CHAPTER 4 I AGRICULTURE IN VIET NAM UNDER THE IMPACT OF CLIMATE CHANGE I 211
[ Figure 4.7 ] Present and projected Salinity intrusion and Rice cultivation area
Impact of salinity intrusion on rice area. a) Contour lines of the present time surface water salinity from 0 ‰ the most inland to 2, 4, 6 ..20 ‰ (P50) ; b) Contour lines from the projection for 2050 under scenarios RCP8.5 (river discharge), with extreme scenarios for subsidence (B2), riverbed level changes (RB3) and sea level rise (+60 cm) (Cf. Chapter 9) ; c) Winter-Spring rice map overlaid with contour lines for 2 ‰ salinity (P50) for the present time (light blue) and for 2050 (dark blue); d) rice area (in red) which will be less suitable for rice cultivation in 2050.
chosen to roughly assess the future area suitable for rice cropping. Figure 4.7c shows the map of the present Winter-Spring rice overlaid with the contour lines of 2‰, for the present time (light blue curve) and the projection for 2050 (dark blue). Figure 4.7d shows the portion of rice area which could be lost in 2050 in this extreme scenario (for water salinity > 2‰). In this case, 143 000 ha (or 10.5% of the 1.36 M ha of 2020’s rice-harvested area) are found less suitable for rice cultivation
in 2050. These are located mainly in the provinces of Tien Giang, Vinh Long, Tra Vinh and Soc Trang. Mitigation of saline intrusion has been object of different measures [ Nhan et al., 2012 ]. In the MARD action plan to respond to climate change in the period of 2008-2020 [ MARD & MOST, 2008 ], mitigation measures include: 1 ] development of large-scale salinity management structures (i.e. dykes, sluices and reservoirs), 2 ] development of small-scale
