B.A., Biology, St. Olaf College
M.S., Geography, University of Wisconin-Madison
Commodity-driven land use change and it's effect on United States carbon emissions:
Land use decisions and their environmental impact are sensitive to economic and political changes. High commodity prices in the mid- to late 2000s, for example, spurred elevated rates of cropland expansion throughout the United States. To determine the amount of carbon emitted to the atmosphere as a result of these changes, I developed a data-driven model that combines high-resolution national maps of cropland expansion, remotely sensed carbon stocks, and statistical relationships describing their sensitivity to change. In colaboration with others, this model is now being used to (i) assess the environmental impacts of US biofuel policy and (ii) to improve life cycle assessment of US commodity crop supply chains.
Mapping the global geographies of biomass and soil organic carbon stocks:
This project leverages new satellite measurements to re-examine the geography of terrestrial carbon stocks. Plants and soils store vast amounts of carbon and thereby help to regulate global climate. In many areas of the world, this carbon is threatened either directly or indirectly by human activity. Knowing the nature and location of carbon around the world improves our ability to predict how these stocks will respond to emerging pressures.
Characterizing the space for land management in climate change mitigation:
I am also a member of two multi-institution teams of academic and NGO researchers seeking to better understand how and when intentioned land management can be used to mitigated global climate change. The first projects aim to assess the potential of various land managment activities to reduce carbon emissions and increase carbon sequestration. The second project is identifying ecosystems that are effectively irreplaceable in terms of the carbon they store and their ability to re-absorb that carbon if disturbed. Both projects intent to shape conservation and environmental policy using the principles of ecosystem sciece.
Spawn, S.A., T.J. Lark, H.K. Gibbs. Carbon emissions from cropland expansion in the United States. Environmental Research Letters. (2019) doi: 10.1088/1748-9326/ab0399
Fargione, J.E., S. Bassett, T. Boucher, S.D. Bridham, R.T. Conant ,..., S.A. Spawn, et al.. Natural climate solutions for the United States. Science Advances. (2018) doi: 10.1126/sciadv.aat1869
Kropp, H., M.M. Loranty, H.D. Alexander, L.T. Berner, S.M. Natali, S.A. Spawn. Environmental constraints on transpiration and stomatal conductance in a Siberian Arctic boreal forest. Journal of Geophysical Research - Biogeosciences. (2017) doi: 10.1002/2016jg003709
Crawford, J.T., L.C. Loken, W.E. West, B. Crary, S.A. Spawn, N. Gubbins, S.E. Jones, R.G. Striegl, E.H. Stanley. Spatial heterogeneity of within-stream methane concentrations. Journal of Geophysical Research - Biogeosciences. (2017) doi: 10.1002/2016JG003698
Schade, J.D. E.C. Seybold, T. Drake, S.A. Spawn, W.V. Sobczak, K.E. Frey, R.M. Holmes, N.Zimov. Variation in summer nitrogen and phosphorus uptake among Siberian headwater streams. Polar Research. (2016) doi: 10.3402/polarv35.24571
Spawn, S.A., S.T. Dunn, G.J. Fiske, S.M. Natali, J.D. Schade, N. Zimov. Summer methane ebullition from a headwater catchment in Northeastern Siberia. Inland Waters. (2015) do:10.5268/iw-5.3.845
Kannenberg, S.A., S.T. Dunn, S.M. Ludwig, S.A. Spawn. J.D. Schade. Effects of drying and rewetting on potential methanogenesis in seasonally saturated wetland soils. Wetlands. (2015). doi: 10.1007/s13157-015-0653-3
Crawford. J.T., E.H. Stanley, S.A. Spawn, J.C. Finlay, L.C. Loken, R.G. Striegl. Ebullitive methane emissions from oxygenated wetland streams. Global Change Biology. (2014) doi: 10.1111/gcb.12614
Awards and Honors
National Geographic Society - Young Explorer
The Explorer's Club - Exploration Fund Grant
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