Soil Carbon Measurement Costs and Protocols Using a Linked Economic and Biophysical Model Forestry and Agriculture GHG Modeling Forum October 9th, 2002 Siân Mooney Dept. Agricultural and Applied Economics University of Wyoming

Other Collaborators John Antle and Susan Capalbo Dept. Agricultural Economics and Economics Montana State University Keith Paustian Natural Resource Ecology Laboratory Colorado State University

Motivation C sequestration in agricultural soils C is “invisible” Is it possible to sell? Need monitoring/measurement Possibly have large number of producers How to design monitoring/measurement Will it be too costly?

Study Objectives Develop a measurement protocol for C credits sequestered in agricultural soils Estimate its cost for a region of the US Examine characteristics that influence measurement costs

Influence of Contract Design Contract design will determine monitoring and measurement needs Per-hectare contract Per-credit contract $MM=$monitoring practice+$measuring C

Measurement Issues Several producers – cover large area Statistical sampling $M=f(#samples,$/sample,frequency) Combine field measurements and predictive models

Measurement - General Predictive biophysical models – estimate C Measure baseline – statistical sampling/field samples/lab testing Measure C periodically over duration of contract Measure C at end of contract

Measurement - Specific Stratified random sampling Sample population – producers with contracts to supply C-credits Strata based on crop system change Cost/sample $16.37 Frequency – 4 times Years 1, 5, 10, 20.

Study Area Field level production data Climate, soil and biophysical characteristics

Models parameter estimates carbon estimates Econometric Models (output supply, input demand) Century Ecosystem Model (NREL) parameter estimates carbon estimates 1. #producers participating 2. #producers in each strata 3. Opportunity cost of system changes Land use simulation -stochastic output and input prices -policy designs and payment levels

Cost per credit (5% , 95% confid)   Price /credit ($) Sub-MLRA 52-high Sub-MLRA 52-low Sub-MLRA 53-high MPC ($) M Cost (% of Price) 10 0.18 1.81 0.30 3.03 0.29 2.99 50 0.05 0.10 0.13 0.26 0.19 0.38 100 0.03 0.09 0.16     Price /credit ($) Sub-MLRA 53-low Sub-MLRA 58-high Sub-MLRA 58-low MPC ($) M Cost (% of Price) M Cost 10 1.05 10.57 0.14 1.39 0.29 2.92 50 0.51 1.03 0.07 0.18 0.37 100 0.39 0.05 0.13    

C Change Variability and Cost per Credit 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.5 1 1.5 2 2.5 3 3.5 Cost/credit Coefficient of Variation in C Changes 52H 52L 53H 53l 58H 58L Variability Decreasing

Conclusions Measurement costs not large enough to prevent producers from participating in C market Efficiency of measurement protocol depends on the price of credits Measurement costs largest in spatially heterogeneous areas

Other issues Uncertainty associated with initial C change estimates (see other paper on web) Baseline – will change costs per credit

Additional Information Siân Mooney Dept. Agricultural and Applied Economics University of Wyoming Phone: 307-766-2389 E-Mail: smooney@uwyo.edu