The structure of crop hydroclimate vulnerability and its implications | 9am PT Tues, March 24, 2026

[Grigory Bronevetsky]

Modeling Talks

The structure of crop hydroclimate vulnerability and its implications Jennifer Anne Burney, Stanford Tues, March 24, 2026 | 9am PT Youtube Stream Hi all, The presentation will be via Meet and all questions will be addressed there. If you cannot attend live, the event will be recorded and can be found afterward at https://sites.google.com/modelingtalks.org/entry/the-structure-of-crop-hydroclimate-vulnerability-and-its-implications More information on previous and future talks: https://sites.google.com/modelingtalks.org/entry/home Abstract: Agriculture is exposed to weather and climate change in multiple ways. Effective, efficient, and appropriate adaptation thus requires understanding in detail where, when, and how crop vulnerability arises. Here I present findings from a series of studies on crop-hydroclimate interactions and their implications for effective policy design. First, using atmospheric and ground-based isotope observations, we show that global distribution of crop water origins and explain why crops that depend more on land-originating moisture are more sensitive to seasonal and sub-seasonal water conditions. Second, we link land-use change within a crop area’s “precipitation-shed” to changes in land-originating atmospheric moisture and rainfall. Focusing on sub-Saharan Africa, we show that the productivity of new croplands tends to be lower than existing croplands, partially due to hydroclimate changes from land conversion / deforestation. Together these findings help illuminate why some croplands are more vulnerable to climate and land use changes than others, what might be done to best adapt in those regions, and how new thinking about terrestrial carbon reserves might help catalyze investment in such adaptations.   Bio: Jen Burney is a professor in Global Environmental Policy and Earth System Science and is the Deputy Director of Center on Food Security and the Environment. Jen is a member of the Standing Panel on Impact Assessment (SPIA) of the CGIAR system, the Food Security Leadership Council (FSLC), and the Center for Effective Global Action (CEGA), where she is co-chair of the Digital Agricultural Innovations & Services Initiative (DAISI). Before joining the Doerr School in 2025, she spent 12 years on the faculty at UC San Diego's School of Global Policy and Strategy (GPS) and the Scripps Institution of Oceanography (SIO), and has been a member of the National Geographic Explorers (NGS) family since 2011. Education: BA, Harvard College (History & Science), 1999; PhD Stanford University (Physics), 2007

[Grigory Bronevetsky]

Video Recording: https://sites.google.com/modelingtalks.org/entry/the-structure-of-crop-hydroclimate-vulnerability-and-its-implications

Slides: https://drive.google.com/file/d/1SY6GdQdY2PuDDOVbU0W-de2GMgz7qF9-/view?usp=sharing

Summary:

• Focus: Climate change and agriculture and the food system

• Emissions - Pollution - Adaptation nexus

• How to better model the interaction to make better decisions

• Where does crop water come from?

  • Motivations:

    • Food insecurity is rising after dropping for decades

    • Food production emits a lot of GHGs. How do we reduce it without increasing hunger?

    • Challenging to feed without emissions. E.g. 1.5 degree scenario: population plateaus/drops, emissions drops, forested area massively increases (overly optimistic)

    • We need land to feed people, which can cause deforestation; immediate carbon loss, changes long-term carbon potential

  • We know most global agriculture are rainfed

    • Rain comes from evaporation from water and land, which will evolve differently under climate change

      • Evaporation from oceans will intensify with climate change

      • Evaporation from land will evolve differently based on how it is used

    • Approach: use satellite observations to track isotopes in water vapor

      • Can track deuterium concentrations; more depleted->more from ocean/further away

      • Oceanic water has known ratios

      • Land-source water has measured long-term ratios, captured from stream gauges

    • Analyzing water sources across the world shows useful patterns

      • E.g. Indian monsoon is kicked off by terrestrial water and then continued with oceanic water

      • Water source encodes useful sub-seasonal dynamics, with a simple threshold on water source (f_land_sourced=36%) predicting key soil moisture metrics

        • P-PET: Potential evapotranspiration

        • RZSM: Root zone soil moisture

      • Intuition: inland areas don’t get much ocean-sourced water, rely mostly on land-sourced water

      • Many global crops have high land-water dependence (>36% threshold)

      • Areas with high fraction of land-sourced water are more sensitive to droughts and will likely experience more severe droughts

      • Drops in land-sourced water will matter for the global food supply!

  • Can track flow of air and water to identify where the water raining at a given location comes from

    • P = Plocal+Pupwind_land+Pupwind_ocean

    • E.g. Congo basin is a major source of water for all of Africa

• Analysis:

  • Statistically determine whether change in green-ness varies based on deforestation

  • Agricultural deforestation has a bigger impact on regional deforestation than more industrial land use

  • Deforestation associated with lower nearby yields

• What does it mean for policy?

  • Land-sourced water is critical

  • Agricultural demand is a major driver of deforestation and emissions

  • Global social drivers are pointing towards higher emission scenarios

  • Emissions due to emissions of fossil carbon are the same everywhere; methodologies for social cost of carbon are clear and well-established

  • Losing terrestrial carbon are very location-specific; will require changes in social cost of carbon methodologies

[Grigory Bronevetsky]

Corrected links

Video Recording: https://youtu.be/uGB5LbnsVak