My research currently has five distinct foci:

  1. Carbon Inverse Modeling: The inverse approach uses spatiotemporal patterns of atmospheric CO2and knowledge of atmospheric transport to infer sources and sinks of carbon. Inverse modelers have used this tool to hunt for the "missing sink" – a large amount of carbon that is entering the terrestrial biosphere and oceans each year (though not enough to fully counter that put into the atmosphere due to fossil fuel emissions) which lacks clear quantification and mechanistic understanding. I currently direct an international experiment, "TransCom", which continues to explore many aspects of this problem. My research in this area is called "Tara" (Goddess of self-mastery and self-guidance)
  2. Quantification of fossil fuel CO2 emissions in high space and time resolution. This research exemplified by the "Vulcan","Hestia" and "FFDAS" projects. The Vulcan Project has quantified all fossil/industrial CO2 source for North America at sub-county and sub-monthly scales (support from NASA and the DOE) and is now growing from its 2002 year estimate into a complete time series from 1999 to 2011. The Hestia Project has downscaled Vulcan to the urban landscape (all building, roads, etc). The original pilot effort uses the city of Indianapolis as a test case and was supported by Knauf Insulation, the Showalter Trust and the Purdue Climate Change Research Center. It is now part of the INFLUX experiment in Indianapolis. The Hestia system has been used to quantify FFCO2 in Salt Lake City, with ongoing efforts in Los Angeles and Phoenix. FFDAS performs high-resolution FFCO2 emissions quantification for the whole planet at the 10km/hourly scale (support from NASA).
  3. Climate Variability and Carbon The exchange of carbon with the terrestrial biosphere is driven by a variety of factors. One of these is climate variability. This work links the interannual varying carbon exchange estimates from the inverse approach to observations of climate variability. Through principal component and lagged correlation analysis, patterns are emerging that provide biogeochemical explanations for some of the interannual varying carbon exchange. This work is supported through the NICCR program of the DOE.
  4. Carbon/Climate Science/Policy Since the mid-1990s I have been attending the United Nations climate change treaty negotiations as an expert advisor to a consortium of non-governmental organizations. My focus has been on those aspects of the climate treaty that intersect with carbon cycle science. Much of this work centers on projections of net carbon exchange for countries across the globe. Recent focus is on global deforestation policy.
  5. Deforestation-climate-socioeconomics This new effort is aimed at building a socioeconomic deforestation module into the NCAR CCSM4 (public in June 2010) to explore the multiple cross-feedbacks that occur between deforestation, climate change and the socioeconomic variables constraining land-use decisions in tropical forest lands. I thank the PCCRC for seed support and the Fulbright Foundation for support of Kendra Castillo.

In addition to the core focus area illuminated above, I also continue work on previous research I have been involved with over the years. In broad terms, these can be placed under the banners of climate change science and ozone depletion.

A recent talk given to the Association of Science Writers on "surprises" in the climate
system – October 2009

Walking the Talk: 800 Watt solar power array at "StoneReekil", our carbon neutral
cabin at 9000 feet in the Rocky Mountains. Go the full article in the PCCRC newsletter.
Featured: Helen, Kevin, Liza, Hogan (RIP).