Anticipated Climate Change and Impact on Kenyan Agriculture

E. Gacheru , P. GicheruE. Gacheru , P. GicheruC. K. Gachene .C. K. Gachene .and L. Claessen and L. Claessen

General overviewClimate change and Agriculture

• “Climate change. a serious global risks, demanding urgent global response” Stern review 2006)

• Global warming trend for Africa (0.50C-20C) % 10% reduction in rainfall

• Agriculture sector from developing countries most vulnerable

• Africa is the most affected by negative impacts (TAR ,IPCC 2001)

• Vulnerability and adaptation challenges highlighted by TAR IPCC 2001

• Contributing to further deterioration existing challenges ( PCC 2001; Mathews et al 2007, UNFCCC, 2007;DFID, 2006)

- land degradation- food and water insecurity

- poverty and HIV/AIDS

Observed Temperature Changes in Africa (Source: IPCC (2001) Climate Change 2001, Impacts, Adaptation and Vulnerability)

Kenya

• Situated at the Eastern coast of Africa• Neighbours, Sudan & Ethiopia, north; Somalia east;

Uganda, west; and Tanzania in the south• Area ~582 km2 ; Popn 28.7 mill (1999 census)

• Agriculture main stay of Kenyan economy-26% GDP-60% foreign exchange- Employment to 75% of counties labour force-Lifeline for 85% of population - Generates 60% of foreign exchange earnings

Agricultural production systems-Mainly mixed farming – raising of crops and livestock. - More intensive high potential areas

-Maize main staple food crop,-Dry bean most important legume crop.

- Coffee, tea, and sugarcane major commercial crops.- >75% agriculture practiced by small holder farmers

Importance of Potato and Sweet potato

Sweet potatoes (Republic of Kenya 2006) – important food security crop after cassava – Mainly grown in, Nyanza and western and central

province– Production increased from 546,309 in 2004, to

671,709 in 2005 • Irish potatoes (republic of Kenya 2006)

– Ranked second as staple after maize and 5th among the 20 most important agric commodities

– Grown in the high altitude zones of central province, eastern (Embu, Meru and Machakos*) and rift Valley

– Grows best between 1500m to 3000m– In urban areas, utilization indicates improving

standards of living

Kenya

ACZ CLASS RAINFALL

(mm)

I humid 1100-2700

II Sub-humid 1000-1600

III Semi humid

800-1400

IV Sh-SArid 600-1100

V Semi Arid 450-900

VI Arid 300-550

VII V Arid 150-350

Divided into seven agro-climatic zones (ACZ) based on suitable area for growing major food and cash crops. 18 % high agriculture potentials & 80% ASAL

Climate change concerns in Kenya

Period Temp ∆ (0C)

∆ in Rainfall (mm)

GCM Source

1869-2000 0.9 -91.8 ObservedFalloon et al 2007

2000-2100 5.9 +213 HadCM3LC

By 2030 (AEZ III-IV)

2.89 Variation LR(-) SR (+)

GFDLMati 2000

By 2030 (AEZ III-IV)

2.29 Variation LR(-) SR (+)

CCCM

By 2030 3.5 - CCCM Mariara & Karanja 2007; Karanja 2007

4.0 - GFDL

Mean for 1937-1968 vs 1981-2000 LM &LL Zones E. Kenya

0.35-0.5

- ObservedJaetzod 2006

Observed and anticipated Climate change in Kenya

Impacts of climate change; on agriculture productivity

– Increased temperature and reduction in precipitation expected to reduce crop

– Impact will vary from zone to zone– Increased temperature is more critical than rainfall (Mariara

& Karanja 2007)

Climate Scenario Medium & low potential Zones

High potential

All zones

+3.5 0C 80.05 (24%) -3.54 (-1%) 68.45 (20%)

+4.00C 108.79 (32%)

11.91 (3%) 93,04 (27%)

20% reduction in rainfall 69.54 (21%) 20.14 (7%) 24/39 (7%)

+3.5 0C+ 20% reduction in rainfall

149 (44%) 32.05 (27%)

92.84 (27%)

+4.00C+20% reduction in rainfall

178.33 (53%)

32.05 (9%) 117.43 (34%)

Predicted impacts on net revenue by Zones, Richardia analysis in (US$ ha-2)

source Mariara and Karanja 2007

Impact continued

Crop Scenario ET0

(mm)ETm (mm)

Ya Ym ETA (mm)

% ∆ in crop water use

IWR

Beans

Original 509 321 471 2500 94.4 19

CCCM-LR

559 352 471 2500 103.7 9.8 29.3

CCCM-HR

559 352 471 2500 103.7 9.8 21.5

GDFL-LR 566 357 471 2500 105.1 11.3 30.1

GDFL-HR

566 357 471 2500 105.1 11.3 22.2

Maize

Original 663 444 1137 9000 133.7 61.3

CCCM-LR

727 487 1137 9000 146.6 9.7 93.1

CCCM-HR

727 487 1137 9000 146.6 9.7 72.8

GDFL-LR 735 493 1137 9000 148.3 10.9 95.1

GDFL-HR

735 493 1137 9000 148.3 10.9 74.7

Increased temperatures and reductions in precipitation will increase crop water requirement

Impact of climate change in water use in Kwale district

(Adapted from Karanja 2007)

Adaptation • Policy/national level ( TNA 2000)

Increased frequency and intensity of extreme events has contributed to an increased awareness of impacts of climate

Examples of effort to responded include– Formation of the National Disaster mgt Authority– Crop early warning systems– Dissemination of weather & climate information ( Radio

internet& the formation of the Kenya Network of Journalists & Meteorologists

– Formation of a Inter-Ministerial Committee on Environment,,

– Plant breeding drought/disease tolerant crop varieties

At community level examples include– crop diversification, – different dates of planting, – irrigation, water – conservation and tree planting

Lack of capital/credit a constraint to adaptation

Predicted impacts and adaptation effects on maize Yield

Site Climate Model Yields for different planting dates

Original 15th Feb

1st March 15th March

1st April

15th April

Homa Bay

Normal climate

5813 4740 1500 0 77

CCCM ((2xCO2)

6684 5652 3534 296 0

GDFL( 2xCO2) 6609 5538 3724 474 0

Paponditi

Normal climate

1559 1407 1149 821 158

CCCM ((2xCO2)

1337 633 1416 1692 396

GDFL( 2xCO2) 1112 558 949 1644 554

Kichaka Simba

Normal climate

2056 2399 2393 2166 2190

CCCM ((2xCO2)

1988 2402 2566 1966 1861

GDFL( 2xCO2) 1820 2185 1800 1848 1217

Kampi ya Mawe

Normal climate

1153 343 123 0 0

CCCM ((2xCO2)

1881 1293 608 7 216

GDFL( 2xCO2) 1440 1306 420 0 322

Adapted from Mati 2000

Study Title

Effects of farmers resource endowment, anticipated temperature increase and

rainfall variation, on soil Organic carbon and intern its effect on potato

and sweet potato yields in Eastern Kenya

Justification• Exacerbation of existing vulnerability/ challenges of poor

farmers (land degradation, food insecurity, pests & diseases)

• Warmer temperatures /hydrological changes are likely to affect soil processes (SOM) mineralization and other processes that affect soil fertility (IPCC 2007).

• Technologies that may assist farmers reduce the anticipated global warming impact available

Impact of climate change on agriculture Ecosystem• Climate change may impact directly or indirectly on

ecosystems• Direct effects

• Temperature; Rainfall amounts/distribution• Indirect• Human activity as they respond to climate change

• Change of crop/diversification and change in mgt

• Som whose dynamics is driven by climate, plays an essential role in in determining soil fertility and productivity

Justification

Earlier studies on climate change and agriculture

• Looked at individual systems in isolation and failed to consider other interacting factors (Cohen et al 1994)

• Earlier studies on climate change and agriculture emphasized on crop response and impacts on food security and failed to consider other interacting factors like soil fertility (Parry 1990; Morton 2000)

• In Kenya most available information is on impacts; on agriculture in general or cereals

• Developing countries have different and unique circumstances, such as variable biophysical conditions, social cultural and economic situation that influence the impacts of climate change (Fischer and Velthuizen 2003).

• Shepherd and Soule 1998 reported variation on soil nutrient balances in western Kenya based on resource endowment; with low and medium resource endowment farms indicating negative nutrient balances,

Justification continued

In order to develop effective, such heterogeneity must be put into consideration when designing climate change adaptation strategies.

• Also the differences in adaptation capacity/options between the poor and wealthy need to be considered.

• Understanding on how systems will respond to change (Adaptation) is crucial in reducing vulnerability to climate change

• The relevance adaptive strategies to climate change impacts to a given region/community

• Agriculture should be managed to enhance ecosystem services beyond production (The millennium ecosystem service evaluation 2007 )

Objectives • Broad objectiveAssess the effects of temperature, precipitation and

farmers’ resource endowment and soil mgt on soil organic carbon and the effect of soil organic carbon on sweet potato and potato yields in different AEZ.

Specific objectivesTo assess the role of farmers’ resource endowment and

soil fertility mgt on soil organic carbonTo determine the impact of anticipated temperature and

precipitation due to climate change on soc and nitrogen dynamics in different AEZ

To determine the yield of potato and sweet potato varieties under varying soil organic matter content in small holder farms of Easten of Kenya

To assess the interaction effects of climate change and soil fertility on selected potato and sweet potato varieties yield in small holder farms in Kenya

To analyse the potential contribution of potato and sweet potato to climate change adaptation of small holder farms in Kenya

farming systems

Materials and Methods

• a) Literature review (Climate change analogies)

• Analogues scenarios represent possible future climate based on observed climate regime in space or time

• This method have advantages over controlled conditions (Lab and green house) by providing ecosystem microclimate dynamics and cheaper( Harts & Perry 1999)

• Even small changes in temperature will affect N cycling (Harts and Perry 199

• Using spatial analogue, Bottnier et al 2000, estimated a possible C mineralization of 25-25% with a temperature increase of 30C

Materials and methods continued

• Role of resource endowment and soil fertility mgt on SOC

Participatory wealth ranking, Participatory Learning and action research (PLAR) for soil fertility mgt classification and soil sampling

• Impact of climate change on socUsing PCV soil cores, soil will be tran-slocated across a AEZ

transect and soc and N dynamics monitored (See Harts and Perry 1999, Harts 2006, Bottner et al 2000)

• Potato and sweet potato yield trialsFarms will be selected on the bases of soc content and the

performance of yield performance of potato and sweet potato determined

Analysis of adaptation potential Using down scaled data from GCM, climate change analogue

procedures the impact of climate change on soc, N dynamics and adaptation potential of potato and sweet potato will be analysed

Study area (Embu,Mbere Meru districts

Characteristics District

Embu Mbeere Meru Central

Size (km2) 729 2097 2982

Administration divisions 6 4 11

Population 278196 170,953 498880

Population density 381 82 167

Arable land (km2) 300.1 1695 1952

Ave Farm size (ha) 0.86 4.8

Main AEZ UM1-3 LM3-5 UH1-2, UM1-3, UM2-5, LM2-5

Area cover (ha)/or % 133.9 (67%) 1813 (86%) Several AEZ

Altitude 600m in Mbeere - 2100m Embu

750M -2900

Mean temperature (0C) 15.8 in UH to 25.5 in LM 11.7-20.6

Rain fall (Bimodal) 640mm in Mbeere -2200mm Embu

500mm-2600mm

AEZ and soil types Embu & Mbeere districts

Farming system Embu and Mbeere

• EMBU– , mixed livestock system.– Land use varies with AEZ – Cash crops /tea and coffee(40%landa rea– Declining yields – Important food crops Maize, beans and potato – At individual farm occupies 30%, 15 and 7% respectively

• Mbeere -Most of the district is marginal land- 48% of population depend on mixed farming and 56% marginal mixed

livestock and farming - Main food crops-maize, beans, cowpea pigeon peas,

Meru central

• Land use • International level -Conservation of forest/national

parks• National level-part of national food and cash crop

basket• Cash crops-tea, coffee, tobacco, & horticultural crops• 1000 farms> 20 ha and 8100 less than 2 ha • In 2002, 39\000, 40,00 and 15700 ha grown to Maize,

beans and potato respectively• Potato production threatened by incidences of

bacteria wilt, blight & potato moth