Direct and Indirect Human Contributions to Terrestrial Carbon Fluxes A Workshop Summary (2004) / Chapter Skim
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4 Summary of the State of the Science and Its Policy Implications
4 Summary of the State of the Science and Its Policy Implications
Pages 48-55
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From page 48... ...
Geological Survey, led a discussion to summarize the state of the science on quantifying a change in carbon stocks and partitioning the carbon fluxes by cause and the implications for policy makers. Sundquist stated that the current challenge is to address the scientific questions in ways that contribute to the information needs of the policy community.
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From page 49... ...
Workshop participants noted that there is a large and growing set of data important for characterizing carbon stocks and fluxes and the mechanisms involved over varying spatial and temporal scales, and these measurements are increasing in extent, resolution, and reliability. Nevertheless, several data needs were highlighted to improve the assessment of terrestrial carbon stocks.
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From page 50... ...
It was noted that fire suppression can cause a forest to lose its resilience to a catastrophic fire, thereby causing a massive release of stored carbon and making the forest more vulnerable to a fire that completely alters the forest structure. Workshop participants also addressed a closely related question: What is the efficacy and longevity of various carbon storage practices and technology?
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From page 51... ...
The carbon savings associated with decreased emissions, however, will continue as long as the no tillage management practice continues. In evaluating the efficacy of carbon storage practices, several participants expressed concern that the total costs of management be considered, including other greenhouse gas emissions and the carbon costs of fertilizer production or irrigation.
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From page 52... ...
Workshop speakers confirmed that indirect human-induced effects can alter the timing and magnitude of emissions and removals, although some participants suggested that if the influence of past management changes on carbon fluxes could be accurately estimated, the indirect effects might appear insignificant. The workshop discussions highlighted how indirect and natural effects are difficult to estimate and predict.
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From page 53... ...
What methods are available to distinguish direct human-induced changes in terrestrial carbon stocks and related greenhouse gas emissions from those caused by indirect human-induced effects, natural effects, and effects due to past practices in forests and current or former agricultural lands? Workshop participants suggested a progression of approaches that could be used for estimating direct effects and potentially developed for separating those effects from indirect human-induced effects, natural effects, and effects due to past land use practices: · Inventory data analysis enables estimations of the areas over which direct effects are taking place and the amount of carbon change per unit area.
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From page 54... ...
Workshop participants also discussed the feasibility and practicality of separating direct and indirect human-induced effects. Many participants expressed the opinion that a quantitative separation of direct and indirect effects in any detail is not practical at this time, and if it were required as part of national inventories, it would add significantly to the reporting costs.
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From page 55... ...
While the above methods were not considered to be adequately developed for separation of direct, indirect, and natural effects at this time, several workshop participants expressed optimism that over the next decade or so information from these methods could provide reasonable constraints on estimates of these processes.
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