Food Security: The Challenge of Feeding 9 Billion People

2010·0.41 MB·English

by  Godfray, H. Charles J.

duringthe18th-and19th-centuryIndustrialand
REVIEW Agricultural Revolutions and the 20th-century
Green Revolution. Increases in production will
Food Security: The Challenge of
haveanimportantparttoplay,buttheywillbe
constrainedasneverbeforebythefiniteresources
Feeding 9 Billion People provided by Earth’s lands, oceans, and atmo-
sphere(10).
Patternsinglobalfoodpricesareindicatorsof
H.CharlesJ.Godfray,1*JohnR.Beddington,2IanR.Crute,3LawrenceHaddad,4DavidLawrence,5 trendsintheavailabilityoffood,atleastforthose
JamesF.Muir,6JulesPretty,7ShermanRobinson,8SandyM.Thomas,9CamillaToulmin10 whocanafforditandhaveaccesstoworldmar-
kets.Overthepastcentury,grossfoodpriceshave
Continuingpopulationandconsumptiongrowthwillmeanthattheglobaldemandforfoodwill generallyfallen,levelingoffinthepastthreedec-
increaseforatleastanother40years.Growingcompetitionforland,water,andenergy,inadditionto adesbutpunctuatedbypricespikessuchasthat
theoverexploitationoffisheries,willaffectourabilitytoproducefood,aswilltheurgentrequirement causedbythe1970soilcrisis.Inmid-2008,there
toreducetheimpactofthefoodsystemontheenvironment.Theeffectsofclimatechangearea was an unexpected rapid rise in food prices, the
furtherthreat.Buttheworldcanproducemorefoodandcanensurethatitisusedmoreefficientlyand causeofwhichisstillbeingdebated,thatsubsided 5555555
equitably.Amultifacetedandlinkedglobalstrategyisneededtoensuresustainableandequitablefood whentheworldeconomywentintorecession(11). 01010101010101
security,differentcomponentsofwhichareexploredhere. However,many(butnotall)commentatorshave 2222222
predictedthatthisspikeheraldsaperiodofrising 8, 8, 8, 8, 8, 8, 8,
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The past half-century has seen marked fromalargerandmoreaffluentpopulationtoits andmorevolatilefoodpricesdrivenprimarilyby r r r r r r r
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growthinfoodproduction,allowingfora supply; do so in ways that areenvironmentally increaseddemandfromrapidlydevelopingcoun- bbbbbbb
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dramaticdecreaseintheproportionofthe and socially sustainable; and ensure that the tries,aswellasbycompetitionforresourcesfrom
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world’speoplethatarehungry,despiteadoubling world’s poorest people are no longer hungry. first-generationbiofuelsproduction(12).Increased vvvvvvv
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of the total population (Fig. 1) (1, 2). Neverthe- Thischallengerequireschangesinthewayfood food prices will stimulate greater investment in NNNNNNN
less,morethanoneinsevenpeopletodaystilldo is produced, stored, processed, distributed, and foodproduction,butthecriticalimportanceoffood n n n n n n n
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not have access to sufficient protein and energy accessedthatareasradicalasthosethatoccurred tohumanwell-beingandalsotosocialandpo- g g g g g g g
fromtheirdiet,andevenmoresufferfromsome litical stability makes it likely that ororororororor
form of micronutrient malnourishment (3). The governmentsandotherorganizations g.g.g.g.g.g.g.
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worldisnowfacinganewsetofintersectingchal- 3.5 Main grains (wheat, barley, will want to encourage food pro- mmmmmmm
lenges(4).Theglobalpopulationwillcontinueto maize, rice, oats) ductionbeyondthatdrivenbysim- cecececececece
grow,yetitislikelytoplateauatsome9billion 3.0 C(moiallerst,e s gorraginhsu m) ple market mechanisms (13). The enenenenenenen
people by roughly the middle of this century. A long-term nature of returns on in- cicicicicicici
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majorcorrelateofthisdecelerationinpopulation n 2.5 (cassava, potato) vestmentformanyaspectsoffood w.w.w.w.w.w.w.
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water,andenergy,andtheneedtocurbthemany primary solution to food shortages ooooooo
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negative effects of food production on the envi- has been to bring more land into wwwwwww
ronment is becoming increasingly clear (5, 6). 0.5 agriculture and to exploit new fish ooooooo
1960 1970 1980 1990 2000 2010 DDDDDDD
Overarchingalloftheseissuesisthethreatofthe stocks.Yetoverthepast5decades,
effectsofsubstantialclimatechangeandconcerns B while grain production has more
about how mitigation and adaptation measures 5.0 than doubled, the amount of land
Chickens
mayaffectthefoodsystem(7,8). 4.5 Pigs devotedtoarableagricultureglobal-
Athreefoldchallengenowfacestheworld(9): Cattle and buffalo lyhasincreasedbyonly~9%(14).
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Match the rapidly changing demand for food Sheep and goats Some new land could be brought
1Department of Zoology and Institute of Biodiversity at the mbers 33..50 itinotnofcourltliavnadtiofrno,mboutthethrehucmomanpeatci--
JPSacamirekensscReMo,aa1drt,iVnOicx2tf1oorsritdaCOSeXtnr1teue3rtyP,SSL,cohUnoKdo.oln,2UUS.nKWi.v1eGHrosvitOeyrEnoTmf,OUenxKft.oOr3dAf,fgiScreoicufuotlh-r ve nu 2.5 tuinvliitkieeslymaankdesctohsitslyansoilnuctrieoans,inpgalry-
tKuerneilwaonrdth,HWoratircwuilctukrsehirDeeCveVl8op2mTeL,ntUKB.oa4rIdn,stiStutoteneolefigDhevePlaorpk-, Relati 21..05 taincdulathrleypiufbplircotgeoctoindgs pbrioovdiidveedrsibtyy
mentStudies,Falmer,BrightonBN19RE,UK.5SyngentaAG, natural ecosystems (for example,
PostOfficeBox,CH-4002Basel,Switzerland.6InstituteofAqua- 1.0
culture,UniversityofStirling,StirlingFK94LA,UK.7Department 0.5 carbon storage in rainforest) are
of Biological Sciences, University of Essex, Wivenhoe Park, 1960 1970 1980 1990 2000 2010 givenhigherpriority(15).Inrecent
Colchester, Essex CO4 3SQ, UK. 8Institute of Development decades, agricultural land that was
Studies,Falmer,BrightonBN19RE,UK.9Foresight,U.K.Gov- formerly productive has been lost
ernment Office for Science, 1 Victoria Street, London SW1H
OET,UK.10InternationalInstituteforEnvironmentandDevelop- Fig.1.Changesintherelativeglobalproductionofcropsand to urbanization and other human
ment,3EndsleighStreet,LondonWC1H0DD,UK. animals since 1961 (when relative production scaled to 1 in uses, as well as to desertification,
*To whom correspondence should be addressed. E-mail: 1961).(A)Majorcropplantsand(B)majortypesoflivestock. salinization,soilerosion,andother
[email protected] [Source:(2)] consequences of unsustainable land
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SPECIALSECTION
management (16). Further losses, which may increasing productivity or for economic reasons Ayieldgapmayalsoexistbecausethehigh
be exacerbated by climate change, are likely arising from market conditions. For example, costsofinputsorthelowreturnsfromincreased
(7). Recent policy decisions to produce first- farmers may not have access to the technical production make it economically suboptimal to
generationbiofuelsongoodqualityagricultural knowledge and skills required to increase pro- raiseproductiontothemaximumtechnicallyat-
land have added to the competitive pressures duction,thefinancesrequiredtoinvestinhigher tainable. Poor transport and market infrastruc-
(17).Thus,themostlikelyscenarioisthatmore production (e.g., irrigation, fertilizer, machinery, tureraisethepricesofinputs,suchasfertilizers
food will need to be produced from the same crop-protection products, and soil-conservation andwater,andincreasethecostsofmovingthe
amount of (or even less) land. Moreover, there measures), or the crop and livestock varieties food produced into national or world markets.
arenomajornewfishinggrounds:Virtuallyall thatmaximizeyields.Afterharvestorslaughter, Wheretherisksofinvestmentarehighandthe
capture fisheries are fully exploited, and most they may not be able to store the produce or means to offset them are absent, not investing
areoverexploited. haveaccesstotheinfrastructuretotransportthe can be the most rational decision, part of the
Recent studies suggest that the world will producetoconsumermarkets.Farmersmayalso “poverty trap.” Food production in developing
need70to100%morefoodby2050(1,18).In choose not to invest in improving agricultural countries can be severely affected by market
this article, major strategies interventions in the developed
for contributing to the chal- world,suchassubsidiesorprice
lenge of feeding 9 billion supports.Theseneedtobecare-
Box1.Sustainableintensification.
people, including the most fullydesignedandimplemented
disadvantaged,areexplored. Producingmorefoodfromthesameareaoflandwhilereducingtheenvironmental so that their effects on global
Particular emphasis is given impactsrequireswhathasbeencalled“sustainableintensification”(18).Inexactlythe commoditypricesdonotactas
to sustainability, as well as same waythatyields canbe increased withtheuse of existing technologies,many disincentives to production in
to the combined role of the optionscurrentlyexisttoreducenegativeexternalities(47).Netreductionsinsome othercountries(23).
natural and social sciences greenhouse gas emissions can potentially be achieved by changing agronomic The globalization of the
in analyzing and addressing practices, the adoption of integrated pest management methods, the integrated food system offers some local
thechallenge. managementofwasteinlivestockproduction,andtheuseofagroforestry.However, foodproducersaccesstolarger
theeffectsofdifferentagronomicpracticesonthefullrangeofgreenhousegasescan markets, as well as to capital
Closing the YieldGap beverycomplexandmaydependonthetemporalandspatialscaleofmeasurement. for investment. At the aggre-
Thereiswidegeographicvar- Moreresearchisrequiredtoallowabetterassessmentofcompetingpolicyoptions. gate level, it also appears to
iation in crop and livestock Strategies such as zero or reduced tillage (the reduction in inversion ploughing), increase the global efficiency
productivity, even across re- contourfarming,mulches,andcovercropsimprovewaterandsoilconservation,but offoodproductionbyallowing
gionsthatexperiencesimilar they may not increase stocks of soil carbon or reduce emissions of nitrous oxide. regional specialization in the
climates. The difference be- Precisionagriculturereferstoaseriesoftechnologies thatallow theapplicationof production of the locally most
tween realized productivity water,nutrients,andpesticidesonlytotheplacesandatthetimestheyarerequired, appropriatefoods.Becausethe
and the best that can be therebyoptimizingtheuseofinputs(48).Finally,agriculturallandandwaterbodies expansion of food production
achieved using current ge- usedforaquacultureandfisheriescanbemanagedinwaysspecificallydesignedto and the growth of population
netic material and available reducenegativeimpactsonbiodiversity. both occur atdifferentratesin
technologies and manage- different geographic regions,
ment is termed the “yield global trade is necessary to ba-
gap.” The best yields that lancesupplyanddemandacross
can be obtained locally depend on the capacity productivitybecausethereturnsdonotcompare regions. However, the environmental costs of
offarmerstoaccessanduse,amongotherthings, wellwithotherusesofcapitalandlabor. foodproductionmightincreasewithglobaliza-
seeds, water, nutrients, pest management, soils, Exactlyhowbesttofacilitateincreasedfood tion,forexample,becauseofincreasedgreenhouse
biodiversity, and knowledge. It has been esti- production is highly site-specific. In the most gasemissionsassociatedwithincreasedproduc-
mated that in those parts of Southeast Asia extremecasesoffailedstatesandnonfunction- tionandfoodtransport(24).Anunfetteredmar-
whereirrigationisavailable,averagemaximum ing markets, the solution lies completely out- ketcanalsopenalizeparticularcommunitiesand
climate-adjusted rice yields are 8.5 metric tons side thefood system. Where a functioning state sectors,especiallythepoorestwhohavetheleast
per hectare, yet the average actually achieved exists, there is a balance to be struck between influence on how global markets are structured
yieldsare60%ofthisfigure(19).Similaryield investinginoveralleconomicgrowthasaspur andregulated.Expandedtradecanprovideinsur-
gapsarefoundinrain-fedwheatincentralAsia toagricultureandfocusingoninvestinginag- anceagainstregionalshocksonproductionsuch
and rain-fed cereals in Argentina and Brazil. ricultureasaspurtoeconomicgrowth,though asconflict,epidemics,droughts,orfloods—shocks
Another way to illustrate the yield gap is to thetwoareobviouslylinkedinregions,suchas thatarelikelytoincreaseinfrequencyasclimate
compare changes in per capita food production sub-Saharan Africa, where agriculture typically change occurs. Conversely, a highly connected
overthepast50years.InAsia,thisamounthas makes up 20 to 40% gross domestic product. food system may lead to the more widespread
increasedapproximatelytwofold(inChina,bya In some situations, such as low-income food- propagationofeconomicperturbations,asinthe
factorofnearly3.5),andinLatinAmerica,ithas importingcountries,investingpurelyingenerat- recent banking crisis, thus affecting more peo-
increased1.6-fold;inAfrica,percapitaproduc- ing widespread income growth to allow food ple.Thereisanurgentneedforabetterunder-
tionfellbackfromthemid-1970sandhasonly purchases from regionsandcountrieswithbet- standing of the effects of globalization on the
just reached the same level as in 1961 (2, 20). ter production capabilities may be the best fullfoodsystemanditsexternalities.
Substantiallymorefood,aswellastheincometo choice. When investment is targeted at food Theyieldgapisnotstatic.Maintaining,let
purchase food, could be produced with current production, a further issue is the balance be- alone increasing, productivity depends on con-
crops and livestock if methods were found to tween putting resources into regional and na- tinuedinnovationtocontrolweeds,diseases,in-
closetheyieldgaps. tional infrastructure, such as roads and ports, sects, and other pests as they evolve resistance
Low yields occur because of technical con- and investing in local social and economic to different control measures, or as new spe-
straints that prevent local food producers from capital(21,22). cies emerge or are dispersed to new regions.
www.sciencemag.org SCIENCE VOL327 12FEBRUARY2010 813
Innovation involves both traditional and ad- practice,howfastshouldweseektomovefrom search on the ability of these and related pro-
vanced crop and livestock breeding, as well as thestatusquotoasustainablefoodsystem?The grams to be scaled up to country and regional
the continuing development of better chemical, challenges of climate change and competition levelsshouldbeapriority(Fig.2).
agronomic, and agro-ecological control mea- forwater,fossilfuels,andotherresourcessuggest Strategiesdesignedtoclosetheyieldgapin
sures.Themaximumattainableyieldindifferent thatarapidtransitionisessential.Nevertheless, thepoorestcountries facesomeparticular chal-
regions will also shift as the effects of climate itisalsolegitimatetoexplorethepossibilitythat lenges (28). Much production is dominated by
changearefelt.IncreasingatmosphericCO lev- superiortechnologiesmaybecomeavailableand small-holderagriculturewithwomenoftentaking
2
els can directly stimulate crop growth, though that future generations may be wealthier and, adominantroleintheworkforce.Whereviable,
withinthecontextofrealagriculturalproduction hence,betterabletoabsorbthecostsofthetran- investment in the social and economic mecha-
systems,themagnitudeofthiseffectisnotclear sition.Finally,wedonotyethavegoodenough nisms to enable improved small-holder yields,
(7). More important will be the ability to grow
cropsinplacesthatarecurrentlyunsuitable,par-
ticularly the northern temperate regions (though
expansionofagricultureattheexpenseofboreal
forestwouldleadtomajorgreenhousegasemis-
sions), and the loss of currently productive re-
gions because of excessively high temperatures
and drought. Models that couple the physics of
climatechangewiththebiologyofcropgrowth
will be important to help policy-makers antici-
patethesechanges,aswellastoevaluatetherole
of “agricultural biodiversity” in helping mitigate
theireffects(25).
Closing the yield gap would dramatically
increase the supply of food, but with uncertain
impactsontheenvironmentandpotentialfeed-
backsthatcouldunderminefuturefoodproduc-
tion. Food production has important negative
“externalities,”namelyeffectsontheenvironment
or economy that are not reflected in the cost of
Fig.2.Anexampleofamajorsuccessfulsustainableagricultureproject.Nigerwasstronglyaffectedby
food.Theseinclude the release ofgreenhouse
aseriesofdroughtyearsinthe1970sand1980sandbyenvironmentaldegradation.Fromtheearly
gases [especially methane and nitrous oxide,
1980s, donors invested substantially in soil and water conservation. The total area treated is on the
which are more damaging than CO and for
2 orderof300,000ha,mostofwhichwentintotherehabilitationofdegradedland.Theprojectinthe
which agriculture is a major source (26)], envi- IlleladistrictofNigerpromotedsimplewater-harvestingtechniques.Contourstonebunds,halfmoons,
ronmentalpollutionduetonutrientrun-off,water stonebunding,andimprovedtraditionalplantingpits(zaı¨)wereusedtorehabilitatebarren,crusted
shortages due to overextraction, soil degrada- land.Morethan300,000hahavebeenrehabilitated,andcropyieldshaveincreasedandbecomemore
tion and the loss of biodiversity through land stablefromyeartoyear.Treecoverhasincreased,asshowninthephotographs.Developmentofthe
conversion or inappropriate management, and landmarketandcontinuedincrementalexpansionofthetreatedareawithoutfurtherprojectassistance
ecosystem disruptiondue totheintensivehar- indicatethattheoutcomesaresustainable(51,52).
vestingoffishandotheraquaticfoods(6).
To address these negative effects, it is now metrics of sustainability,a major problem when especially wheretargeted at women, can beim-
widelyrecognizedthatfoodproductionsystems evaluating alternative strategies and negotiat- portant means of increasing the income of both
andthefoodchainingeneralmustbecomefully ing trade-offs. This is the case for relatively cir- farmandruralnonfarmhouseholds.Thelackof
sustainable (18). The principle of sustainability cumscribed activities, such as crop production securelandrightscanbeaparticularproblemfor
impliestheuseofresourcesatratesthatdonot on individual farms, and even harder when the manypoorcommunities,mayactasadisincen-
exceed the capacity of Earth to replace them. completefoodchainisincludedorforcomplex tive for small holders to invest in managing the
By definition, dependency on nonrenewable products that may contain ingredients sourced landmoreproductively,andmaymakeitharder
inputs is unsustainable, even if in the short fromallaroundtheglobe.Thereisalsoadanger toraiseinvestmentcapital(29).Inatimeofris-
termitisnecessaryaspartofatrajectorytoward that an overemphasis on what can be measured ing prices for food and land, it can also render
sustainability. relativelysimply(carbon,forexample)maylead thesecommunitiesvulnerabletodisplacementby
Therearemanydifficultiesinmakingsustain- to dimensions of sustainability that are harder more powerful interest groups. Where the polit-
abilityoperational.Overwhatspatialscaleshould toquantify(suchasbiodiversity)beingignored. ical will and organizational infrastructure exist,
foodproductionbesustainable?Clearlyanover- These are areas at the interface of science, en- title definition and protection could be greatly
arching goal is global sustainability, but should gineering,andeconomicsthaturgentlyneedmore assisted by the application of modern informa-
thisgoalalsoapplyatlowerlevels,suchasre- attention (see Box 1). The introduction of mea- tion and communication technologies. Even so,
gions(oroceans),nations,orfarms?Couldhigh sures to promote sustainability does not neces- there will be many people who cannot afford to
levelsofconsumptionornegativeexternalities sarilyreduceyieldsorprofits.Onestudyof286 purchase sufficient calories and nutrients for a
insomeregionsbemitigatedbyimprovements agriculturalsustainabilityprojectsindeveloping healthylifeandwhowillrequiresocialprotection
in other areas, or could some unsustainable countries, involving 12.6 million chiefly small- programs to increase their ability to obtain food.
activitiesinthefoodsystembeoffsetbyactions holderfarmerson37millionhectares,foundan However, if properly designed, these programs
in the nonfood sector (through carbon-trading, averageyieldincreaseof79%acrossaverywide can help stimulate local agriculture by providing
for example)? Though simple definitions of varietyofsystemsandcroptypes(27).One-quarter small holders with increased certainty about the
sustainability are independent of time scale, in oftheprojectsreportedadoublingofyield.Re- demandfortheirproducts.
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SPECIALSECTION
There is also a role for large-scale farming Table1.ExamplesofcurrentandpotentialfutureapplicationsofGMtechnologyforcropgenetic
operationsinpoor-countryagriculture,thoughthe improvement. [Source: (18,49)]
value and contexts in which this is feasible are
muchdebated(30).Thisdebatehasbeenfanned Timescale Targetcroptrait Targetcrops
by a substantial increase in the number of sov- Current Tolerancetobroad-spectrum Maize,soybean,oilseed
ereign wealth funds, companies, and individuals herbicide brassica
leasing, purchasing, or attempting to purchase Resistancetochewinginsect Maize,cotton,oilseed
large tracts of agricultural land in developing pests brassica
countries.Thisexternalinvestmentindeveloping- Short-term Nutritionalbio-fortification Staplecerealcrops,sweet
country agriculture may bring major benefits, (5–10 years) potato
especially where investors bring considerable Resistancetofungusandvirus Potato,wheat,rice,banana,
improvements to crop production and process- pathogens fruits,vegetables
ing, but only if the rights and welfare of the Resistancetosuckinginsectpests Rice,fruits,vegetables
tenantsandexistingresourceusersareproperly Improvedprocessingandstorage Wheat,potato,fruits,
addressed(31). vegetables
Manyoftheverypoorestpeopleliveinareas Droughttolerance Staplecerealandtubercrops
so remote that they are effectively disconnected Medium-term Salinitytolerance Staplecerealandtubercrops
from national and world food markets. But for (10–20years) Increasednitrogen-use
others, especially the urban poor, higher food efficiency
priceshaveadirectnegativeeffectontheirability High-temperaturetolerance
to purchase a healthy diet. Many rural farmers Long-term apomixis Staplecerealandtubercrops
andotherfoodproducerslivenearthemarginof (>20 years) Nitrogenfixation
beingnetfoodconsumersandproducersandwill Denitrificationinhibitor
beaffectedincomplexwaysbyrisingfoodprices, production
with some benefitting and some being harmed Conversiontoperennialhabit
(21).Thus,whereasreducingdistortingagricul- Increasedphotosyntheticefficiency
turalsupportmechanismsindevelopedcountries
and liberalizing world trade should stimulate
overall food production in developing countries, Theseincludecropssuchassorghum,millet,cas- tion (with some notable exceptions, such as in
not everyone will gain (23, 32). Better models sava,andbanana,speciesthatarestaplefoodsfor China and Brazil) and a switch from public to
that can more accurately predict these complex manyoftheworld’spoorestcommunities(34). privatesources(1).Fairreturnsoninvestmentare
interactionsareurgentlyneeded. Currently,themajor commercialized geneti- essential for the proper functioning of the pri-
callymodified(GM)cropsinvolverelativelysim- vate sector, but the extension of the protection
Increasing Production Limits plemanipulations,suchastheinsertionofagene ofintellectualpropertyrightstobiotechnology
The most productive crops, such as sugar cane, forherbicideresistanceoranotherforapest-insect hasledtoagrowingpublicperceptioninsome
growinginoptimumconditions,canconvertsolar toxin.Thenextdecadewillseethedevelopment countries that biotech research purely benefits
energy into biomass with an efficiency of ~2%, of combinations of desirable traits and the intro- commercial interests and offers no long-term
resulting in high yields of biomass (up to 150 duction of new traits such as drought tolerance. public good. Just as seriously, it also led to a
metric tons per hectare) (33). There is much de- By mid-century, much more radical options in- virtualmonopolyofGMtraitsinsomepartsof
bate over exactly what the theoretical limits are volving highly polygenic traits may be feasible theworld,byarestrictednumberofcompanies,
forthemajorcropsunderdifferentconditions,and (Table1).Productionofclonedanimalswithen- which limits innovation and investment in the
similarly,forthemaximumyieldthatcanbeob- gineeredinnateimmunitytodiseasesthatreduce technology.Findingwaystoincentivizewideac-
tainedforlivestockrearing(18).However,thereis production efficiency has the potential to reduce cessandsustainability,whileencouragingacom-
clearlyconsiderablescopeforincreasingproduc- substantial losses arising from mortality and petitive and innovative private sector to make
tionlimits. subclinicalinfections.Biotechnologycouldalso best use of developing technology, is a major
The Green Revolution succeeded by using produce plants for animal feed with modified governancechallenge.
conventionalbreedingtodevelopF hybridvari- compositionthatincreasetheefficiencyofmeat The issue of trust and public acceptance of
1
eties of maize and semi-dwarf, disease-resistant productionandlowermethaneemissions. biotechnologyhasbeenhighlightedbythedebate
varietiesofwheatandrice.Thesevarietiescould Domestication inevitably means that only a overtheacceptanceofGMtechnologies.Because
be provided with more irrigation and fertilizer subsetofthegenesavailableinthewild-species genetic modification involves germline modifi-
(20)withouttheriskofmajorcroplossesdueto progenitorgenepoolisrepresentedamongcrop cationofanorganismanditsintroductiontothe
lodging (falling over) or severe rust epidemics. varieties and livestock breeds. Unexploited ge- environment and food chain, a number of par-
Increasedyieldisstillamajorgoal,buttheim- netic material from land races, rarebreeds, and ticularenvironmentalandfoodsafetyissuesneed
portance of greater water- and nutrient-use effi- wild relatives will be important in allowing to be assessed. Despite the introduction of rig-
ciency, as well as tolerance of abiotic stress, is breeders to respond to new challenges. Interna- orousscience-basedriskassessment,thisdiscus-
alsolikelytoincrease.Moderngenetictechniques tional collections and gene banks provide val- sionhasbecomehighlypoliticizedandpolarized
andabetterunderstandingofcropphysiologyal- uablerepositoriesforsuchgeneticvariation,but in some countries, particularly those in Europe.
low for a more directed approach to selection itisneverthelessnecessarytoensurethatlocally Ourviewisthatgeneticmodificationisapoten-
acrossmultipletraits.Thespeedandcostsatwhich adaptedcropandlivestockgermplasmisnotlost tiallyvaluabletechnologywhoseadvantagesand
genomestodaycanbesequencedorresequenced in the process of their displacement by modern, disadvantagesneedtobeconsideredrigorously
now means that these techniques can be more improved varieties and breeds. The trend over onanevidential,inclusive,case-by-casebasis:
easilyappliedtodevelopvarietiesofcropspecies recentdecadesisofageneraldeclineininvest- Geneticmodificationshouldneitherbeprivileged
thatwillyieldwellinchallengingenvironments. mentintechnologicalinnovationinfoodproduc- nor automatically dismissed. We also accept the
www.sciencemag.org SCIENCE VOL327 12FEBRUARY2010 815
need for this technology to gain greater public blemished products. Commercial pressures can vocacy, education, and possibly legislation may
acceptanceandtrustbeforeitcanbeconsidered encourage waste: The food service industry fre- also reduce waste in the food service and retail
as one among a set of technologies that may quentlyuses“super-sized”portionsasacompet- sectors.Legislationsuchasthatonsell-bydates
contributetoimprovedglobalfoodsecurity. itivelever,whereas“buyonegetonefree”offers and swill that has inadvertently increased food
There are particular issues involving new have the same function for retailers. Litigation waste should be reexamined within a more in-
technologies, both GM and non-GM, that are andlackofeducationonfoodsafety havelead clusive competing-risks framework. Reducing
targetedathelpingtheleast-developedcountries to a reliance on “use by” dates, whose safety developed-countryfoodwasteisparticularlychal-
(35, 36). The technologies must be directed at margins often mean that food fit for consump- lenging, as it is so closely linked to individual
theneedsofthosecommunities,whichareoften tion is thrown away. In some developed behaviorandculturalattitudestowardfood.
differentfromthoseofmoredevelopedcountry countries, unwanted food goes to a landfill
farmers.Toincreasethelikelihoodthatnewtech- insteadofbeingusedasanimalfeedorcompost ChangingDiets
nologyworksfor,andisadoptedby,thepoorest becauseoflegislationtocontrolpriondiseases. The conversion efficiency of plant into animal
nations, they need to be involved matteris~10%;thus,thereisaprimafaciecase
in the framing, prioritization, risk that more people could be supported from the
assessment,andregulationofinno- same amount of land if they were vegetarians.
vations.Thiswilloftenrequirethe Aboutone-thirdofglobalcerealproductionisfed
creation of innovative institutional Developing to animals (42). But currently, one of the major
andgovernancemechanismsthatac- countries challenges to the food system is the rapidly in-
countforsocio-culturalcontext(for creasingdemandformeatanddairyproductsthat
example,theimportanceofwomen has led, over the past 50 years, to a ~1.5-fold
in developing-country food produc- increase in the global numbers of cattle, sheep,
USA
tion). New technologies offer major andgoats,withequivalentincreasesof~2.5-and
promise, but there are risks of lost ~4.5-fold for pigs and chickens, respectively (2)
trust if their potential benefits are (Fig.1).Thisislargelyattributabletotheincreased
exaggeratedinpublicdebate.Efforts UK wealth of consumers everywhere and most re-
to increase sustainable production centlyincountriessuchasChinaandIndia.
limitsthatbenefitthepoorestnations However, the argument that all meat con-
will need to be based around new 0% 50% 100% sumptionisbadisoverlysimplistic.First,there
alliancesofbusinesses,civilsociety is substantial variation in the production effi-
On-farm Transport and processing
organizations,andgovernments. ciency and environmental impact of the major
Reta i l F ood Service Home and municipal classes of meat consumed by people (Table 2).
Reducing Waste Second, although a substantial fraction of live-
Roughly30to40%offoodinboth Fig.3. Makeupoftotalfoodwasteindevelopedanddevelop- stockisfedongrainandotherplantproteinthat
thedevelopedanddevelopingworlds ing countries. Retail, food service, and home and municipal could feed humans, there remains a very sub-
is lost to waste, though the causes categories are lumped together for developing countries. stantialproportionthatisgrass-fed.Muchofthe
behindthisareverydifferent(Fig.3) [Source:(16,37–39)] grassland that is used to feed these animals
(16,37–39).Inthedevelopingworld, could not be converted to arable land or could
losses are mainly attributable to the absence of Different strategies are required to tackle the onlybeconvertedwithmajorlyadverseenviron-
food-chaininfrastructureandthelackofknowl- twotypesofwaste.Indevelopingcountries,pub- mental outcomes. In addition, pigs and poultry
edge or investment in storage technologies on lic investment in transport infrastructure would are often fed on human food “waste.” Third,
thefarm,althoughdataarescarce.Forexample, reduce the opportunities for spoilage, whereas through better rearing or improved breeds, it
inIndia,itisestimatedthat35to40%offresh better-functioning markets and the availability may be possible to increasethe efficiency with
produce is lost because neither wholesale nor of capital would increase the efficiency of the which meat is produced. Finally, in developing
retail outlets have cold storage (16). Even with food chain, for example, by allowing the intro- countries,meatrepresentsthemostconcentrated
ricegrain,whichcanbestoredmorereadily,as duction of cold storage (though this has implica- sourceofsomevitaminsandminerals,whichis
much as one-third of the harvest in Southeast tionsforgreenhousegasemissions)(38).Existing importantforindividualssuchasyoungchildren.
Asiacanbelostafterharvesttopestsandspoil- technologiesandbestpracticesneedtobespread Livestockalsoareusedforploughingandtrans-
age(40).Butthepictureismorecomplexthan by education and extension services, and market port,providealocalsupplyofmanure,canbea
a simple lack of storage facilities: Although and finance mechanisms are required to protect vitalsourceofincome,andareofhugecultural
storage after harvest when there is a glut of farmersfromhavingtosellatpeaksupply,lead- importanceformanypoorercommunities.
foodwouldseemtomakeeconomicsense,the ingtoglutsandwastage.Thereisalsoaneedfor Reducing the consumption of meat and in-
farmer often has to sell immediately to raise continuing research in postharvest storage tech- creasingtheproportionthatisderivedfromthe
cash. nologies. Improved technology for small-scale mostefficientsourcesofferanopportunitytofeed
Incontrast,inthedevelopedworld,pre-retail food storage in poorer contexts is a prime can- more people and also present other advantages
losses are much lower, but those arising at the didate for the introduction of state incentives for (37).Well-balanceddietsrichingrainsandother
retail,foodservice,andhomestagesofthefood privateinnovation,withtheinvolvementofsmall- vegetable products are considered to be more
chain have grown dramatically in recent years, scaletraders,millers,andproducers. healthfulthanthosecontainingahighproportion
for a variety of reasons (41). At present, food is If food prices were to rise again, it is likely ofmeat(especiallyredmeat)anddairyproducts.
relatively cheap, at least for these consumers, that therewould beadecreaseinthevolumeof As developing countries consume more meat in
whichreducestheincentivestoavoidwaste.Con- wasteproducedbyconsumersindevelopedcoun- combinationwithhigh-sugarand-fatfoods,they
sumers have become accustomed to purchasing tries.Wastemayalsobereducedbyalertingcon- mayfindthemselveshavingtodealwithobesity
foods of thehighest cosmeticstandards; hence, sumers to the scale of the issue, as well as to before they have overcome undernutrition, lead-
retailers discard many edible, yet only slightly domestic strategies for reducing food loss. Ad- ingtoanincreaseinspendingonhealththatcould
816 12FEBRUARY 2010 VOL 327 SCIENCE www.sciencemag.org
SPECIALSECTION
Table2.Comparisonoftheimpactofgrazingandintensive(confined/industrialized)grain-fedlivestock vationinthefoodsystem,butnotasanexcuse
systems onwateruse,grainrequirement,andmethaneproduction.Servicewateristhat requiredfor todelaydifficultdecisionstoday.
cleaningandwashinglivestockhousingandotherfacilities.Dashesindicatecombinationsforwhichno Any optimism must be tempered by the
dataareavailable(eitherbecauseitcannotbemeasuredorbecausethecombinationdoesnotexist). enormous challenges of making food produc-
Thistabledoesnotincludeotherimpactsofdifferinglivestockmanagementsystemssuchas(i)nutrient tion sustainable while controlling greenhouse
run-offandpollutiontosurfaceandgroundwater,(ii)protozoanandbacterialcontaminationofwater gas emission and conserving dwindling water
andfood,(iii)antibioticresiduesinwaterandfood,(iv)heavymetalfromfeedinsoilsandwater,(v)
supplies, as well as meeting the Millennium De-
odor nuisance from wastes, (vi) inputs used for feed production and lost to the environment, (vii)
velopmentGoalofendinghunger.Moreover,we
livestock-relatedland-usechange.[Source:(7,50)]
must avoid the temptation to further sacrifice
Earth’salreadyhugelydepletedbiodiversityfor
Water Measureofwateruse Grazing Intensive
easygainsinfoodproduction,notonlybecause
Litersday–1peranimalat15°C biodiversityprovidesmanyofthepublicgoods
Cattle Drinkingwater:all 22 103 onwhichmankindreliesbutalsobecausewedo
Servicewater:beef 5 11 nothavetherighttodeprivefuturegenerationsof
Servicewater:dairy 5 22 itseconomicandculturalbenefits.Together,these
Pigs(lactatingadult) Drinkingwater 17 17 challengesamounttoaperfectstorm.
Servicewater 25 125 Navigatingthestormwillrequirearevolution
Sheep(lactatingadult) Drinkingwater 9 9 inthesocialandnaturalsciencesconcernedwith
Servicewater 5 5 food production, as well as a breaking down of
Chicken(broilerandlayer) Drinkingwater 1.3–1.8 1.3–1.8 barriers between fields. The goal is no longer
Servicewater 0.09–0.15 0.09–0.15 simplytomaximizeproductivity,buttooptimize
Feedrequiredtoproduce1kgofmeat kgofcerealperanimal acrossafarmorecomplexlandscapeofproduc-
Cattle – 8 tion,environmental,andsocialjusticeoutcomes.
Pigs – 4
Chicken(broiler) – 1 ReferencesandNotes
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moresogiventheadditionalpressurescreated
REVIEW
by global environmental changes.
Breeding Technologies to Increase
GlobalEnvironmentalChangeAlters
BreedingTargets
Crop Production in a Changing World
Certain aspects of global environmental change
arebeneficialtoagriculture.RisingCO actsasa
2
fertilizerforC3cropsandisestimatedtoaccount
Mark Tester*and Peter Langridge
forapproximately0.3%oftheobserved1%risein
globalwheatproduction(4),althoughthisbenefit
Tofeedtheseveralbillionpeoplelivingonthisplanet,theproductionofhigh-qualityfoodmust
islikelytodiminish,becauserisingtemperatures
increasewithreducedinputs,butthisaccomplishmentwillbeparticularlychallenginginthefaceof
will increase photorespiration and nighttime res-
globalenvironmentalchange.Plantbreedersneedtofocusontraitswiththegreatestpotentialto
piration. A benefit of rising temperatures is the
increaseyield.Hence,newtechnologiesmustbedevelopedtoacceleratebreedingthroughimproving
alleviationoflow-temperatureinhibitionofgrowth,
genotypingandphenotypingmethodsandbyincreasingtheavailablegeneticdiversityinbreeding
whichisawidespreadlimitationathigherlatitudes
germplasm.Themostgainwillcomefromdeliveringthesetechnologiesindevelopingcountries,but
andaltitudes.Offsettingthesebenefits,however,
thetechnologieswillhavetobeeconomicallyaccessibleandreadilydisseminated.Cropimprovement
areobvious deleterious changes, suchas anin-
throughbreedingbringsimmensevaluerelativetoinvestmentandoffersaneffectiveapproachto
creasedfrequencyofdamaginghigh-temperature
improvingfoodsecurity.
events, new pest and disease pressures, and al-
teredpatternsofdrought.Negativeeffectsofother
Althoughmorefoodisneededfortherapidly versionofsubstantialquantitiesoffoodintothe pollutants,notablyozone,willalsoreducebenefits
growing human population, food quality productionofbiofuelsputsfurtherpressureon toplantgrowthfromrisingCO andtemperature.
2
alsoneedstobeimproved,particularlyfor worldfoodsupplies(1). Particularly challenging for society will be
increased nutrient content. In addition, agricul- Breeding and agronomic improvements have, changes in weather patterns that will require
turalinputsmustbereduced,especiallythoseof on average, achieved a linear increase in food alterationsinfarmingpracticesandinfrastructure;
nitrogenous fertilizers, if we are to reduce en- productionglobally,atanaveragerateof32million forexample,waterstorageandtransportnetworks.
vironmental degradation caused by emissions metrictonsperyear(2)(Fig.1).However,tomeet Becauseone-thirdoftheworld’sfoodisproduced
ofCO andnitrogenouscompoundsfromagri- the recent Declaration of the World Summit on on irrigated land (5, 6), the likely impacts on
2
culturalprocesses.Furthermore,therearenow Food Security (3) target of 70% more food by global food production are many. Along with
concerns about our ability to increase or even 2050,anaverageannualincreaseinproductionof agronomic-andmanagement-basedapproachesto
sustaincropyieldandqualityinthefaceofdy- 44millionmetrictonsperyearisrequired(Fig.1), improving food production, improvements in a
namicenvironmentalandbioticthreatsthatwill representing a 38% increase over historical crop’sabilitytomaintainyieldswithlowerwater
beparticularlychallenginginthefaceofrapid increases in production, to be sustained for 40 supplyandqualitywillbecritical.Putsimply,we
global environmental change. The current di- years. This scale of sustained increase in global needtoincreasethetoleranceofcropstodrought
food production is unprecedented and requires andsalinity.
substantial changes in methods for agronomic Inthecontextofglobalenvironmentalchange,
AustralianCentreforPlantFunctionalGenomics,Universityof
Adelaide,SouthAustraliaSA5064,Australia. processes and crop improvement. Achieving this theefficiencyofnitrogenusehasalsoemergedas
increaseinfoodproductioninastableenvironment akey target.Human activityhas alreadymore
*To whom correspondence should be addressed. E-mail:
[email protected] wouldbechallenging,butisundoubtedly much thandoubledtheamountofatmosphericN2fixed
818 12FEBRUARY 2010 VOL 327 SCIENCE www.sciencemag.org
Food Security: The Challenge of Feeding 9 Billion People
H. Charles J. Godfray et al.
Science 327, 812 (2010);
DOI: 10.1126/science.1185383
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