1. Stanford University Global Climate & Energy Project Biomass Energy: the Climate Protective Domain Chris Field cfield@ciw.edu http://dge.ciw.edu Sept, 2008

2. 2 Constraints Food Fuel Fossil offsetsOther emissions EnergyNature

3. 3 Climate-protective biofuels Grow more plants –Without more environmental downsides Get more energy per unit of plant biomass Figure out where it does and doesn’t make sense to produce biofuels

4. 4 Land Type Area (Mha) Mean NPP (ton C/ha/y) Total NPP (Pg C/y) Total Energy* (EJ/y) GlobalCrop1,4454.66.7119 Pasture3,3213.411.3200 USCrop1735.71.018 Pasture2263.50.814 Global Primary Energy = 480 EJ/y * In ½ biomass (to allow for roots), assume 45% C Energy in ag and pastures?

5. 5 Will yields increase dramatically? Historical trends – a century of success –1-2%/y for major crops Will this continue? –Can it accelerate?

6. 6 Ag yields – a century of success increases of 1-2% y -1 Lobell and Field ERL 2007

7. 7 Extracting climate sensitivity First difference yield Define locally-weighted climate Regress against –Growing season t max, t min, precip –Define growing season based on explained variance Reconstruct trend with (observed) and without (climate corrected) climate

8. 8 Lobell and Field ERL 2007

9. 9 Global area, production, and yield changes for six major world crops Wheatricemaizebarleysoybeansorghum 2002 Area (Mha)214148139557942 2002 Production (Mt yr -1 )57457860213718154 Yield change, 1981-2002 (kg/ha)84611091178473632-80 Climate driven yield change, 1981-2002 (kg/ha)-60.1-6.5-89.5-140.323.1-20.0 Climate driven production change, 1981-2002 (Mt yr -1 )-12.9-12.4-7.81.8-0.8

10. 10 Lobell and Field ERL 2007

11. 11 Ag in relation to natural NPP –Ag/NPP -- Globally about 65% Global average crop yields unlikely to exceed natural NPP for at least the next several decades

12. Field, Campbell, Lobell TREE 2008

14. Field et al TREE 2008

15. 15 Land Type Area (Mha) Mean NPP (ton C / ha / yr) Total NPP (Pg C / yr) GlobalCrop1,4454.66.7 Pasture3,3213.411.3 Abandoned474-5794.72.2-2.7 Potential from abandoned land Campbell et al ES&T 2008

16. 16 Land Type Area (Mha) Mean NPP (ton C / ha / yr) Total NPP (Pg C / yr) GlobalCrop1,4454.66.7 Pasture3,3213.411.3 Abandoned474-5794.72.2-2.7 In Forest726.50.5 In Urban185.00.1 In Other385-4724.31.6-2.1 From available abandoned land 1.6 – 2.1 Pg C x 2 g Plant/g C x 0.5 g top/g plant x 20 EJ/Pg = 32 - 41 EJ = 7-8% of current global energy system

17. 17

18. 18 Bioenergy Climate impact depends on pre-existing ecosystem Indirect as well as direct paths to carbon loss Natural NPP reasonable proxy for potential yield under ag management Available land resource limited –Quantity and quality Big potential in absolute terms But a small slice of present or future demand

19. 19 Biomass energy: the climate protective domain Food/Biomass energy interactions –Roz Naylor, Holly Gibbs Biomass in areas converted to bioenergy –Greg Asner, Scott Loarie Albedo feedbacks from bioenergy agriculture –David Lobell, Matt Georgescu Available land, potential yield, GHG balance –Chris Field, Elliott Campbell

20. 20 Future energy needs: Many times current

21. 21 Biomass energy Corn $190/ton CoalPower River$15/ton Central Appalachia$149/ton Crude oil $820/ton

22. 22 Ferment or burn?

23. 23 Understanding deforestation Where is it occurring? Where will it occur in the future? What are the drivers?

24. PRODES deforestation matches low biomass from RADAR PRODES not forested, 2000RADAR low biomass, 2000

25. 25 Large-scale patterns: Kernel approach to deforestation rate fraction not forested, 2000fraction low biomass, 2000

26. 26 Year-by-year deforestation Pre-deforestation biomass (Mg ha -1 )

27. 27 Greater biomass in remaining forests