of ghg and n agricultural emissions, mitigation, and ...gross agriculture emissions in 2008: 463 mt...
TRANSCRIPT
Assessment of GHG and N agricultural emissions, mitigation, and projectionsemissions, mitigation, and projections for the Packard Foundation
Presentation to C‐AGG
March 1 2012March 1, 2012
Project overviewPage 2
Provide the Packard Foundation with a concise synthesis of the following:
1) What was the range of plausible scenarios for US agriculture emissions and sequestration between 2008 and 2020 and what trajectory are we following?following?
2) What are the sources of GHG from agriculture in the US?
3) What are the most promising opportunities for US agriculture to mitigate climate change?climate change?
4) What was the range of plausible scenarios for nitrogen pollution associated with US agriculture between 2008 and 2020 and what trajectory are we following?trajectory are we following?
5) What are the sources of nitrogen pollution from agriculture in the US?
6) What are the most promising opportunities for US agriculture to mitigate i ll i ?nitrogen pollution?
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GHG EmissionsGHG EmissionsIntroduction> GHG emissions > GHG mitigation > Nitrogen pollution > Nitrogen mitigation
Scenarios‐ Scenarios‐ Global and national context ‐ US agricultural emissions overviewLivestock‐ Livestock
‐ Croplands
Additional projections have been run in recent years. While there is notable variance, the trend lines are comparable excluding outliner projections.
l l h d & b l h d
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• Blue lines are historic projections and 2008 inventory & regression – emissions seem to be lower than was expected.
• Red lines show the most recent inventory and the expected trajectory from this data. From 1990‐2010, agricultural emissions grew by about 0.5% per year.
• Green lines show the most recent set of models and projections. The steep green line is the EPA’s draft 2011 Global Anthropogenic projections are out of line with other models and the trajectory implied by the most recent inventoryAnthropogenic projections are out of line with other models and the trajectory implied by the most recent inventory and we have reason to believe it has some flaws.
Available scenarios currently include:• EPA’s 2006 Global Anthropogenic
575
CO2e emissions (Mt)
EPA s 2006 Global Anthropogenic Non‐CO2 GHG projections
• EPA’s 2011 Global Non‐CO2 GHG projections (draft)
• EPA’s 2005 GHG Mitigation Potential in U.S. Forestry and
525
EPA ‐ 2005 (FASOM)
EPA ‐ 2006 (global projections)
EPA ‐ 2008 InventoryAgriculture (Murray et al., uses FASOMGHG model)
• Nicholas Institute’s 2011 GHG Emissions and Nitrogen Use in U.S. Agriculture (uses FASOMGHG
d l)425
475
EPA 2008 Inventory
EPA 2008 trajectory
EPA 2011 Inventory
model)• Iowa State University’s 2011 GHG and Nitrogen Fertilizer Scenarios (uses FAPRI model)
• EPA’s 2011 Inventory of U.S. Greenhouse Gas Emissions and
375
EPA 2011 trajectory
EPA ‐ 2011 (global projections)
Greenhouse Gas Emissions and Sinks: 1990‐2009325
1990
1995
2000
2005
2010
2015
2020
2025
2030
ISU baseline (FAPRI)
While the projections seem to have a wide range, they are all well within the certainty range provided by the most recent inventory.
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600 2010 emissions (Mt CO2e)
Upper bound620
489453 455
431
390419
400
500
200
300 Lower bound293
100
200
Hi t i l j ti B k iReported
0EPA ‐ 2005 (FASOM) EPA ‐ 2006 EPA ‐ 2011 ISU baseline (FAPRI) NI ‐ baseline
(FASOM)EPA Inventory (2009)
Historical projections Back casting (For 2009)
Source: need correct citations
ISU scenarios show the emissions from agriculture are very difficult to reduce without taking land out of production ‐ which is a losing proposition.
h ff i i h l d i ifi l i d G G i i l b ll
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The afforestation scenario, however, leads to significantly increased GHG emissions globally because of land use change in other countries. • Domestic GHG emissions change surprisingly little between all of the scenarios except for afforestation (the only
scenario that takes a significant amount of land out of production).
• The afforestation scenario, however, leads to a net increase in global GHG emissions (6.6%) because of land use change in other countries. This land is generally less productive from a yields perspective (and thus more is required) and is also typically converted from native vegetation.
ISU scenarios440
445
450 US GHG emissions (Mt CO2e)
ISU scenarios1) Nitrogen prices increase by 10%
over baseline2) 20% decline in the price of crude
oil, and 10% reduction in natural gas, compared with baseline425
430
435 ISU baseline (FAPRI)
ISU fertilizer
ISU low energy
ISU credit duty3) Biofuels tax credit and duties are
reintroduced (not included in baseline)
4) 15% reduction in cropland (50 million acre reduction)
415
420
425 y
ISU afforestation
4101990 2000 2010 2012 2014 2016 2018 2020
Source: Elobeid et al. 2011, “Greenhouse Gas and Nitrogen Fertilizer Scenarios for U.S. Agriculture and Global Biofuels”, Iowa State University.
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GHG EmissionsGHG EmissionsIntroduction> GHG emissions > GHG mitigation > Nitrogen pollution > Nitrogen mitigation
Scenarios‐ Scenarios‐ Global and national context ‐ US agricultural emissions overviewLivestock‐ Livestock
‐ Croplands
US agricultural emissions are 1% of global GHG emissions
Gl b l G G i i i 200 8 G CO
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Global GHG emissions in 2005: 45.8 Gt CO2e
• Global agricultural emissions in 2005: 6.2 Gt CO2e
• US agricultural emissions in 2005: 415 Mt CO2e
Waste
BuildingsBuildings
Transport
US Agriculture
Agriculture (non‐US)Agriculture (non US)
Forest + peat conversion
Industry
Power
Global agricultural emissions (including US) are 14% of global GHG emissions.
US agriculturalUS agricultural emissions are 1% of global GHG emissions.
Source: McKinsey Global Cost Curves + EPA 2011 U.S. Greenhouse Gas Inventory Report
US agricultural emissions have fairly consistently been 6‐7% of all US emissions.
i i h f h i l l d ll f h S h b l
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Emissions growth rates for the agricultural sector and all of the US are shown below. From 1990 – 2008 agricultural emissions grew by 17% and all US emissions grew by 14%.
1990 – 1995 1995 – 2000 2000 ‐ 2005 2005 – 2008
7,000
8,000 Land Use, Land‐Use Change, and Forestry (Sinks)
U.S. Territories
1990 1995Ag emissions: 8% All emissions: 6%
1995 2000Ag emissions: 4% All emissions: 9%
2000 2005Ag emissions: 2%All emissions: 1%
2005 2008Ag emissions: 2%All emissions: ‐2%
4,000
5,000
6,000Residential
Commercial
2,000
3,000
,
Agriculture
Industry
‐1,000
0
1,000
1990 1995 2000 2005 2008
Transportation
Electric Power Industry
‐2,000
Source: EPA 2011 U.S. Greenhouse Gas Inventory Report
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GHG EmissionsGHG EmissionsIntroduction> GHG emissions > GHG mitigation > Nitrogen pollution > Nitrogen mitigation
Scenarios‐ Scenarios‐ Global and national context ‐ US agricultural emissions overview‐ Livestock Croplands‐ Croplands
Both cropland and grassland (grazed land) emissions have high levels of uncertainty. Grassland emissions are the least certain, but emissions are greater for cropland; thus cropland and grassland contributes about equally to overall uncertainty
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Agriculture Greenhouse Gas Emissions Estimates and Uncertainty Intervals, 2008
Source Estimate Lower Bound Upper Bound Range Lower Bound Upper Bound
cropland and grassland contributes about equally to overall uncertainty.
Source Estimate Lower Bound Upper Bound Range Lower Bound Upper Bound
Tg CO2e
Livestock 203 185 230 45 ‐9 +14
Crops1 154 84 215 131 ‐34 +71
Grassland1 33 5 132 127 ‐84 +298
Tg CO 2e percent
Grassland 33 5 132 127 84 +298Net Emissions 390 274 577 303 ‐30 +48
1 ‐ Includes sequestration in agricultural soils.
Source: USDA Agriculture and Forestry Greenhouse Gas Inventory: 1990‐2008
Gross agricultural GHG emissions are split 58/42 between livestock and cropland. The biggest contributors are agricultural soils (~33%) and enteric fermentation (~30%).
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Gross agriculture emissions in 2008: 463 Mt CO2e• Net emissions totaled 390 Mt, due to C sinks in Grazed Lands and Mineral Soils
• Gross emissions for livestock and crops combined have risen 9% since 1990.
Gross GHG emissions in 2008 (Mt CO2e)
Source: EPA 2011 U.S. Greenhouse Gas Inventory Report
Texas, Iowa, and California lead the country in per state agricultural GHG emissions, together accounting for nearly 25% of US agricultural emissions.
13
Mt COMt CO2eTexas – 40 Iowa – 30California ‐ 27
Maps created by GreenInfo Network
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GHG EmissionsGHG EmissionsIntroduction> GHG emissions > GHG mitigation > Nitrogen pollution > Nitrogen mitigation
Scenarios‐ Scenarios‐ Global and national context ‐ US agricultural emissions overview‐ Livestock Croplands‐ Croplands
There are three primary sources of livestock emissions which are highly correlated with animal type.
di f i i b i l (2008)
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Leading sources of emissions by animal type (2008):• Enteric fermentation: Livestock, primarily rumens, emit methane directly as a byproduct of digestion
• Manure management: Livestock manure and urine cause CH4 emissions through increased decomposition, and N2O emissions through nitrification/denitrification.decomposition, and N2O emissions through nitrification/denitrification.
• Grazed lands: N2O emissions from forage nitrogen fixation and manure from grazing livestock. Grazed lands can also act as a source or sink for atmospheric carbon dioxide, depending on whether carbon inputs to the soil from plant residues and manure exceed carbon losses from decomposition of soil organic matterorganic matter.
Source: EPA 2011 U.S. Greenhouse Gas Inventory Report
Livestock emissions are driven primarily by cattle, both beef and dairy.
l i i f i k (2008) 208 CO
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Total emissions from Livestock (2008): 208 Mt CO2e
• Emissions from dairy cattle have grown by 26% from 1990 to 2008
• Emissions from swine have grown by 46% from 1990 to 2008
• Emissions from beef have grown by 8% from 1990 to 2008• Emissions from beef have grown by 8% from 1990 to 2008
Source: EPA 2011 U.S. Greenhouse Gas Inventory Report
Dairy cattle are by far the largest emitters on a per head basis
D i l b i i i d h i 1) i d i CH4 d 2)
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• Dairy cattle carbon intensity is due to their 1) size x production rate: CH4 and 2) manure management intensity (a high percent are in feedlots)
• Variability in beef cattle (and horse) per head emissions, are from grazed lands
• There has been significant growth in per head emissions from dairy cattle (due to manure, see next g g p y ( ,slides)
Source: EPA 2011 U.S. Greenhouse Gas Inventory Report
Dairy cattle lead emissions per head for manure by a staggering amount
Wh j id i i f h d b i d i l ff
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• When we just consider emissions from manure management on a per head basis, dairy cattle are off the charts: over 6x the emissions per head of the next most significant animal type (swine)
• Dairy cattle emissions per head has increased over time as dairy operations consolidate and move from pasture to feedlot
• Beef cattle manure emissions are negligible because the vast majority of them are raised on pasture
Source: EPA 2011 U.S. Greenhouse Gas Inventory Report
Even when looking at just enteric fermentation emissions, dairy cattle’s emissions factor – per head – is over 2x that of beef cattle
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• Dairy cattle enteric fermentation rates are high because they are mature animals operating at high levels of production (~100 lbs of milk per day) they EAT A LOT!
Source: EPA 2011 U.S. Greenhouse Gas Inventory Report
Texas, California, and Iowa lead the country in per state livestock GHG emissions –together accounting for 30% of US livestock emissions.
20
Mt CO2eTexas – 35 California – 20Iowa ‐ 14
Maps created by GreenInfo Network
Texas leads the country in enteric fermentation emissions (13% of country total) because it has by far the biggest population of beef cattle.
21
Mt COMt CO2eTexas – 18California – 9Nebraska – 9Kansas ‐ 8
Maps created by GreenInfo Network
Dairy cattle in California and swine in Iowa and North Carolina lead GHG emissions from manure. These three states account for 35% of US manure emissions.
22
Mt COMt CO2eCalifornia – 9 Iowa – 8No Carolina ‐ 5
Maps created by GreenInfo Network
Texas alone accounts for 20% of US grazed land emissions – due to its beef cattle population.
23
Mt COMt CO2eTexas – 12Montana, Nebraska, Oklahoma & New Mexico ‐ 3
Maps created by GreenInfo Network
GHG efficiency on a per head basis for beef cattle is within a 35% range for the states with the largest aggregate emissions.
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Note: California is the 10th largest state in terms of aggregate Beef Cattle Emissions and has emissions
Source: EPA 2011 U.S. Greenhouse Gas Inventory Report
per head at 1.2 Mt CO2e.
For dairy cattle, California is by far the largest aggregate emitter, driven by the number of head and by relative inefficiency of production on a GHG basis
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Source: EPA 2011 U.S. Greenhouse Gas Inventory Report
Iowa, the largest GHG emitter for swine, is a relatively efficient place to locate production on a GHG basis.
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Source: EPA 2011 U.S. Greenhouse Gas Inventory Report
Methane emissions potential varies greatly by type of manure system. Liquid systems tend to have higher methane emissions.
27
M h i i i i h id i d W li l d hi h• Methane emissions varies with residence time and temperature. Warmer climates lead to higher emissions.
• Dry systems have higher nitrous oxide emissions, but overall, nitrous oxide emissions are a smaller contributor to manure emissions.
Source: Center for Rural Affairs, “Soil Carbon and Agriculture”.
Methane emissions potential (percent of initial content) for manure management systems in the Midwest and Great Plains
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GHG EmissionsGHG EmissionsIntroduction> GHG emissions > GHG mitigation > Nitrogen pollution > Nitrogen mitigation
Scenarios‐ Scenarios‐ Global and national context ‐ US agricultural emissions overview‐ Livestock Croplands‐ Croplands
Cropland emissions are almost exclusively driven by soil management, with corn accounting for the greatest emissions on a per crop basis.
l i i f l d (2008) 96 CO
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Total gross emissions from Cropland (2008): 196 Mt CO2e• Net emissions = 154 Mt CO2e
• 153 Mt from soil management (78% of gross emissions)
• Negligible emissions from residue burning (1 5 Mt) and rice cultivation (7 2 Mt)• Negligible emissions from residue burning (1.5 Mt) and rice cultivation (7.2 Mt)
Source: EPA 2011 U.S. Greenhouse Gas Inventory Report
Corn is both the largest GHG emitter and the least efficient on a per unit area basis Page 30
Corn emissions are larger than other crops on a per hectare basis because of they require much more fertilizer on a per hectare basis.
Note inefficiency of rice compared to other crops. On an aggregate basis, however, rice emissions are very low
Source: EPA 2011 U.S. Greenhouse Gas Inventory Report
Five Midwestern states and California account for 40% of cropland emissions 31
Mt COMt CO2eIowa – 16Illinois – 12Minnesota – 10Indiana – 8Ohio – 7California ‐ 7
Maps created by GreenInfo Network
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GHG MitigationGHG MitigationIntroduction> GHG emissions > GHG mitigation > Nitrogen pollution > Nitrogen mitigation
There are several different approaches to mitigation of agricultural emissions. Those that shift production to less efficient locations should be avoided.
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Category Sub‐category Risks & limitations Intervention options
Reduce demand for carbon intensive agricultural commodities
• Reduce per capita meat consumption
• Reduce % of food waste
• Very distributed problem • Difficult to develop mandates or incentives
• Vegetarianism campaign• Food service campaign• Change in expiration dateagricultural commodities • Reduce % of food waste incentives • Change in expiration date protocols
Reduce agricultural commodity production
• Afforestation• Restoration of wetlands, organic soils
Leakage – without a simultaneous shift in demand, production will likely just shift elsewhere,
• Production tax• Expand CRP• No grazing on fed lands
• Convert land to set‐asides or buffers
possibly to a less carbon efficient location.
• Stricter CWA regulations • Decrease commodity subsidies • End biofuels subsidies• Pay farmers not to farm
Shift production to less GHG intensive commodities
• Use more perennials • Increase production of woody crops, agroforestry
• Convert cropland to pastureland
May also be a risk of leakage with these interventions. The dynamics of specific changes in production patterns would need to be modeled.
• Subsidize the lowest GHG crops• Revenue neutral tax on top GHG ag products (e.g. dairy and corn)
p• Diversify crop rotation
Change practices to reduce GHG intensity of production
• Improve productivity and management of grazed lands
• Improve productivity and management of croplands (e.g.
• Some of the practices in this category may have positive leakage effects and/or positive environmental co‐benefits.
• USDA programs • Supply chain pressure• Carbon markets• Other PES marketsmanagement of croplands (e.g.
tillage, cover crops, nutrient use efficiency)
• Improve livestock efficiency • Improved manure management
environmental co benefits.• Some may have negative impacts on other environmental resources (e.g. water, pesticides).
Other P S markets
We scanned the literature for assessments of mitigation potential. We based our analysis on data provided by the Nicholas Institute’s (T‐AGG) US Agricultural GHG Assessment Literature Review because it provided the best data on a per practice
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Assessment Literature Review because it provided the best data on a per practice basis.
Study region ‐ practice gas considered price of CO2mitigation potential estimate (Mt CO2e / yr)
Paustian et al (2006) US ‐ all measures CO2 biophysical potential 70 ‐ 221 MMT C Paustian et al (2006) US ‐ all measures N20 biophysical potential 23‐ 31 MMT CPaustian et al (2006) US ‐ all measures CH4 biophysical potential 9 ‐ 18 MMT CMurray et al. (2005) (EPA) (2025 abatement) US ‐ all measures N2O and CH4 US $15 t CO2e 36M Ki C t C (2030 b t t) US l d CO2 N2O CH4 t i i 128 97McKinsey Cost Curves (2030 abatement) US ‐ cropland CO2, N2O, CH4 at various prices 128.97Lal et al. (2003) US ‐ cropland CO2 biophysical potential 165‐360Sperow et al (2003) US ‐ cropland CO2 biophysical potential 220‐257Smith et al (2007) US ‐ cropland CO2 biophysical potential 140Murray et al (2005) (EPA) (2025 abatement) US ‐ cropland CO2 US $15 t CO2e 204McKinsey Cost Curves (2030 abatement) US ‐ grassland CO2, N2O, CH4 biophysical potential 63.73McKinsey Cost Curves (2030 abatement) US grassland CO2, N2O, CH4 biophysical potential 63.73Lal et al (2003) US ‐ grassland CO2 biophysical potential 48‐257Smith et al (2007) US ‐ grassland CO2 biophysical potential 60Lal et al (2003) US ‐ land conversion CO2 biophysical potential 77‐282Lal et al (2003) US ‐ land restoration CO2 biophysical potential 92‐220Smith et al (2007) US ‐ land restoration CO2 biophysical potential 30McKinsey Cost Curves (2030 abatement) US ‐ livestock CO2, N2O, CH4 biophysical potential 18.29US EPA (2006) US ‐ livestock CH4 US $20 t CO2e 40Smith et al (2007) US ‐ livestock CO2 US $20 t CO2e 32
Current literature is reasonably consistent in its assessment of GHG mitigation potential in US agriculture. Soil carbon sequestration presents the greatest opportunity
35
opportunity.
all measurescropland soil carbon
grassland soil carbon
Land conversion, soil carbon livestock
A review of the biophysical potential of cropland and grassland mitigation practices
The Nicholas Institute published a series of reports in the fall of 2011 / winter 2012 presenting a thorough review and synthesis of the literature on the greenhouse gas mitigation potential from US agriculture. • We used the Nicholas Institute’s January 2012 “Greenhouse Gas Mitigation Potential of Agricultural• We used the Nicholas Institute s January 2012 Greenhouse Gas Mitigation Potential of Agricultural
Land Management in the United States: A Synthesis of the Literature” to conduct the following analysis.
• This report provided mean estimates as well as high and low ranges for the soil carbon sequestration i l h d i id i i d i i l d dpotential, methane and nitrous oxide emissions reductions potential, and process and upstream
emissions reductions potential for 42 mitigation practices.
• The report also provided an assessment of the maximum area available for each mitigation practice.
• Although there are many data gaps and high levels of uncertainty for many of the practices, and there g y g p g y y p ,is a wide range in the level of scientific certainty between the different practices, this report provides by far the best data set of the biophysical potential for cropland and grassland mitigation in the U.S.
• The authors chose not to aggregate the data to show overall biophysical mitigation potential per practice because they felt that the resulting data could be misleading for several reasons including:practice because they felt that the resulting data could be misleading for several reasons including:
• It over emphasizes the opportunity to sequester soil carbon because many practices are occurring on the same land base and would not be additive.
• It does not take into account the economic potential of these practices.
Comparison of mitigation opportunities (t CO2e) on a per hectare basis Page 37
Apply biochar to cropland **
Set aside cropland or plant herbaceous buffers
Establish agroforestry (windbreaks, buffers, etc.) on cropland **
Switch to short‐rotation woody crops
Restore wetlands
Reduce rice area **
Manage farmed histosols **
Switch to no‐till
Use winter cover crops
Establish agroforestry on grazing land **
Apply organic material (e.g., manure) **
Convert cropland to pasture **
Fertilize grazing land **
Irrigate grazing land **
Plant rice cultivars that produce less CH4
Convert dry land to irrigated land **
Adjust rice water management
Introduce rotational grazing on pasture **
Replace annuals with perennial crops
CO2
N2O
CH4
Process and Upstream
Manage species composition on grazing land
Switch fertilizer N source from ammonium‐based to urea
Switch to other conservation tillage
Include perennials in crop rotations
Improve manure management to reduce N2O **
Improve grazing management on pasture **
Double asterisk (**) indicates practices that are based on data with significant research gaps.
p
Switch to slow‐release fertilizer N source
Change fertilizer N placement
Reduce fertilizer N application rate by 15%
Use nitrification inhibitors
Eliminate summer fallow
Improve irrigation management (e.g., drip) **Set aside histosol cropland has been removed to provide a more granular scale. On a per ha basis, set aside histosol cropland provides on average 37 t CO2e of mitigation potential.
‐4 ‐2 0 2 4 6 8 10 12
Introduce rotational grazing on rangeland **
Set aside grazing land **
Diversify annual crop rotations
Change fertilizer N timing
The most promising practices are those that have a high biophysical potential on a per ha basis, and a low implementation cost.
38
• The economic viability of these practices needs to be considered. Unfortunately, we lack an economic analysis at a comparable level of detail.
• We do know that practices that require taking land out of production have a high opportunity cost and thus are only viable if there is there is a comparably high payment for doing so.
T i k l f h i h il i d d id l li bl ( ill• Transaction costs are kept low for those practices that are easily monitored and widely applicable (e.g. tillage, cover crops, fallow mgmt.)
Requires land use change or significant change in crop
biophysical potential applicable enviro co‐ scientific
Practice production patterns (CO2e per ha) area (Mha) benefits certaintyUse winter cover crops N 1.9 66 + HSwitch to no‐till N 1.5 94 + HAdjust rice water management N 1.1 1.3 HSwitch to other conservation tillage N 0 7 72 + HSwitch to other conservation tillage N 0.7 72 + HEliminate summer fallow N 0.4 20 + HReduce fertilizer N application rate by 15% N 0.3 68 + HPlant rice cultivars that produce less CH4 N 1.0 1.3 MSwitch fertilizer N source from ammonium‐based to urea N 0.6 37 MManage species composition on grazing land N 0.6 80 MUse nitrification inhibitors N 0.4 92 + MChange fertilizer N placement N 0.3 63 + MSwitch to slow‐release fertilizer N source N 0 2 93 + MSwitch to slow release fertilizer N source N 0.2 93 + MChange fertilizer N timing N 0.2 53 + M
Practices that take land out of production or significantly change crop production patterns have a high opportunity cost and may not be beneficial on a net global GHG basis
39
basis. • Several studies indicate that taking land out of production in the US can result in a net increase in GHG emissions on
a global basis.
• Those practices that do not require a change in land use but may reduce yields (e.g. perennials, fertilizer N t) d f th t dmanagement), may need further study.
Requires land use change or significant change in crop
biophysical potential applicable enviro co‐ scientific
Practicechange in crop production patterns
potential
(CO2e per ha)applicable area (Mha)
enviro co‐benefits
scientific certainty
Establish agroforestry (windbreaks, buffers, etc. partial 3.9 21 + LSwitch to short‐rotation woody crops Y 3.9 40 + HSet aside cropland or plant herbaceous buffers Y 3.6 17 + HConvert cropland to pasture Y 3.1 unknown + HInclude perennials in crop rotations Y 0.7 56 + HDiversify annual crop rotations Y 0.2 46 + HSet aside histosol cropland Y 37.8 0.8 + LReduce rice area Y 6 3 1 3 LReduce rice area Y 6.3 1.3 LSet aside grazing land Y ‐1.0 unknown + LRestore wetlands Y 3.9 3.8 + MReplace annuals with perennial crops Y 1.4 13 + M
40
Several mitigation practices do not have sufficient data to be pursued aggressively at this time. The practices listed below are worth pursuing because they are likely to have positive mitigation potentialhave positive mitigation potential. • Given the available data, the technical potential of biochar seems to dwarf other mitigation opportunities, but we do
not know enough about the economic potential or the life cycle impacts. Further research is necessary.
• Grazing land management is an area that deserves further inquiry. Mitigation opportunities on pasture land seems t h t i t ti l th l d b t th h f l d i th US th t th
Requires land use bi h i l
to have more certain potential than rangelands, but the sheer acreage of rangelands in the US mean that the potential could be very significant and further research would be a worthwhile investment.
Practice
change or significant change in crop production patterns
biophysical potential
(CO2e per ha)applicable area (Mha)
enviro co‐benefits
scientific certainty
Apply biochar to cropland N 10.1 124 + LManage farmed histosols N 7.5 0.8 + LManage farmed histosols N 7.5 0.8 + LApply organic material (e.g., manure) N 2.6 8.5 + LEstablish agroforestry on grazing land N 2.1 70 + LIntroduce rotational grazing on pasture N 1.4 42 LImprove manure management to reduce N2O N 0.8 12 + L
( )Improve irrigation management (e.g., drip) N 0.5 20 + LIncrease cropping intensity N unknown L
High level take‐aways from Nicholas Institute’s assessment
Soil carbon sequestration provides a bigger opportunity than reduction of N2O or CH4.2 4• Understanding the aggregate mitigation opportunity for soil carbon is challenging because the ability of any single ha
of cropland to sequester soil is limited and only 1‐2 practices can be applied at one time. Adding the potential of all of these practices together is counting the same carbon multiple times.
• The additionality, reversibility, and additive (i.e. time limited) characteristics of soil carbon sequestration need to be considered.
• Because soil carbon sequestration opportunities are largely diffuse, they may be costly to implement.
• The soil sequestration potential of both biochar and grazing lands may be very large and should be studied further.
The impact of mitigation practices on commodity markets needs to be carefully consideredThe impact of mitigation practices on commodity markets needs to be carefully considered. • Baker et al. 2011 finds that “climate mitigation opportunities increase the demand for land for nonfood benefits,
reduce commodity supply, and result in significant commodity market impacts.”
• Recent studies from both Iowa State University (Elobeid et al. 2011) and Nicholas Institute (Mosnier et al. 2012) find that taking land out of food production in the US either for biofuel production or afforestation can lead to a net risethat taking land out of food production in the US, either for biofuel production or afforestation, can lead to a net rise in global GHG emissions.
Nutrient use efficiency that is managed so as not to reduce yields is worth pursing despite implementation barriers. It has potential to be a low cost, scientifically valid, widely applicable opportunity with significant environmental co‐benefits.
Mitigation opportunities that are only applicable to very limited areas (e.g. rice, organic soils restoration, wetlands restoration) may be low hanging fruit and worth pursing, but will not have a significant impact in the aggregate.
Livestock mitigation opportunities are less well studied, but seem to have lower potential overall than soils management.
• Based on an initial literature review, it seems that livestock mitigation potential is less than 50 Mt CO2e per year.
• The McKinsey study indicates that livestock mitigation potential may be lower hanging fruit from an economic perspectivefrom an economic perspective.
• Enteric fermentation emissions reductions (methane) • The production efficiency gains inherent in reducing enteric fermentation emissions support the hypothesis
that these mitigation practices are cost effective.
• Opportunities are focused on improving diet quality (higher quality forage, feed additives).
• There seems to be an important opportunity to further research forage crops and forage crop breeding to improve their digestibility. Few public sector breeders work on forage crops.
• Manure management emissions reductions (methane and nitrous oxide) g ( )• Opportunities include: changing diet to reduce manure production, improved management of manure
application to fields, and changing manure storage systems.
• Methane digesters and other improved manure management systems are relatively well proven technologies that should be supported.
• Improved management of manure application on fields is a ripe opportunity at the intersection of livestock and croplands emissions. Improving management of this resource will help close the loop on the nitrogen cycle, improve water quality, and reduce nitrous oxide emissions.
The mitigation potential for carbon sequestration is concentrated in the Midwest, particularly in the Corn Belt.
h i h l li i id d l h il bl i i i i b
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The Nicholas literature review provided total hectares available per mitigation practice, but did not provide regional distribution for this potential within the US. Murray et al. 2005, while outdated, provides some indication of where in the U.S. mitigation potential is greatest.• This data was generated from an earlier version of the FASOMGHG model – thus up‐to‐date versionsThis data was generated from an earlier version of the FASOMGHG model thus up to date versions
of this analysis are possible from the modelers.
• While these results are dated, we believe that the concentration of mitigation potential in the Midwest, especially in the Corn Belt, is still valid.
CB C B lt
Regional distributions of soil carbon sequestration under payment for soil carbon only: $15/t CO2e
CB – Corn BeltGP – Great PlainsLS – Lake States SW – SouthwestSC – South‐CentralRM – Rocky MountainsRM Rocky MountainsSE ‐ SoutheastNE – NortheastPNWE – Pacific Northwest‐east sidePSW – Pacific Southwest (California)
Source: Murray et al. 2005 “Greenhouse Gas Mitigation Potential in U.S. Forestry and Agriculture”, U.S. EPA.
A 2009 study of mitigation opportunities in the Midwest supports the finding that approximately half of the agricultural mitigation opportunities in the US can be found in the Midwest
44
in the Midwest.
This study, sponsored by the Chicago Council on Global Affairs estimates total agricultural mitigation potential i th US t b 330 Mt din the US to be 330 Mt, and mitigation potential in the Midwest to be approximately 170 Mt.
Source: “Embracing the Future: The Midwest and a New National Energy Policy”, 2009. Data source: McKinsey analysis.
Most economic studies apply sectoral economic models to determine the potential of different broad categories of practices at different prices of carbon.
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Th M Ki t d ff l ti l l i l i d i di t th t i lt l iti ti• The McKinsey study offers a relatively granular economic analysis and indicates that agricultural mitigation opportunities are relatively cost effective.
• However, the McKinsey findings were not generated with a sectoral economic model and are most useful for comparing the relative scale of practice types and should not be relied upon for supporting the development of individual practices.
20
Abatement cost€ per tCO2e
Organic soils restorationDegraded land restoration
Agronomy practices
individual practices.
175 200‐10
10
0
50
‐20
25 150125100750
Abatement volumeMtCO2e
‐60
‐50
‐40
‐30
Rice Management ‐ shallow flooding
Grassland management
‐90
‐80
‐70
Tillage and residue management practices
Livestock ‐ antimethanogenvaccine
Grassland nutrient management
Cropland nutrient management
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Nitrogen pollutionNitrogen pollutionIntroduction> GHG emissions > GHG mitigation > Nitrogen pollution > Nitrogen mitigation
Question?Page 47
1) What was the range of plausible scenarios for US agriculture emissions and sequestration between 2008 and 2020 and what trajectory are we following?
2) What are the sources of GHG from agriculture in the US?
3) What are the most promising opportunities for US agriculture to mitigate ) p g pp g gclimate change?
4) What was the range of plausible scenarios for nitrogen pollution associated with US agriculture between 2008 and 2020 and what gtrajectory are we following?
5) What are the sources of nitrogen pollution from agriculture in the US?
6) What are the most promising opportunities for US agriculture to mitigate6) What are the most promising opportunities for US agriculture to mitigate nitrogen pollution?
About 35 Tg of reactive nitrogen is added generated each year in the US. Agriculture is responsible for more than half, and for almost 2/3 of anthropogenic sources.
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A i l l i i i b 1 5%• Agricultural nitrogen is growing at about 1.5% per year.
• Crop biological fixation is growing more quickly than synthetic fertilizer (2.4% vs. 0.9%).
• Future growth rates will depend a lot on ethanol production patterns.
Sources of new reactive nitrogen ‐ 2008
25
New sources of reactive N (Tg N)
Synthetic fertilizer11.433%
Fossil Fuel combustion
Natural sources6.518%
15
20
Agriculture
Crop biological fixation8.324%
Industrial sources4.212%
4.513%
10
15 Agriculture
Agriculture trajectory
Natural sources
Fossil fuel combustion
Industrial sources
5
Source: Davidson et al. 2011, “Issues in Ecology”, Ecological Society of America. EPA Science Advisory Board 2011, Reactive Nitrogen in the United States
01990 1996 2002 2008 2014 2020
After substantial growth through the 1960s, 70s, nitrogen fertilizer use has leveled off in recent decades.
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14,000
Nutrient use on US agricultural lands 1960 – 2009 (1,000 tons)‐0.7%1.7%0.4%4.7%11.0%
10 000
12,000
Average growth rate by decade
8,000
10,000
Nitrogen (N)
Phosphate (P2O5)
4,000
6,000Phosphate (P2O5)
Potash (K2O)
0
2,000
60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 00 02 04 06 08
196
196
196
196
196
197
197
197
197
197
198
198
198
198
198
199
199
199
199
199
200
200
200
200
200
Source: NASS
All cereal crops together use 66% of nitrogen fertilizer, with corn being the single biggest user
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6 000
Nutrient use by crop 1960 – 2009 (1,000 tons)Corn receives 43% of
5,000
6,000 all nitrogen fertilizer application in the United States.
3,000
4,000
Corn
Cotton
Soybeans
1,000
2,000 Wheat
0
1964
1966
1968
1970
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
Source: NASS – ask Mark for full source, and EPA Science Advisory Board 2011, Reactive Nitrogen in the United States
On a per hectare basis, corn consumes the most nitrogen of the row crops. Many specialty crops demand more nitrogen per ha, but have much smaller acreage.
51
Kg N applied per crop per ha
• In 2010, there were 88 million hectares of corn planted in the US
• California had 8.9 million total hectares of cropland in production in 2007
250
300
350
Kg N applied per crop, per ha
100
150
200
250
0
50
100
Data from NASS, 2010 Data from California Nitrogen Data from NASS, 2010 gAssessment, 2002 – 2007 average
Source: Tomich, T., T. Rosenstock, D. Liptzin, S. Scow, R. Dahlgren, D. Sumner, S. Brodt, K. Thomas, A. White, C. Bishop. California Nitrogen Assessment. Unpublished data. Agricultural Sustainability Institute, University of California, Davis.
The good news is that nutrient use efficiency for corn has been rising since the mid‐70s.
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i hi d i i NU h N f ili k ffi i f i h• Despite this steady increase in NUE, the average N fertilizer uptake efficiency for corn in the north‐central U.S. was 37% of applied N in 2000 (Cassman et al. 2002).
• These results indicate that greater than 50% of applied N fertilizer is vulnerable to loss pathways such as volatilization, denitrification, runoff, and leaching.
Trend in corn grain produced per unit of applied fertilizer in the US
Source: EPA Science Advisory Board 2011, Reactive Nitrogen in the United States.