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Climate Change and it’s Impact on Agriculture in the Vietnamese Mekong Delta, Van Pham Dang Tri

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This presentation is part of the ProSPER.Net Young Researchers' School 2017 ‘Water Security for Sustainable Development in a Changing Climate’.

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Climate Change and it’s Impact on Agriculture in the Vietnamese Mekong Delta, Van Pham Dang Tri

  1. 1. Climate change and impacts on agriculture in the Vietnamese Mekong Mekong Delta Van Pham Dang Tri, Assoc. Prof., Ph.D. College of Environment and Natural Resources (email: vpdtri@ctu.edu.vn)
  2. 2. Content - The international Mekong river - Water crisis in the Vietnamese Mekong Delta (VMD) - Food security vs. Climate change - Ring dykes development vs. Food security - Saline intrusion vs. Food security - Sinking delta vs. sea level rise
  3. 3. 0 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000 50,000 6 7 8 9 10 11 Monthlyaveragedischarge(m3s-1) Month Historical mean monthly discharge CLC1 CLC2 Figure: Historical and projected mean monthly discharges at Kratie; CLC1 and CLC2: Climate Change Scenario 1 and 2, respectively; the standard deviation bars of the historical and projected mean monthly discharges according to CLC1 and 2 were presented from left to right. Figure: Measured sea levels in the East (A) and West (B) Sea on the selected dates. Hydrology of the VMD Main-river flow Over-bank flow
  4. 4. The International Mekong River Threatened by:  Hydrological condition modifications driven by climate change;  Socio-economic development in agriculture, forestry, industry and energy. Consequent impacts: • Flows modified – flood, saline intrusion and sediment loads, both in terms of magnitude and time; • Changes in sediment load and increasing water pollution • Damages in different socio-economic sectors; • Existing agro-ecological zones – physically distorted.
  5. 5. Climate Change in the Mekong Basin Figure: Viet Nam, winter mean temperature, 1901 to 1998. (Source: Schaefer. 2002) Figure: Viet Nam, summer mean temperature, 1901 to 1998. (Source: Schaefer. 2002) Temperature increases in March, April and May
  6. 6. Water crisis in the Vietnamese Mekong Delta http://vnexpress.net/infographic/thoi-su/dong-bang-song-cuu-long-bi-xam-nhap-man-the-nao-3363559.html 22/02/2016 Damages: 5,572 B. VND ~ 450 M. USD 28/04/2016
  7. 7. • … after this servere drought year - 2016 (given impacts of the El Nino) wet years of heavy rain and fluvial floods (given impacts of La Nina) are expected Water crisis – the shifting patterns • What is the magnitude of the flood? • How will upstream hydro-power dams be operated? • Recently, saline intrusion is of great concerns • WHAT ARE EXPECTED DAMAGES???
  8. 8. Hydrological zones in the Delta Flood zones Fresh-water zones Saline-influenced zones
  9. 9. Hydrological alteration from water infrastructure development -Great impact on the natural hydrological regime -Spatial distribution of flooding  Increase the risk of future conflicts among region, economic sectors, and the ecological values Thanh, D.D., T.A. Cochrane, M.E. Arias, P.D.T. Van, T. de Vries (2016). Hydrological alterations from water infrastructure development in the Mekong floodplains. Hydrological Processes, In proof. http://doi: 10.1002/hyp.10894 Buffer upstream dam impacts to the VMD Flood prevention structures
  10. 10. With the sea level rise, the upstream flood would be extended further to the sea. The proportion of discharge loaded along the Mekong and Bassac would be heavily modified! Less fresh-water entering the Bassac especially if the sharp-hydrograph in Kratie occurred! Significant modification of the eco- hydrological conditions of the vast Ca Mau Peninsula 2000 Future 0 10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,000 90,000 100,000 J J A S O N D Dailydischarge(m3s-1) Recorded events (1991, 1996, 1997, 2000) Projected events (2019, 2021, 2046, 2047) ….among many others (e.g. river morphology) Future flood simulations Van, P.D.T. et al., 2012. A study of the climate change impacts on fluvial flood propagation in the Vietnamese Mekong Delta. Hydrology and Earth System Sciences, 16(12), pp.4637–4649. Available at: http://www.hydrol- earth-syst-sci.net/16/4637/2012/ [Accessed February 21, 2013].
  11. 11. Dykes built – multi-fold impacts - Current management of the full dyke network has been successful in promoting triple cropping rice cultivation, but this practice prevents sediment deposition and future sediment loads are also now under great threat Chapman, A.D., S.E. Darby, H.M. Hong, E.L. Tompkins and T.P.D. Van (2016). Adaptation and development trade- offs: fluvial sediment deposition and the sustainability of rice-cropping in An Giang Province, Mekong Delta. Climate Change, 1 – 16. http://10.1007/s10584-016-1684-3 - River-borne sediments have significant economic value: i) nutrients-bound sedimet; and, (ii) maintaining land above sea-level - Without a continuing supply of sediment triple-cropping rice- cultivation will not continue to be sustainable or profitable over the next 10-20 years
  12. 12. - The economic value of sediment as a free fertiliser is particularly important to poorer farmers who are otherwise at significant risk of debt due to fluctuations in artificial fertiliser prices Chapman, A.D., S.E. Darby, H.M. Hong, E.L. Tompkins and T.P.D. Van (2016). Adaptation and development trade- offs: fluvial sediment deposition and the sustainability of rice-cropping in An Giang Province, Mekong Delta. Climate Change, 1 – 16. http://10.1007/s10584-016-1684-3 - A simple adaptation, to allow full inundation in years of high flood, would increase sediment deposition and greatly increase the sustainability of rice agriculture in the face of future environmental change - If sediment excluding triple-cropping continues, financial support will need to be provided to help poorer farmers cope with increases in artificial fertiliser prices Dykes built – multi-fold impacts
  13. 13. • Rice yields are negatively correlated with higher temperatures Currently, rice is being grown at its upper temperature threshold, so any further increases in temperature could lead to declining yields • Rising CO2 levels may offset yield losses from higher temperatures - but that isn't guaranteed - rising CO2 projections are less confident than rising temperature projections • Any yield losses related to temperature cannot be offset by adding more fertilizer or water. Rice productivity vs. Climate change C. Kontgis, A. Schneider, M. Ozdogan, C. Kucharik, P.D.T. Van, H.D. Nguyen, J. Schatz (in progress). Climate change impacts on rice productivity in the Mekong River Delta. Agricultural and Forest Meteorology. Yield Temperature Water + Fertilizer CO2
  14. 14. Current salinity control systems’ intakes SLR 14cm, upstream discharge reduce 11% (Without upstream agriculture development) SLR 20cm, upstream discharge reduce 38% (With upstream agriculture development) Future issues: Sea level rise + Upstream discharge reduce scenario • Reduce of upstream flow  reduce of sedimentation and increase salinity intrusion: – Reduce/disable the efficiency of the existing salinity control projects – Increase input costs (fertilizer, pesticide, …)
  15. 15. Responding to rising sea levels in the Vietnamese Mekong Delta Saline intrusion: Modelling vs. Actual Smajgl, A., Toan, T. Q., Nhan, D. K., Ward, J., Trung, N. H., Tri, L. Q., … Vu, P. T. (2015). Responding to rising sea levels in the Mekong Delta. Nature Climate Change, 5(2), 167–174. http://doi.org/10.1038/nclimate2469
  16. 16. Responding to rising sea levels in the Vietnamese Mekong Delta • An ensemble of hard and soft policies is likely to provide the most effective results for people’s livelihoods in the VMD. • The consequences of policy deliberations are likely to be felt beyond the VMD as levels of rice cultivation there also affect national and global food security. Smajgl, A., Toan, T. Q., Nhan, D. K., Ward, J., Trung, N. H., Tri, L. Q., … Vu, P. T. (2015). Responding to rising sea levels in the Mekong Delta. Nature Climate Change, 5(2), 167–174. http://doi.org/10.1038/nclimate2469
  17. 17. Sinking Delta – the Rise and Fall project … of great challenge… Interaction between components are very much unknown
  18. 18. Mekong Observatory – to trace sources of water from the Mekong river • To trace sources of water (and other pollutants) ending up in the Delta • To identify strategies to deal with trans-boundary issues in the Mekong Basin http://www.globalrivers.org/
  19. 19. Mekong Observatory – to trace sources of water from the Mekong river • To identify strategies to deal with trans-boundary issues in the Mekong Basin
  20. 20. Bringing stakeholders together: - Scientists (IT and environmental experts) - Government and farmers  Sharing information  Supporting decisions  Improving livelihoods
  21. 21. Climate change adaptation from local- and expert knowledge in the coastal area of the Vietnamese Mekong Delta Climate change (CC) is an on-going process of increasingly greater concern for people living in the low-lying coastal areas of Asia including the Mekong Region. + Different scientific studies  to understand the possible trends and mechanisms of changes and vulnerabilities in the Vietnamese Mekong Delta (VMD) (Figure 1), including numerical modelling. + Local communities in the VMD - subjected to seasonally varying flows and hydrological conditions and already developed adaptation mechanisms to cope with such variability. This study – to create a mechanism to bridge gaps between the types of knowledge generated from different sources i.e. local and expert knowledge  bringing them together effectively leads to more appropriate adaptation strategies to CC in the coastal area of the VMD. The study is expected to encourage scientists from different fields and local stakeholders to work together to improve livelihoods of local residents under variable and changing climates, especially in the most vulnerable areas affected by sea level rise and changes in upstream river flow. Figure 1: The study river network in the Vietnamese Mekong Delta. Figure 2: Study framework; CCA: Climate change adaptation. EXPECTED RESULTS (1) Scenarios of future climate patterns and possible impacts. (2) Suitable sets of adaptation techniques (from the local and expert knowledge). (3) Suitable approaches to bridge the gap(s) between the local and expert knowledge. (4) Educational material on climate change adaptation for Undergraduate and Master students of relevant topics in Can Tho University. (5) A policy brief and peer-reviewed publication(s). Can the gap(s) between local- and expert knowledge about climate change adaptation be bridged? M-POWER website: http://www.mpowernetwork.org/index.html
  22. 22. Water resources management for rice farming systems in the Vietnamese Mekong Delta in the context of climate change INTRODUCTION -The main focus of the study is to investigate water storage capacity in the canals which can be used to irrigate rice during the water-shortage period, when water in the main rivers would not be suitable for rice (i.e. saltilized). METHODOLOGY - Based on the physical features of the study area (including: local weather, canals system, existing farming system) and bio-characteristics of crops (including: growing period and water demand at each growing stage), a cause-and-effect loop model (between the demand and supply of water during the crop season) will be developed. EXPECTED RESULTS - To increase water storage capacity in the canals to help crop pass the water-shortage time caused by salinity intrusion. - To provide assistance to local farmers and state agencies in the areas to adapt to new climate patterns, especially during the shortage of freshwater resources. Figure 4: Water cycle (a) and currently water in field and canal (b) in a rice farming system Figure 2: Relationship between water in canals and rice-fields (b)(a) Figure 3: Dynamic system models of the water- cycle in a farming system Figure 1: Currently of the rice fields and sluices at Nga Nam (Soc Trang)
  23. 23. Field-based experiments LEARNING TOGETHER WITH FARMERS
  24. 24. Who owns the benefits of scientific research? • Local stakeholders to be involved in scientific research • Meet requirements of local area • Support strategies development plan of the area • … Brainstorming issues and possible strategies to sustain development in the coastal part of the Vietnamese Mekong Delta
  25. 25. Field surveys
  26. 26. Thank you very much, Van Pham Dang Tri, Assoc. Prof., Ph.D. College of Environment and Natural Resources (email: vpdtri@ctu.edu.vn)

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