Abandoned Agriculture: Land Use Analysis and Data Elliott Campbell, David Lobell, Chris Field EBI Workshop on Crop Modeling and Land Use October 9, (Photo: Nobel)

1.Global Abandoned Agriculture (Campbell et al., 2008) 2.U.S. County Abandoned Agriculture (In Prep) 3.CRP Land Use Change (In Prep) 4.Yields Preview 2 Overview

Croplands Forest Lands Alternative Lands 3 Biofuels and Land Use (Fargione et al., 2008)

Ramankutty and Foley, 1999 – 210 Mha abandoned cropland – No consideration of present land cover or pasture Abandoned ag applied in global biofuels assessments (Tilman et al., 2006; Hoogwijk et al., 2003) – Houghton, Mha degraded lands Tropical deforestation in Africa, Asia, Latin America – Hall, Mha degraded lands Tropical deforestation and fallow cycle of shifting cultivation 4 Previous Estimates

5 Quantifying Abandoned Agriculture ) Abandoned agriculture areas from historical land use data (HYDE, SAGE) 2) Exclude agriculture-to- forest and agriculture-to-urban (MODIS12C1) 3) High estimate of potential yields from ecosystem model (CASA) 4) Regional bioenergy potential on abandoned agriculture lands.

HYDE (Goldewijk et al., 2007) – 5 minute resolution – Decade time step, – Crop Area – Pasture Area SAGE (Ramankutty and Foley, 1999) – 5 minute resolution – Decade time step, – Crop Area – Crop Yields 6 Agriculture Land Use Data

7 Cropland Time Series: Global

8 Cropland Time Series: U.S.

Crop-to-pasture and Pasture-to-crop transitions not explicit Two approaches 1. Aggregate Approach Abandoned ≤ Max(Pre-2000 Area) – Current Area if Max(Pre-2000 Area) – Current Area > 0 Abandoned + Current ≤ Total Grid Cell 2. Time Series Approach Abandoned = Area t+1 - Area t, if Area t+1 - Area t > 0 If crop increment > 0 and pasture increment < 0 modify abandoned ag increment (and vice-versa) 9 Land Use Analysis

10 Area of Abandoned Agriculture (Campbell et al., 2008)

Land Cover Area (Mha) Average NPP (ton ha -1 y -1 ) Total NPP (billion ton y -1 ) Urban Forest Savannah, Grassland, Shrubland Categories of Abandoned Agriculture

12 Potential Bioenergy from Abandoned Agriculture (Campbell et al., 2008)

13 HYDE Crop and Pasture Areas SAGE Cropland Abandoned Agriculture Data Availability

Some lands perceived to be abandoned are used by the poor (Cotula et al., 2008) Biomass density Some areas not included in this analysis: – Shifting agriculture (Hurtt et al., 2006) – Degraded/abandoned lands not associated with agriculture (Houghton, 1999) – Marginal lands… food price impacts? – CRP Coarse Spatial Resolution 14 Caveats

15 County-Level Abandoned Ag (Waisanen and Bliss, 2002)

16 CRP Availability

NPP model inter-comparison Compare county-level yields and land use trends Experimental trials Atmospheric NPP tracer (Campbell et al., Science, In Revision) 17 Yield Preview

Gridded geospatial data available now for pasture, crop, and abandoned agriculture U.S. county-level and other marginal land areas coming soon Multiple approaches to assessing yields needed 18 Summary