Water footprint assessment considering climate change effects on future agricultural production in Mediterranean region

摘要

Climate change significantly affects every day's human activities such as agriculture and tourism by altering the composition and parameters of global atmosphere over long period of time. In Greece, a substantial part of the national gross domestic product comes from agricultural production the efficiency (e.g. crop yield) of which mainly depends on adequacy and sufficiency of resources such as water and soil fertility. In this concept, the water footprint (WF) could be used as a monitoring indicator to evaluate applied agricultural schemes and potential adaptation measures in cultivated regions in Greece with respect to consumption of freshwater resources and deterioration of water receptors considering climate change scenarios. In the present paper, agricultural WF in two plains in Crete, Messara and Chania, are calculated in order to estimate the environmental impacts of the currently applied agricultural schemes on freshwater resources and soil productivity in the two plains. The analysis was based on a climate change scenario that has been developed up to 2100 to assess the effects of precipitation and temperature variability on crop yield and consumption of freshwater resources in the two plains. The results analysis showed that for all the crops in both Messara and Chania plains the two components of WF, blue and green have a substantial contribution to the overall WF of crops. However, the changes in mean annual temperature and precipitation as they are estimated in the examined climate change scenario may affect the evolution of blue and green WF till 2100 by alternating the source of consumed water between water reserves and rainfall. In both also Cretan plains is observed that an estimation of future water needs based on WF indicator could be obtained considering the particular climate scenario only for irrigated crops due to the similar trend that is followed by temperature and total WF. A similar estimation could not be made for rain-fed crops due to the high variability in future precipitation values (low R-2). Finally, the impact of climate change with respect to WF estimation is considerably higher in water scarce areas like Messara plain. The crop yield sensitivity analysis for citrus demonstrated that there is no pattern by which it is possible to estimate their crop yield considering only mean monthly temperature and precipitation values. The crop yield is decisively influenced by the timing that the different rainfall and temperature events happened during the growing season. By concluding special concern should be paid on adaptation measures in local, regional, and national level in order to control the impact of climate change on crop yields.