Climate Impacts On Food Security And Nutrition

2. Climate changeDefinitions: Climate change and climate variabilityAn important distinction should be made between climate change and climate variability. The former refers tothe long-term trend in weather, generally over decades or centuries. This includes long-term changes or trendsin the average climate (such as annual average temperature or precipitation) or trends in climate extremes(such as the frequency of intense rainfall events). However, people experience climate as individual weatherevents, which naturally fluctuate on an annual, seasonal and decadal basis. In addition to natural variation,climate change will mean a shift in the patterns of weather events, over the long term. The magnitude of theseclimatic changes over the following decades and towards the end of the century will depend on how successfulpolicies are at reducing greenhouse gas emissions and how sensitive the climate system is. (cf. IPCC, 2007).2.1 Long-term climate change2.1.1 Temperature riseGlobal average temperature is expectedto rise as a result of climate change,and the spatial pattern of this rise issuch that all areas will see an increasein temperature. By the 2050s the globalaverage temperature is projected tohave risen between 2–4 C above thepre-industrial climate; however, thisaverage value masks differences inlocal temperature rises. In general, theland will see greater increases thanthe oceans. The largest increases inmean temperature are projected for thehigh latitude regions of the northernhemisphere, with lesser increases intropical and sub-tropical areas. Mostof Canada and Russia are projectedto experience significant warming.The Amazon region and parts ofChina could also see temperatureincreases above those experiencedelsewhere. South Asia and SoutheastAsia are the regions where the lowestincreases in mean temperature areprojected. (Christensen et al., 2007).2.1.2 Changes in precipitation patternsThere is less confidence in the climatemodel projections of changes inprecipitation patterns than changesin temperature. Observed large‑scalepatterns of precipitation are representedwell in many global climate models,leading to high confidence inprojections of general circulation andlarge-scale precipitation patterns.However, there is less certainty inregional projections. Rainfall records inmany parts of the world (e.g. Africaand the Middle East) are sparse,particularly with respect to intenseevents, and satellite measurementsof rainfall over the oceans are stillbeing developed. The lack of thesetypes of data hinders climate modelverification and development. Anadditional problem is that most climatemodels do not resolve monsoonevents and hence their associatedrainfall well (Randall et al., 2007).In general, increases in temperaturewill result in a more active hydrologicalcycle, meaning more rainfall overall.But changes in the patterns andseasonality of rainfall regionally,mean that some areas will stillsee less rainfall, and changes inthe timing and intensity of rainfallevents could also have a significantimpact locally. (Meehl et al., 2007)2.1.3 Changes in other variables andweather patternsChanges in the climate will be felt notonly through increasing temperaturesand changing rainfall patterns, but alsothrough rising sea-levels, changes instorms and storm tracks, glacier meltand changes in large-scale circulations.These changes to the global Earthsystem will be experienced locallyas changes in water availability,drought, storm surge damage andland loss. Although many aspects ofthese changes will be negative, for8 Climate impacts on food security and nutritionsome areas there will also be positivechanges, particularly at lower levelsof climate change. (Parry et al, 2007)2.1.4 Seasonal climate patternsThe seasonal cycles of hunger andundernutrition are generally stronglycorrelated with climatic‑relatedfactors — especially in rural areas.In Sahel and the Horn of Africaclimate‑related factors stronglyinfluence crop and animal production,income, diseases and undernutrition.In Bangladesh, floods and cyclonestend to follow seasonal patterns —with important food and nutritionsecurity implications. Seasonal peaksof hunger and undernutrition are alsoshaped by human or socioeconomicfactors, such as high food pricesor low income opportunities. Forthe past few years seasonality haschanged. Rural communities acrossthe world report that both the timingand the pattern of seasonal rains arechanging dramatically. For example,rainfall is reported to be more erratic,shorter and heavier; even withinrecognisable seasons, ‘unseasonal’events such as heavier rains, drierspells, unusual storms, dense fogs andtemperature fluctuations are increasing.(Devereux and Sabates-Wheeler, 2012).

2.2 Impacts of sea-level rise and remote climate2.2.1 Sea-level riseSummary Climate change will contribute to sea-level rise. Sea-level rise, particularly in low lying coastal zones and river deltas, can have a significant effect on livelihoods andfood security by destroying crops and critical livelihood assets.Although little research has been carriedout on the impacts of sea-level rise onfood security, it is important to assessthe potential effects, particularly in thecontext of low elevation coastal zones.Sea-level rise from thermal expansionof the oceans and melting ice mightaffect food security in two ways: onone hand, it can result in inundationof coastal agricultural lands, especiallywhere the capacity for the introductionor modification of sea defences isrelatively low or non-existent; on theother hand, it can result in increasedgroundwater salinisation which affectsthe quantity and quality of wateravailable for human use (Adams, 1989).In the context of food security, thehighest vulnerabilities are greatestwhere sea-level rise occurs inconjunction with rural coastal zones.Several river deltas are favourable toagricultural production due to thefertility of fluvial soils. In combinationwith tectonic rise and fall, global meansea-level rise is expected to be 2 m by2100 (IPCC, 2007); this is especiallyproblematic in densely populated,low elevation coastal zones. Globally,650 million people currently live incoastal settlements and are exposedto sea-level rise (McGranahan et al.,2007). In Asia and North Africa — wherethe most vulnerable people live in theriver deltas of Myanmar, Bangladesh,India, Pakistan and Egypt — farmingareas in the coastal regions are exposedto sea-level rise (Webster, 2008).Climate impacts on food security and nutrition 9

2.2.2 Remote climate risksSummary Remote changes in climatic conditions can affect food security elsewhere. Changes in river-flow could be detrimental to agricultural production: seasonal increases in river- flow could lead toflooding, while low river-flow during the dry season could result in water scarcity. Accelerated glacial melt under global warming could also contribute to changes in the amount of water available foragriculture and domestic use: initially glacial melt could lead to an increase in the amount of water but in the long runwater flow would become more variable.Remote climate impacts may alsobe critical: for example, agriculturealong the Nile in Egypt dependson rainfall in the upper parts ofthe Nile such as the EthiopianHighlands. In some rivers, includingthe Nile, climate change couldpotentially increase flow throughoutthe year benefiting agriculturalproduction (Gornall et al., 2010).In other catchments, such as theGanges, an increase in runoff resultsfrom an increase in peak flow duringthe monsoon period, but dry seasonriver-flow is still very low. Withoutsufficient storage of peak season flow,water scarcity may affect food securitydespite overall annual increases in wateravailability. Moreover, seasonal increasesin peak flow may also damage croplandthrough flooding (Gornall et al., 2010).The Niger River Basin, which provideswater for several marginal livelihoods inthe Sahel, is another critical basin thatcould experience a decrease in flow.During the 20th century, the river’smean annual discharge declined by40–60% together with a declinein rainfall of around 30%. In thefuture, the Basin could be affectedby changes in rainfall and runoffof about 10% although the limiteddata do not allow for more certainpredictions (Millar, 2007).An additional remote source of wateris glacier- and snow-melt, whichinfluences river-flow, especially inmid- to high-latitudes where warmingpredictions are very high. Warmingin winter is accompanied by lowerprecipitation falling as snow andan earlier melt season. Changingpatterns of snow alter how water isstored and released. Temperaturechanges also affect the timing ofrunoff, causing earlier peak flow inspring. Additional river-flow might beconsidered beneficial to agriculture,but only if there is an ability to storerunoff during surplus times. Globally,few rivers currently have appropriatestorage capacity to cope with largeshifts in seasonality. Where there areno storage capacities, the excess waterwill be lost to oceans (Barnett et al.,2005, Juen et al., 2007). Approximatelyone-sixth of the world’s populationcurrently lives in glacier-fed river basinswhere populations are projected toincrease, particularly in areas suchas the Indo-Gangetic Plain; thesepopulation pressures will result inlower water availability and greaterstress on food security (Stern, 2007).10 Climate impacts on food security and nutritionObservations indicate that the majorityof glaciers around the world areundergoing shrinkage (Zemp et al.,2008). Melting glaciers will initiallyincrease river-flow seasonally, increasingthe risk of glacier lake outburst floods(Juen et al., 2007), and this is especiallyproblematic in densely populatedriver deltas that are fed by glaciers.Water stored in Himalayan glaciersaccount for approximately 12,000 km3of fresh water feeding rivers such asthe Indus, Ganges and Brahmaputra(Cruz et al., 2007). Currently over 500million people rely on these rivers fordomestic and agricultural purposes.Climate change may create seasonalflow scarcities during the dry season(Kehrwald et al., 2008). Combinedwith expected population growth,coastal inundation from sea-level riseand increased population density, thismay lead to further water scarcity andexacerbate food insecurity in the region.

2.3 Impacts of extreme weather eventsSummary Climate change is projected toresult in more intense, frequentand longer extreme eventssuch as droughts and floods,with negative consequenceson food security in the mostvulnerable communities. Extreme weather events canalso complicate food logisticsand distribution.This section summarises the stateof knowledge on the impact ofextreme climate-related eventsand disasters on food security.Climate change will have an effect onthe frequency, intensity and durationof extreme weather events whichcould negatively affect food securityin some of the most vulnerable areas.The gendered impact of extreme weatherand climate-related eventsMen and women are affected differently by extreme climate-related disasters.In inequitable societies, women are more vulnerable than men (and up to14 times likelier to die as a result of a disaster) due to socially constructedgender roles that affect access to resources. In Sub-Saharan Africa, for instance,women are often acknowledged as owners of crops, but not of land. Therole of women in ensuring household food security and their dependenceon natural resources to do this, reinforces their vulnerability to disasters(Neumayer and Pluemper, 2007).In post-disaster situations women are often more vulnerable than men, as theircare-giving roles expand after a disaster and experience shows that their accessto resources for recovery is often constrained (ISDR et al., 2009).Women also lack access to adequate and timely climate information.For example, in Peru, early warning messages about the arrival of El Niño wereonly transmitted to the fishermen, who were warned that fish quantities weregoing to be severely affected with serious economic implications. Womenwere not alerted since they were not directly involved in fishing — but, infact, they managed the household budgets. Had women known about theonset of El Niño, they would have saved more household funds and budgeteddifferently to prepare for the event, reducing the eventual economic impact(Anderson, 2002).The impacts of temperature andprecipitation on crop production andfood access must also be analysed inrelation to the frequency, intensityand duration of extreme weatherevents which can affect food stability.Recurrent extreme weather events, suchas droughts, heatwaves and floods,deteriorate livelihoods and underminethe capacity of communities to adaptto moderate shocks as well as theirability to purchase food, increasing theneed for food assistance. In addition,more frequent and intense extremeweather events can complicate thelogistics of food storage and distributionduring emergencies (Keating, 2010).africa924/Shutterstock.comDue to their heavy reliance on climatesensitive activities such as rain-fedagriculture, food security and livelihoodtrends, Sub-Saharan Africa and Asia areparticularly vulnerable to the impact ofincreasing extreme events (Easterlingand Apps, 2005), particularly droughts(Giannini et al. 2008) and floods(Rodriguez-Llanes et al. 2011).Climate impacts on food security and nutrition 11

2.3.1 DroughtsSummaryDroughts have adverse impacts on food security,affecting the quantity and quality of yields.Droughts also lead to significant economic losses,especially in Africa.Meteorological droughts (resultingfrom insufficient rainfall) are expectedto increase in duration, frequency andintensity (Burke et al., 2006). Droughtsresult in agricultural losses and are amajor driver of food insecurity. Simlarly,drought has been the primary causeof interannual yield variations in someregions of the world (Hlavinka et al.,2006). Globally, the areas sown forthe major crops (barley, maize, rice,sorghum, soya bean and wheat) haveseen an increase in the percentageof area affected by drought since the1960s, from approximately 5–10%to approximately 12–25% (Li et al.,2009). This is especially problematicin the context of population growth.For example, in Africa alone, 650million people are dependent onrainfed agriculture in environmentsObserved trend: Some regions have experienced moreintense and more prolonged droughts (West Africa, East Asia),but opposite trends have been observed in other regions.Projection: An increase in the duration and intensity ofdrought in some regions of the world (especially in theMediterranean and Southern Africa).that are affected by water scarcity,land degradation, recurrent droughtsand floods, and this trend is expectedto exacerbate under climate changeand population growth (FAO, 2008).Financial losses from droughts arealso significant. In 2009, hydrologicaldisasters alone accounted forapproximately 90% of economicdamage from natural disasters inAfrica (Vos et al., 2010) while in 2010,all disaster-related losses were dueto hydrological events (Guha-Sapiret al., 2011). The areas of majorcrop production (barley, maize, rice,sorghum, soya and wheat) have allexperienced an increase in the areaaffected by hydrological drought whichrenders them sensitive to weathervariability in the future (Li et al., 2009).12 Climate impacts on food security and nutritionMoreover, increasing evidencehighlights the sensitivity of keyproduction areas to climate variability:the 2010 Russian drought resultedin wheat yield reductions of 40% insuch areas (USDA, 2010). Indeed, theadverse impacts of drought may offsetsome benefits of carbon fertilisationand increased temperature and seasonlength in mid- to high-latitudes. Modelsof global climate, crop productionand water resources suggest thatin Russia the frequency of foodproduction shortfalls due to droughtare likely to double in many of the maingrowing areas in the 2020s, and maytriple in the 2070s, with significantimplications for crop productionand stability. (Alcamo et al. 2007)

2.3.2 FloodsSummaryFloods can destroy crops, livelihood assets and agricultural land.Observed trend: No observed trend at the global level.Projection: Possible low agreement among models, but an increase in frequencyof heavy precipitation events could lead to flooding. Other factors such as snowmelt could also increase flooding.Food security may also be affected by excessive rainfall. The impact of climate change onflood events is less certain. Globally, total rain falling during heavy rainfall events is increasing,and models suggest that there will be more heavy rainfall events as the climate warms(Held and Soden, 2006).Evidence has linked climate change to a doubling of risk of extreme wet weather in the NorthernHemisphere (Pall et al., 2011). Further attribution work by Min et al. (2011) suggests that increased rainfallintensity in the latter half of the twentieth century cannot be explained by estimates of natural variabilityalone, suggesting that there might be some influence from anthropogenic global warming.In the context of food security, heavyrainfall leading to flooding can destroyentire crops over wide areas, as well asdevastating food stores, assets (such asfarming equipment) and agriculturalland (due to sedimentation) (Falloonand Betts, 2010). Further studies on theimpacts of current climate variabilityin the United Kingdom, Kettlewell etal. (1999) showed that heavy rainfallin August can be linked to lower grainquality due to fungal infections.Climate impacts on food security and nutrition 13

2.3.3 Tropical cyclonesSummaryTropical cyclones can destroy crops, agricultural land,infrastructure, and key livelihoods assets, therebyexacerbating existing vulnerabilities.Observed trend: Increase in frequency of tropical cyclonesbut considerable debate on whether this is due to climatechange or due to improved observational methods.Tropical cyclones can also impact onfood security and nutrition. Somestudies (e.g. Gray, 1990) suggesttropical cyclones may become moreintense in the future with strongerwinds and heavier precipitation butregional variations in cyclone formationare less understood. Recent studiesusing high resolution models alsoindicate the possibility of a decreasein future global tropical cycloneProjection: Possible decrease in frequency but increase inintensity of tropical cyclones in some regions.Vulnerability: Higher vulnerability due to a combination ofpopulation growth and accumulation of wealth in exposedcoastal areas.frequency, but with increased intensityand duration (Knutson et al., 2010; alsoMacDonald et al., 2005; Bengtssonet al., 2007; Gualdi et al., 2008).Tropical cyclones also have the potentialto devastate a region, causing lossof life and widespread destructionto agricultural crops and lands,infrastructure, and livelihoods (Meehl etal., 2007). Cyclone Nargis, for instance,14 Climate impacts on food security and nutritionresulted in significant societal losses inMyanmar. Communities and regions40 km inland were inundated due tostorm surges (Webster, 2008); soilsalinisation made 50,000 acres of ricecropland unfit for planting (Stover andVinck, 2008); and rice seeds, fertilisers,farm machinery

2.2 Impacts of sea-level rise and remote climate 9 2.3 Impacts of extreme weather events 11 3. Climate impacts on food security 15 3.1 Climate change and food production 15 3.2 Climate change impacts on food access and livelihoods 16 3.3 Climate change impacts on nutrition and utilis