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Department of Physics
Portland State University


Current Research Areas

Isotopic atmospheric methane

Emissions from rice agriculture

Role of trees in the methane budget

Methyl halide emissions from estuaries

Carbon flux from cities

Method development





"It is extremely likely (>95%) that human influence has been the dominant cause of the observed warming since the mid-20th century."

– IPCC, 2013: Climate Change 2013: The Physical Science Basis. WG1. AR5

In order to mitigate climate change in the long-term we need a detailed understanding of the controlling mechanisms driving concentrations of greenhouse gases and other related trace gases in the atmosphere. Today there is little doubt that, through their radiative properties, greenhouse gases are responsible for much of the global temperature rise scientists have observed over the past several decades. There is high confidence that as greenhouse gas concentrations continue to rise in the future, so will global temperatures. Of growing importance are the second order questions of how much will temperatures rise and how fast? Here, scientists ability to predict future levels of greenhouse gases – which drives future climate – will ultimately depend on a comprehensive understanding of their sources and sinks and what controls their variability. We will also need increasingly complex Earth system climate models to couple these processes together and quantify the climate sensitivity, which is the climate’s response to radiative forcing.

My research here at PSU focuses on understanding the drivers of climate change. I am interested in contributing to a better understanding of atmospheric trace gas sources and sinks. This work has led our group to address long-standing and up and coming research questions at a variety of scales from the process-based level to the global atmospheric perspective.