Current scientific projects
Trends and drivers of global ammonia emissions inferred from satellite observations
Emissions of ammonia from agricultural intensification have increased over the past fifty years, degrading air quality. Although controlling ammonia emissions has been identified as cost-effective means of improving air quality, policy assessment is hampered by large uncertainties in emission estimates. Here we use satellite data, paired with atmospheric models, our CHEEREIO inversion platform, and machine learning to both calculate trends in ammonia emissions and estimate likely drivers. We find that increasing livestock and chemical fertilizer use explain most of the increase in ammonia emissions, and also that climate change is observably increasing ammonia emissions.
Associated publications and presentations
Pendergrass, D. C., Shindell, D. T., Clarisse, L., Van Damme, M., Beaudor, M., Jiang, J., Zhai, S. Attributing 2013–2024 drivers of global ammonia emissions using IASI observations: implications under future climate change. Submitted.
Pendergrass, D. C. D. T. Shindell, L. Clarisse, M. Van Damme, M. Beaudor, J. Jiang, and S. Zhai. Attributing 2013–2024 drivers of global ammonia emissions using IASI observations: implications for future climate change.
- American Meteorological Society meeting, Denver, Colo., January 2027. Talk.
- 12th International GEOS-Chem Meeting (IGC12), St. Louis, Mo., June 2026. Talk. Link to IGC12 slides
- Methane Action for People & Planet (UN Environmental Programme, Climate and Clean Air Coalition), Ispra, Italy; March 2026. Poster. PDF of UNEP poster
Global methane emissions trends and seasonality inferred from satellite observations
Methane is a potent greenhouse gas. It is emitted both from natural sources (largely wetlands) and human sources including livestock, oil and gas, coal, landfills, wastewater and rice, but emissions magnitudes and spatial distributions are uncertain. In this project, we use satellite observations of atmospheric methane to calculate emissions from both human and natural sources and understand trends and drivers.
Figure: Annual posterior methane emission trends for 2019-2023 disaggregated by region and sector. Emissions are inferred using a localized ensemble transform Kalman filter applied to TROPOMI satellite observations. Panels (a) and (b) show posterior emission changes relative to 2019, disaggregated by region and sector respectively. Inset percentages show changes relative to 2019 values for selected regions/sectors. Error bars show range of the inversion ensemble for the global emission trend. Panel (c) shows 2019-2023 trends in posterior emissions by region obtained from linear regression.
Associated publications and presentations
Zhong, H., Shen, L., Pendergrass, D. C., Qin, K., Peng, S., Qu, M., Jin, J., and Gautam, R. Satellite observations reveal stable global fossil fuel methane emissions despite rising production since 2019. Submitted.
Li, Y†, D. C. Pendergrass, D. J. Jacob, Y. Tang, J. Qiu, and B. Zheng. Trends and drivers of China’s methane emissions 2019–2024 inferred from regional atmospheric inversion. In revision at Atmospheric Chemistry and Physics.
He, M., Jacob, D. J., Estrada, L. A., Varon, D. J., Sulprizio, M., Balasus, N., East, J. D., Penn, E., Pendergrass, D. C., Chen, Z., Mooring, T. A., Maasakkers, J. D., Brodrick, P. G., Frankenberg, C., Bowman, K. W., & Bruhwiler, L. (2026). Attributing 2019–2024 methane growth using TROPOMI satellite observations. Science Advances, 12(15), eadz9007. Link to paper (open access).
Pendergrass, D.C. Jacob, D. J., Balasus, N., Estrada, L., Varon, D. J., East, J. D., He, M., Mooring, T. A., Penn, E., Nesser, H., & Worden, J. R. (2025). Trends and seasonality of 2019–2023 global methane emissions inferred from a localized ensemble transform Kalman filter (CHEEREIO v1.3.1) applied to TROPOMI satellite observations. Atmospheric Chemistry and Physics, 25(21), 14353–14369. Link to paper (open access). Link to PDF. Read a general audience explainer.
Varon, D. J., Jacob, D. J., Estrada, L. A., Balasus, N., East, J. D., Pendergrass, D. C., Chen, Z., Sulprizio, M., Omara, M., Gautam, R., Barkley, Z. R., Saldaña, F. J. C., Reidy, E. K., Kamdar, H., Sherwin, E. D., Biraud, S. C., Jervis, D., Pandey, S., Worden, J. R., … Kleinberg, R. L. (2025). Seasonality and Declining Intensity of Methane Emissions from the Permian and Nearby US Oil and Gas Basins. Environmental Science & Technology. Link to paper (open access).
Pendergrass, D. C., D. J. Jacob, N. Balasus, L. Estrada, D. J. Varon, T. A. Mooring, J. D. East, E. Penn, and H. O. Nesser. Continuous sub-weekly monitoring of global methane emissions from an ensemble Kalman filter at 2°×2.5° degrees using TROPOMI observations.
- Methane Action for People & Planet (UN Environmental Programme, Climate and Clean Air Coalition), Ispra, Italy; March 2026. Poster.
- Gordon Research Seminar, Newry, ME, August 2025. Poster. PDF of Gordon poster
- American Geophysical Union Fall Meeting, Washington, D.C., December 2024. Poster. PDF of AGU poster.
- 11th International GEOS-Chem Meeting (IGC11), St. Louis, Mo., June 2024. Poster. PDF of IGC poster.
Varon, D. J., Jacob, D. J., Hmiel, B., Gautam, R., Lyon, D. R., Omara, M., Sulprizio, M., Shen, L., Pendergrass, D. C., Nesser, H., Qu, Z., Barkley, Z. R., Miles, N. L., Richardson, S. J., Davis, K. J., Pandey, S., Lu, X., Lorente, A., Borsdorff, T., … Aben, I. (2023). Continuous weekly monitoring of methane emissions from the Permian Basin by inversion of TROPOMI satellite observations. Atmospheric Chemistry and Physics, 23(13), 7503–7520. Link to paper (open access).
Chen, Z., Jacob, D. J., Gautam, R., Omara, M., Stavins, R. N., Stowe, R. C., Nesser, H., Sulprizio, M. P., Lorente, A., Varon, D. J., Lu, X., Shen, L., Qu, Z., Pendergrass, D. C., & Hancock, S. (2023). Satellite quantification of methane emissions and oil–gas methane intensities from individual countries in the Middle East and North Africa: Implications for climate action. Atmospheric Chemistry and Physics, 23(10), 5945–5967. PDF. Publisher's version (open access).
CHEEREIO: An open-source tool for chemical data assimilation
CHEEREIO) is a tool that allows scientists to use observations of pollutants or gases in the atmosphere, such as from satellites or surface stations, to update supercomputer models that simulate the Earth. Other scientists have assembled estimates of emissions of various pollutants from around the world, but our emissions estimates are very uncertain. CHEEREIO uses a model called GEOS-Chem to simulate what the atmosphere would look like if those emissions estimates were correct, and then compares those estimates to the real atmosphere as observed by satellites or equipment on the Earth’s surface. CHEEREIO uses the difference between the model simulation and the real world to update our maps of emissions.
Code and documentation are available on Github and ReadTheDocs, both linked from the official site. CHEEREIO and all its components are open-source.
Figure: Schematic of CHEEREIO runtime routines and job control procedures. CHEEREIO is run as an array of m separate jobs on a computational cluster, one for each ensemble member. These m jobs, operating in parallel, alternate between running GEOS-Chem and running the LETKF algorithm for a subset of grid cells, as shown by the light yellow boxes; the m jobs are coordinated by a single job controller shared by the entire ensemble (shown in light red), ensuring that the ensemble remains synchronized. Boxes in blue show data input into CHEEREIO processes.
Associated publications and presentations
Pendergrass, D. C., Shindell, D. T., Clarisse, L., Van Damme, M., Beaudor, M., Jiang, J., Zhai, S. Attributing 2013–2024 drivers of global ammonia emissions using IASI observations: implications under future climate change. Submitted.
Zhong, H., Shen, L., Pendergrass, D. C., Qin, K., Peng, S., Qu, M., Jin, J., and Gautam, R. Satellite observations reveal stable global fossil fuel methane emissions despite rising production since 2019. Submitted.
Li, Y†, D. C. Pendergrass, D. J. Jacob, Y. Tang, J. Qiu, and B. Zheng. Trends and drivers of China’s methane emissions 2019–2024 inferred from regional atmospheric inversion. In revision at Atmospheric Chemistry and Physics.
Pendergrass, D. C. D. T. Shindell, L. Clarisse, M. Van Damme, M. Beaudor, J. Jiang, and S. Zhai. Attributing 2013–2024 drivers of global ammonia emissions using IASI observations: implications for future climate change.
- American Meteorological Society meeting, Denver, Colo., January 2027. Talk.
- 12th International GEOS-Chem Meeting (IGC12), St. Louis, Mo., June 2026. Talk. Link to IGC12 slides
- Methane Action for People & Planet (UN Environmental Programme, Climate and Clean Air Coalition), Ispra, Italy; March 2026. Poster. PDF of UNEP poster
Pendergrass, D. C., Jacob, D. J., Nesser, H., Varon, D. J., Sulprizio, M., Miyazaki, K., & Bowman, K. W. (2023). CHEEREIO 1.0: A versatile and user-friendly ensemble-based chemical data assimilation and emissions inversion platform for the GEOS-Chem chemical transport model. Geoscientific Model Development, 16(16), 4793–4810. Link to paper (open access). Link to PDF. Read a general audience explainer.
Pendergrass, D.C. Jacob, D. J., Balasus, N., Estrada, L., Varon, D. J., East, J. D., He, M., Mooring, T. A., Penn, E., Nesser, H., & Worden, J. R. (2025). Trends and seasonality of 2019–2023 global methane emissions inferred from a localized ensemble transform Kalman filter (CHEEREIO v1.3.1) applied to TROPOMI satellite observations. Atmospheric Chemistry and Physics, 25(21), 14353–14369. Link to paper (open access). Link to PDF. Read a general audience explainer.
Voshtani, S., Jones, D. B. A., Wunch, D., Pendergrass, D. C., Wennberg, P. O., Pollard, D. F., Morino, I., Ohyama, H., Deutscher, N. M., Hase, F., Sussmann, R., Weidmann, D., Kivi, R., García, O., Té, Y., Chen, J., Anderson, K., Stevens, R., Kondragunta, S., … Murata, I. (2025). Quantifying CO emissions from boreal wildfires by assimilating TROPOMI and TCCON observations. Atmospheric Chemistry and Physics, 25(21), 15527–15565. Link to paper (open access).
Pendergrass, D. C., D. J. Jacob, H. O. Nesser, D. J. Varon, M. Sulprizio, K. Miyazaki, and K. W. Bowman (2022). CHEEREIO: a generalized, open-source ensemble-based chemical data assimilation and emissions inversion platform for the GEOS-Chem chemical transport model.
- American Geophysical Union Fall Meeting, Chicago, Ill., December 2022. Poster. PDF of AGU poster.
- GEMS science meeting, Seoul, S. Korea, November 2022. Talk. Slides for Seoul talk.
- 10th International GEOS-Chem Meeting (IGC10), St. Louis, Mo., June 2022. Talk. Slides for St. Louis talk.
Featured interdisciplinary projects
A paper on the politics of Earth System models
Abstract. This paper explores the political uses of images generated by Earth System science. It argues that images of possible climate futures, maps of potential worlds of heatwaves and wildfires, are made legible to policymakers by an alliance with a class of climate-economy models that associate scientific estimates of climate impacts with a prescribed international policy and technology mix. While environmental models have successfully mobilized policymakers in the past by providing images of “planetary scenarios” accompanying different emissions pathways, with climate change a political actor outside the administrative state is required to overcome the entrenchment of fossil capital. The paper suggests such actors are empowered not by the rhetoric of scenario modeling but by the emerging practice of “planetary sensing,” where activists and stakeholders directly mobilize the planetary images generated by Earth System science as they work to evacuate prisons, track pollutants, and repair pipelines.
Pendergrass, D. C. (2024). "From planetary scenarios to planetary sensing: Models, observations, and political legibility." The Anthropocene Review. 20530196241270716. doi:10.1177/20530196241270716 | Read it here | Get the PDF.
Read more of my writing here.
A short primer on the politics of geoengineering
In 2025, I wrote a short essay on the politics of geoengineering for an edited volume called Power Shift from WVU Press. I am in good company (Joshua Clover, Leah Aronowsky, Dominic Boyer, Mijin Cha, Cameron Hu, and Ashley Dawson are among the contributors). You can buy the whole book here.
Pendergrass, D. C. (2025). Geoengineering. In I. Szeman and J. Wenzel (Eds.), Power Shift: Keywords for a New Politics of Energy. West Virginia University Press. | Read it here | Get the PDF.
Read more of my writing here.
A paper on the town-country divide in architecture and in Marxism
In this article, I worked with historian Troy Vettese and architect Filip Mesko to discuss how eco-socialist planning can create a just and sustainable society. We argue that the problem of land scarcity, long a topic of both classical political economy and architecture, is an opportunity to erode the separation of city and country. We consider the intellectual history of the town-country divide and how the category of wilderness and the practice of rewilding can break this binary. The illustration is by Lukas Eigler-Harding and Ariel Noltimier-Strauss and is entitled Half-Earth Diptych (2021).
Vettese, T.G.W, Pendergrass, D. C., and Mesko, F. (2022). "Town, Country, and Wilderness: Designing the Half-Earth." Architectural Design. 92(1), 112–119. doi:10.1002/ad.2780 | Read it here.
Read more of my writing here.
Half-Earth Socialism: A Planetary Crisis Planning Game
The Half-Earth Socialism planning game allows anyone to try their hand as a global planner of a post-capitalist science fiction society. The player aims to overcome the environmental crisis, global poverty and inequality, and pursue other goals, all while keeping global parliament happy (else the player will find themselves out of a job, or worse). Consider it a sandbox where you can play with a wide range of technologies and policies spanning different fields and ideologies. The game simulates the impact of your decisions by calculating emissions and using a real climate model (HECTOR) to work out the climate effects, while also simulating impacts to the food system and biodiversity, among other natural systems. The video game is based on my book, Half-Earth Socialism, and was made by a team including Francis Tseng, Son La Pham, Troy Vettese, and myself.
Play more of my games here.
Half-Earth Socialism
Half-Earth Socialism is a book I co-authored with environmental historian Troy Vettese on how we can get out of our current ecological mess. Published in April 2022 by Verso Books, you can order it from the publisher here. The book has been translated into Italian, Thai, Korean, Spanish, and Swedish; all translations can be ordered from my books page.
Pendergrass, D.C. and Vettese, T.G.W (2022). Half-Earth Socialism: A Plan to Save the Future from Extinction, Climate Change and Pandemics. Verso Books. | Read it here.
Read more about my books here.
Complexity in the air
This story covers the history of the popular reception of complexity and chaos, and how, in the process of translation from natural science to popular culture, ideas like complex systems and the butterfly effect have been used to buttress both deeply reactionary political projects and left-wing ones. This essay asks: Does complexity have any inherent politics? If it does, what are the implications for markets, planning, and collective environmental action?
Pendergrass, D. C. (2026). "Complexity in the air." The Break-Down Magazine. | Read it here | Get the PDF.
Read more of my writing here.
A feature article for Harper's on soil carbon
This story covers a long-term ecological research (LTER) site at Harvard Forest, where some scientists, inspired by the Denver Broncos' snow-melting technology, simulated the effects of climate change on a patch of forest by burying heating coils below the soil.
Pendergrass, D. C. (2020). "Ground Control: How forests adapt to climate change." Harper's Magazine. | Read it here | Get the PDF.
Read more of my writing here.
Other current projects
Newsletter
Writing
I think about economic democracy within planetary boundaries, with an emphasis on connecting science with social movements. As a part of that project, I do scholarship in the broad world of science and technology studies; major works underway include (1) a second book with historian Troy Vettese on economic democracy and (2) an early-stage book project on citizen science in Earth system modeling. See my writing page and CV for details.
Beyond my scholarship, I freelance for a variety of outlets, including Harper's, The Guardian, and The Break—Down. Some of my articles are linked here. I also am revising a completed sci-fi novel set on Titan, moon of Saturn.
Archived science projects
Emissions and concentrations of pollutants in China
Pollutants like tropospheric ozone and fine particulate matter (PM2.5) cause serious public health burdens, especially in eastern China. In response to the severe smog problems, the Chinese government implemented the Action Plan on Air Pollution Prevention and Control in 2013. The plan led to rapid reductions in emissions of ozone precursors like NOx and aerosol precursors like SO2. However, observations show that while PM2.5 has decreased, surface ozone has increased, even though emissions have fallen. This project seeks to understand the PM2.5/ozone tradeoff both in the present day and under various future climate scenarios.
Figure: Air quality changes due to strong NTCF emission reductions in China by midcentury (2045-54); PM2.5 is projected to improve due to modeled emissions mitigation while ozone is projected to worsen.
Associated publications and presentations
Pendergrass, D. C., L.W. Horowitz, and V. Naik. Modeling impact of strong regulation of near-term climate forcers in China on mid-21st century air quality and climate using the GFDL-ESM4 coupled model. American Geophysical Union Fall Meeting, San Francisco, Calif., December 13, 2019. Talk. Slides.
Extreme value theory applied to environmental science
Extreme value theory is a branch of statistics dedicated to the analysis of outliers and rare events. In this project, we used extreme value theory to link winter meteorology in Beijing to severe smog events, which can shut down the city and are a major threat to public health. We find that these extreme events may not be sensitive to climate change because of opposite trends in humidity and temperature.
Figure: Probability (given in colored contours) for PM2.5 in Beijing to exceed 300 μg m-3 given relative humidity and 850-hPa meridional winds. Actual observations are overlaid on top: green dots represent days that exceeded 300 μg m-3, and black dots represent the rest.
Associated publications and presentations
Pendergrass, D. C., Shen, L., Jacob, D. J., & Mickley, L. J. (2019). Predicting the Impact of Climate Change on Severe Wintertime Particulate Pollution Events in Beijing Using Extreme Value Theory. Geophysical Research Letters, 46(3), 1824–1830. Publisher's version (open access). PDF.
Pendergrass, D. C., L. Shen, D. J. Jacob, and L. J. Mickley. Predicting the impact of climate change on severe winter haze pollution events in Beijing using extreme value theory. American Geophysical Union Fall Meeting, Washington D.C., December 11, 2018. Talk. Slides.
Using machine learning and satellite data to map fine particulate matter pollution in east Asia
Fine particulate matter (PM2.5) is an air pollutant associated with millions of deaths per year. Measurements of this pollutant are made at surface sites throughout east Asia, but the vast majority of surface area has no available measurements. Additionally, many areas only have observations starting recently (e.g. after 2015). This means that we can't fully evaluate the impact PM2.5 has on public health. Satellites offer a solution since they image a wide area at once. A geostationary satellite instrument called GOCI has been imaging east Asia 8 times per day. One of the measurements GOCI takes is called Aerosol Optical Depth (AOD), which is a measure of the transparency of the atmosphere. AOD is related to surface PM2.5 but the relationship is complicated; for example, the satellite measures a column of air all at once, and it cannot tell if pollution is high in the sky or on the ground, where humans can inhale it. This project uses machine learning to link AOD, meteorology, and other data to measured surface PM2.5 in east Asia.
Figure: GOCI gap-filled aerosol optical depth (AOD), PM2.5 from air quality networks, and GOCI PM2.5 obtained by applying a RF algorithm to the GOCI AOD data. Data are annual means for 2012 (the first year with complete GOCI data), 2017, and 2022. The gap-filled AOD data provide continuous 2×2 km2 coverage of eastern China, S. Korea, and Japan for 2011-2022. The PM2.5 network data are from individual sites and enlarged for visibility. The S. Korea insets in the middle panels provide greater resolution of network data gaps. PM2.5 measurements from the AirKorea network started in 2015, and the S. Korea PM2.5 network data shown for 2012 are from a RF reconstruction.
Associated publications and presentations
Pendergrass, D.C., Jacob, D. J., Oak, Y. J., Lee, J., Kim, M., Kim, J., Lee, S., Zhai, S., Irie, H., & Liao, H. (2025). A continuous 2011–2022 record of fine particulate matter (PM2.5) in East Asia at daily 2-km resolution from geostationary satellite observations: Population exposure and long-term trends. Atmospheric Environment, 346, 121068. Link to paper (open access). Link to PDF. Read a general audience explainer.
Pendergrass, D. C., S. Zhai, J. Kim, J-H. Koo, S. Lee, M. Bae, S. Kim, H. Liao, and D. J. Jacob. (2022). Continuous mapping of fine particulate matter (PM2.5) air quality in East Asia at daily 6x6 km2 resolution by application of a random forest algorithm to 2011-2019 GOCI geostationary satellite data. Atmospheric Measurement Techniques, 15, 1075–1091. PDF. Publisher's version (open access). Associated dataset available from Dataverse. Video of 15-minute oral presentation at AGU.
Pendergrass, D. C., D. J. Jacob, Y. Oak, J. Kim, J. Lee, S. Lee, S. Zhai, and H. Liao. High spatiotemporal resolution trends of fine particulate matter (PM2.5) in East Asia inferred from the GOCI geostationary instrument, 2011-2022.
- GEMS science meeting, Jeju, S. Korea, September 2023. Talk. Slides for GEMS talk.
- American Meteorological Society annual meeting, Baltimore, Md., February 2024. Poster. PDF of AMS poster
Pendergrass, D. C., D. J. Jacob, S. Zhai, J. Kim, J-H. Koo, M. Bae, and S. Kim. Continuous Mapping of Fine Particulate Matter (PM2.5) Air Quality in East Asia by Application of a Random Forest Algorithm to GOCI Geostationary Satellite Data.
- American Geophysical Union Fall Meeting, New Orleans, La., December 13, 2021. Talk. Slides. Video of 15-minute oral presentation.
- GEMS science meeting, Seoul, S. Korea, October 2022. Poster. PDF of GEMS poster.
2011-22 trends in winter PM2.5 in South Korea
Fine particulate matter (PM2.5) is a severe air pollution problem in South Korea and is worst in winter. Strong local emissions controls and emissions reductions upwind have led winter PM2.5 to decline throughout South Korea. However, PM2.5 around Seoul (where half the population lives) has been resistant to decrease and only declined after 2019. With an ensemble of surface observations augmented by machine learning, we find that PM2.5 composition in Seoul has shifted toward two kinds of secondary PM2.5, meaning that they are formed in the atmosphere through chemical reactions rather than emitted directly, and that these species are both resistant to decrease. More details are given in a general audience explainer.
Associated publications and presentations
Pendergrass, D. C., Jacob, D. J., Oak, Y. J., Dang, R., Yang, L. H., Beaudry, E., Colombi, N. K., Zhai, S., Kim, H., Choi, J., Park, J., Kim, S., Li, K., & Liao, H. (2025). Wintertime Trends of Fine Particulate Matter (PM2.5) in South Korea, 2012–2022: Response of Nitrate and Organic Components to Decreasing NOx Emissions. Geophysical Research Letters, 52(19), e2025GL116091. Link to paper (open access). Link to PDF. Read a general audience explainer.
Pendergrass, D. C., D. J. Jacob, Y. J. Oak, R. Dang, L. H. Yang, E. Beaudry, N. K. Colombi, S. Zhai, H. Kim, J.-s. Choi, J.-s. Park, S. Kim, and H. Liao. Interpreting fine particulate matter (PM2.5) trends in South Korea, 2011-2022.
- Gordon Research Conference, Newry, ME, August 2025. Poster. PDF of Gordon poster
- American Meteorological Society meeting, New Orleans, La., January 2025. Talk. Slides for talk
Other archived projects
Musical Composition
I am a composer of modern and experimental music, though I haven't written much in a while. You can learn more about my compositions on my music website and you can listen to my works on my SoundCloud.
Alchemy
Alchemy is a single-player military strategy game written in Java. More on the game's website here.
Log on wheels
A hot new startup that sells logs on wheels for personal transporation.