project or for an individual country, some estimates of forested area and carbon sequestration have been available and when necessary, improved by extensive fieldwork. However, the currently available data are poor for understanding global forests. The only data about global forests are in the form of nationally self-reported information compiled roughly at 5-year intervals by the United Nations’ Food and Agricultural Organization (FAO). The limited quality of these data is widely recognized by the FAO (for example, see discussion in Matthews and Grainger 2002) and by many other experts (for instance, Irland 2009, Grainger 2008). The data limitations confound estimates of net primary productivity, in turn the basis for deriving marginal costs of forest carbon (see Naidoo et al, 2007; Kindermann et al, 2006). Changes in forest are also poorly documented. For instance, measures of deforestation in tropical countries and rates of reforestation or afforestation in boreal and temperate countries are often unreliable (Waggoner 2009).

Remote sensing technology from the vantage point of instruments on satellites and aircraft is available to potentially provide the quality of data needed to improve estimates of forest carbon sequestration and to monitor forestry offsets, but the technology is not yet fully deployed. The institutional and economic barriers are large because forestry resources represent both private (nationally sovereign resources) and public (carbon sequestration) goods. Nations might pay for gathering and reporting such data if, for example, their forest carbon is a valued asset and has some marketability. Voluntary carbon initiatives include some requirements for a census of protocolquality data for global forested area.64

Because forested area is only part of the allometric equation by which to estimate forest carbon storage, fusing or integrating data from different types of remote sensing instruments will overcome some limits. For example, Asner (2009) has led a recent effort to use medium resolution satellite imagery to map the areal extent of tropical forests and then use airborne LIDAR to map a sample of the region. LIDAR (Light Detection And Ranging) uses scattered light to find the distance to an object. LIDAR can penetrate the tree canopy and provide data on the topography of the underlying terrain with estimates at about 80 percent accuracy (Fagan and DeFries). Combining estimates of area and timber volume enable a closer approximation of forest carbon than area measures alone.

Remote sensing can serve additionally to help monitor how forests are being used and provide information


Macauley is Research Director and Senior Fellow, Resources for the Future, This paper draws from research supported by the Alfred P. Sloan Foundation and Resources for the Future and including technical reports by Danny Morris, Ruth DeFries, Paul Waggoner, and Matt Fagan. Responsibility for errors and opinions rests with the author.


More technically, these processes represent stocks and fluxes (changes in stocks requiring measures of carbon gas uptake and release, including influences such as vegetation productivity, pest infestations and the extent and frequency of fires). Above ground carbon in trees represents, on average, less than half of the total carbon in forests (although this varies greatly among forests; see Fagan and DeFries 2009). Significant carbon pools exist in belowground biomass (roots), soil organic matter, dead wood (fallen trees), and litter (such as leaves and branches).


Note that wood products produced from forest timber store carbon.


Japan’s Advanced Land Observing Satellite uses a related but different type of instrument, PALSAR, which is radar operating in the “p-band” of the electromagnetic spectrum. Research using PALSAR data suggest that it may be very promising for improved estimates of biomass. At present, however, Japan has limited the number of researchers who may access these data (Fagan and DeFries). The first map of global forest heights using one uniform method was completed in July 2010 by scientists using data from three satellites operated by the U.S. National Aeronautics and Space Administration. The scientists based the map on data collected during seven years.

Suggested Citation:"Measurement and Monitoring of Forests in Climate Policy Design--Molly K. Macauley." National Research Council. 2011. Modeling the Economics of Greenhouse Gas Mitigation: Summary of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/13023.

for both monitoring the global carbon cycle and enforcing possible policy mechanisms (for example, if forestry offsets are included GHG management). Managing forests to store carbon, given the opportunity cost of forested land including agricultural production and timber supply, could lead to changes in land use elsewhere and in turn complicate modeling and design of effective climate policy. The effort to decrease deforestation or increase afforestation in one geographic area and the shifting of deforestation to another area is a concern that has come to be called leakage. Murray et al. (2004) estimate leakage at 10 to 90 percent for various activities within the U.S. and Sohngen and Brown (2004) examine leakage in an international context (see also discussion in Sohngen 2010). Some forest carbon management proposals allow discounting or rental of forest assets and transferability of the assets to account for the possibility of their impermanence (Pfaff et al. 2000, Kim et al 2008). For these reasons, there would also be the need to update periodically the observations of global changes in forests.

One of the largest challenges to deployment of technology to serve these measurement and observational purposes is the financing of investments in instruments, spacecraft, and aircraft. Discussion of climate policy design has tended to overlook investment requirements. The existing fleet of instruments and craft has largely been underwritten by the space programs of national governments, and national space programs serve a wide range of objectives (Macauley et al. 2009). Moving forward, the financing of measurement and monitoring optimized for forest carbon remains a question.


Asner, Gregory P. 2009. “Tropical Forest Carbon Assessment: Integrating Satellite and Airborne Mapping Approaches,” Environmental Research Letters 4.

Denman, K.L. et al. 2007. “Couplings between Changes in the Climate System and Biogeochemistry,” in S.D. Solomon et al. (eds), Climate Change 2007: The Physical Science Basis Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (Cambridge and NY: Cambridge University Press).

Fagan, M. and R. DeFries. 2009. “Measurement and Monitoring of the World’s Forests: A Review and Summary of Remote Sensing Technical Capability, 2009-2015,” RFF Report, December. (Washington, DC: Resources for the Future).

Grainger, Alan. 2008. “Difficulties in Tracking the Long-term Global Trend in Tropical Forest Area,” Proceedings of the National Academy of Sciences 105:818-23.

Houghton, R.A. and S.J. Goetz. 2008. “New Satellites Help Quantify Carbon Sources and Sinks,” Eos Transactions, American Geophysical Union 89(43): 417-418.

Irland, Lloyd Corell. 2009. “Assessing Sustainability for Global Forests: A Proposed Pathway to Fill Critical Data Gaps,” European Journal of Forest Research.

Kim, Man-Keun, Bruce A. McCarl, and Brian C. Murray. 2008. “Permanence Discounting for Land-Based Carbon Sequestration,” Ecological Economics 64, 763-769.

Kindermann, Georg E., Michael Obersteiner, Ewald Rametsteiner and Ian McCallum. 2006. “Predicting the Deforestation-Trend Under Different Carbon Prices,” Carbon Balance and Management 1:1-15.

Macauley, Molly K., Daniel Morris, Roger Sedjo, Kate Farley, and Brent Sohngen. 2009. “Forest Measurement and Monitoring: Technical Capacity and ‘How Good is Good Enough?’” RFF Report, December (Washington, DC: Resources for the Future).

Matthews, Emily and Alan Grainger. 2002. “Evaluation of FAO’s Global Forest Resources Assessment from the User Perspective,” FAO Corporate Document, at (accessed March 2010).

Murray, Brian C., Bruce A. McCarl, and Heng-Chi Lee. 2004. “Estimating Leakage from Forest Carbon Sequestration Programs,” UWO Department of Economics Working Paper 20043 (London, Canada: University of Western Ontario, Department of Economics).

Naidoo, Robin and Takuya Iwamura. 2007. “Global-Scale Mapping of Economic Benefits from Agricultural Lands: Implications for Conservation Priorities,” Biological Conservation140:40-49.

Pfaff, Alexander S.P., Suzi Kerr, R.Flint Hughes, Shuguang Liu, G. Arturo Sanchez-Azofeifa, David Schimel, Joseph Tosi, and Vicente Watson. 2000. “The Kyoto Protocol and Payments for Tropical Forest: An Interdisciplinary Method for Estimating Carbon-Offset Supply and Increasing the Feasibility of a Carbon Market Under the CDM,” Ecological Economics 35203-221.

Sohngen, B., and S. Brown. 2004. “Measuring Leakage from Carbon Projects in Open Economies,” Canadian Journal of Forest Research, 34,: 8929-839.

Waggoner, Paul. 2009. “Forest Inventories: Discrepancies and Uncertainties,” RFF Discussion Paper 09-29, August (Washington, DC: Resources for the Future).

Suggested Citation:"Measurement and Monitoring of Forests in Climate Policy Design--Molly K. Macauley." National Research Council. 2011. Modeling the Economics of Greenhouse Gas Mitigation: Summary of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/13023.
Page 109
Suggested Citation:"Measurement and Monitoring of Forests in Climate Policy Design--Molly K. Macauley." National Research Council. 2011. Modeling the Economics of Greenhouse Gas Mitigation: Summary of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/13023.
Page 110
Next: International Offsets Usage in Proposed U.S. Climate Change Legislation--Allen A. Fawcett »
Modeling the Economics of Greenhouse Gas Mitigation: Summary of a Workshop Get This Book
Buy Paperback | $47.00 Buy Ebook | $37.99
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

Models are fundamental for estimating the possible costs and effectiveness of different policies for reducing greenhouse gas (GHG) emissions. There is a wide array of models to perform such analysis, differing in the level of technological detail, treatment of technological progress, spatial and sector details, and representation of the interaction of the energy sector to the overall economy and environment. These differences impact model results, including cost estimates. More fundamentally, these models differ as to how they represent fundamental processes that have a large impact on policy analysis--such as how different models represent technological learning and cost reductions that come through increasing production volumes, or how different models represent baseline conditions.

Reliable estimates of the costs and potential impacts on the United States economy of various emissions reduction and other mitigation strategies are critical to the development of the federal climate change research and development portfolio. At the request of the U.S. Department of Energy (DOE), the National Academies organized a workshop, summarized in this volume, to consider some of these types of modeling issues.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook,'s online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    Switch between the Original Pages, where you can read the report as it appeared in print, and Text Pages for the web version, where you can highlight and search the text.

    « Back Next »
  6. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  7. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  8. ×

    View our suggested citation for this chapter.

    « Back Next »
  9. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!