Agricultural productivity and food security in the lower Mekong - PowerPoint PPT Presentation

Agricultural productivity and food security in the lower Mekong Basin: impacts of climate change and options for adaptation Dr Mohammed Mainuddin CSIRO Land and Water, Canberra, Australia Presentation at the 1 st Meeting of Climate Change Adaptation Demonstration Projects, 21-22 July 2011, Ho Chi Minh City, Vietnam

The Mekong China China Myanmar Myanmar Laos Laos • 6 countries, 4 in Mekong River Luang Prabang Luang Prabang Agreement, China and Myanmar observers Thailand Thailand Tonle Sap Tonle Sap • ~65 m people, majority rural Cambodia Cambodia Vietnam Vietnam 500 km 500 km 500 km Phnom Phnom • ~4,200 km long; 795,000 km 2 ; 495,000 mcm discharge (495 km 3 )

Background: The Mekong Basin • Agriculture, along with fisheries and forestry, employs 85% of the people living in the Basin • The population of the Mekong expected to increase from the current 65 million to 90 million in 2050 • Proportion of urban dwellers will increase from 20% to about 40% • Current economic growth is around 4.5% per annum • These factors will drive great change in the Basin and the food demand will increase greatly • Climate change has emerged as one potential additional driver, particularly in terms of more long-term changes

Climate threats? • Climate change may affect the yield of crop directly and also lead to increased demand for irrigation water in dry season - could reduce yields unless extra irrigation water • Climate change may raise sea level, leading to greater saline area in delta and less land for rice • Climate change may also increase extreme events such as flooding, drought and cyclones (both intensity and duration) having widespread damage

Importance Sowe need to know; • What are the potential impacts of climate change on crop yield? • What climatic parameters is having significant impact? • What are the feasible adaptation strategies in both long-term and short-term? • How food security might be affected in the future considering population growth?

The study Here I present; • Impacts of climate change on the yield of rainfed rice, irrigated rice and Maize of the LMB (covers ~90% of the total crop harvested area of the basin) • What parameters are having significant impact • Results of testing of some simple adaptation strategies on rainfed rice • An analysis of food security of the basin (country-wise) at 2050 considering climate impact and population growth.

Climate model and scenario • Climate change data used - projection based on ECHAM4 (European Centre Hamburg Model) General Circulation Model (GCM) from Max Planck Institute for Meteorology, Germany and downscaled using the PRECIS system developed by Hadley Centre • Model has been run for A2 and B2 climate scenario for the period of 2010 to 2050 • CO2 emission has been considered varying from year to year according to SRES scenario

Study site No of provinces in each group: Laos 1 (Savannakhet) – 6 Laos 2 (Vientiane) – 7 Laos 3 (Oudomxay) – 5 Thailand 1 (Ubon Ratchathani) – 2 Thailand 2 (Sakhon Nakhon) – 5 Thailand 3 (Roi Et) – 7 Thailand 4 (Nakhon Ratchasima) – 8 Cambodia (Kampong Speo) – 4 Cambodia (Battambang) – 5 Cambodia (Kratie) – 8 Cambodia (Siem Reap) – 3 Vietnam 1(Gia Lai) – 4 Vietnam 2 (Kien Giang) - 5 Vietnam 2 (Dong Thap) - 7 Model application site

Model set-up – observed vs modelled yield of rainfed rice for baseline condition, overall comparison 5.00 5.00 Modelled yield, tonne/ha 4.00 4.00 Modelled average 3.00 3.00 2.00 2.00 1.00 1.00 0.00 0.00 1.00 2.00 3.00 4.00 5.00 0.00 0.00 1.00 2.00 3.00 4.00 5.00 Observed yield, tonne/ha Observed average Modelled yield vs observed for irrigated rice Modelled yield vs observed for rainfed rice 5.00 4.00 Modelled yield, tonne/ha The model represents well the average 3.00 condition for the period of 1996-2000 2.00 1.00 0.00 0.00 1.00 2.00 3.00 4.00 5.00 Observed yield, tonne/ha Modelled yield vs observed for maize

Results – change in yield of rainfed rice 40 A2 B2 Change from baseline, % 20 0 L1 L2 L3 T1 T2 T3 T4 C1 C2 C3 C4 V1 V2 V3 -20 -40 • Yield increases in A2 scenario for all sites except two • In B2 scenario, in general yield decreases in Cambodia and Vietnam • Yield increase is higher in A2 than that of B2 • For few location (eg. L1 and V2) yield increase in A2 and decreases in B2

Results – change in average yield of rainfed rice (up- scaling)

Change in rainfall Change (%) of mean annual rainfall during 2010-50 relative to 1985-2000

Change in temperature Change ( ° C) of mean annual daily average temperature during 2010-50 relative to 1985-2000

Impact of CO 2 and temperature • No or negligible direct impact of temperature on yield of rainfed rice • Increased CO 2 concentration in the atmosphere help increases yield 40 30 Change of yield from baseline, % 20 10 0 C1 L3 -10 -20 -30 -40 A2 + Constant CO2 A2 B2 + Constant CO2 B2

Results – Irrigated rice 6.00 Average yield, tonne/ha 4.00 Considered 3 sites with higher temperature and intensive irrigation 2.00 Simulation was carried out considering varying CO2 and keeping CO2 at 2000 level to see impact of higher temperature only 0.00 Laos 1 Thailand 3 Vietnam 2 Yield increases for both A2 and B2 scenarios Baseline A2 + Constant CO2 A2 + A2 CO2 B2 + Constant CO2 B2 + B2 CO2 Comparison of average yield Yield decreases slightly if CO2 is kept at the 2000 level for future. This indicates that higher temperature slightly affect the yield adversely. 30 The increase CO2 level in atmosphere offset the Change of yield from baseline, % 20 negative impact of temperature and also help 10 increase yield 0 Laos 1 Thailand 3 Vietnam 2 -10 -20 -30 A2 + Constant CO2 A2 + A2 CO2 B2 + Constant CO2 B2 + B2 CO2 Percentage change from the baseline condition

Results – Maize 8.00 Average yield, tonne/ha 6.00 Considered 8 (2 in each countries) sites in provinces 4.00 with intensive maize cultivation Simulation was carried out considering varying CO2 2.00 and keeping CO2 at 2000 level to see impact of higher temperature only 0.00 Laos 2 Laos 3 Thailand 3 Thailand 4 Cambodia Cambodia Vietnam 1 Vietnam 3 2 3 Yield increases for both A2 and B2 scenarios Baseline A2 + Constant CO2 A2 + A2 CO2 B2 + Constant CO2 B2 + B2 CO2 Comparison of average yield No change in yield if CO2 is kept at the 2000 level for future. This indicates that higher temperature does not affect the yield adversely. 30 Change of yield from baseline, % The increase CO2 level in atmosphere help increase 20 yield 10 0 Laos 2 Laos 3 Thailand 3 Thailand 4 Cambodia Cambodia Vietnam 1 Vietnam 3 2 3 -10 A2 + Constant CO2 A2 + A2 CO2 B2 + Constant CO2 B2 + B2 CO2 Percentage change from the baseline condition

Key points • There is potential to increase yield particularly in Laos and Thailand • Yield would slightly decrease in Cambodia and Vietnam • The impact of yield is mainly due to change in rainfall and CO 2 concentration in the atmosphere • There is no impact of climate change on the yield of irrigated rice if increased irrigation requirements (11%) are met. • There is slight direct impact of temperature increase on the yield of irrigated rice. However, this is offset and net increase in yield is achieved due in CO 2 concentration in the atmosphere. • Yield of maize would increase all over the basin due to climate change.

Adaptation scenarios for rainfed rice in the Mekong • Shift planting date 2 weeks forward and 2 weeks backward from the date considered in the baseline condition • Reduce fertilizer stress or increase fertilizer application • Use supplementary irrigation when necessary

Adaptation for rainfed rice – results of shift planting date 40.0 • Simulation was carried out for all 30.0 sites 20.0 Change from baseline, % 10.0 • Yield decreases for shifting planting A2B 0.0 A2 date backwards in Laos, Cambodia L1 L2 L3 T1 T2 T3 T4 C1 C2 C3 C4 V1 V2 V3 A2F and Vietnam but increases for -10.0 Thailand for A2 scenario. -20.0 -30.0 • Shifting planting date forward -40.0 increases yield in Cambodia and A2 Vietnam, decreases in Laos and Thailand for A2 scenario. 40.0 B2 scenario.. 30.0 20.0 Change from baseline, % • Results are similar to that of A2 10.0 scenario except for Thailand. Yield B2B 0.0 B2 increases for forward planting and L1 L2 L3 T1 T2 T3 T4 C1 C2 C3 C4 V1 V2 V3 B2F decreases for backward planting. -10.0 -20.0 -30.0 -40.0 B2

Basin wide changes with adaptation of shifting the planting dates

Basin wide changes with adaptation of shifting the planting dates