Biofuels, Land Use Change, and Climate

Size: px
Start display at page:

Download "Biofuels, Land Use Change, and Climate"

Transcription

1 Biofuels, Land Use Change, and Climate Andrew Jones PhD Candidate University of CA, Berkeley 0

2 1

3 California has set ambitious targets and has designed policies to foster innovation CA GHG Emissions (MMTCO2E/yr) Historical with electricity imports Historical, no electricity imports Forecast baseline emissions Goals (with imports) Executive Order S-3-05 GHG emission reduction targets 2010: maintain 2000 levels (~10% reduction from baseline) 2020: return to 1990 levels (~25% reduction from baseline) AB : attain 80% below 1990 levels Climate Stabilization 2

4 3

5 LCFS liquid fuel concept + = = 2020 Reduce the life cycle carbon intensity of transport fuels at least 10% relative to 2006, by 2020 Source: Michael O Hare 4

6 LCFS basics Carbon intensity must be measured on a lifecycle basis Average Fuel Carbon Intensity (AFCI) measured in gco2e/mj AFCI must decline by at least 10% by 2020 Stimulate technological innovation Use performance standard, with tightening over time Measures desired outcome (GHGs), not a proxy (renewable) Different fuels (electricity, biofuels, fossil, etc.) compete with one another, so government does not pick winners (or losers!) Compliance by manufacturers or importers of fuels (mostly oil refiners) Additional to vehicle performance standards Overcompliance creates credits that can be traded in a market or banked for later use Default and opt-in approach (Thanks to the U.K.) 5

7 Major challenges for the LCFS Subsidy for some GHG emissions Intensity target alone is not very stringent Leakage Change in trade patterns Global emissions do not change Little innovation Life-Cycle Analysis Uncertainties and innovation Indirect land use 6

8 Source: Farrell et al,

9 Life-Cycle Fuel GHG Values Fuel CI (gco2e/mj) Adjusted* (gco2e/mj) Notes CA gasoline Tailpipe 78 (85%) CA diesel Based on US 2007 vehicles FT diesel coal Ethanol coal dry mill No indirect emissions Ethanol advanced corn No indirect emissions Ethanol - switchgrass No indirect emissions Electricity CA avg Hydrogen Natural gas Fuel cell vehicle Credits (?) Notes: * Adjustment is for efficiency of drive train. Based on GREET- California reported on University of California August 2007 report 8

10 Regulatory implementation requires a new approach to Life Cycle Analysis Plant-specific analysis is required May be proprietary and thus must be protected by government Mechanisms for certifying data are needed Key assumptions must be agreed-upon by all users, else the model produces any answer you want (e.g. forecasts) Uncertainties must be calculated and evaluated. Factors that cannot be represented in a LCA need to be added Land use change Must be usable by regulated entities, resistant to fraud, and easy to verify. 9

11 10

12 11

13 Agriculture and land conversion are already major sources of GHG Source - World Resources Institute 12

14 Process Emissions Indirect Process Emissions Intensification New Demand Price Adjustment Soy farmers everywhere use more inputs to increase yields Substitution U.S. corn farmer switches from corn/soy to corn/corn U.S. soy exports go down and world soy prices rise Extensification World consumption of soybean decreases Indirect Land Cover Change Emissions Additional land in Brazil (for instance) is put into soy production 13

15 How to estimate land cover change All of these steps introduce uncertainty and raise methodological questions 14

16 What we used to think Net energy and net GHG estimates for 6 studies of corn ethanol, as well as 3 cases. Gasoline is shown for reference. The cellulosic case is switchgrass grown on prime crop land. Adapted from - Farrell et al,

17 What might actually be the case! Searchinger considering LUC Net energy and net GHG estimates for 6 studies of corn ethanol, as well as 3 cases. Gasoline is shown for reference. The cellulosic case is switchgrass grown on prime crop land. Adapted from - Farrell et al, 2006 and Searchinger et al,

18 Our current best estimate using the GTAP model Net energy and net GHG estimates for 6 studies of corn ethanol, as well as 3 cases. Gasoline is shown for reference. The cellulosic case is switchgrass grown on prime crop land. Adapted from - Farrell et al,

19 There are many uncertainties Biophysical Uncertainties Economic Uncertainties Conceptual Uncertainties ecosystem types converted elasticities of substitution amortization carbon stocks per land technological innovation derating of future portion of carbon released baseline demands discounting of future albedo changes availability of lands consistency of GWI values hydrocycle changes trade policies role of land reversion nitrogen cycle disruption regulations role of short lived gases investment dynamics 18

20 Insights from LCFS Experience Land use change confounds efforts to precisely rate the GHG impacts of biofuels Fuel policies are not the best way to address land use issues 19

21 What might a comprehensive approach to addressing land use change and climate look like? 20

22 What are the necessary/desirable features such a strategy Monitorable Enforceable Equitable Inclusive of many values Recognizes market dynamics (leakage) Accounts for complex climate dynamics 21

23 Climate Policies dealing with Land Use Change Clean Development Mechanisms (CDM) Reduced Emissions from Deforestation and Degradation (REDD) Biofuels / Clean Fuels Programs Agricultural Offset Programs 22

24 Climate Policies dealing with Land Use Change Clean Development Mechanisms (CDM) Reduced Emissions from Deforestation and Degradation (REDD) Biofuels / Clean Fuels Programs Agricultural Offset Programs All of these focus on GHG emissions to measure climate impacts! 23

25 How does Land Use Affect Climate? Land Conversion Ongoing Management Aerosols, Black Carbon Biophysical Change GHG Emissions 24

26 Biophysical Effects of Land Use Change Cropland Forest Source - RB Jackson et al Environ. Res. Lett. 3 (2008)

27 About Biophysical Change Can easily outweigh GHG effects at regional scale Globally responsible for slight anthropogenic cooling Produces confounding effects for Boreal deforestation, reinforces warming from Tropical deforestation Perturb the climate through multiple mechanisms, not all warming Could potentially offset global warming in mid latitude agricultural zones May have far-reaching teleconnections 26

28 Policy Questions about Biophysical Change When does it matter for policy? At what scale? For whom? Mitigation vs. Adaptation? How should it be incorporated into policy? Performance vs. practice regulation? How is it best measured or estimated? Which metrics are appropriate when? 27

29 Biophysical and GHG not effects expressed through common metric Biophysical and GHG effects expressed through common metric Terrestrial GHG not traded with fossil and industrial GHG Terrestrial GHG traded with fossil and industrial GHG 28

30 Climate Metrics Useful to examine dominant paradigm Global Warming Potential W / m^2-kg N2O CH4 CO2 years 29

31 Human Activity Climate Forcing Climate Outcomes Damages 30

32 Human Activity Climate Forcing Climate Outcomes Damages Feedbacks 31

33 Human Activity Climate Forcing Climate Outcomes Damages Feedbacks Adaptation 32

34 GWP Human Activity Climate Forcing Climate Outcomes Damages Feedbacks 33

35 Spatial Extent of Biophysical Change Spatial Extent of Albedo Forcing Albedo Change Carbon Stocks Mg CO2e Mg CO2e 1 ha 9*10^ all US ag and forest land 13, all of earth

36 What about GTP? GWP GTP Human Activity Climate Forcing Climate Outcomes Damages Feedbacks 35

37 Not All Biophysical Effects are Radiative GWP GTP Absolute Difference Human Activity Climate Forcing Climate Outcomes Damages Feedbacks 36

38 Climate Stabilization vs. Optimization Absolute Difference GWP GTP Damage Function Human Activity Climate Forcing Climate Outcomes Damages Feedbacks 37

39 Multiple Metrics Sustainability Metrics GWP GTP Absolute Difference Damage Function Human Activity Climate Forcing Climate Outcomes Damages Feedbacks 38

40 Modeling Biofuels Biophysical Effects For corn ethanol, most land use is indirect Searchinger et al FAPRI analysis Hertel et al GTAP analysis EPA FAPRI/FASOM analysis 39

41 The Community Land Model (CLM) 40

42 The Community Land Model (CLM) 41

43 Coupling CLM to the Atmosphere Community Atmopshere Model (CAM) Full General Circulation Model Designed to work with CLM Weather Research and Forecasting Model (WRF) Regional model Can resolve finer processes 42

44 Scenario Generation Downscaling algorithm needed to translate scenarios to grid level 43

45 New Model Functionality New plant functional types (PFT s) for crops / biofuels Currently only 1 simple crop type Crop management Management Regime (MR) 44

46 Impact Analysis Spatial / temporal footprint of land use change Diverse climate outcomes Temperature Precipitation 45

47 Sensitivity Analysis Which aspects of of PFT and MR matter most? 46

48 Empirical Component How easy is it to detect Biophysical Change in climate record? No need to model feedbacks Potential advantage for policy implementation Undercuts model uncertainty Test predictions of the model But can only do this for historic scenarios 47

49 Sketch of Method Regress remotely sensed land cover change onto temperature and precip across a broad spatial and temporal domain Year 1 Year 2 Year 3 Ha Converted in Gridcell X Ha Converted in Gridcell Y Temp in Gridcell T

50 Issues Remotely sensed or directly measured T? Which T? Mean? Daytime Max? Nightime Min? Precip Data? How to constrain the search signal? Biofuel modeling and lit review Possible meta-analysis of literature 49

51 Some Discussion Points We should have global treaties on CO2 However, for land use, this is not the whole story Treating only part of the climate signal from land use could produce unintended consequences Non-GHG effects of land use do not fit easily into the GWP metric Perhaps a practice-based approach is preferable, but we still need to rank preferred practices More fundamental research is needed to understand the climate signal of land use change 50

52 Thank You Alex Farrell Margaret Torn Dan Kammen Michael O Hare 51

53 Backup slides 52

54 The climate effects of land use have different spatial and temporal scales, pathways Efflux or surface property Lifetime Spatial Scale Climate influence CO 2 multi-year Global W/m 2 GWP = 1 N 2 O 114 y Global W/m 2 GWP = 310 CH y Global W/m 2 GWP = 21 H 2 O, ET/Sensible Heat Aerosols Ozone Albedo Roughness Source: M. Torn 2July days Days-wks Days-wks veg veg Local - Reg. Regional/Cont. Local- Regional Local Local Temperature, PBL, Precip, W/m 2 Cloud condensation nuclei, W/m 2, W/m 2 W/m 2 Turbulent heat transfer, ET 53

55 54