Agricultural productivity and food security in the lower Mekong Basin: impacts of climate change and options for adaptation

Transcription

1 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, July 2011, Ho Chi Minh City, Vietnam

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

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

4 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

5 Importance So we 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?

6 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.

7 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

8 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

9 Model set-up observed vs modelled yield of rainfed rice for baseline condition, overall comparison Modelled average Observed average Modelled yield, tonne/ha Observed yield, tonne/ha Modelled yield vs observed for rainfed rice Modelled yield vs observed for irrigated rice 5.00 Modelled yield, tonne/ha The model represents well the average condition for the period of Observed yield, tonne/ha Modelled yield vs observed for maize

10 Results change in yield of rainfed rice 40 A2 B2 Change from baseline, % L1 L2 L3 T1 T2 T3 T4 C1 C2 C3 C4 V1 V2 V3-40 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

11 Results change in average yield of rainfed rice (upscaling)

12 Change in rainfall Change (%) of mean annual rainfall during relative to

13 Change in temperature Change ( C) of mean annual daily average temperature during relative to

14 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 Change of yield from baseline, % C1 L3-40 A2 + Constant CO2 A2 B2 + Constant CO2 B2

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

16 Results Maize 8.00 Average yield, tonne/ha Comparison of average yield 30 Laos 2 Laos 3 Thailand 3 Thailand 4 Cambodia 2 Cambodia 3 Vietnam 1 Vietnam 3 Baseline A2 + Constant CO2 A2 + A2 CO2 B2 + Constant CO2 B2 + B2 CO2 Considered 8 (2 in each countries) sites in provinces with intensive maize cultivation Simulation was carried out considering varying CO2 and keeping CO2 at 2000 level to see impact of higher temperature only Yield increases for both A2 and B2 scenarios 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. Change of yield from baseline, % Laos 2 Laos 3 Thailand 3 Thailand 4 Cambodia 2 Cambodia 3 Vietnam 1 Vietnam 3 The increase CO2 level in atmosphere help increase yield -10 A2 + Constant CO2 A2 + A2 CO2 B2 + Constant CO2 B2 + B2 CO2 Percentage change from the baseline condition

17 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.

18 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

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

20 Basin wide changes with adaptation of shifting the planting dates

21 Basin wide changes with adaptation of shifting the planting dates

22 Adaptation for rainfed rice results of shift planting date, forward planting and supplementary irrigation Change in yield from baseline (%) A2 A2 + 2WFP A2 + SI A2 + RFS A2 + RFS + 2WFP Adaptation strategies C1 V3 Simulation was carried out in two worst affected sites Fertilizer stress was reduced by 10% Supplementary irrigation was given when necessary Results Change in yield from baseline (%) Scenario A2 0 B2 B2 + 2WFP B2 + SI B2 + RFS B2 + RFS + 2WFP Adaptation strategies C1 V3 Yield increases greatly for the site in Cambodia from the baseline condition for reduced fertility stress, and supplementary irrigation. Highest increase can be achieved by 2 weeks forward planting and reducing the fertility stress In Vietnam, highest increase can be achieved by providing supplementary irrigation Scenario B2

23 Food security Rough rice consumption and production per capita, and country-wise current and projected average yield Country Projected populatio n of Rough rice consumptio n per capita (2000) 2 Rough rice production per capita (2000) Rough rice production per capita considering 2050 production and population (with adaptive planting date) Average yield of rice considering total production and total harvested area in 2000 Projected average yield with adaptive planting date in 2050 Average yield necessary to maintain current per capita production with no additional area (kg/capita) (million) (kg/capita) (kg/capita) (tonne/ha) (tonne/ha) (tonne/ha) A2 B2 A2 B2 Laos Thailand Cambodia Vietnam Lower Basin Current trend suggest increase in productivity Food security (in terms of total production) and export potential is unlikely to be affected

24 Key points Over the last ten years, crop production and productivity has increased everywhere in the basin The current rate of increase is considerably greater than the rate required to feed the expected extra population by 2050 Combined with the expected increases under climate change scenarios, it appears unlikely that food security, in terms of the total food available, will be threatened for at least the next few decades However, food security for all individuals also requires that the production is distributed equitably Do not consider the impact of extreme events such as floods, sea level rise, cyclones, storm, etc. which may become more frequent with higher intensity due to climate change Studies show that impact of sea level rise in the deltas could have large impacts on agriculture

25 Flood Area based on Maximum Flood Depth DEV-A DEV-B Impacts from future climate change (CC) and development (DEV) on flood areas (%) compared to flood area in 2000 Maximum Flood ECHAM4 A2 Year 2048 ECHAM4 B2 Year 2047 Depth CC CC + DEV DEV CC CC + DEV DEV > 0.0 m > 0.5 m

26 Saline Area based on Maximum Salinity DEV-A DEV-B Impacts from future climate change (CC) and future development (DEV) on the changes of saline areas (%) compared to saline area year 1998 of baseline scenario Maximum Saline ECHAM4 A2 Year 2022 ECHAM4 B2 Year 2037 Concentration CC CC + DEV DEV CC CC + DEV DEV 0 g/l g/l

27 Overall conclusion Estimates of impact of climate change could be biased by the uncertainties in climate change scenarios Due to these uncertainties, the magnitude of impacts may be different in different models but the trend of impacts in most cases points towards the same direction Need to develop new planning frameworks and methods that will minimize the impacts and can work well across a number of scenarios and uncertainties Climate change should be in the mainstream of any National Policy & Development Planning There should be greater collaboration between GO and NGO on collaborative research & community based adaptation activities

28 Major publication Available at:

29 This presentation are based on projects funded by the following organizations: Australian Agency for International Development (AusAID) Water for a Healthy Country Flagship of CSIRO Mekong River Commission Mohammed Mainuddin Mohammed.Mainuddin@csiro.au Water for a Healthy Country Flagship Land and Water Division Thank you