session 5: water and food production foodcrops underglobal

Climate Change and Water Extremes An International Meeting of The Water Tribune of EXPOZARAGOZA 2008

Session 5: Water and Food Production

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M. Bindi 1 & M. Howden 2

1 Dept. of Agronomy and Land Management, University of Florence, Italy

2 CSIRO Climate Adaptation Flagship, Canberra, Australia

Zaragoza, July 21st23rd, 2008

ARGUMENTS

•• Food crops systemsFood crops systems

•• Climate change projections relevantClimate change projections relevant for food cropsfor food crops

•• Food crops responsesFood crops responses

•• Adaptation and mitigation strategiesAdaptation and mitigation strategies

•• Research challenges for the nextResearch challenges for the next yearsyears

ARGUMENTS

ARGUMENTS

••Food crops systemsFood crops systems •• Climate projections relevant for foodClimate projections relevant for food cropscrops



•• Research challenges for the next yearsResearch challenges for the next years

ARGUMENTS

Food crops systems

-

’ -

Food crops systems

RainRain--fed and Irrigated crops:fed and Irrigated crops:

– Rain-fed crops: • Covers 80% of global agricultural

land • Rain fed crops yields are rather

lower than irrigated crops • Crop productivity depends solely

on sufficient precipitation

– Irrigated crops: • Covers a mere 18% of global

agricultural land • Produces about half the world

total grain supply

• Crop productivity depends on water also in the form of available water resources for irrigation

(IWMI s GMRCA and GIAM, 2007)

Food crops systems

Food crops systems

Unprecedented Conditions to face:Unprecedented Conditions to face:

6.7 Billions

World population Food calorie intake

Higher calorie

intake

Increase in

food demand

High Temp. and CO2

Climate change

Reduction in food availably

ARGUMENTS

•• Food crops systemFood crops system

••Climate changeClimate change projections relevant forprojections relevant for food cropsfood crops




ARGUMENTS

Climate change projections relevant for food crops

-


– CO2 concentration in the

atmosphere for alternative

SRES development paths

is expected to increase by

2100:

• from 550 ppm B1

• to 950 ppm A1F 300

400

500

600

700

800

900

1000

1980 2000 2020 2040 2060 2080 2100 C

O2

pp

m

A1B

A1F

A2

B1

B2

SRES IPCC, 2000

Atmospheric CO2 concentration:


-


Temperature:

– Mean changes: �� from 1.8°C (B1)

to 4.0°C (A1FI) – Changes in extremes:

�� heat waves

�� Frosts

Precipitation:

– Mean changes: �� 5% over lands

(�� in most subtropical land regions,

20%; �� high altitude and tropical

Pacific)

– Changes in extremes:

�� heavy precipitation events

�� dry spells WGI, FAR IPCC, 2007

Climate projections relevant for food crops

-

Climate projections relevant for food crops

• Evaporation: �� on overall

�� in North Africa and Central and Southeast America

�� in Southeast Asia and at high latitudes

• Soil moisture: � in the subtropics and the

Mediterranean type regions

� in east Africa, central Asia

� high latitudes (lower snow cover)

WGI, FAR IPCC, 2007

ARGUMENTS


•• Climate change projections relevant forClimate change projections relevant for food cropsfood crops

••Food crops responsesFood crops responses •• Adaptation and mitigation strategiesAdaptation and mitigation strategies


ARGUMENTS

Food crops responses: CO2

Food crops responses: CO2

– Increasing the RUE:

• Higher in C3 food crops such as cereals, legumes, oil and root

crops

• Lower in C4 food crops such as maize, sorghum, millet, and

sugarcane

– Increasing WAU with a reduction water losses

Yield: – crop yields increase at 550 ppm

CO2 in the range of:

• 10-20% for C3 crops

• 0-10% for C4 crops

Assimilation and Transpiration:

Food crops responses: temperature

Food crops responses: temperature

Suitable area for cultivation:

– crop producing areas may expand polewards:

• Longer length of the potential growing season

• Suitable temperature and precipitation regimes

Growing season: – shorter life cycle of

determinate crops such as cereal crops, peas, beans, and oil seed crops

– longer life cycle of indeterminate crops like grass, sugar beet, carrots

HadCM3, 2080s from Fischer et al., 2002

Food crops responses: (temp+prec+CO2)

-


YieldYield:: – Temperate regions:

increases up to (1-3.5ºC),

along with associated CO2

increases and rainfall changes may produce small beneficial

impacts on crop

– Tropical regions: temperature increases higher

than 0.5-1.5°C are likely to

have negative yield impacts

– Further warming has increasingly negative impacts

in all regions

WGII, FAR IPCC, 2007



ProductionProduction (yield x cult. Area)(yield x cult. Area) of rainof rain--fed cereals:fed cereals:

• Global production is expected to decrease by 24%

• Regional production changes may show different signs:

– Increase in mid to high latitude countries (e.g.

Canada, Russia,

Scandinavia countries)

– Reduction in mid to low latitude countries (e.g.

Africa, Mediterranean

countries)

HadCM3, 2080s from Fischer et al., 2002

-


• Global irrigation requirements are expected to increase by +20%

• Regional increase in irrigation requirements may be rather different:

– Higher and evenly distributed in developed

regions (+35-45%)

– Lower and not uniform in

developing regions (+17%)

• largest increases were computed in East Asia (+35 47%)

MDC, developed countries; LDC, developing countries; NAM, North America; WEU, Other developed countries (mainly Europe, including Turkey); PAO, Developed Pacific Asia; EEU+FSU, Eastern Europe and former USSR; AFR, Sub-Saharan Africa; LAM, Latin America; MEA, Middle East and North Africa; CPA, East Asia; SAS, South Asia; PAS, Developing countries in Southeast Asia.


Water requirement for irrigated crops:Water requirement for irrigated crops:

Fischer et al., 2007

ARGUMENTS


•• Climate observation and projectionsClimate observation and projections


••Adaptation andAdaptation and mitigation strategiesmitigation strategies


ARGUMENTS

Adaptation and Mitigation strategies

Adaptation and Mitigation strategies

•• Adaptation:Adaptation: Adjustments which reduce damages or

exploit beneficial opportunities related to climatic effects:

–from autonomous: varieties/species with increased resistance

to heat shock and drought; modification of irrigation techniques (amount, timing or technology); modification of crop calendars

(timing or location of cropping activities)

– to planned: developing new infrastructure, policies, and

institutions that support, facilitate, coordinate and maximise the use

of water

•• Mitigation:Mitigation: Strategies to reduce greenhouse gas

sources and emissions and enhancing greenhouse gas

sinks (e.g. renewables for water extraction and delivery, reduced

tillage, energy crops)

Adaptation and mitigation strategies

-


Role on crop yieldsRole on crop yields

(adaptation):(adaptation):

–Adaptations strategies (e.g. changes in planting, changes in cultivar, and shifts from rain-fed to irrigated conditions) may allow to shift the temperature increase thresholds determining yield reductions from:

• 0.5-1.5°C to 2.5-3°C in

tropical regions

• 1-3.5°C to 4.5 to 5°C in

temperate regions

__ no adaptation __ with adaptationWGII, FAR IPCC, 2007


Role on vulnerability (Role on vulnerability (adapt.+mitigationadapt.+mitigation):):


• Adaptation: adaptation alone still cannot reduce extreme vulnerability (map b)

• Mitigation: reduces vulnerability across much of the world but extreme vulnerability persists in developing countries (map c)

• Adaptation + Mitigation: Climate risks are substantially reduced but developing countries are still most vulnerable (map d)

A2, 2100 from Yohe et al., 2006

ARGUMENTS


•• Climate projections relevant for foodClimate projections relevant for food cropscrops



••Research challenges forResearch challenges for the next yearsthe next years

ARGUMENTS

Research challenges

Research challenges

•• Response ofResponse of important crops for rural poor peopleimportant crops for rural poor people toto climate changeclimate change (e.g. root crops, millet)(e.g. root crops, millet)

•• Interactions among crops, weeds, pests and diseaseInteractions among crops, weeds, pests and disease under a changing climateunder a changing climate

•• ModellingModelling the impact ofthe impact of extreme climate eventsextreme climate events on foodon food crops yieldscrops yields (e.g. heat waves at flowering time)(e.g. heat waves at flowering time)

•• Uncertainties of theUncertainties of the climate change impact, adaptationclimate change impact, adaptation and mitigation assessmentsand mitigation assessments (e.g. probability assessment)(e.g. probability assessment)

•• Role ofRole of traditional and biotechnology techniquestraditional and biotechnology techniques forfor coping with drought, heat and other climate related problemscoping with drought, heat and other climate related problems

•• Climate change andClimate change and irrigation requirementsirrigation requirements

•• PotentialPotential synergies betweensynergies between adaptation and mitigationadaptation and mitigation strategiesstrategies

Messages

Messages

•• Water availability for food cropWater availability for food crop is projected to declineis pro jected to decline significantly in many regionssignificantly in many regions (e.g.(e.g. ‘‘Mediterranean type climate regionsMediterranean type climate regions’’))

•• Suitable area for cultivation and growing seasonSuitable area for cultivation and growing season of food crops will be affected:of food crops will be affected: –– crop producing areas may expandcrop producing areas may expand polewardspolewards –– shorter life cycle of crops such as cereal crops and oil seed crshorter life cycle of crops such as cereal crops and oil seed cropsops

•• Temperature increases higher than 3Temperature increases higher than 3ººCC withwith associated COassociated CO22 increases and rainfall changesincreases and rainfall changes may determine decreasesmay determine decreases yields in all regionsyields in all regions

•• Global productionGlobal production is expected to decreaseis expected to decrease, but regional, but regional production changes may rather differentproduction changes may rather different (e.g. increases in high latitude(e.g. inc reases in high latitude countries, reduction in mid to low latitude countries)countries, reduction in mid to low latitude countries)

•• Global irrigation requirementsGlobal irrigation requirements are expected toare expected to significantly increasesignificantly increase (higher increases in developed regions, +35(higher inc reases in developed regions, +3545%)45%)

•• Mitigation and adaptation strategiesMitigation and adaptation strategies need to beneed to be optimized to support synergies and avoid conflictsoptimized to support synergies and avoid conflicts

session 5: water and food production foodcrops underglobal

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