Our research broadly falls into the following categories:

Agricultural, Biomass, and Land-Use Emissions

Emissions from processes involving our land base -- agricultural production, forestry, biomass burning, and conversion of one habitat to another -- comprise around 1/3 of total global emissions. What processes and demand sources are driving these emissions, and what are their downstream impacts? Better measurements and detailed accounting can help us understand the possibilities for mitigation and identify where different types of policy instruments are needed. Perhaps most important, this type of accounting can help quantify what fraction of these emissions are "locked in" -- absolutely necessary for food security and already as low as possible -- to identify key new research frontiers. Check out the Comprehensive Accounting of Land-Use Emissions (CALUE) database here.

Air Pollution & Climate Impacts on Human Systems

Emissions of long-lived greenhouse gases (LLGHGs) like carbon dioxide are the main drivers of anthropogenic climate change, but emissions of other short-lived climate pollutants (SLCPs) also impact global and regional climate. We are working to understand the role that SLCPs play in the coupled climate-human system. These pollutants (including compounds like aerosol particulate matter of different types and sizes, as well as tropospheric ozone and its precursors) are emitted in different combinations, they evolve in the atmosphere, and have a wide range of impacts on the general climate circulation, as well as people and plants. On the policy side, these pollutants contribute to air quality and climate inequities; and synergies between local air quality impacts and broader climate objectives may be especially important to achieving regional and global cooperation on environmental stewardship.

Irrigation and Agricultural Adaptation

What does it mean to adapt to climate change? In the ecological literature, resilience is conceptualized as the stability of the current equilibrium state: would a small disturbance to the ecosystem be followed by a quick (or slow) return to the original state, would it result in a shift to a new equilibrium state, or would it result in a runaway instability? We apply these concepts to smallholder farming households to understand what types of technologies and strategies help farmers in hydrologically variable regions decouple their production from weather, particularly as baseline climate changes. Of particular interest is the role that irrigation can play in meeting local and global food security, both now and sustainably into the future. I’m co-chair / scientific co-director of the new JPAL/CEGA Digital Agricultural Innovation and Services Initiative (DAISI) — please take a look and consider submitting to one of our upcoming RFPs.

Environmental Connections to Kawasaki Disease

Kawasaki Disease (KD) is the leading cause of acquired heart disease in the United States. It typically affects young children, and while the more dramatic external symptoms (fever, rash, lymph nodes, peeling skin, 🍓 tongue) resolve with time, it can also quietly cause aneurysms of the coronary arteries (learn more here). Importantly, its etiology is unknown, but hypothesis is that KD may be triggered by inhaled aerosols. San Diego is a KD hotspot, but we benefit from having a group of world-leading doctors who see all KD patients within a large catchment area, and have therefore assembled some of the most complete and detailed KD data on the planet. Our group is exploring the statistics of KD incidence and its associations with climate and environmental factors in the hopes that it will lead to the cause of this mysterious illness.