Climate change impacts on water quantity and quality: Implications for agriculture

Uniting agriculture and nature for poverty reduction

Climate change impacts on water quantity and quality: Implications for agriculture

Claudia Ringler, IFPRI

(with Tingju Zhu, Hua Xie & Mark Rosegrant andthe IMPACT Food model team)

Water Policy for Food SecurityUC Davis, October 5-6

1. Higher emissions increase water-related risks (exposure to

water shortages but also floods)

2. Impact of climate-induced water variability on agriculture as

part of climate change has yet to be assessed

3. Impact of climate change on water pollution remains under-

studied

4. Trade has a key role to play in addressing agricultural

impacts from climate change (i.e. food prices)

5. CBA of water-based adaptation options versus agriculture-

focused options versus non-agriculture focused options (i.e.

trade) under variability and change have yet to be studied in

a comprehensive manner

Key messages

The IMPACT modeling suite

Change of Mean Annual Runoff by 2050 – HadGEM2-RCP6.0 Scenario

Notes: 2040-2070 future period relative to the 1951-2000 historical period.

The impact of climate change on water

resources

Source: IFPRI, IMPACT version 3.2, 8 September 2015

For every 1 degree of warming, another 7% of the pop experiences a 20% decline in wateravailability; today already 30-40% exposed to water shortages; also population exposed to100-year flood triples from low to high emissions scenarios

0.58

0.6

0.62

0.64

0.66

0.68

0.7

0.72

0.74

0.76

0.78

2000 2030 2050

base

CSI_a1

CSI_b1

MIR_a1

MIR_b1

0.5

0.6

0.7

0.8

0.9

1

2000 2030 2050

NAE

0.5

0.6

0.7

0.8

0.9

1

2000 2030 2050

ESAP

0.5

0.6

0.7

0.8

0.9

1

2000 2030 2050

SSA

0.5

0.6

0.7

0.8

0.9

1

2000 2030 2050

CWANA

World Average

Projections of Irrigation Water Supply Reliability under Climate Change

Source: IFPRI, IMPACT 2014.

Price effects of socioeconomic andclimate drivers


Cereals Fruits & vegetables Meat

SSP

sR

CPs

Yield effects of climate change, by region (SSP2)


Cereals

Maize

Wheat

WLD = World; EAP = East Asia and Pacific; EUR = Europe; FSU = Former Soviet Union; LAC = Latin America and Caribbean; MEN = Middle East and North Africa; NAM = North America; SAS = South Asia; SSA = Sub-Saharan Africa; Note: SSP2 assumes

population growth below the UN medium variant growth (UN 2015) and income growth in excess of 5%/yr in SSA over 40 years.

Climate change effects on food prices


Maize Wheat Rice

Beef Pork


Rice

Wheat

Maize

Impact of CC on net cereal trade (SSP2,

RCP 8.5)

DVG = Developing Countries; EAP = East Asia and Pacific; SAS = South Asia; FSU = Former Soviet Union;MEN = Middle East and North Africa; SSA = Sub-Saharan Africa; LAC = Latin America and Caribbean; NAM: North America; Note: SSP2 assumes population growth below the

UN medium variant growth (UN 2015) and income growth in excess of 5%/yr in SSA over 40 years.

Population at risk of hunger (SSP2, RCP8.5)


EAP = East Asia and Pacific; SAS = South Asia; FSU = Former Soviet Union; MEN = Middle East and North Africa; SSA = Sub-Saharan Africa; LAC = Latin America and Caribbean; Note: SSP2 assumes population growth below the UN medium variant growth (UN

2015) and income growth in excess of 5%/yr in SSA over 40 years.

How to address water variability?

1. Enhance rainfed water management (watershed level

management, RWH, joint management of inputs on farm,

agricultural R&D – breeding)

2. Increase water storage (above, below ground and in the soil)

3. Address water variability in irrigation systems

4. Improve the enabling environment (water and land rights,

incentives to use water sustainably)

5. Focus on non-water policies and assess their impact on

water (trade policy, ag R&D, energy development, input and

output support policies)


Global Production and Price Effects of Removing Economic Water Scarcity through Infrastructure Investment

Simulated 2010 production and prices under baseline and infrastructure scenario

INFRA: adequate investment in surface water infrastructure

INFRA retains GW withdrawal limits

In SSA, irrigated maize yield increases by 32% on average, and more in bad years, under INFRA

Probability that rice price could exceed US$400 reduced from 21% to 0.7%

Source: Sadoff et al. (2015)

0

100

200

300

400

500

600

Maize Rice Wheat

2005 No-CC 2050 CC 2050 CC INFRA 2050

INFRA – 2050 w/o VAR: Food prices(US$/mt, SSP2, RCP6.0)


0

20

40

60

80

100

120

140

East Asia South Asia SSA LAC MENA

No-CC 2050 CC 2050 CC INFRA 2050

INFRA 2050 w/o Var: Population at risk of hunger (millions, SSP2, RCP6.0)


Yield effects from climate smart agrictechnologies(RCP 8.5)

Source: Koo et al. (2015)


Climate change impacts and trade

Impacts of climate change and trade policy on yields, area, production, exports and prices of five commodities, (% deviation from baseline values in 2050 without climate change)

SSP1, RCP4.5 SSP3, RCP8.5

Source: Wiebe et al. (ERL 2015)

Impact of growing water pollution

Source: IFPRI-Veolia (2015).

Estimated global loadings of BOD, N and P in base period (2000-2005)


(a) BOD (b) Nitrogen (N)

(c) Phosphorus (P)

Loading(million ton/yr)

Population at risk

BOD 209 1 in 8 people or 651 million

N 131 1 in 6 people or 973 million

P 10 1 in 4 people or 1,287 million

CSIRO-

medium

CSIRO-

optimistic

CSIRO-

pessimistic

MIROC-

medium

MIROC-

optimistic

MIROC-

pessimistic

Population in 2050 9.3 billion 8.1 billion 10.6 billion 9.3 billion 8.1 billion 10.6 billion

Annual, average

rate of GDP growth 3.2% 3.6% 1.9% 3.2% 3.6% 1.9%

Crop harv. area +17.5% +14.7% 18.4% +20.0% +17.2% 20.9%

Crop nutrient use

efficiency +20% +40% No change +20% +40% No change

Livestock numbers +26% +28% +14% +25% +27% +16%

Improvement in

municipal

wastewater

treatment levels

+15% +30% No change +15% +30% No change

Socioeconomic development and climate change scenarios ─ AR4 2050


Increases in loading volumes under alternative climate change and socioeconomic scenarios


209

248227

270252

231

275

131

187 177197 202 191

21210

12.411.5

13.1 13.312.4

14.1

0

2

4

6

8

10

12

14

16

0

50

100

150

200

250

300

Base period CSIRO_medium CSIRO_optimistic CSIRO_pessimistic MIROC_medium MIROC_optimistic MIROC_pessimistic

P lo

adin

g (m

illio

n t

on

/yr)

BO

D &

N lo

adin

g (m

illio

n

ton

/yr)

BOD N Pad4 P

USA

Brazil

China

India

2050 CSIRO-medium 2050 MIROC-medium

BOD1 in 5 people or 1,589

million1 in 6 people or 1,372

million

N1 in 3 people or 2,645


million

P1 in 3 people or 2,948


million


How to address water degradation?

For consumers, cities and industrial sectors, solutions include:

1) More aggressive investment in wastewater treatment

2) Adoption of innovative and alternative approaches, such as the use of Green Infrastructure

3) Improved home and industrial design to minimize pollution

4) Enhanced management of stormwater runoff to avoid contamination of treated water supplies

5) Close nutrient cycles: Recovery of effluents and sewage and safe reuse in agriculture

For the agricultural sector:

1) Enhanced nutrient use efficiency

2) Phased out fertilizer subsidies

3) No-till or reduced tillage and other conservation measures

4) Manure management

Cross-sectoral measures:

1) Water quality trading

2) Increased implementation of the polluter-pays-principle

3) Enhanced monitoring of both point and non-point sources

4) Enforcement of existing regulations on water pollution

1. Climate change increases a host of water and related

impacts: wetter wet seasons and drier dry seasons;

increased crop water demand; increased reliance on storage

2. Climate smart practices can increase or reduce adverse

water [energy] impacts (neg: biofuel development; pos:

manure management)

3. Water-based [storage/drip]; water-related [nitrogen-use

efficiency, no till, DT/HT, reforestation, WUAs, water

markets]; non-water measures [trade, pop/econ growth, ag

input and output support policies, PHL] are all important

pieces in addressing growing water variability, shortages and

degradation

Concluding thoughts

Climate change impacts on water quantity and quality: Implications for agriculture

Education