We have been studing changes in dust deposition over the past five thousand years using lake sediments from the San Juan Mountains in SW Colorado. Our work on this topic was recently published in Nature Geosciences and shows that following the settlement of the Western US in the mid 1800s, dust deposition increased dramatically with a peak around the turn of the 20th century. This event, which continues today, is very different from the dust bowl years of the 1930s in that it has occured over a much longer time and was caused by very different uses of the land. A collection of selected links to recent news stories is below.

J.C. Neff, A.P. Ballantyne, G.L. Famer, N.M. Mahowald, J.L. Conroy, C.C. Landry, J.T. Overpeck, T.H. Painter, C.R. Lawrence, and R.L. Reynolds.(2008). Recent increase in eolian dust deposition related to human activity in the Western United States. Nature - Geosciences.

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	A dusty day in Canyonlands National Park

Forest Fires and Carbon Dioxide

We have been working to understand how much CO2 is released from wildfires in the US and how this may impact attempts to develop regional carbon emission control and observation programs. The problem with biosphere/atmosphere CO2 exchange is that these fluxes of gases can complicate attempts to model or measure industrial emissions of CO2. If these natural fluxes change, they may also offset or exacerbate emissions of CO2 from industrial sources. Using a model developed for other air quality concerns by Christine Wiedinmyer at NCAR, we estimated emissions for the US over the past several years. The results published in Carbon Balance and Management, show that at a state level fires can be a very large portion of total CO2 emissions and with a very high degree of uncertainty, these fires may complicate attempts to estimate the sources and sinks of carbon from atmospheric measurements.

C. Wiedinmyer and J.C. Neff. (2007). Estimates of CO2 from fires in the United States: Implications for Carbon Management. Carbon Balance and Management. 2:10

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Burned forest near Fairbanks, Alaska