of GHG and N agricultural emissions, mitigation, and ...Gross agriculture emissions in 2008: 463 Mt...

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 overview

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?

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

• 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.

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

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.


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

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

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


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

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%).

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)


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

There are three primary sources of livestock emissions which are highly correlated with animal type.

di f i i b i l (2008)

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.


Livestock emissions are driven primarily by cattle, both beef and dairy.

l i i f i k (2008) 208 CO

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


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)

• 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)


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

• 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


Even when looking at just enteric fermentation emissions, dairy cattle’s emissions factor – per head – is over 2x that of beef cattle

• 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!


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


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


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


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


GHG efficiency on a per head basis for beef cattle is within a 35% range for the states with the largest aggregate emissions.

Note: California is the 10th largest state in terms of aggregate Beef Cattle Emissions and has emissions


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


Iowa, the largest GHG emitter for swine, is a relatively efficient place to locate production on a GHG basis.


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

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

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)


Corn is both the largest GHG emitter and the least efficient on a per unit area basis

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


Five Midwestern states and California account for 40% of cropland emissions 31

Mt COMt CO2eIowa – 16Illinois – 12Minnesota – 10Indiana – 8Ohio – 7California ‐ 7


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.

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

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

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

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.

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

Nitrogen pollutionNitrogen pollutionIntroduction> GHG emissions > GHG mitigation > Nitrogen pollution > Nitrogen mitigation

Question?

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.

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.

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

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.

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.

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