Water Security Challenges Research Articles

An Overview of Managed Aquifer Recharge in Brazil

In order to face the severe climate conditions in semiarid regions, many managed aquifer recharge (MAR) and rainwater storage systems have been implemented by local communities. Governmental programs have helped to propagate the concept of MAR. Based on a systematic review, popular initiatives, current legislation, and research lines and programs were compiled and analyzed. Although the MAR global inventory points to the prevalence of in-channel modifications among ninety MAR sites, the Barraginhas Project alone has been responsible for the construction of more than 500,000 infiltration ponds up to 2013. In urban areas, aquifer recharge initiatives mostly aim to reduce runoff peak flows. In some cases these initiatives have been stimulated by urban drainage public policies. Compared to countries such as the USA and Australia, Brazil is still at an early stage in MAR initiatives and needs to overcome technical, legal, and socio-cultural challenges to adopt MAR approaches, in order to help in facing water security challenges in a future climate change scenario. This article aims to provide an overview of the state of the art concerning technological, scientific, and legal issues around MAR in Brazil and the respective challenges for the adoption of this approach at a national level.

Declining Soil Moisture Threatens Water Availability in the U.S. Great Plains

HighlightsFuture water security in the U.S. Great Plains is threated by a drying trend in average annual soil moisture.Agricultural management will become increasingly challenging due to declines in surface water storage.Alternative management strategies are needed to meet future environmental and anthropogenic surface water demand.Abstract. Spatiotemporal trends in soil moisture are of considerable importance within the food-energy-water nexus. Soil moisture dictates the productivity of ecosystems, plays a major role in land-atmosphere interactions, influences climate change projections, and shapes future water security. Monitoring of long-term soil moisture trends has proven useful for managing water resource allocation and developing solutions to global water security challenges. Thus, we examine annual trends in surface soil moisture throughout the U.S. Great Plains region from 1987 to 2016 using data from NASA’s observation-driven SPoRT-LIS land surface model at 3 km resolution. Results reveal a drying trend in soil moisture for a majority of the U.S. Great Plains, although wetter conditions have been realized in the northernmost region of the Missouri River basin. These results, when coupled with climate change-driven increases in temperature and evapotranspiration, will inevitably drive baseline soil moisture to drier conditions in the future. Under drying soil moisture conditions, future agricultural production and water resource management in the U.S. Great Plains will become increasingly complicated, thereby threatening future food and water security. However, these results can be applied to inform and improve climate change adaptation strategies in order to ensure adequate volumes of freshwater to meet future human and environmental water demand. Keywords: Climate change, SPoRT-LIS, Trend analysis, Water security.

Global Water Security: Current Research and Priorities for Action

HighlightsWe provide context and perspectives on 13 articles in the Global Water Security collection.Limited irrigation, precision irrigation, and sustainable water resources management were critical themes.The collection emphasizes the need for adopting location-specific technologies to achieve global water security.Advances in data acquisition, data analysis, and modeling should be utilized to aid managing water resources. Abstract. This article introduces the Global Water Security collection in this issue of Transactions of the ASABE and issue 36(1) of Applied Engineering in Agriculture. Researchers, educators, industry partners, agricultural producers, and policymakers from 19 countries met at Hyderabad, India, to discuss critical issues and advancements at the Global Water Security Conference for Agriculture and Natural Resources. The conference was organized jointly by ASABE and the Indian Society of Agricultural Engineers (ISAE). This special collection consists of 13 articles selected from the 245 meeting presentations as well as invited articles. A perspectives article in this collection summarizes seven key priorities identified for action at the conference: reduce food waste, increase wastewater reuse, increase agricultural resiliency and efficiency, optimize irrigation efficiency and increase crop water productivity, improve water supply management, improve water resource infrastructure, and enhance water resource decision-making and policy formulation. The remaining 12 articles address a wide range of water security topics grouped by four themes: sustainable management of water resources (3 articles), limited irrigation for water conservation (5 articles), precision irrigation management (2 articles), and water management in hilly regions (2 articles). While these articles are not inclusive of all water security challenges in the agriculture and natural resources sectors, they highlight selected important challenges and potential solutions. The research presented in this special collection emphasizes the importance of developing and using appropriate location-specific technologies that increase water application efficiency and water use efficiency while maintaining adequate water supplies for natural resource functions and ecosystem services to ensure global water security. Keywords: Climate change, Crop water productivity, Food security, Irrigation efficiency, Natural resource policy, Wastewater reuse, Water resource infrastructure, Water scarcity.

Application of the Soil Security Concept to Two Contrasting Soil Landscape Systems—Implications for Soil Capability and Sustainable Land Management

Soil security identifies global challenges and a series of dimensions that are necessary requirements to meet those global challenges using sustainable land management. The soil security concept is applied to two contrasting soil landscape systems with varying climate, landform and soil types. Previous methodologies for assessing land and soil capability are combined within the soil security conceptual approach. The land and soil capability methodologies are used to assess how the soil condition changes in response to the stresses and forcing associated with land management and land and soil degradation processes. It is the soil capability that defines how the soil condition changes between the reference state of the soil condition, or the genoform, and the soil condition under land use, or the phenoform. The conclusion is that soil capability, which is one of the dimensions used to apply the soil security concept, is a complex dimension and has several aspects or further facets to be considered to achieve sustainable land management. It is apparent that in assessing soil capability, the following facets are relevant. I: The capacity of the soil to provide ecosystem services to meet the global challenges outlined for Soil Security. II: The stability of the soil condition to land degradation processes resulting from the effects of land management practices and the environmental stresses on the soil. III: The capacity to recover following degradation. Facets II and III can be considered the resilience. An important conclusion is that the soil capability cannot be assessed without taking into account features of the landscape including climate and landform. Two examples from south eastern Australia of the application of these facets of soil capability to on-ground situations are presented. The Cowra Trough Red Soils in the Australian wheat belt are a set of soils, primarily contributing to meeting the global challenge of food security. The major degradation processes threatening the stability of these soils are water erosion and soil acidification. The Kosciusko National Park in the Snowy Mountains region is primarily contributing to meeting the challenges of water security for the irrigation industry in the Murray Darling Basins and energy security through the production of hydroelectricity. The set of soil landscapes also contributes to biodiversity protection and human health and well-being. The major degradation processes threatening the stability of these soils and their capacity to meet the global challenges are water and wind erosion. A major limitation is the poor capacity of these soils to recover once degraded. Identifying the main ecosystem services provided by the two examples, together with the major risks of land degradation can clarify extension, economic and policy aspects of sustainable land management for the two sets of soil landscapes. For the Cowra Trough Red Soils, management of water erosion and soil acidification are essential for maintaining the contribution of the area to food security. For the Kosciusko National Park, the control of water and wind erosion are essential to maintain the contribution of the area to water and energy security.

Challenges for Water Security and Sustainable Socio-Economic Development: A Case Study of Industrial, Domestic Water Use and Pollution Management in Shandong, China

Comprehensive analysis of water use and pollution management plays an important role in regional water security and sustainable socio-economic development. This study applies the environmental Kuznets curve (EKC), Gini index and elasticity coefficient methods to conduct an investigation of industrial and domestic water use and pollution management in Shandong. The results show that industrial water pollution generally displayed a coordinated relationship with socio-economic development, while an uncoordinated relationship occurred between domestic water pollution and socio-economic development. Meanwhile, the Gini index between domestic water use and population in 2017 (0.101) was superior to that of 2003 (0.165), and the Gini index of industrial water use and second industry output in 2017 (0.273) was better than that of 2003 (0.292), indicating that the allocation and equity of domestic and industrial water use in Shandong kept to a good development trend. Additionally, the industrial effect is better than the domestic effect in terms of the control of wastewater emissions and the governance of typical pollutants in wastewater. Accordingly, domestic water pollution has gradually become one of the major sources of water pollution, and the allocation of industrial and domestic water use has room to improve further in Shandong. Conjunctive use of the aforementioned three methods provides an approach to investigate the integrated management of water use and water pollution control from multiple angles.

The Global Social and Economic Consequences of Mountain Cryospheric Change

Mountain cryosphere provides fresh water and other ecosystem services to half of humanity. The loss of mountain cryosphere due to global warming is already evident in many parts of the world, which has direct implications to people living in mountain areas and indirect implication to people living downstream of glaciated river basins. Despite the growing concerns, the relationship between cryosphere change and human society has yet to be assessed systematically. A better understanding of how cryosphere change affects human systems and human security would provide much needed support to the planning of global and regional actions to mitigate impacts and facilitate adaptation. This paper synthesizes the current evidence for and potential impacts of cryosphere change on water, energy, food, and the environment in different mountain regions in the world. The analysis reveals that the changes in the cryosphere and the associated environmental change has already impacted people living in high mountain areas and are likely to introduce new challenges for water, energy, and food security, and exacerbate ecosystem and environmental degradation in the future. The effects of cryospheric changes are also likely to extend to downstream river basins where glacier melt contributes significantly to dry season river flows and supports irrigation, fisheries, and navigation, as well as water supply to many big cities. Appropriate adaptive and mitigative measures are needed to prevent risks and uncertainties being further compounded

Disaster-Risk, Water Security Challenges and Strategies in Small Island Developing States (SIDS)

Small island developing states (SIDS) are typically characterized by being environmentally and socio-economically vulnerable to disasters and climate change. Additionally, they often have limited resources for freshwater provisioning services. This article presents an assessment of disaster risk and water security-related challenges in SIDS focusing on three major dimensions: (a) how disaster risks are perceived and addressed in the SIDS context using a case study method, (b) analyzing the current status of water security in these regions using an indicator-based approach and (c) assessing gaps and needs in institutions and policies that can facilitate sustainable development goals (SDGs) and targets, adaptation and resilience building in SIDS. In this regard, information on all SIDS is collected to be able to distinguish trends in and between SIDS based on amongst others geographical location and characteristics. This synthesis noted two key observations: first, that in SIDS, the number of disasters is increasing at a higher rate than the global average, and that the frequency and intensity of the disasters will likely increase because of climate change. These combined factors will impact SIDS on the societal level and on environmental levels, reducing their adaptive capacity, resources, and resilience. Second, most SIDS are already water-scarce with low groundwater volumes. Because of increasing demand (e.g., population growth and tourism) and decreasing supply (e.g., pollution and changes in precipitation patterns) freshwater resources are becoming increasingly limited, often suffering from the spillover effects of competing and conflicting uses. Threatened ecosystems and limited economic resources further influence the adaptive capacities of communities in SIDS. In this light, key solutions to address disaster-risk and water security-related challenges can be found by sharing best practices and lessons learned—from examples of good governance, integrated policies, improved community-resilience, and capacity-building. Added to their fragile situation, SIDS struggle to find enough funding to put their development plans, programs, and policies into action.

Beyond hydropower: towards an integrated solution for water, energy and food security in South Asia

ABSTRACT South Asia is energy-poor, water-stressed, and food-deficient, and these problems are expected to intensify with high population growth, rapid economic growth and industrialization, urbanization, and changing climate. Although the water, energy, and food security challenges are interconnected, they are dealt with in isolation, which fails to address the challenge of trade-offs and exacerbates the problems. The increased resource scarcity underlines the need for integrated solutions which ensure optimal resource use and maximize benefits. This article uses a nexus perspective to explore possible integrated solutions that support multiple uses of water at different scales and times. The analysis shows that the potential of water resources is underdeveloped and synergies between water, energy, and food are not fully harnessed. With proper coordination and management, water resources can generate multiple benefits for both upstream and downstream areas, including regional public goods such as regional connectivity and flood and drought management.

Soft Materials Research at IMRE

Front Cover: At the Institute of Materials Research and Engineering (IMRE), soft materials research encompasses interdisciplinary fields in polymer science and engineering with the aim to design and create next-generation polymers. This special issue celebrates the 20th anniversary of IMRE by presenting some of its recent research achievements towards developing soft materials solutions for the global challenges of energy, healthcare, and food and water security. Further details can be found in article number 1800914.

State of future water regimes in the world’s river basins: balancing the water between society and nature

Global freshwater resources have faced critical water security challenges during the 21st century in the world’s river basins. Shortages of water have impaired economic development by disrupting regimes of river flows, ecosystem functioning and food security. Excessive surface and groundwater withdrawals have almost reached the threshold. The current withdrawals of total water (4700 km3·y−1) suggest the imbalance of water use and renewal rates in the world’s river basins. The water security issues are further intensified by phosphate and nitrate pollution from land use and climate change. Today, about 400 million people worldwide experience extreme shortages of water for daily use. Limited availability of water which needs to meet the basic needs of hygiene and sanitation for consumption and other uses has increased competition among users. While the society demands more water-intensive goods and services, the ecosystems are however left behind, consequently leading to increased conflicts and insecurity. Equitable water allocation for people and nature is becoming increasingly urgent. However, understanding the complex interactions between the society and nature in the world’s river basins is limited. This paper aims to unravel some key strategies that enhance future water security through the advancement of science, knowledge and technologies in the world’s river basins.

Big Data Driven Agriculture: Big Data Analytics in Plant Breeding, Genomics, and the Use of Remote Sensing Technologies to Advance Crop Productivity

Core Ideas Interdisciplinary efforts in high‐throughput field phenotyping Linking proximal and remote field phenotyping Cyberinfrastructure for high‐throughput field phenotyping Plant breeding and agronomy are labor‐intensive sciences, and the success of these disciplines is critical to meet planetary challenges of food and water security for the world's growing population. Recent gains in sensor technology, remote sensing, robotics and autonomy, big data analytics, and genomics are being adopted by agricultural scientists for high‐throughput phenotyping, precision agriculture, and crop‐scouting platforms. These technological gains are ushering in an era of digital agriculture that should greatly enhance the capacity of plant breeders and agronomists. This report encompasses the priorities and recommendations that emerged from two USDA National Institute of Food and Agriculture (NIFA)‐funded Big Data Driven Agriculture workshops held on 26–27 Feb. 2018 in Arlington, VA. The objectives of the workshops were to bring together diverse subject‐matter experts in the represented disciplines of plant breeding, machine learning, remote sensing, and big data infrastructure and analytics to (i) explore how large and comprehensive datasets in plant breeding, genomics, remote sensing, and analytics will benefit agriculture; (ii) discuss strategies for creating a successful field phenotyping campaign and to determine protocols for the collection and analysis of agricultural big data; (iii) consider how to best engage the broader community of public and private plant breeders and agronomists to determine additional challenges, make wider use of the data, and ensure application of standardized methods to other datasets; and (iv) generate a report describing cross‐cutting short‐ and long‐term funding needs for continued success in this domain.

River stresses in anthropogenic times: Large-scale global patterns and extended environmental timelines

Global perspectives on the complexities of environmental change impacts associated with past and present human activity are needed for the food and water security challenges of the twenty-first century. This is especially true for rivers, for which the onset and persistence of a range in human activities, altering their function and form, have been temporally and spatially variable. Ancient civilisations, states and empires extended geographically to cover sub-continental areas where their river modifying activities became linked to regional Earth system stresses arising from climate and land use change. We present a new interpretative framework for characterising and classifying human impact on river systems, emphasising that this has taken place over decadal to millennial time periods on a sub-continental scale. This 16-element classification and documentation of different human transformations, including land management, urbanisation, industry and engineering activities, is used to explore anthropogenic channel and floodplain disruptions that have followed each other in different sequences in different places. It is significant that these inadvertent and deliberate human interventions have also taken place in parallel with contrasting climatic fluctuations that have been sub-continental in scale and varied in time. We assess the influence of the dominant modes of regional climate variability (monsoons, El Niño Southern Oscillation, Indian Ocean Dipole, North Atlantic Oscillation, Pacific Decadal Oscillation and Siberian High) on the speed and pattern of river system adjustment to anthropogenic perturbations. Some river civilisations have proved resilient to change given their adaptive management, while others have been overwhelmed by climate-related changes in river morphodynamics. We conclude that integrated socioeconomic, climatic and hydromorphological histories provide usefully instructive antecedents for sensibly managing, as they evolve, the even more serious coupled environmental stresses likely in the future.

A 30-m landsat-derived cropland extent product of Australia and China using random forest machine learning algorithm on Google Earth Engine cloud computing platform

Mapping high resolution (30-m or better) cropland extent over very large areas such as continents or large countries or regions accurately, precisely, repeatedly, and rapidly is of great importance for addressing the global food and water security challenges. Such cropland extent products capture individual farm fields, small or large, and are crucial for developing accurate higher-level cropland products such as cropping intensities, crop types, crop watering methods (irrigated or rainfed), crop productivity, and crop water productivity. It also brings many challenges that include handling massively large data volumes, computing power, and collecting resource intensive reference training and validation data over complex geographic and political boundaries. Thereby, this study developed a precise and accurate Landsat 30-m derived cropland extent product for two very important, distinct, diverse, and large countries: Australia and China. The study used of eight bands (blue, green, red, NIR, SWIR1, SWIR2, TIR1, and NDVI) of Landsat-8 every 16-day Operational Land Imager (OLI) data for the years 2013–2015. The classification was performed by using a pixel-based supervised random forest (RF) machine learning algorithm (MLA) executed on the Google Earth Engine (GEE) cloud computing platform. Each band was time-composited over 4–6 time-periods over a year using median value for various agro-ecological zones (AEZs) of Australia and China. This resulted in a 32–48-layer mega-file data-cube (MFDC) for each of the AEZs. Reference training and validation data were gathered from: (a) field visits, (b) sub-meter to 5-m very high spatial resolution imagery (VHRI) data, and (c) ancillary sources such as from the National agriculture bureaus. Croplands versus non-croplands knowledge base for training the RF algorithm were derived from MFDC using 958 reference-training samples for Australia and 2130 reference-training samples for China. The resulting 30-m cropland extent product was assessed for accuracies using independent validation samples: 900 for Australia and 1972 for China. The 30-m cropland extent product of Australia showed an overall accuracy of 97.6% with a producer’s accuracy of 98.8% (errors of omissions = 1.2%), and user’s accuracy of 79% (errors of commissions = 21%) for the cropland class. For China, overall accuracies were 94% with a producer’s accuracy of 80% (errors of omissions = 20%), and user’s accuracy of 84.2% (errors of commissions = 15.8%) for cropland class. Total cropland areas of Australia were estimated as 35.1 million hectares and 165.2 million hectares for China. These estimates were higher by 8.6% for Australia and 3.9% for China when compared with the traditionally derived national statistics. The cropland extent product further demonstrated the ability to estimate sub-national cropland areas accurately by providing an R2 value of 0.85 when compared with province-wise cropland areas of China. The study provides a paradigm-shift on how cropland maps are produced using multi-date remote sensing. These products can be browsed at www.croplands.org and made available for download at NASA’s Land Processes Distributed Active Archive Center (LP DAAC) https://www.lpdaac.usgs.gov/node/1282.

Stormwater volume reduction and water quality improvement by bioretention: Potentials and challenges for water security in a subtropical catchment

Climate change scenarios tend to intensify extreme rainfall events and drought in Brazil threatening urban water security. Low Impact Development (LID) practices are decentralized alternatives for flood mitigation and prevention. Recently, their potential has increasingly been studied in terms of stormwater harvesting. However, there is still a lack of knowledge about their potentialities in subtropical climate regions. Therefore, this study evaluated the behavior of a bioretention cell in a Brazilian city, during the dry period, which is critical in terms of pollutant accumulation and water availability. In addition to the runoff reduction and pollutant removal efficiency, this paper analyzed the potential for water reuse in terms of the stored volume and water quality guidelines. The results obtained show an average runoff retention efficiency of 70%. Considering only the water availability aspects, the potential stored runoff could be reused for non-potable purposes, reducing the water demand in the catchment by at least half during the dry season. On the other hand, the bioretention presented two different conditions for pollutant removal: Condition A – the concentration values are within the recommended limits for water reuse. The parameters found in this condition were NO3, NO2, Zn, Mn, Cu, Cr; Condition B – the pollutant concentrations are above the guideline limits for water reuse and cannot be directly used for different purposes. The parameters found in this condition were Fe, Pb, Ni, Cd and color. Considering water reuse, an additional treatment is required for parameters in this second condition. Further studies should evaluate the design aspects that can allow collection of LIDs effluent, additional treatment if necessary, and reuse in the catchment.

Graphene Oxide‐Based Polymeric Membranes for Water Treatment

AbstractMembrane technologies for water treatment and desalination are increasingly developed and utilized to address the global challenges of water security and supply. Membrane‐based separations can produce water with desirable qualities from a wide range of water sources, such as groundwater, seawater, brackish water, and wastewater. However, the membranes, which are typically made from polymers, are still restricted by their inherent limitations, including a permeability/selectivity trade‐off and a high fouling propensity. Functionalized graphene (i.e., graphene oxide and its functionalized derivates) is regarded as a very promising nanomaterial for overcoming these limitations owing to its superior hydrophilicity, mechanical stability, bacteriostasis, and biocidal properties. The addition of a small amount of this nanomaterial (normally less 1 wt% based on the weight of polymer) into polymeric membranes significantly improves their physicochemical properties and provides new functionalities. In this review, the recent advances in the preparation of functionalized graphene and its integration into polymer membranes for water treatment are summarized. The influences of functionalized graphene on the separation performance, antifouling ability, chlorine resistance, and mechanical properties of membranes are revealed. Current challenges and future perspectives in the development of high‐performance functionalized graphene–polymer membranes are also discussed.

Component analysis for optimal leakage management in Madaba, Jordan

Non-revenue water (NRW) is a major challenge for urban water security in Jordan. Quantifying of leakage is a difficult task in intermittent supply systems. This study aims to provide a structured analysis to determine the volume of leakage and its components in Madaba9s water distribution network. The study also offers recommendations to reduce the physical losses as an important component of water losses through an infrastructure, repair, economic, awareness and pressure (IREAP) framework as a way of systematically engaging the NRW challenge in Jordan. The real loss sub-components were analysed using Burst and Background Estimates (BABE), and field records of the failures in the network. The potential impact of interventions to reduce losses were measured for efficiency/efficacy by analysing pressure management, chronic leakage detection surveys and response time minimization. The findings showed that Madaba9s NRW amounted to 3.5 million m 3 in 2014, corresponding to a loss of 2.8 million USD to the utility, of which 1.7 million USD is the cost of real losses. The reported failures in Madaba accounted for 37.2% of the total volume of real losses which can be improved by enhancing response polices and asset management, while the unreported failures constituted 26.6 and 36.20%, respectively, which could be reduced by pressure management and active leakage control.

Collaborative Risk Informed Decision Analysis: A water security case study in the Philippines

More frequent and intense hydrologic events under climate change are expected to enhance challenges for water security and flood risk management worldwide. Traditional planning approaches must be adapted to address climate change and develop solutions with an appropriate level of robustness and flexibility. The Collaborative Risk Informed Decision Analysis (CRIDA) method is a novel planning approach embodying a suite of complementary methods, including decision scaling and adaptation pathways, in a stakeholder driven process which guides decision makers through the planning and decision process, taking into account how the confidence in the available science, the consequences in the system, and the capacity of institutions should influence strategy selection. The purpose of this study is to apply the CRIDA approach to a water supply case study in Central Cebu, the Philippines in order to evaluate the added benefits of the method for planning and design under climate change uncertainty. This work will equip practitioners and decision makers with an example of a structured process for decision making under climate uncertainty that can be scaled as needed to the problem at hand.

Megacity precipitationsheds reveal tele-connected water security challenges.

Urbanization is a global process that has taken billions of people from the rural countryside to concentrated urban centers, adding pressure to existing water resources. Many cities are specifically reliant on renewable freshwater regularly refilled by precipitation, rather than fossil groundwater or desalination. A precipitationshed can be considered the “watershed of the sky” and identifies the origin of precipitation falling in a given region. In this paper, we use this concept to determine the sources of precipitation that supply renewable water in the watersheds of the largest cities of the world. We quantify the sources of precipitation for 29 megacities and analyze their differences between dry and wet years. Our results reveal that 19 of 29 megacities depend for more than a third of their water supply on evaporation from land. We also show that for many of the megacities, the terrestrial dependence is higher in dry years. This high dependence on terrestrial evaporation for their precipitation exposes these cities to potential land-use change that could reduce the evaporation that generates precipitation. Combining indicators of water stress, moisture recycling exposure, economic capacity, vegetation-regulated evaporation, land-use change, and dry-season moisture recycling sensitivity reveals four highly vulnerable megacities (Karachi, Shanghai, Wuhan, and Chongqing). A further six megacities were found to have medium vulnerability with regard to their water supply. We conclude that understanding how upwind landscapes affect downwind municipal water resources could be a key component for understanding the complexity of urban water security.

Impacts of Near‐Term Climate Change on Irrigation Demands and Crop Yields in the Columbia River Basin

AbstractAdaptation to a changing climate is critical to address future global food and water security challenges. While these challenges are global, successful adaptation strategies are often generated at regional scales; therefore, regional‐scale studies are critical to inform adaptation decision making. While climate change affects both water supply and demand, water demand is relatively understudied, especially at regional scales. The goal of this work is to address this gap, and characterize the direct impacts of near‐term (for the 2030s) climate change and elevated CO2 levels on regional‐scale crop yields and irrigation demands for the Columbia River basin (CRB). This question is addressed through a coupled crop‐hydrology model that accounts for site‐specific and crop‐specific characteristics that control regional‐scale response to climate change. The overall near‐term outlook for agricultural production in the CRB is largely positive, with yield increases for most crops and small overall increases in irrigation demand. However, there are crop‐specific and location‐specific negative impacts as well, and the aggregate regional response of irrigation demands to climate change is highly sensitive to the spatial crop mix. Low‐value pasture/hay varieties of crops—typically not considered in climate change assessments—play a significant role in determining the regional response of irrigation demands to climate change, and thus cannot be overlooked. While, the overall near‐term outlook for agriculture in the region is largely positive, there may be potential for a negative outlook further into the future, and it is important to consider this in long‐term planning.

Analysis of the relationship between rainfall and economic growth in Indian states

Abstract The relationship between rainfall variability and economic growth is complex, and tends to be significant in economies like India where agriculture plays a major role in economic output and food security. This paper seeks to provide insight into this relationship using Indian state-level economic and rainfall data from 1961 to 2012. We examine all 15 Indian states with populations exceeding 20m as of 2000, totalling 920m people, about 12% of the global population. Physical and human geography vary greatly between, and even within, these states, reflecting the global range of water security challenges and providing an analogue for a range of global economic development and environmental conditions. We identify three patterns of interdependence between rainfall variability and economic growth: i) Continuous Correlation of rainfall and economic growth rates, ii) Decayed Correlation from a significant to an insignificant relationship, and iii) Never Correlated i.e. no significant observable correlation between rainfall and growth. Sensitivity to rainfall variability is somewhat less in wetter states. Investment in irrigation infrastructure has helped states to reduce their economic sensitivity to rainfall variability, with three of the four states that have Decayed Correlation of growth with rainfall having the highest percentage expansion in irrigated areas of the 15 states. Greater use of groundwater supplies (rather than surface water) does not, however, appear to influence the sensitivity of economic growth to rainfall variability. The relationship between rainfall-growth correlation and long term income is complex; states which are correlated generally appear to be growing faster than states which are not correlated, but that growth is occurring from a lower per capita income level. Finally, confirming national trends for India, the paper does not find that economic diversification away from agriculture has reduced economic sensitivity to rainfall variability. The observation that growth in economically-diversified states can still be dependent on rainfall invites further research into the ways in which rainfall either directly, or through other hydro-climatic variables, influences the general economy.