Foodfocused adaptation

As discussed, the food-focused adaptation strategy is oriented towards two adaptation strategies: (i) changing the cropped area; and (ii) changing the amount of water delivered for irrigation. The change in cropped area is here implemented by only looking at the rice area, since rice is the dominant crop. The irrigation depth is adjusted

Fig. 10.6. Impact of adaptation strategies on food and environmental quantity and security using the baseline climate period 1961-1990.

Fig. 10.6. Impact of adaptation strategies on food and environmental quantity and security using the baseline climate period 1961-1990.

according to water requirements. The model simulates whether the higher or lower demand can be fulfilled and, if not, adjusts. Actual levels are used for crop production calculations with the SWAP model.

The combined field- and basin-scale modelling framework has been run for different adaptation combinations of irrigation applications and cropped areas. Again, this has been done for the baseline period (1960-1990) to provide a reference, and for the near (2010-2039) and distant future (2070-2099). Figure 10.6 shows the effect of adaptation measures if future climate conditions are similar to those in the reference period 1961-1990. This graph provides information about food quantity (total rice production in the basin) as well as security (the combined variation in rice production between years, between Maha and Yala, and between different irrigation districts). The 100% value indicates the current situation, although since over-irrigation has been a common practice, the reality is more like 100% cropped area and 120% irrigation depth. The graph shows that for higher or lower irrigation depths, total production would remain similar. However, food security (expressed as the coefficient of variation between the 30 years, the different irrigation systems and the Maha and Yala seasons) would be lower with decreasing irrigation depths. The best option

Production (t/year)

Outflow to sea (MCM/year)

CP

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-> s-

ft

o

10

12

14

14

Yield CV (%)

Outflow to sea (MCM/year)

50 75 100 125 150 50 75 100 125 150

Production (t/year) [Outflow to sea (MCM/year) |

Production (t/year) [Outflow to sea (MCM/year) |

Fig. 10.7. Impact of adaptation strategies on food and environment quantity and security. Displayed are differences between the baseline period (1961-1990) and the near future (2010-2039, top) and the distant future (2070-2099, bottom).

Fig. 10.7. Impact of adaptation strategies on food and environment quantity and security. Displayed are differences between the baseline period (1961-1990) and the near future (2010-2039, top) and the distant future (2070-2099, bottom).

to increase total production would have been to increase the cropped area, but this would have a negative impact on food security.

It is more interesting to look at the effect of the same adaptation options under climate change. Figure 10.7 shows the effect of adaptation strategies for the two selected periods of 30 years: 2010-2039 and 2070-2099. The most important conclusion is that compared to the business as usual scenario (100% irrigation and 100% cropped area), total production will be higher, especially in the distant future. However, the variation in production will increase from 72% in 1960-1999 to 82% in 2010-2039 and 80% in 2070-2099. It is up to water resources managers, but essentially to policy makers, whether such an increase is acceptable or whether intervention is required. Options, beside water managerial ones, are increasing the buffer capacity, by for example intervention prices, improved banking systems, social security systems, etc. The effectiveness of those options for alleviating climate change impacts, however, has not been explored in this project.

The graphs presented in the three figures can also be used to explore options in changing cropped areas and irrigation supplies. If we take the example of the increase in variation in production and have as a policy that an increase in variation, that is in food insecurity, is unacceptable, then the graphs can be helpful in exploring adaptation strategies. For the period 2010-2039, it may be concluded that cropped area should be reduced to about 75% of the current area and irrigation needs increase to a level of 130%. This will result in a variation in yield similar to the reference period, but total long-term production will be about 200,000 t/year, which is about 30,000 t less than the reference period.

The impact of increased water consumption by other sectors can be assessed in the same figures. If the expected increase in urban, industrial and service-oriented activities is 100 X 106 m3, then diversions of water for agriculture should reduce by about 10%. The figures show that the impact on total production will be low, but variation in yield will increase.

The graphs presented are a useful tool for policy makers and water managers to explore the impact of climate change and climate variability and what kind of adaptation strategies can be developed towards food production and security.

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