Projects Funded for Maximilian Auffhammmer


Leaky Cows: Regulating Methane Emissions from California’s Dairy Sector


Empirical Estimation of Climate Impacts on Dairy Production and Quality


Specific Objectives of the Project

This project estimated the empirical effects of historical temperature on dairy production and quality, specifically measured by volume, fat content and protein content. This estimation will be used to both forecast the expected costs to the dairy sector of future climate change, and estimate the historical cost of recent climate change.

Project Report/Summary of Results
Dairy is a crucial part of the California and United States' food systems. Milk is California's largest agricultural commodity by value, producing approximately $8 billion per year for farmers. Dairy constitutes 19% of the protein content of the US diet, provides half of the total calcium and vitamin D, and provides a quarter of the total vitamin A and vitamin B12. Globally, dairy is also very important, constituting 10% of total protein and 26% of the total protein consumed from all animal sources. It is the largest animal product globally both in terms of contribution to protein supply and calorie supply.

This project finds that the production response of California dairies to temperature is increasing up to 15-20°C, and more steeply decreasing thereafter. The model estimates that taking an hour at 15-20°C and moving it to 35-40°C would result in a reduction in production of approximately 30% (for that hour), a statistically significant reduction. The quality measures (fat proportion and solids-not-fat proportion) exhibit a significant negative relationship with temperature, across the temperature spectrum, that is economically small. The model estimates that the same temperature change would result in reductions of these proportions of less than 0.2% (not percentage points). These results allow researchers to confidently work with data on raw quantities of dairy production, which is much more readily available than the nutritional quality data.

This project also finds that predominantly pasture-based dairy systems respond to hot temperatures to a much larger degree than concentrated feeding operations. We find that the production response for pasture-based counties is increasing up to 10-15°C and decreasing thereafter. The model estimates that taking an hour at 10-15°C and moving it to 20-25°C would result in a reduction in production of approximately 60%, a much larger impact than that for Central Valley counties. The difference can be explained by a combination of differences in the ease of protection of the cows (fans and evaporative cooling cannot be employed in pasture-based systems) and differences in the proportion of feed grown locally.

A next step in this project is a careful accounting of the impacts on upstream feed production for the Central Valley farms. A simple projection of future climate change would naïvely omi omit these important effects. A working paper will be available in August.


Central Pivot Irrigation and Technology Switching: An Assessment from Space


Specific Objectives of the Project

The objective of this minigrant project was to collect information on central pivot irrigation (CPI) in California through automated analysis of satellite imagery. We have successfully mapped the extent all detected CPI fields in California, along with a web service for vegetation analysis from NASA satellite imagery. The web service, called an Application Programming Interface (API), is useful for agricultural applications beyond the scope of this project.


Auffhammer_Fig1.jpg The CPI fields were identified through kernel density differencing. The difference between a spatial convolution of circles and squares was calculated for all available NASA Landsat 8 annual composites (2013/2014).
The difference, in theory, will be greatest at the center of circles in the images. The convolution was run for plot sizes between 200m and 600m. The results served as a screening dataset, which was subsequently verified by hand using halfmeter, commercial satellite imagery supplied by DigitalGlobe. Ultimately, there were 121 CPI fields detected in the state of California. A sample is displayed in the first
figure, and a web map is available here (along with the generating code and raw data).

Auffhammer_Fig2.jpg An additional webservice was built to calculate the vegetation density for any polygon and for any month between January 2000 and the present from NASA satellite imagery. The Enhanced Vegetation Index (EVI) is a measure of vegetation density, derived from monthly, cloudfree composites of NASA Landsat 7 scenes. The service is technically a Representational State Transfer (REST) API. The HTTPS GET request accepts a bounding box and a date range, and returns a series of EVI measurements useful for CPI analysis. Specifically, the service returns three measurements for both the inner circle and remaining corners of the CPI field: (1) the average EVI, (2) the standard deviation of the EVI, and (3) the area in meters squared. These three measures, when taken together, can calculate the test statistic to determine whether the vegetation was significantly different within the inner circle, relative to the rest of the plot. This test statistic is sufficient to identify whether CPI was used at any given month. Our initial analysis reveals that CPI fields are converted frequently to furrow or other irrigations systems there is a significant amount of switching.

Project Report/Summary of Results

The graph below shows the time series decomposition of the EVI series into its trend, seasonal, and idiosyncratic components. The returned series (which is graphed using code in the client library of the opensource repository) clearly shows an increase in vegetation intensity for this particular field in the past few years. This CPI field is 455,948m 2 in size with 171 observations between 20010101 and 20150509. There is a seasonal component that is bimodal. This type of analysis can be replicated for all 121 CPI plots in California and any arbitrary extent in the world.


HTTP request :
GET enviroserver.
JSON response :
  "count": 1,
  "begin": "20150101",
  "end": "20150130",
  "results": [
    "date": "20150101",
    "outer": {
      "mu": 0.49969901965467495,
      "stdev": 0.19776504937925868,
      "area": 126019.74502437406
    "inner": {
      "mu": 0.557700789530968,
      "stdev": 0.1346491316223512,
      "area": 487167.2190757549

Extensions and associated services

This online database with structured access points is highly useful for climate researchers. The service enables research into the behavior changes over time of agriculturalists in response to exogenous factors. One such factor is water level. A parallel endpoint (developed separately) tracks surface water for any polygon in the world over time. These services, when taken together, offer a powerful set of tools to show the behavioral response to water scarcity in California.


Detecting and Attributing the Impact of Historical Climate Change on California Agriculture


Specific Objectives of the Project

Use all available data California's major and specialty crops to estimate the impact of historical impact of climate change on California's Agricultural sector.

Summary of Results

We have put together a large dataset on county level crop yields for California by drawing on studies conducted under the auspices of the CEC's now defunct PIER project. We have extended these databases to current day using county level crop reports. We have matched these reported yields to the crop calendar for each crop and measures of weather from the data product provide d by Roberts and Schlenker. In order to come up with historical weather without climate change, we have obtained the IPCC's AR5 historical and future climate series with and without anthropogenic forcing. We have estimated yield response functions and are finishing the simulations this summer. This study was motivated by questions I received during an outreach activity with farming lobbyists organized by the Secretary of Agriculture in Modesto earlier this year.


Forecasting California's Urban Water Demand


Specific Objectives of the Project

Construct a forecasting model based on the most extensive retailer level consumption and price dataset ever collected for the State of California.

Summary of Results

We have built the code and data for the forecasting model and it works. We can generate results for Southern California and are working on completing the Northern California results. We hope to have a working paper targeted at Water Resources Research by the end of the summer. Progress was a bit slower than anticipated due to unforeseen complications in writing code that estimates 250,000+ models a few hundred times each.


Family Tree of Agricultural Economics


Specific Objectives of the Project
Construct a family tree of academic agricultural and resource economists, which highlights the influence of members of the Giannini Foundation in current day agricultural economics research.

Project Report/Summary of Results
Agricultural and Resource Economics is one of the oldest sub fields in economic research. Its history is told in several review articles, yet no one has traced its origins in a systematic way. We have improved an existing academic family tree piece of software, which much like a regular family tree traces the history of the field by linking students and advisors.


Market Based Impacts of Federal Critical Habitat Designation


The paper examines the effects of critical habitat (CH) designation on the value of vacant land. The regulation is designed to generate benefits by protecting habitat for endangered and threatened species under the ESA. Critical habitat is a controversial provision of the act, as property owners argue that it can result in large, negative economic impacts. In this paper we provide the first estimates of the impacts of CH designation on vacant land values, based on observed market transactions in two counties. We show that designation results in a statistically significant decrease in land value. Further, the market impact of critical habitat designation is shown to depend on local land use regulation. Parcels inside the urban growth boundary (UGB) designated as critical habitat lose in excess of 56% of their value. We also find that designated parcels outside the UGB experience a more moderate increase in value, perhaps because their value as mitigation land increases with designation as critical habitat.


Estimating the Impacts of Ground Level Ozone on Agricultural Yields


The objective of the project was to identify the impact of ground level Ozone pollution of yields of California's main field and perennial crops.

We have completed an econometric model, which regresses county level yields by crop on ozone concentration and county and year fixed effects. We show a significant nonlinear impact of ozone concentration on yields of soybeans and corn. A fter instrumenting for Ozone concentrations using an indicator of the county level NOx control program, we show that the estimated effects are larger than in the OLS regression.


Estimating Direct and Indirect Impacts of Aerosol Pollution on California Agriculture