COMPENDIUM Climate-Smart Irrigation Compendium on Climate-Smart Irrigation Concepts, evidence and options for a climate- smart approach to improving the performance of irrigated cropping systems Compendium on Climate-Smart Irrigation Concepts, evidence and options for a climate- smart approach to improving the performance of irrigated cropping systems Charles Batchelor, Julian Schnetzer Global Alliance for Climate-Smart Agriculture Rome, 2018 CONTENTS CONTENTS .......................................................................................................... II FIGURES ............................................................................................................. VI PHOTOS ........................................................................................................... VIII TABLES ............................................................................................................... IX BOXES .................................................................................................................. X FOREWORD ......................................................................................................... XI ACKNOWLEDGEMENTS ...................................................................................... XII PREFACE .......................................................................................................... XIII LIST OF ACRONYMS ........................................................................................... XV EXECUTIVE SUMMARY ..................................................................................... XVII 1. INTRODUCTION ............................................................................................... 1 1.1 Brief introduction to climate-smart agriculture ................................................................ 1 1.1.1 What is climate-smart agriculture? .......................................................................................... 1 1.1.2 What is the climate-smart agriculture approach? ...................................................................... 1 1.2 Brief introduction to climate-smart irrigation ................................................................... 2 1.2.1 What is climate-smart irrigation? ............................................................................................ 2 1.2.2 What differentiates climate-smart irrigation from good irrigation practice? ................................... 3 1.2.3 What are the value additions of climate-smart irrigation relative to good irrigation practices? ......... 4 1.3 Current status and future trends in global irrigation development ...................................... 6 1.4 Irrigation sector challenges in the face of climate change ................................................. 8 1.4.1 Uncertainty .......................................................................................................................... 8 1.4.2 Sector reforms ..................................................................................................................... 9 1.4.3 Efficiency/productivity conundrum ......................................................................................... 11 1.4.4 Evidence informed planning .................................................................................................. 11 1.4.5 Resistance to change ........................................................................................................... 12 1.4.6 Resilience ........................................................................................................................... 12 1.4.7 Water related beliefs and misconceptions................................................................................ 12 1.4.8 Reducing GHG emissions ...................................................................................................... 14 1.4.9 Synergies and trade-offs....................................................................................................... 15 1.5 Key messages ............................................................................................................ 16 2. IMPLICATIONS OF CLIMATE CHANGE FOR IRRIGATION ................................ 17 2.1 Expected changes in global climate and sea levels .......................................................... 17 2.1.1 Global warming ................................................................................................................... 17 2.1.2 Changes in climate............................................................................................................... 18 2.1.3 Changes in sea level ............................................................................................................ 18 2.2 Expected direct and indirect impacts of climate change ................................................... 19 2.3 Relative impacts of climate change and irrigation development ........................................ 19 II COMPENDIUM | CLIMATE-SMART IRRIGATION 2.4 Relative impacts of climate change on public and private irrigation schemes ...................... 20 2.5 Potential climate change impacts by region ................................................................... 25 2.6 Potential climate change impacts on food security .......................................................... 28 2.7 Potential climate change impacts on global distribution of irrigation .................................. 30 2.8 Key messages ............................................................................................................ 32 3. CLIMATE-SMART IRRIGATION ....................................................................... 34 3.1 Introduction and overview ........................................................................................... 34 3.2 CS1 Pillar 1: Increased agricultural productivity and farmer incomes ................................ 35 3.2.1 Introduction and overview .................................................................................................... 35 3.2.2 River basin scale (National institutional level) .......................................................................... 39 Policies ................................................................................................................................... 39 Integrated approaches to water resources management ............................................................... 40 Regulation and oversight .......................................................................................................... 42 3.2.3 Irrigation scheme scale (District or intermediate institutional level) ............................................ 44 Irrigation scheme typology ........................................................................................................ 44 Performance of irrigation schemes ............................................................................................. 44 Services delivery approach ........................................................................................................ 47 Scope for improving the performance of irrigation schemes ........................................................... 48 3.2.4 Field or farm scale (Local institutional level) ............................................................................ 49 ‘Save and Grow’ model ............................................................................................................. 49 Local level impacts of irrigation .................................................................................................. 50 Sources of water ...................................................................................................................... 50 Drainage and waterlogging ........................................................................................................ 50 Selection of an irrigation method ............................................................................................... 51 Advantages and limitations of irrigation methods relative to CSI pillars ........................................... 52 Irrigation scheduling ................................................................................................................. 53 Efficiency and productivity of irrigation systems ........................................................................... 60 Options for improving irrigation efficiency, crop productivity and/or water availability ....................... 63 Factors influencing decisions to use water more efficiently and productively .................................... 64 3.2.5 Key messages ..................................................................................................................... 64 3.3 CS1 Pillar 2: Irrigation related adaptation ...................................................................... 66 3.3.1 Introduction and overview .................................................................................................... 66 CSI adaptation rationale ........................................................................................................... 66 The Paris Climate Agreement ..................................................................................................... 67 Planning and implementing CSI adaptation strategies ................................................................... 67 CSI diversification ...................................................................................................................