Robert Warren Howarth

David R. Atkinson Professor of Ecology and Environmental Biology


I am a biogeochemist and ecosystem scientist, an active research scientist who also enjoys teaching and is deeply involved in the environmental management and policy communities in the State, nationally, and internationally. My training was in oceanography, and much of my research still focuses on coastal marine ecosystems. However, I also work on freshwater systems (both rivers and lakes) and on large river basins. I teach a variety of courses at Cornell including:BioEE 1610 Ecology and the Environment, BioEE 3610 Advanced Ecology, BioEE 4780 Ecosystem Biology, and BioEE 6680 Principles of Biogeochemistry.

Research Focus

My research laboratory works broadly on human alteration of element cycles (particularly nutrients) in coastal marine ecosystems and in the watersheds that feed them. We also work on the environmental consequences of energy systems, particularly from oil and gas development and from biofuels, emphasizing water quality and greenhouse gas emissions. Specific current topics of study include: 1) the biogeochemical feedbacks which may either aggravate or partially ameliorate eutrophication that occurs in seagrass-dominated systems as nutrient loads increase: 2) the influences of climate change, land use, and management practices on the export of nutrients and sediment from large river basins; 3) the importance of dry deposition of nitrogen gases from the atmosphere (particularly in the near proximity of vehicle emissions) as a source of nutrient pollution to coastal waters; 4) the environmental consequences of biofuels; 5) the greenhouse gas footprint of natural gas extracted from shale formations such as the Marcellus shale.



  • Goyette, J.O., E. Bennett, R.W. Howarth, and R. Maranger. 2016. Changes in anthropogenic nitrogen and phosphorus inputs to the St. Lawrence Basin over 110 years: Impacts on riverine export. Global Biogeochemical Cycles, in press.
  • Marino, R.M., and R.W. Howarth. 2015. Why is planktonic nitrogen fixation so rare in coastal marine ecosystems? Insights from a cross-systems approach. In P. Glibert and T. Kana (editors), Aquatic Nutrient Biogeochemistry and Microbial Ecology: A Dual Perspective. Springer, Dordrecht. In press.
  • Gao, W., B. Hong, D.P. Swaney, R.W. Howarth, and H. Guo. 2016. A system dynamics model for managing regional N inputs from human activities. Ecological Modelling 322: 82-91.
  • Hong, B., and R.W. Howarth. 2016. Greenhouse gas emissions from domestic hot water: heat pumps compared to most commonly used systems. Energy Science & Engineering doi: 10.1002/ese3.112


  • Reynolds, L.K., R. Marino, M.F. Muth, N. McLenaghan, M. Hayn, A.C. Tyler, K.J. McGlathery, and R.W. Howarth. 2015. Evidence of grazer control on nitrogen fixation by eelgrass epiphytes in a temperate coastal bay. Marine Ecology Progress Series 526: 11-19, doi: 10.3354/meps11234
  • Zhang, W.S., D. P. Swaney, X.Y. Li, B. Hong, R.W. Howarth, and S.H. Ding. 2015. Anthropogenic point-source and non-point-source nitrogen inputs into Huai River basin and their impacts on riverine ammonia–nitrogen flux. Biogeosciences 12: 4275-4289, doi:10.5194/bg-12-4275-2015 4
  • Gao, W., R.W. Howarth, D.P. Swaney, B. Hong, and H. Guo. 2015. Enhanced N input to Lake Dianchi Basin from 1980 to 2010: Drivers and consequences. Science of The Total Environment 505: 376-384,
  • Howarth, R.W. 2015. Perspectives on air emissions of methane and climatic warming risk from hydraulic fracturing and shale-gas development: Implications for policy. Energy & Emission Control Technologies 3: 45-54.
  • Costello, C., X. Xue, and R.W. Howarth. 2015. Comparison of production-phase environmental impact metrics derived at the farm- and national-scale for United States agricultural commodities. Environmental Research Letters 10: 114004 doi:10.1088/1748-9326/10/11/114004
  • Howarth, R.W. 2015. Editorial: Misconduct in scientific publications. Limnology & Oceanography, 60(#4), doi: 10.1002/lno.10131
  • Howarth, R.W. 2015. Editorial. Limnology & Oceanography, 60(#1), doi: 10.1002/lno.10030


  • Howarth, R.W. 2014. A bridge to nowhere: Methane emissions and the greenhouse gas footprint of natural gas. Energy Science & Engineering 2: 47-60, doi 10.1002/ese3.35
  • Begon, M., R.W. Howarth, and C. Townsend. 2014. Essentials of Ecology, 4th Edition. Wiley, Chichester. 480 pages. ISBN-13: 978-0470909133
  • Bringezu, S, H. Schütz, W. Pengue, M. O´Brien, F. Garcia, R. Sims, R. Howarth, L. Kauppi, M. Swilling, and J. Herrick. 2014. Assessing Global Land Use: Balancing Consumption with Sustainable Supply. A Report of the Working Group on Land and Soils of the International Resource Panel. United Nations Environment Program, Paris, France. ISBN: 978-92-807-3330-3
  • Caulton, D.R., P. B. Shepson, R.L. Santor0, J.P. Sparks, R.W. Howarth, A. Ingraffea, M.O. Camaliza, C. Sweeney, A. Karion, K.J. Davis, B.H. Stirm, S.A. Montzka, and B. Miller. 2014. Toward a better understanding and quantification of methane emissions from shale gas development. Proceedings of the National Academy of Sciences 111: 6237-6242. doi/10.1073/pnas.1316546111
  • Howarth, R.W., M. Hayn, R.M. Marino, N. Ganju, K. Foreman, K. McGlathery, A.E. Giblin, P. Berg, and D. Walker. 2014. Metabolism of a nitrogen-enriched coastal marine lagoon during the summertime. Biogeochemistry 118: 1-20. DOI 10.1007/s10533-013-9901-x
  • Butler, T., R. Marino, D. Schwede, R. Howarth, J. Sparks, and K. Sparks. 2014. Atmospheric ammonia measurements at low concentration sites in the northeastern USA: implications for total nitrogen deposition and comparison with CMAQ estimates. Biogeochemistry doi10.1007/s10533-014-0036-5
  • Gao, W., R.W. Howarth, B. Hong, D.P. Swaney, and H.C. Guo. 2014. Estimating net anthropogenic nitrogen inputs (NANI) in the Lake Dianchi basin of China. Biogeosciences 11: 4577 – 4586. doi:10.5194/bg-11-4577-2014
  • Del Barrio, P., N. Ganju, A. L. Aretxabaleta, M. Hayn, A. Garcia, and R. W. Howarth. 2014. Modeling future scenarios of light attenuation and potential seagrass success in a eutrophic estuary. Estuarine and Coastal Shelf Science 149: 13-23. doi 10.1016/j.ecss.2014.07.005
  • Jacobson, M.Z., M.A. Delucchi, A.R. Ingraffea, R.W. Howarth, G. Bazouin, B. Bridgeland, K. Burkart, M. Change, N. Chowdhury, R. Cook, G. Escher, M. Galka, L. Han, C. Heavey, A. Hernandez, D.F. Jacobson, D.S. Jacobson, B. Miranda, G. Novotny, M. Pellat, P. Quach, A. Romano, D. Steward, L. Vogel, S. Wang, H. Wang, L. Willman, and T. Yeskoo. 2014. A 5 A roadmap for repowering California for all purposes with wind, water, and sunlight. Energy,
  • Howarth, R. W., and A. Ingraffea. 2014. Shale gas: Time to go slow. In World Energy Monitor, World Energy Forum. United Nations. New York, NY.


  • Howarth, R. W., and J. Mohan (editors). 2013. Biomes and Ecosystems. Salem Press. 1,440 pages, ISBN 978-1-4298-3813-9
  • Hayn M., R.W. Howarth, R. Marino, N. Ganju, P. Berg, K. Foreman, A.E. Giblin, and K. McGlathery. 2013. Exchange of nitrogen and phosphorus between a shallow lagoon and coastal waters. Estuaries & Coasts doi10.1007/s12237-013-9699-8
  • Jacobson, M.Z., R.W. Howarth, M.A. Delucchi, S.R. Scobies, J.M. Barth, M.J. Dvorak, M. Klevze, H. Katkhuda, B. Miranda, N.A. Chowdhury, R. Jones, L. Plano, and A.R. Ingraffea. 2013. Examining the feasibility of converting New York State’s all-purpose energy infrastructure to one using wind, water, and sunlight. Energy Policy 57: 585-601,
  • Jacobson, M.Z., R.W. Howarth, M.A. Delucchi, S.R. Scobies, J.M. Barth, M.J. Dvorak, M. Klevze, H. Katkhuda, B. Miranda, N.A. Chowdhury, R. Jones, L. Plano, and A.R. Ingraffea.
  • Response to comment on paper examining the feasibility of changing New York State's energy infrastructure to one derived from wind, water, and sunlight. Energy Policy 62: 1212-1215,
  • Hong, B., D.P. Swaney, and R.W. Howarth. 2013. Estimating net anthropogenic nitrogen inputs (NANI) to US watersheds: comparison of methodologies. Environmental Science & Technology 47: 5199−5207
  • Gettel, G., A. Giblin, and R.W. Howarth. 2013. Controls of benthic nitrogen fixation and primary production from nutrient enrichment of oligotrophic, arctic lakes. Ecosystems doi 10.1007/s10021-013-9701-0
  • Tartowski, S.L., and R. W. Howarth. 2013. Nitrogen, nitrogen cycle. Encyclopedia of Biodiversity, Elsevier.
  • Bettez, N., R. Marino, R.W. Howarth, and E.A. Davidson. 2013. Roads as nitrogen deposition hot spots. Biogeochemistry 114: 149-163.
  • Berg, P., M.H. Long, M. Huettel, J.E. Rheuban, K.J. McGlathery, R.W. Howarth, K.H. Foreman, A.E. Giblin, and R. Marino. 2013. Eddy correlation measurements of oxygen fluxes in permeable sediments exposed to varying current flow and light. Limnology & Oceanography 58: 1329-1343.
  • Howarth, R. W. 2013. Shale gas extraction. Pages 354-359 in Craig, R.K., B. Pryd, J.C. Nagle, O. Schmitz, and W. Smith (eds.), The Berkshire Encyclopedia of Sustainability: Vol. 5, Ecosystem management and Sustainability. Berkshire, Great Barrington, MA.


In the news