for want of food: groundwater and agricultureag-groundwater.org/files/56589.pdf · ground-water...

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For Want of Food:For Want of Food:Groundwater and Groundwater and

AgricultureAgriculture

Thomas HarterThomas HarterUniversity of California, DavisUniversity of California, Davis

[email protected]@ucdavis.eduhttp://groundwater.ucdavis.eduhttp://groundwater.ucdavis.edu

http://aghttp://ag--groundwater.orggroundwater.org

Thomas Harter, University of California, Davis, 2010

OutlineOutline

Global water and groundwater useRole of groundwater in agriculture, especially global food productionCurrent and future challenges to groundwater in ag/rural areas


Timm Sauer et al., WRR, 10 June 2010:

“The complex interdependencies between water

resources and food production …. an evolving global

food crisis”


Total Water Use MapTotal Water Use Map

LargestWater Users

IndiaChina

United StatesPakistanJapan

ThailandIndonesia

BangladeshMexico

Russian Federation

modified from:United Nations World Water Development Report, 2009

LargestGroundwater Users

(80% of global)IndiaChina

United StatesIran

BangladeshPakistan

100 km3

= 80 MAF

CA:

4,000 km3

3,200 MAF+6,400 km3

+5,100 MAFfrom rain

to ag

Global Use:

55


Groundwater Connection to Food: USE OF GROUNDWATERGroundwater Connection to Food: USE OF GROUNDWATER

modified from: United Nations World Water Development Report, 2009

Asia: 30%US: 42%CA: 30%-60%


Water UseWater Use

46%

Groundwater Irrigated Area Data are from: Shah, Villholth, Burke, “Groundwater: a global assessment of scale and significance”, IWMI, 2007

53%

50%

16%

20%

And % Share of Groundwater-Irrigated Area

(km3)


Trends inTrends inGroundwater UseGroundwater Use

from: United Nations World Water Development Report, 2009

MAF

200

160

120

80

40

240km3

from: Shah et al, 2007

CA: 13-25 km3/ 10-20 MAF


Groundwater for IrrigationGroundwater for Irrigation

UN World Water Development Report II, 2006

Shah, Villholth, Burke, “Groundwater: a global assessment of scale and significance”, IWMI, 2007

Total irrigated area:1,200 Mac/480 Mha

GW irrigated area:320 Mac/130 Mha

IWMI, 2007

Thomas Harter, University of California, Davis, 2010http://www.psychohistorian.org/img/adnd/world-building/climate/koppen-map.jpg

Climate Type and GW Use CentersClimate Type and GW Use Centers


Groundwater RechargeGroundwater Recharge& Major GW Use in Agriculture& Major GW Use in Agriculture

from: United Nations World Water Development Report, 2009; Shah, Villholth, and Burke, 2007

• Total precip on land: 100,000 km3 (90,000 MAF)• Evaporative returns: 67% of precip• Renewable supply: 29,000 km3 (23,000 MAF)• Total applied water use: 4,000 km3 (3,200 MAF)

=>Irrigated ag applied water: 2,800 km3 (2,200 MAF)

• Irrigated ag ET: 1,550 km3 from AW, 650 km3 from rain

• Groundwater in ag: ~1,000 km3 (800 MAF)• Total rainfed ag water use: 6,400 km3 (5,100 MAF)• Total groundwater recharge: 2,200 km3 (1,800 MAF)


Global Fraction of CroplandGlobal Fraction of CroplandRelative to GW Pumping Centers, 1992Relative to GW Pumping Centers, 1992

Ramankutty N and Foley JA (1999) Estimating historical changes in global land cover: Croplands from 1700 to 1992. Global Biogeochemical Cycles, 13, 997-1027.

majorgroundwater

users

CA:•14% of US crop, 7.5% of US livestock•$100 billion economic value•$36 billion farm cash receipts•81,500 farms and ranches•400 commodities•nearly half of U.S.-grown fruits, nuts and vegetables


Population Map of the WorldPopulation Map of the World& Major GW Withdrawal Centers& Major GW Withdrawal Centers

Modified with world population map from: Nature 439, 800 (16 February 2006) | doi:10.1038/439800a


World PopulationWorld Population

IPCC, Fourth Assessment Report, 2007, Workgroup III

UN, World Population Growth to 1700-2300, 2004

10

15


2020thth Largest Countries by PopulationLargest Countries by Population

UN

, Wor

ld P

opul

atio

n G

row

th to

170

0-23

00, 2

004

Thomas Harter, University of California, Davis, 2010from: IWMI, Comp Assess. Water Mgmt in Ag, 2007

Per Capita Meat Consumption

Per Capita Grain Demand (driven by feed)


from

: IW

MI,

Com

p As

sess

. Wat

er M

gmt i

n A

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007

Water Use

Land Use

2050

20

50


Challenges to Meeting the Groundwater NeedsChallenges to Meeting the Groundwater Needsfor Global Food Securityfor Global Food Security

Groundwater Storage LossGroundwater Storage Loss18 km3/yr

450,000 km2 area0.3m/yr water level decline

1.7 km3/yr (1.3MAF/yr) 1962-2003 (satellite & USGS Model)

110,000 km2 areaLarge annual fluctuationsDuring drought: up to 6m/yr water level decline

10 km3/yr (0.8 MAF/yr)450,000 km2 areaAverage decline: 0.1m/yrsome areas: few m/yr decline

M Rodell et al. Nature 460, 999-1002 (2009) doi:10.1038/nature08238

GRACE averaging function.

M Rodell and Famiglietti, J. Hydrol 263:245-256

INDIA

HIGH PLAINS AQUIFER, USA


Additional Groundwater Demands: Additional Groundwater Demands: BiofuelsBiofuels

Global: 10% of energy from biomass (4/5 from wood, dung, crop reGlobal: 10% of energy from biomass (4/5 from wood, dung, crop residue)sidue)Global: 5% of biomass production for liquid fuel => 2% of transpGlobal: 5% of biomass production for liquid fuel => 2% of transport ort energy;energy;BiofuelsBiofuels: Brazil (54% of all sugar cane) and U.S. (23% of all corn) => 7: Brazil (54% of all sugar cane) and U.S. (23% of all corn) => 77% 7% of global market in 2007of global market in 2007Only sugar cane has better GHG footprint than fossil fuelsOnly sugar cane has better GHG footprint than fossil fuelsTotal irrigation water use for Total irrigation water use for biofuelsbiofuels::

Currently 44 kmCurrently 44 km3 3 (35 MAF), 3% in U.S., 2% in China(35 MAF), 3% in U.S., 2% in China225 km225 km3 3 (180 MAF) after implementation of current national policies (an(180 MAF) after implementation of current national policies (and 30M d 30M ha (75M acres) additional ha (75M acres) additional landuselanduse))

from: United Nations World Water Development Report, 2009


Water and EnergyWater and Energy

from: United Nations World Water Development Report, 2009Thomas Harter, University of California, Davis, 2010

Climate Change:Climate Change:Change in GW RechargeChange in GW Recharge

Salt water intrusion Salt water intrusion (coastal areas)(coastal areas)Changes in ETChanges in ETChange in Change in ““safe safe yield:yield:””

Less recharge from Less recharge from streams in arid and streams in arid and semisemi--arid regionsarid regionsChange in diffuse Change in diffuse recharge from recharge from precipprecip

More extreme More extreme events, including events, including droughts => more droughts => more reliance on reliance on groundwater groundwater (savings account)(savings account)

From: Döll and Flörke, 2005In: IPCC 4th Assessment Report; http://www.ipcc.ch/publications_and_data/ar4/wg2/en/ch3s3-4-2.html


Groundwater Connection to Food: IMPACTGroundwater Connection to Food: IMPACT1. Groundwater Salinization1. Groundwater Salinization

Example: Eastern San Joaquin ValleyExample: Eastern San Joaquin Valley

EC-F

ield

[uS/

cm]

UplandMerced

ModestoTurlock

0

500

1000

1500

2000

2500

3000

UplandMerced

ModestoTurlock

Mean Mean±SE Mean±SD

Original GAMA data from Table 1 and 4 in:

Landon and Belitz, 2008. Ground-Water Quality Data in the Central Eastside San Joaquin Basin 2006: Results from the California GAMA Program, USGS Data Series 325.

57 Public Supply Wells(USGS – GAMA)

20 Flowpath &Monitor Wells

Non-Dairy Ag Landuse(USGS – GAMA)49 Hilmar Domestic Wells

(1986, 2001 – no trend)

4 ModestoDairy

Domestic Wells(2008)


Groundwater Connection to Food: IMPACTGroundwater Connection to Food: IMPACT2. Nitrate in Groundwater2. Nitrate in Groundwater

UN World Water Development Report II, 2006

Note: 10 mg N/l = 10 kg N/km2/yr for each 1 mm/yr recharge


N Balance in Three Corn SystemsN Balance in Three Corn SystemsKenya Kenya –– North China North China –– Midwest USMidwest US

Vitousek et al., Science, 2009


Groundwater Loading fromGroundwater Loading fromAnimal Agriculture with Manure Reuse in Intense Feed CropsAnimal Agriculture with Manure Reuse in Intense Feed Crops


Impact 1950Impact 1950--2007:2007:Nitrate in California Domestic/Municipal WellsNitrate in California Domestic/Municipal Wells


Future Impacts Likely Increase:Future Impacts Likely Increase:Delay of Impact due to GW AgeDelay of Impact due to GW Age

Age at 100 ft (30 m) depth

Age at 300 ft (100 m) depth

Harter et al., 2009


Ways out of a Global Food CrisisWays out of a Global Food Crisis

Improvements in water storage (reservoirs, Improvements in water storage (reservoirs, groundwater banking) and delivery efficiencygroundwater banking) and delivery efficiencyImprovements in Improvements in agag water productivity through water productivity through new breeding / genetically modified cropsnew breeding / genetically modified crops

Drought and salt (!!) toleranceDrought and salt (!!) toleranceHigher yieldHigher yield

Desalination (brackish water, seawater, water Desalination (brackish water, seawater, water reuse in farming and urban areas)reuse in farming and urban areas)Liberate water as a free market commodity & Liberate water as a free market commodity & include externalities / supply & demandinclude externalities / supply & demand


Future Challenges toFuture Challenges toFood Supply & WaterFood Supply & Water

Around the GlobeAround the Globe

Decelerating agricultural productivity growth (ultimately due toDecelerating agricultural productivity growth (ultimately due tobiophysical limits [biophysical limits [Beadle and Long, 1985Beadle and Long, 1985; ; BugbeeBugbee and Salisbury, and Salisbury, 19881988])])Physical limits to crop land expansion (current reserves mostly Physical limits to crop land expansion (current reserves mostly in in Africa, Africa, S.AmericaS.America))Conflicting demands to Conflicting demands to landuselanduse & water use [& water use [BouwerBouwer, 2000, 2000; ; RosegrantRosegrant et al., 2002et al., 2002, Hightower & Pierce, 2008], Hightower & Pierce, 2008]

Urban vs. industrial vs. agricultural vs. energyUrban vs. industrial vs. agricultural vs. energyWithin Within agag: Food vs. feed vs. fiber vs. (: Food vs. feed vs. fiber vs. (bio)fuelbio)fuel

Declining soil quality (e.g., tropical soils) [Declining soil quality (e.g., tropical soils) [Foley et al., 2005Foley et al., 2005; ; RamankuttyRamankutty et al., 2002et al., 2002]]Constrains to Constrains to agag intensification due to environmental and human intensification due to environmental and human health regulations [health regulations [RockstroemRockstroem et al., 2004et al., 2004; ; TilmanTilman et al., 2001et al., 2001; ; Van Van HofwegenHofwegen, 2006, 2006].].

=> nitrate, pesticides, salts, pharmaceuticals, pathogen => nitrate, pesticides, salts, pharmaceuticals, pathogen contamination of groundwatercontamination of groundwater

Climate change => agricultural productivity changeClimate change => agricultural productivity change


Groundwater Resources:Groundwater Resources:Challenges around the GlobeChallenges around the Globe

Overdraft in most productive Overdraft in most productive agag regions (e.g., CA, High Plains, regions (e.g., CA, High Plains, NW India, North China Plain)NW India, North China Plain)Increased food, feed & Increased food, feed & biofuelbiofuel demands => expanded water demands => expanded water useuseIncreased pumping cost (due to overdraft)Increased pumping cost (due to overdraft)Energy requirements (e.g., India)Energy requirements (e.g., India)Compromise to future water security in fossil Compromise to future water security in fossil gwgw use areas use areas (Middle East/North Africa)(Middle East/North Africa)Degradation of groundwaterDegradation of groundwater

SalinizationSalinizationNutrients, pesticidesNutrients, pesticidesEmerging contaminants?Emerging contaminants?

Impact to wetlands, streams, downstream usersImpact to wetlands, streams, downstream usersCompetition with urban water users, environmental water Competition with urban water users, environmental water needsneeds

Modified from: Shah, Villholth, Burke, “Groundwater: a global assessment of scale and significance”, IWMI, 2007 Thomas Harter, University of California, Davis, 2010

IMPACT USE

Groundwater

SurfaceWater

NaturalResources

Urban/Domestic/IndustrialActivities

EcosystemsEnergySector

AgricultureClimate Change


IMPACT USE

Groundwater

SurfaceWater

NaturalResources

Urban/Domestic/IndustrialActivities

EcosystemsEnergySector

AgricultureClimate Change

Ag-Groundwater-Climate Change

Salinity

Nutrients/Nitrogen

Animal Ag => Pathogens/Pharmaceuticals

Livelihood

EnvironmentalJustice

GW Use & Quality @Ag-Urban-Ecosystem Interface

GW & Global Food Security

Ag-Groundwater-Energy Nexus


Toward Sustainable GW Use?Toward Sustainable GW Use?

Controlled increase in Controlled increase in gwgw use in Latin America and Subuse in Latin America and Sub--Saharan Africa to Saharan Africa to improve rural livelihoodimprove rural livelihoodImplement effective direct/indirect means to regulate Implement effective direct/indirect means to regulate gwgw withdrawalswithdrawals

supplysupply--side managementside managementArtificial recharge, aquifer recovery, rainwater harvestingArtificial recharge, aquifer recovery, rainwater harvestingWastewater reuseWastewater reuseConjunctive use, groundwater banking, integrated water managemenConjunctive use, groundwater banking, integrated water managementtInterbasinInterbasin transferstransfers

demanddemand--side managementside managementPricing (energy, water)Pricing (energy, water)Legal and regulatory controlLegal and regulatory controlWaterWater--rights/permitsrights/permitsIncentivesIncentives

GW Demand ManagementGW Demand ManagementIrrigation efficiency increaseIrrigation efficiency increaseDrought & salt tolerant crops (reuse!)Drought & salt tolerant crops (reuse!)Breeding of crops with higher water productivityBreeding of crops with higher water productivityCrop diversification: more cash per dropCrop diversification: more cash per dropOccupational diversificationOccupational diversification

Improve data base / data collection / monitoringImprove data base / data collection / monitoringBetter understanding of Better understanding of gwgw supply and demandsupply and demandPublic educationPublic education

Modified from: Shah, Villholth, Burke, “Groundwater: a global assessment of scale and significance”, IWMI, 2007


Resource evaluationResource evaluationAgricultural Agricultural management practicesmanagement practicesHazard assessmentHazard assessmentPollution controlPollution controlPollution assessmentPollution assessment

GeochemistryGeochemistryMicrobiologyMicrobiologyTransport / Physics Transport / Physics & Geology& GeologyMonitoringMonitoring

Water rightsWater rightsDischarge Discharge regulationsregulationsLanduseLanduseplanningplanningEconomic Economic incentivesincentivesLocal/regional Local/regional planning and planning and managementmanagementStakeholder Stakeholder interestsinterestsPoliciesPolicies

GROUNDWATER

QuantityQuality

AGRICULTURE,Ecosystems,

& Urban/Industry/EnergyLanduse Systems:

Demand (Quantity)Usability (Quality)

IMPACT USE

Technical Measures

Institutional Measures

Education

StakeholderParticipation

Imag

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…how obligate exactly…

…how facultative exactly…

Homo sapiens –Obligate or Facultative groundwater species?

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