Building Blue Carbon Projects - An Introductory Guide

soils at a rate that is impactful over multi-centennial time scales. Now it is recognized that the anthropogenic emissions of carbon dioxide resulting from conversion and disturbance of vulnerable carbon stock is meaningful in a decadal-scale. What followed was an imperative to understand coastal wetlands in the climate change context. As a result, and at an accelerating pace, the synthesis of science on ecosystem processes is being coupled with new, focused investigations of coastal ecosystem carbon stocks and greenhouse gas flux assessments. Of the three major Blue Carbon ecosystems, carbon stocks are most well understood for mangrove forests. Remote sensing allows for the mapping of mangrove forest distribution, and thorough analysis of Landsat time series data illustrates the rates of change through time. Research is in the process of linking field-based carbon stocks assessments (including living biomass and soils) to remotely sensed data to map the distribution of carbon pools within mangrove forests. Such investigations have yet to be developed for salt marsh and seagrass ecosystems. By contrast, the understanding of greenhouse gas flux from natural wetlands and disturbed coastal systems is most advanced in investigations of tidal wetland systems. The status of the science on Blue Carbon and other wetland ecosystems has advanced enough to enable the Intergovernmental Panel on Climate Change (IPCC) to draft methodological guidance on estimating human-induced greenhouse gas emissions and removals from wetlands and drained soils (known as the 2013 Wetlands Supplement (Intergovernmental Panel on Climate Change, 2013)). The availability of these accounting guidelines for coastal wetland management is an important advancement in estimating the human impact on greenhouse gas dynamics in Blue Carbon ecosystems. Alongside these research advancements, there remain additional areas for expanding scientific understanding. One such example is the further refinement of quantifying the local landscape differences in these fluxes. Additional work is also needed to understand the distribution of vulnerable organic wetland soils, which are hotspots for potential emissions. Addressing remote sensing and mapping needs would aid in quantifying the carbon stocks and fluxes in seagrass and salt marsh ecosystems. Detailed measurements would further the development of models for estimating emissions and removals at the field level. While more work is needed, the status of the science is sufficient to realize that swift action is required to improve the management of Blue Carbon ecosystems.

Further information on the status of Blue Carbon science can be found in the following:

State of the Science on Coastal Blue Carbon: A Summary for Policy Makers (Sifleet et al ., 2012) http://nicholasinstitute.duke.edu/sites/default/files/publications/state-of-science-coastal-blue- carbon-paper.pdf 2013 Wetlands Supplement (IPCC, 2013) http://www.ipcc-nggip.iges.or.jp/public/wetlands/

Building Blue Carbon Projects An Introductory Guide

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