Analyzing Growth-Track and Uncertainties in Asia’s Irrigated Areas

Asia holds 70% of global irrigated areas which accounts for 62% of world food demand. Reliable information regarding irrigated areas are of crucial importance for effective future planning. National datasets for irrigated areas, collected by different agencies, e.g. statistical agency, agriculture department, irrigation authorities often vary from each other, while global datasets such as FAO’s show a huge divergence with remote sensing estimates of irrigated areas. Confusions about the accuracy and reliability of data could jeopardize the effectiveness of future policies aiming at securing food production for rapidly growing population of Asia. Without having consistent and dependable data of such a basic input, food and water security of Asian nations would be at stake. In addition, global commitments such as SDGs, climate change, increasing domestic and industrial water demand and ecological concerns would also put more pressure on irrigated agriculture. In this study, a detailed analysis has been conducted for the growth track of irrigated areas in Asia, with the purpose to understand the development of different types of irrigation, investments, trends and resilience of irrigated agriculture against major climate events over the time. Secondly, comprehensive comparison has been made within national statistics, FAO’s data and high resolution irrigated area maps (up to 250m) from IWMI (International Water Management Institute) together with other available raster datasets. Variations in data have been estimated using different statistical tools while distribution and dispersion analysis has also been made to look into the extent of irrigated areas in different climatic regions and to find country wise clusters/patterns of large, medium and small scale irrigation schemes. Furthermore, country’s reporting methods have been investigated thoroughly for the limitations and strengths of existing data collection mechanisms to find the possible loop holes, which might induce uncertainty in data. Results of the study showed a 15% average decline per decade in irrigated areas growth in Asia for last 50 years, while focus on rehabilitation of old infrastructure and implementation of climate smart irrigation has been relatively increased. Uncertainty analysis indicated significant difference in irrigated areas information collected from different sources. Remote sensing estimates were found 96% higher than country estimates on an average, while dispersion analysis showed 300 M ha of non-reported irrigated areas in large scale irrigated schemes for Asia. Qualitative analysis of irrigated areas’ reporting mechanisms showed that mostly traditional statistical methods are used by data collection agencies, e.g. sample surveys based on farmer interviews and global datasets also receive their information from same agencies. Reliability of these methods have been scaled by developing a scoring mechanism by using a quantitative analysis approach. On the other hand, implications of uncertainty came up with some critical questions, i.e. what is the actual annual land productivity? what about per capita irrigated areas? What is the actually utilized irrigation potential? Consequently this study has been concluded by putting forward some genuine facts and recommendations to improve the existing reporting systems of irrigated areas information and to look for imminent role of remote sensing to compare the national statistics with ground facts.