crop adaptation to climate change (yadav/crop adaptation to climate change) || climate change,...

P1: SFK/UKS P2: SFK Color: 1C

BLBS082-1-1 BLBS082-Yadav July 12, 2011 12:39 Trim: 246mm X 189mm

Chapter 1.1

Climate Change, Population Growth, and CropProduction: An OverviewHermann Lotze-Campen

Introduction

The publication of the Stern Review on theEconomics of Climate Change in 2006 and theFourth Assessment Report by the Intergovern-mental Panel on Climate Change (IPCC) in 2007have pushed the scientific and public debate onclimate change a decisive step forward. It is nowbeyond doubt that anthropogenic greenhouse gas(GHG) emissions are the main cause for re-cently observed climate change and that earlyand bold mitigation measures will eventually bemuch cheaper than later adaptation to potentiallydrastic climate impacts. The agricultural sector isdirectly affected by changes in temperature, pre-cipitation, and CO2 concentrations in the atmo-sphere, but it is also contributing about one-thirdto total GHG emissions, mainly through live-stock and rice production, nitrogen fertilization,and tropical deforestation. Agriculture currentlyaccounts for 5% of world economic output, em-ploys 22% of the global workforce, and occu-pies 40% of the total land area. In the developingcountries, about 70% of the population lives inrural areas, where agriculture is the largest sup-porter of livelihoods. In many developing coun-tries, the economy is heavily depending on agri-culture. The sector accounts for 40% of gross

domestic product (GDP) in Africa and 28% inSouth Asia. However, in the future, agriculturewill have to compete for scarce land and water re-sources with growing urban areas and industrialproduction.

A large share of the world’s poor populationlives in arid or semiarid regions, which are al-ready characterized by highly volatile climateconditions. Under conditions of future climatechange, a worldwide increase in climate vari-ability and extreme weather events is very likely.The connections between agricultural develop-ment and climate change reveal some fundamen-tal issues of global justice. The industrializedcountries, mostly located in medium to high lat-itudes, are responsible for the major share ofaccumulated GHG emissions. They are econom-ically less dependent on agriculture, they will beless affected by climate impacts, and they haveon average a higher adaptive capacity. Most de-veloping countries are located in the lower lat-itudes, they are dependent on agriculture, theywill be strongly affected by climate impacts, andthey have lower (or nonexistent) adaptive capac-ity. Creating more options for climate changeadaptation and improving the adaptive capacityin the agricultural sector will be crucial for im-proving food security and preventing an increase

Crop Adaptation to Climate Change, First Edition. Edited by Shyam S. Yadav, Robert J. Redden, Jerry L. Hatfield,Hermann Lotze-Campen and Anthony E. Hall.c© 2011 John Wiley & Sons, Ltd. Published 2011 by John Wiley & Sons, Ltd.

1



2 CROP ADAPTATION TO CLIMATE CHANGE

in global inequality in living standards in the fu-ture. However, in the developing world, this isoften prevented by the lack of information, fi-nancial resources, and good governance.

Global scenarios on futuregreenhouse gas emissions andpopulation growth

Future emissions of anthropogenic GHG mainlydepend on population growth, socioeconomicdevelopment, and technological change. Futuretrends in these driving forces are highly un-certain, especially over the course of the nextdecades until the end of the century. For a sys-tematic description of the range of possible fu-tures, the IPCC has developed a set of long-termemission scenarios that were published in theSpecial Report on Emission Scenarios (SRES;Nakicenovic et al. 2000). Four different narrativestorylines were developed to represent differentdemographic, social, economic, technological,and environmental conditions and trends, thuscovering a wide range of possible GHG emis-sion outcomes. For each storyline, several emis-sion scenarios were developed using differentintegrated assessment modeling approaches.

Table 1.1.1 summarizes the main drivingforces for the four emission scenarios by the endof the century.

The A1 storyline describes a future world ofvery rapid economic growth, global populationthat peaks at about 9 billion in mid-century anddeclines thereafter, and the rapid introduction ofnew and more efficient technologies. The un-derlying theme is that regions will converge andcultural and social interactions will increase witha substantial reduction in regional differences inper capita income. The scenario groups are de-termined by different directions of technologicalchange in the energy system. A1FI is fossil inten-sive, A1T heavily uses nonfossil energy sources,and the A1B is a scenario with a balance acrossall energy sources.

The A2 storyline describes a very hetero-geneous world. The underlying theme is self-

reliance and preservation of local identities. Pop-ulation will continuously increase, up to 15 bil-lion in 2100, and economic development is pri-marily regionally oriented. Per capita economicgrowth and technological change are more frag-mented and slower than in other storylines. TheB1 storyline describes a convergent world withthe same global population as in A1 that peaksat mid-century and declines thereafter. However,major differences come from rapid changes ineconomic structures toward a service and in-formation economy, with reductions in mate-rial intensity and the introduction of clean andresource-efficient technologies. The main fea-ture is a global solution to economic, social, andenvironmental sustainability with improved eq-uity but without additional climate initiatives.The B2 storyline describes a world of local so-lutions to economic, social, and environmentalsustainability. It is a world with continuously in-creasing global population at a rate lower thanA2 (about 10 billion in 2100), intermediate lev-els of economic development, and less rapid andmore diverse technological change than in theB1 and A1 storylines.

Figure 1.1.1 shows the projected temperatureincreases for the four SRES scenario groups,including the different energy technology op-tions of A1. Each emission scenario was ana-lyzed with several global climate models, to takeuncertainties about the climate sensitivity of dif-ferent models into account. Highest temperatureincreases are projected for A1FI due to very highemissions. The mean model results for globaltemperature increase across all climate modelsrange between 2.4◦C (B1) and 4.6◦C (A1FI),compared to the preindustrial level. Several mod-els show a wider range of outcomes, possibly aslow as 1.6◦C for the B1 scenario but also ashigh as 6.4◦C for the fossil-fuel-intensive A1FIscenario.

Climate impacts on cropproductivity

Plant growth and yield will be both positively andnegatively affected by climate change. Diverging



CLIMATE CHANGE, POPULATION GROWTH, AND CROP PRODUCTION 3

Table 1.1.1. Overview of main driving forces for the four SRES storylines in 2100.

Peoplea

billion (B)Economicgrowthb % p.a.

Incomec

GDP/capitaPrimary energyuse

Hydrocarbonresource used

Land usechangeb

A1 Low∼7 B.1.4 IND5.6 DEV

Very high1990-20: 3.31990-50: 3.61990-100: 2.9

Very highIND 107,300DEV 66,500

Very high2.226 EJLow intensity4.2 MJ/US$

Scenario:Oil low—VH20.8 ZJGas high—VH42.2 ZJCoal med—VH15.9 ZJ

Low1990-100:cropland +3%grassland +6%forests +2%

A2 High15 B.2.2 IND12.9 DEV

Medium1990-20: 2.21990-50: 2.31990-100: 2.3

Low in DEVMedium inINDIND 46,200DEV 11,000

High1,717 EJHigh intensity7.1 MJ/US$

Scenario:Oil VL—med17.3 ZJGas low—high24.6 ZJCoal Med - VH46.8 ZJ

Mediumn.a.

B1 Low∼7 B.1.4 IND5.7 DEV

High1990-20: 3.11990-50: 3.11990-100: 2.5

HighIND 72,800DEV 40,200

Low514 EJVery lowintensity 1.6EJ/US$

Scenario:Oil VL—high19.6 ZJGas med—high14.7 ZJCoal Vl—high13.2 ZJ

High1990-100:cropland −28%grassland −45%forests +30%

B2 Median∼10 B.1.3 IND9.1 DEV

Medium1990-20: 3.01990-2050: 2.81990-100: 2.2

MediumIND 54,400DEV 18,000

Medium1,357 EJMediumintensity 5.8MJ/US$

Scenario:Oil low—med19.5 ZJGas low—med26.9 ZJCoal low—VH12.6 ZJ

Medium1990-100:cropland +22%grassland +9%forests +5%

Source: Nakicenovic et al. (2000), Table 4.4a, http://www.grida.no/climate/ipcc/emission/097.htm.aIND, industrialized countries; DEV, developing countries.b1990 > 2000.cUS$.dVL, very low; med, medium; VH, very high.

effects are caused by rising CO2 concentrations,higher temperatures, changing precipitation pat-terns, changing water availability, increased fre-quency of weather extremes (i.e., floods, heavystorms and droughts), climate-induced soil ero-sion, and sea-level rise. While some of theseimpacts have been studied in isolation, com-plex interactions between different factors andespecially extreme events are still not wellunderstood.

CO2 fertilization

Yields of most agricultural crops increase un-der elevated CO2 concentration. Free air carbonenrichment (FACE) experiments indicate pro-ductivity increases in the range of 15–25% forC3 crops (like wheat, rice, and soybeans) and5–10% for C4 crops (like maize, sorghum, andsugarcane). Higher levels of CO2 also improvewater-use efficiency of both C3 and C4 plants.




Fig. 1.1.1. Projected temperature increases for the four SRES emission scenario groups.(Source: IPCC 2007, p. 14.)

However, the experiments do not address im-portant colimitations because of water and nu-trient availability. Some studies expect muchless favorable crop response to elevated CO2

in practice than that asserted on experimentalsites (e.g., Long et al. 2006), while others agreewith findings from FACE experiments (Tubielloet al. 2007). Thus, the magnitude of the positiveyield effect due to enhanced CO2 concentrationis still uncertain (Parry et al. 2004; Easterlinget al. 2007).

Higher temperatures

Warming is observed over the entire globe, butwith significant regional and seasonal variations.Highest rates can be found at Northern latitudesand during winter and spring (Solomon et al.2007). In the Northern Hemisphere, in higherlatitudes, rising temperatures imply lengtheningof the growing season by 1.2–3.6 days per decade(Gitay et al. 2001). This allows earlier plantingof crops in spring, earlier maturing and harvest,and the possibility for two or more cropping cy-cles. An expansion of suitable crop area may be-come possible in the Russian Federation, North

America, Northern Europe, and Northeast Asia.In contrast, significant losses are predicted forAfrica due to heat and water stress and an ex-pansion of arid and semiarid regions (Fischeret al. 2005). Temperature increases are likely tosupport positive effects of enhanced CO2 un-til temperature thresholds are reached. Beyondthese thresholds, crop yields will be negativelyaffected. Increased water supply can help to bal-ance high temperatures. In the tropics, additionalwarming of less than 2◦C will lead to crop yieldlosses, while crops in temperate regions willbroadly benefit from temperature increases ofup to 2◦C. Further warming will negatively af-fect plant health in temperate regions (Easterlinget al. 2007).

Water availability

Agriculture highly depends on water availabil-ity. More than 80% of global cropland is rain-fed, but irrigated cropland with an area share of16% produces about 40% of the world’s food.Agricultural irrigation accounts for around 70%of global freshwater withdrawals (Gitay et al.2001). Because of growing global food demand




and rising temperatures, even more water willbe required in the future. Climate impacts oncrop productivity will fundamentally depend onprecipitation changes. Precipitation projectionsshow large variability of quantity and distribu-tion. This is also due to the fact that historical cli-mate records as an input for modeling are scarcein many poor countries. Annual mean runofflargely follows projected changes in precipita-tion with an increase in high latitudes and thewet tropics, and with a decrease in mid-latitudesand some parts of the dry tropics (Solomon et al.2007). The decline in water availability will af-fect areas currently suitable for rainfed crops,like the Mediterranean basin, Central America,and subtropical regions of Africa and Australia(Easterling et al. 2007). Moreover, in warmer anddryer regions, agricultural water demand will in-crease. Global irrigation requirements are esti-mated to increase by 5–8% by 2070 with re-gional differences of up to +15% in South Asia(Doll 2002). While irrigated agriculture is ex-pected to become more important, water sup-ply may be insufficient. In regions that are de-pending on steady water supplies from glaciers(e.g., Andes and Himalaya), water availabilitymay increase in the near to medium term dueto accelerating glacier retreat, whereas it maybreak down later, once glaciers are completelymelted. In some regions (e.g., northern India andMidwest United States) groundwater is depletedat fast rates, which could clearly lead to watershortages in the future. In addition to decreasingwater supply, agriculture in many fast-growingregions will also face increasing competition forwater due to rising demand from households andindustry.

Climate variability, extreme events,and sea-level rise

Extreme climate events such as heat waves,heavy storms, floods, or droughts may damagecrops in specific development stages. A substan-tial and widespread increase in the number ofheavy rainfall events is expected, even in regions

where total precipitation amount decreases(Solomon et al. 2007). Heavy rainfalls are verylikely in Southern and Eastern Asia and in North-ern Europe, which are major agricultural produc-tion areas. On the other hand, observations showan increase in frequency and duration of warmweather extremes. In many regions, especiallyin the tropics and subtropics, droughts have beenlonger and more intensive since the 1970s be-cause of higher temperatures and reduced pre-cipitation (Solomon et al. 2007). Climate changewill deepen these trends. In arid and semiarid re-gions, higher rainfall intensity will increase risksof soil erosion and salinization. Rice yield is al-ready close to the limit of maximum tempera-ture tolerance in South Asia. Thus, even highertemperatures will negatively affect yields. Addi-tionally, increasing flood frequency will damagecrop production in countries like Bangladesh.In the United States, heavy precipitation eventsare expected to cause severe production lossesalready by 2030 (Rosenzweig and Hillel 1995;Easterling et al. 2007). The European heat wavein the summer of 2003 with temperatures of 6◦Cabove long-term averages and severe precipita-tion shortfalls caused severe economic losses forthe agricultural sector across Europe. In North-ern Italy, a record yield drop of 36% was ob-served, while in France maize yield was reducedby 30% when compared to 2002 (Easterlinget al. 2007).

In low-lying countries with long coastlines,sea-level rise will threaten large areas of fer-tile land. This is a special problem, e.g., inBangladesh and many Pacific Islands. Anotherproblem related to rising sea levels is saltwaterintrusion, which may negatively affect soil fer-tility and quality of irrigation water in coastalareas.

Soil degradation

Climate change affects soils by increasing therate of nutrient leaching and soil erosion. Nu-trient conservation is affected by warmer tem-peratures because higher temperatures are likely




to increase the natural decomposition of organicmatter because of a stimulation of microbial ac-tivity. If mineralization exceeds plant uptake, nu-trient leaching will be the consequence. It pri-marily occurs when plant demand is low andrising soil temperature increases nitrogen min-eralization rates. This process is enforced by in-creased precipitation and loss of snow cover aspredicted for many temperate regions (Niklaus2007). Soil erosion is increased by intensive rain-fall, which is likely to increase under climatechange. One percent increase in precipitation isexpected to lead to 1.5–2% increase in erosionrates (Nearing et al. 2004). Extreme rainfall andshifting from snow to rain will also increase therate of erosion. Changes of plant biomass canfurther increase these effects: plant canopies re-duce soil erosion by weakening the power ofrain, roots stabilize soils, and crop residues re-duce sediment transportation. In arid and semi-arid regions, dry soils are sensitive to soil ero-sion through wind and rain. Increased frequencyof droughts further intensifies erosive losses asplant biomass and its positive effects on soils arereduced (Nearing et al. 2004; Niklaus 2007).

Weeds, pests, and pathogens

In current agriculture, preharvest losses topests in major food and cash crops are esti-mated to be 42% of global potential production(Gitay et al. 2001). Temperature rise and ele-vated CO2 concentration could increase plantdamage from pests in future decades, althoughonly a few quantitative analyses exist to date(Easterling et al. 2007; Ziska and Runion 2007).Weeds, like crops, show positive response toelevated CO2. Moreover, weeds show a largerrange of responses, including larger growth, toelevated CO2 because of their greater geneticdiversity (Ziska and Runion 2007). Several im-portant crop weeds in the United States haveexpanded since the 1970s, which is consistentwith climate trends (Gitay et al. 2001). How-ever, future weed distribution and the accompa-nied changes in weed–crop competition remain

highly uncertain. Temperature rise will boost in-sect growth and development by increasing ge-ographical distribution and increasing overwin-tering (Ziska and Runion 2007). Pathogens arerecognized as a significant limitation on agro-nomic productivity. While elevated CO2 will notdirectly affect the pathogens, it will alter plantdefense mechanisms. Especially, higher wintertemperatures will lead to an increasing occur-rence of plant diseases in cooler regions (Ziskaand Runion 2007).

Climate impacts on agricultural markets

According to currently available studies, aggre-gated global impacts of climate change on worldfood production are likely to be small. Parryet al. (2004) predict negative impacts on worldcrop production by −5% by the end of the cen-tury. According to Fischer et al. (2005), produc-tion losses in developing countries in the rangeof 5–15% will be compensated by similar in-creases of production in the developed coun-tries, in particular North America and Russia.Thus, climate change will result in larger tradeflows from mid- and high-latitudes to the lowlatitudes (Easterling et al. 2007). However, mostof the studies available to date only cover grad-ual scenarios of climate change and related im-pacts. If tipping points in the climate systemare transgressed, the picture is likely to becomemuch bleaker (Battisti and Naylor 2009). Evenwithout climate change, there will be a grow-ing dependency of developing countries on netcereal imports. Climate change will further in-crease this dependency by 10–40% (Fischer et al.2005). In the past, the average rate of productiv-ity growth in agriculture and food productionexceeded population growth. Supply exceededdemand, which resulted in a long-term declineof real food prices until the turn of the millen-nium. Even if the strong food price increasesin 2007/2008 may have been an exception, itcan be expected that world food prices willgradually increase in the future. Besides climatechange, the dynamics of population, income, and




technology will continue to play an importantrole. Furthermore, depending on technologicaland policy changes in the energy sector, an in-creasing demand for bioenergy will have an im-pact on agricultural markets. In poor, net foodimporting countries, food security could deteri-orate as a result. For countries with a strong pro-duction potential, bioenergy demand could alsobecome an engine for agricultural and economicgrowth.

Climate impacts on food security

Food security has four major components: Foodavailability through production and trade; sta-bility of food supplies; access to food; andactual food utilization. They all can be af-fected by climate change (Gregory et al. 2005;Easterling et al. 2007). Assessments of crop pro-duction can therefore only provide a partial as-sessment of climate change impacts on food se-curity. In addition, climate change is not the onlyfactor that may cause food security problems.Regional conflicts, changes in international tradeagreements and policies, infectious diseases, andother societal factors may exacerbate the impacts(Easterling et al. 2007). The capacity to copewith environmental stress is as important as thedegree of exposure to climate-related stresses.Thus, projections of undernourishment dependon climate impacts and also on economic de-velopment, technical conditions, and populationgrowth (Gregory et al. 2005). At the beginningof the millennium, between 800 and 900 mil-lion people were at risk of hunger. Most of themlived in Asia and sub-Saharan Africa (FAO 2006,p. 8). In the future, many factors including cli-mate change and socioeconomic developmentwill influence the number of people at risk, andthere are still a lot of uncertainties about re-gional climate impacts on food supply and de-mand. However, it is very likely that sub-SaharanAfrica will surpass South Asia as the mostfood-insecure world region (Tubiello and Fischer2007). Few studies have tried to quantify theimpacts of climate change and socioeconomic

factors on food security (Fischer et al. 2002,2005; Parry et al. 2004; Tubiello and Fischer2007). They indicate that the number of peopleat risk of hunger will mostly depend on socioeco-nomic development. Economic growth and slow-ing population growth can significantly reducethe number of people at risk of hunger. In a pes-simistic scenario with strong global warming,high population growth, and no CO2-fertilizationeffects, the number of additional people at riskof hunger may be as high as 500–600 millionby 2080 (Parry et al. 2004). Again, the situa-tion may become even worse, if tipping points inthe climate system are transgressed (Battisti andNaylor 2009).

Adaptation options in agriculture

Agricultural vulnerability

In the past, adaptation in agriculture was thenorm rather than the exception. Farmers havedemonstrated sufficient adaptive capacity to copewith weather variations on weekly, seasonal, an-nual and even longer timescales (Burton and Lim2005; Rosenzweig and Tubiello 2007). Mod-ern agricultural technologies have minimized cli-mate impacts through irrigation, the use of pes-ticides and fertilizers, and the manipulation ofgenetic resources (Kandlikar and Risbey 2000).In the future, however, climate will change ata rate that has not been previously experiencedin human history. Adaptive capacity of farmersis determined by their wealth, human capital,information and technology, material resourcesand infrastructure, and institutions and entitle-ments of the society (Kandlikar and Risbey 2000;Belliveau et al. 2006; Easterling et al. 2007). It isobvious that rich countries are better equippedto cope with climate variations than develop-ing countries, where decisions are made in thecontext of the local agricultural cycle, poverty,and often limited access to markets. Many pos-sible adjustments are prevented by the lackof information, financial resources, and institu-tional support. New technologies are often not




implemented due to lack of education (Kandlikarand Risbey 2000; Smithers and Blay-Palmer2001).

Adjustments in production technology

Technical improvements and management ad-justments at the farm level include the following:

� Shifted dates of planting allow farmers to takeadvantage of the longer growing season thatis permitted by higher winter temperatures inhigher latitudes. Earlier planting can lead toan increase in the yield potential by using cul-tivars that need longer time to mature. Thepotential for earlier harvesting can avoid heatand drought stress in late summer (Easterling1996; Olesen and Bindi 2002; Rosenzweig andTubiello 2007).

� New crop varieties can provide more appro-priate thermal requirements and increased re-sistance to heat shock and drought. Breedingof new varieties is certainly a major option forimproved adaptation, but development of newvarieties, which are well adapted to specificregional conditions, is expensive and typicallyneeds a decade or longer until they can bedistributed to farmers. Hence, breeding pro-grams need to be planned at a longer timescale(Olesen and Bindi 2002; Smit and Skinner2002; Rosenzweig and Tubiello 2007).

� Altering and widening existing crop rotationscan help to adapt to changing climate condi-tions by introducing new, better adapted croptypes. A broader crop mix will decrease thedependency on weather conditions in a certaingrowing season and hence stabilize produc-tion and farm income under higher climatevariability. However, it will also require tech-nical and management adjustments and mayreduce some gains from specialization in theproduction of certain crops (Olesen and Bindi2002; Easterling et al. 2007; Rosenzweig andTubiello 2007).

� Rising water demand caused by higher tem-peratures can be balanced by improved wa-ter management and irrigation. A shift from

rainfed to irrigated agriculture may be an op-tion, although water availability, costs, andcompetition with other economic sectors needto be considered. Adjustments like timing ofirrigation and improvement of water-use ef-ficiency can ensure water supply for cropseven under warmer and dryer climate. More-over, crop residue retention and altered tillagepractices can reduce water demand. Varioustypes of low-cost “rainwater harvesting” prac-tices have been developed in poor countries(Easterling 1996; Smithers and Blay-Palmer2001; Smit and Skinner 2002).

These adjustments, alone or in combination,can minimize climate impacts on agriculture. Onaverage, adaptation can provide around 10–15%yield benefit compared to a situation withoutadaptation measures. Thus, adaptation may shiftnegative yield changes caused by rising temper-atures from 1.5◦C to 3◦C warming in low lati-tude regions and from 4.5◦C to 5◦C in mid- tohigh-latitude regions. If temperatures rise abovethese thresholds, the adaptive capacity is likelyto be exhausted and severe losses are to be ex-pected (Easterling et al. 2007). However, inter-actions between different adaptation options andeconomic, institutional, and cultural barriers toadaptation are not considered in most availablestudies (Easterling et al. 2007).

Insurance schemes

In addition to changes in production technol-ogy, insurance schemes (e.g., crop insuranceor income stabilization programs) can providecompensation for crop and property damagescaused by climate-related hazards, like droughtsor floods. However, these options are not avail-able for farmers everywhere, not even in all de-veloped countries (Bielza et al. 2007). Thereare specific challenges for insurance schemes inthe agricultural sector. Extreme weather eventscan affect a large group of people at the sametime, and the insurance pool may not be able tocover all the claims. If reinsurance mechanisms




or government support schemes are not available,insurance companies would have to charge highpremiums, which may be unaffordable for mostfarmers. Thus, agricultural insurance schemesare usually supported by the public sector to pro-vide broad coverage at affordable premiums (Eu-ropean Commission 2001; Bielza et al. 2007). Insome developed countries, financial support forcrop insurance and disaster payments are a ma-jor part of their agricultural sector policies. TheUnited States, Canada, and Spain have the mostdeveloped agricultural insurance policies. Up to60% of farmers in these countries purchase atleast one insurance policy (Garrido and Zilber-man 2007). Insurance in developing countries isonly available to a limited extent. In India, theNational Agriculture Insurance Scheme was im-plemented to protect farmers against losses dueto crop failure caused by drought, flood, hail-storm, cyclone, fire, pests, and diseases. All foodcrops, oilseeds, and annual commercial and hor-ticultural crops are covered. However, only 4%of farmers are currently protected by the cropinsurance scheme. Almost half of the farmers inIndia still do not even know about the insuranceoption (Bhise et al. 2007).

International trade

On average, global food production is likely tobe sufficient to meet global consumption overthe coming decades. However, climate changewill reduce crop yield in some regions, whileit will have beneficial effects in others. A well-functioning system of international trade flows,which is responsive to price signals, will beneeded to balance production and consumptionbetween and within nations. Increased agricul-tural output in a region where agricultural pro-duction improves can then be used to compen-sate potential losses in other regions (Julia andDuchin 2007). It has been shown in the past thatopen markets are promoting economic devel-opment. In the agricultural sector, protectionistpolicies in the industrialized countries are stillpreventing the developing countries from partic-ipating to a larger share in international markets.

In the future, international trade between richand poor countries, but also among poor coun-tries, can to a certain degree serve as an insurancemechanism against severe production shortfallsdue to extreme weather events. Even in a chang-ing climate, it is unlikely that extremely bad har-vests will occur at the same time in several majorsupply regions.

Government policies to supportadaptation in agriculture

The adaptive capacity at the farm level is unlikelyto be sufficient in many poor regions. Noncli-matic forces such as economic conditions andpolicies have significant influences on agricul-tural decision-making. Therefore, changes in na-tional and international policies for the agricul-tural sector are needed to support adaptation atthe local level (Smit and Skinner 2002; Rosen-zweig and Tubiello 2007). The weight given toclimate change in the policy process will dependon national and local circumstances, includinglocal risks, needs, and capacities. Further reformof agricultural policies in developed countriesshould not only make agricultural productionmore climate-friendly, but also provide betteroptions for poor countries to improve their adap-tive capacity. More financial resources have to beshifted away from direct farm income support to-ward better agricultural education, research, andtechnological development to assure yield im-provement and yield stabilization under chang-ing climate and market conditions. Improvedinfrastructure is needed for the extension of irri-gation or for appropriate storage, transportationfacilities, and better weather forecasting and cli-mate impact research. Low density of weatherstations and limited historical weather data, es-pecially in Africa and other developing regions,is one reason for high uncertainties in current cli-mate model scenario outputs. This in turn makesit more difficult for these countries to developappropriate adaptation strategies (Belliveau et al.2006; Easterling et al. 2007).

Improved policies can also guide transitionswhere major land use changes, changes of




industry locations, or migration occur. Financialand material support can create alternative liveli-hood options. Planning and management of suchtransitions may also result in less habitat loss andlower environmental damage. The establishmentof functioning and accessible markets for inputssuch as seeds, fertilizers, and labor, as well asfinancial services can improve income securityfor farmers (Easterling et al. 2007).

Conclusions

Climate impacts on agriculture strongly dependon regional and local circumstances. Adaptivecapacity and adaptation options are largely de-termined by the level of economic developmentand institutional setting, which also differ widelyacross the globe. While positive and negativeeffects of climate change on global agriculturemay on average almost compensate each other,the uneven spatial distribution is likely to af-fect food security in a harmful way in manyregions. Food security could be severely threat-ened, if tipping points in the climate system aretransgressed. One prominent example of a cli-mate tipping point is the dynamics of the In-dian monsoon, which could be disrupted undercertain conditions (Zickfeld et al. 2005). Thiswould negatively affect agricultural productionconditions in large parts of South Asia. Gener-ally speaking, developing countries in the tropicswill face the strongest direct climate impacts,while having the lowest level of adaptive ca-pacity. The most affected regions are expectedto be sub-Saharan Africa and the Indian sub-continent. If global mean temperature will riseby more than 2–3◦C compared to preindustriallevels, countries in mid and high latitudes willalso be strongly affected. Uncertainties still pre-vail with regard to future precipitation patternsand water availability at the regional level, theimpacts of extreme events on agriculture, andchanges in soil fertility and agricultural pests andpathogens. Further research is also required onthe interactions between various climate-relatedstress factors. The role of CO2 fertilization in

connection with nutrient and water limitationsneeds further clarification. Negative climate im-pacts on agriculture may be reduced througha range of adaptation measures. Adjustmentsin production technology and soil management,crop insurance schemes, diversified internationaltrade flows, and better designed agricultural poli-cies can improve regional food availability andsecurity of farm income. However, limited re-sources such as fertile soils, freshwater, financialmeans, and institutional support may often pre-vent the required adjustments.

References

Belliveau S, Bradshaw B, Smit B, Reid S, Sawyer B(2006) Farm-level Adaptation to Multiple Risks: ClimateChange and Other Concerns. Guelph, Department ofGeography, University of Guelph.

Battisti DS, Naylor RL (2009) Historical warnings of fu-ture food insecurity with unprecedented seasonal heat.Science 323: 240–244.

Bhise VB, Ambhore SS, Jagdale SH (2007) Performance ofagricultural insurance schemes in India. Conference Pro-ceeding: 101st EAAE Seminar: Management of ClimateRisks in Agriculture, Berlin, July 05–06, 2007.

Bielza M, Stroblmair J, Gallego J (2007) Agricultural riskmanagement in Europe. Conference Proceeding: 101stEAAE Seminar: Management of Climate Risks in Agri-culture, Berlin, July 05–06, 2007.

Burton I, Lim B (2005) Achieving adequate adaptation inagriculture. Climatic Change 70: 191–200.

Doll P (2002) Impact of climate change and variability onirrigation requirements: A global perspective. ClimaticChange 54: 269–293.

Easterling WE (1996) Adapting North American agricultureto climate change in review. Agricultural and Forest Me-teorology 80: 1–53.

Easterling WE, Aggarwal PK, Batima P, Brander KM, ErdaL, Howden SM, Kirilenko A, Morton J, Soussana J-F,Schmidhuber J, Tubiello FN (2007) Food, fibre and for-est products. In: ML Parry, OF Canziani, JP Palutikof, PJvan der Linden, and CE Hanson (eds) Climate Change2007: Impacts, Adaptation and Vulnerability. Contribu-tion of Working Group II to the Fourth Assessment Reportof the Intergovernmental Panel on Climate Change, pp.273–313. Cambridge University Press, Cambridge, UK.

European Commission (2001) Risk management tools for EUagriculture with a special focus on insurance. Workingpaper, Brussels.

FAO (2006) The state of food insecurity in the world. FAO,Rome, Italy.

Fischer G, Shah M, van Velthuizen H (2002) Climate changeand agricultural vulnerability. International Institute




for Applied Systems Analysis under United NationsInstitutional Contract Agreement No.1113 on ClimateChange and Agricultural Vulnerability as a Contribu-tion to the World Summit on Sustainable Development,Johannesburg.

Fischer G, Shah M, Tubiello FN, van Velhuizen H (2005)Socio-economic and climate change impacts on agricul-ture: An integrated assessment, 1990–2080. Philosophi-cal Transactions of the Royal Society B: Biological Sci-ences 360: 2067–2083.

Garrido A, Zilberman D (2007) Revisiting the demand ofagricultural insurance: The case of Spain. ConferenceProceeding: 101st EAAE Seminar: Management of Cli-mate Risks in Agriculture, Berlin, July 05–06, 2007.

Gitay H, Brown S, Easterling W, Jallow B (2001) Ecosys-tems and their goods and services. In: JJ McCarthy, OFCanziani, NA Leary, DJ Dokken, and KS White (eds)Climate Change 2001: Impacts, Adaptation, and Vulner-ability, Contribution of Working Group II to the ThirdAssessment Report of IPCC, pp. 235–342. CambridgeUniversity Press, Cambridge, UK.

Gregory PJ, Ingram JSI Brklacich M (2005) Climate changeand food security. Philosophical Transactions of theRoyal Society B: Biological Sciences 360: 2139–2148.

IPCC (2007) Summary for policymakers. In: S Solomon, DQin, M Manning, Z Chen, M Marquis, KB Averyt, MTignor, and HL Miller (eds) Climate Change 2007: ThePhysical Science Basis. Contribution of Working Group Ito the Fourth Assessment Report of the IntergovernmentalPanel on Climate Change. Cambridge University Press,Cambridge.

Julia R, Duchin F (2007) World trade as the adjustment mech-anism of agriculture to climate change. Climatic Change82: 393–409.

Kandlikar M, Risbey J (2000) Agricultural impacts of climatechange: If adaptation is the answer, what is the question?Climatic Change 45: 529–539.

Long SP, Ainsworth EA, Leakey ADB, Nosberger J, Ort DR(2006) Food for thought: Lower-than-expected crop yieldstimulation with rising CO2 concentrations. Science 312:1918–1921.

Nakicenovic N, Alcamo J, Davis G, de Vries B, FenhannJ, Gaffin S, Gregory K, Grobler A, Jung TY, Kram T,La Rovere EL, Michaelis L, Mori S, Morita T, PepperW, Pitcher H, Price L, Riahi K, Roehrl A, Rogner HH,Sankovski A, Schlesinger M, Shukla P, Smith S, SwartR, van Rooijen S, Victor N, Dani Z (2000) IPCC SpecialReport on Emission Scenarios: A Special Report of Work-ing Group III of the Intergovernmental Panel on ClimateChange, p. 599. Cambridge University Press, Cambridge,UK.

Nearing MA, Pruski FF, O’Neal MR (2004) Expected cli-mate change impacts on soil erosion rates: A review.Journal of Soil and Water Conservation 59(1): 43–50.

Niklaus PA (2007) Climate change effects on biogeochemi-cal cycles, nutrients, and water supply. In: P Newton, RA

Carran, GR Edwards, and PA Niklaus (eds) Agroecosys-tems in a changing climate, pp. 11–52. Taylor & Francis,Boca Raton, FL.

Olesen JE, Bindi M (2002) Consequences of climate changefor European agricultural productivity, land use and pol-icy. European Journal of Agronomy 16: 239–262.

Parry ML, Rosenzweig C, Iglesias A, Livermore M,Fischer G (2004) Effects of climate change on globalfood production under SRES emissions and socio-economic scenarios. Global Environmental Change 14:53–67.

Rosenzweig C, Hillel D (1995) Potential impacts of climatechange on agriculture and world food supply. Conse-quences 1(2): 23–32.

Rosenzweig C, Tubiello FN (2007) Adaptation and mitiga-tion strategies in agriculture: An analysis of potential syn-ergies. Mitigation and Adaptation Strategies for GlobalChange 12: 855–873.

Smit B, Skinner MW (2002) Adaptation options in agri-culture to climate change: A typology. Mitigation andAdaptation Strategies for Global Change 7: 85–114.

Smithers J, Blay-Palmer A (2001) Technology innovation asa strategy for climate adaptation in agriculture. AppliedGeography 21: 175–197.

Solomon S, Qin D, Manning M, Alley RB, Berntsen T, Bind-off NL, Chen Z, Chidthaisong A, Gregory JM, HegerlGC, Heimann M, Hewitson B, Hoskins BJ, Joos F,Jouzel J, Kattsov V, Lohmann U, Matsuno T, MolinaM, Nicholls N, Overpeck J, Raga G, Ramaswamy V,Ren J, Rusticucci M, Somerville R, Stocker TF, WhettonP, Wood RA, Wratt D (2007) Technical summary. In: SSolomon, D Qin, M Manning, Z Chen, M Marquis, KBAveryt, M Tignor, and HL Miller (eds) Climate Change2007: The Physical Science Basis. Contribution of Work-ing Group I to the Fourth Assessment Report of the In-tergovernmental Panel on Climate Change, pp. 19–92.Cambridge University Press, Cambridge.

Tubiello FN, Amthor JS, Boote KJ, Donatelli M,Easterling W, Fischer G, Gifford RM, Howden M,Reilly J, Rosenweig C (2007) Crop response to elevatedCO2 and world food supply: A comment on “Food forThought. . .” by Long et al. 2006, Science 312: 1918–1921. European Journal of Agronomy 26: 215–223.

Tubiello FN, Fischer G (2007) Reducing climate changeimpacts on agriculture: Global and regional effects ofmitigation, 2000–2080. Technological Forecasting andSocial Change 74: 1030–1056.

Zickfeld K, Knopf B, Petoukhov V, and SchellnhuberHJ (2005) Is the Indian summer monsoon stableagainst global change? Geophysical Research Letters 32:L15707.

Ziska LH, Runion GB (2007) Future weed, pest, and dis-ease problems for plants. In: P Newton, RA Carran, GREdwards, and PA Niklaus (eds) Agroecosystems in aChanging Climate, pp. 261–287. Taylor & Francis, BocaRaton, FL.

crop adaptation to climate change (yadav/crop adaptation to climate change) || climate change,...

Documents