Ian P. Holman

China’s water–energy nexus: greenhouse-gas emissions from groundwater use for agriculture

China is the world’s largest emitter of greenhouse gases (GHGs) and the agricultural sector in China is responsible for 17‐20% of annual emissions and 62% of total freshwater use. Groundwater abstraction in China has increased rapidly from 10 km 3 yr 1 in the 1950s to more than 100 km 3 yr 1 in the 2000s, such that roughly 70% of the irrigated area in northern China is now groundwater-fed. Pumping of water for irrigation is one of the most energy consuming on-farm processes; however, to date this source of GHG emissions in China and elsewhere has been relatively neglected. We derive the first detailed estimate of GHG emissions from groundwater pumping for irrigation in China, using extensive village survey data from 11 provinces, broadly representative of the situation during the mid-2000s. The 11 provinces cover roughly half of China’s irrigated cropland and we upscale to the national level using government statistics for the remaining 20 provinces. Our results show emissions of 33.1 MtCO2e, just over half a per cent of the national total. Groundwater abstraction represents an important source of GHG emissions that has been rapidly increasing and which at present is largely unregulated. Water scarcity in China is already driving policies to improve water conservation. These results suggest that significant potential exists to promote the co-benefits of water and energy saving in order to meet national planning targets.

Towards best practice for assessing the impacts of climate change on groundwater

Groundwater is vital to human well-being, providing 2 billion people with drinking water (Morris et al. 2003), supporting

Combining qualitative and quantitative understanding for exploring cross-sectoral climate change impacts, adaptation and vulnerability in Europe.

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An assessment of the risk to surface water ecosystems of groundwater P in the UK and Ireland

230 billion of annual global output of irrigated agricultural produce (Shah et al. 2007), and controlling the flows of water through the world’s biomes (Alley et al. 2002). Given this importance, it is all the more disappointing that the Fourth Report of the Intergovernmental Panel on Climate Change (IPCC) still reports that there “has been very little research on the impact of climate change on groundwater” and that “the few studies of climate impacts on groundwater for various aquifers show very site-specific results” (Kundzewicz et al. 2007). To contribute to addressing these perceived shortcomings and to maximize future study value, methodological recommendations are provided here for hydrogeologists to consider in groundwater-related climate change impact and adaptation studies.

European participatory scenario development: strengthening the link between stories and models

Climate change will affect all sectors of society and the environment at all scales, ranging from the continental to the national and local. Decision-makers and other interested citizens need to be able to access reliable science-based information to help them respond to the risks of climate change impacts and assess opportunities for adaptation. Participatory integrated assessment (IA) tools combine knowledge from diverse scientific disciplines, take account of the value and importance of stakeholder ‘lay insight’ and facilitate a two-way iterative process of exploration of ‘what if’s’ to enable decision-makers to test ideas and improve their understanding of the complex issues surrounding adaptation to climate change. This paper describes the conceptual design of a participatory IA tool, the CLIMSAVE IA Platform, based on a professionally facilitated stakeholder engagement process. The CLIMSAVE (climate change integrated methodology for cross-sectoral adaptation and vulnerability in Europe) Platform is a user-friendly, interactive web-based tool that allows stakeholders to assess climate change impacts and vulnerabilities for a range of sectors, including agriculture, forests, biodiversity, coasts, water resources and urban development. The linking of models for the different sectors enables stakeholders to see how their interactions could affect European landscape change. The relationship between choice, uncertainty and constraints is a key cross-cutting theme in the conduct of past participatory IA. Integrating scenario development processes with an interactive modelling platform is shown to allow the exploration of future uncertainty as a structural feature of such complex problems, encouraging stakeholders to explore adaptation choices within real-world constraints of future resource availability and environmental and institutional capacities, rather than seeking the ‘right’ answers.

Assessing cross-sectoral climate change impacts, vulnerability and adaptation: an introduction to the CLIMSAVE project

A good quantitative understanding of phosphorus (P) delivery is essential in the design of management strategies to prevent eutrophication of terrestrial freshwaters. Most research to date has focussed on surface and near-surface hydrological pathways, under the common assumption that little P leaches to groundwater. Here we present an analysis of national patterns of groundwater phosphate concentrations in England and Wales, Scotland, and the Republic of Ireland, which shows that many groundwater bodies have median P concentrations above ecologically significant thresholds for freshwaters. The potential risk to receptor ecosystems of high observed groundwater P concentrations will depend on (1) whether the observed groundwater P concentrations are above the natural background; (2) the influence of local hydrogeological settings (pathways) on the likelihood of significant P transfers to the receptor; (3) the sensitivity of the receptor to P; and, (4) the relative magnitude of P transfers from groundwater compared to other P sources. Our research suggests that, although there is often a high degree of uncertainty in many of these factors, groundwater has the potential to trigger and/or maintain eutrophication under certain scenarios: the assumption of groundwater contribution to river flows as a ubiquitous source of dilution for P-rich surface runoff must therefore be questioned. Given the regulatory importance of P concentrations in triggering ecological quality thresholds, there is an urgent need for detailed monitoring and research to characterise the extent and magnitude of different groundwater P sources, the likelihood for P transformation and/or storage along aquifer-hyporheic zone flow paths and to identify the subsequent risk to receptor ecosystems.

Untangling relative contributions of recent climate and CO2 trends to national cereal production in China

Scenario development methods get to grips with taking a long-term view on complex issues such as climate change through involvement of stakeholders. Many of the recent (global) scenario exercises have been structured according to a Story-and-Simulation approach. Although elaborately studied, conceptual and practical issues remain in linking qualitative stories and quantitative models. In this paper, we show how stakeholders can directly estimate model parameter values using a three-step approach called Fuzzy Set Theory. We focus on the effect of multiple iterations between stories and models. Results show that we were successful in quickly delivering stakeholder-based quantification of key model parameters, with full consistency between linguistic terms used in stories and numeric values. Yet, values changed strongly from one iteration to the next. A minimum of two and preferably at least three iterations is needed to harmonise stories and models. We conclude that the application of Fuzzy Set Theory enabled a highly valuable, structured and reproducible process to increase consistency between stories and models, but that future work is needed to show its true potential, particularly related to the effect of iterations. Additionally, the number of tools that need to be applied in a short period of time to execute a Story-And-Simulation approach introduces drawbacks that need to be studied. However, an approach such as Story-And-Simulation is indispensable and effective in marrying the perspectives of scientists and other stakeholders when studying complex systems and complex problems.

Developing adaptive capacity within groundwater abstraction management systems

Quantitative participatory exploration of the many complex issues surrounding cross-sectoral climate change impacts, vulnerability and adaptation under uncertain futures is dependent on the provision, in some form, of scenarios and scenario outputs. However, the normal provision by the research community of pre-defined scenario outputs results in a lack of flexibility for stakeholders regarding choice of climate models, scenarios, scenario quantification and output indicators which in turn can lead to a lack of trust. This Special Issue describes the development and application of a web-based interactive simulation and display environment, called the CLIMSAVE Integrated Assessment (IA) Platform, which provides a holistic (cross-sectoral, climate and socio-economic change) modelling framework. The IA Platform guides the user through simulation of (1) potential impacts under scenarios of climate and/or socio-economic change, (2) identification of sectoral and multi-sectoral vulnerability ‘hotspots’ either before or after adaptation, (3) the potential for adaptation to reduce impacts within the capital constraints of the selected scenario(s), and (4) the cost-effectiveness of adaptation measures. The Special Issue explores how the IA Platform has been: (i) designed to provide a user-friendly, intuitive and facilitating, rather than predictive or prescriptive, environment for users; and (ii) utilised to quantitatively explore a diverse range of uncertain futures across Europe.

Water quality targets and maintenance of valued landscape character – Experience in the Axe catchment, UK

There is increasing evidence of crop yield response to recent global warming, yet there is poor understanding of the relative contributions of different climatic variables to changes in crop production. Using a spatially calibrated crop model with cultivars and crop inputs held constant for the year 2000, we simulate idealized national cereal production during the period 1961–2010 under different combinations of observed climate and CO2 forcings. With increasing CO2 and all climate forcings, production shows a slight and insignificant change (−0.9% between 1961 and 2010); however, without CO2 the combined climate forcings decrease production (−8.6%). Changing one climate variable at a time, whilst holding the other variables constant at 1961 values, observed warming has virtually no overall effect on production (0.01%), precipitation decreases it by 1.2% and radiation decreases it by 7.0%. The effects are management and crop dependent, with decreasing radiation responsible for reduced irrigated crop production, and precipitation for variability in rain-fed crop production. Rice is the most sensitive crop, with the largest decline (−12.4%) in simulated production. Wheat shows reduced yield (−9.7%) owing to climate factors, whilst offset by CO2 fertilization (overall change 0.9%). Maize shows insignificant change (−1.2%) and moderate increase in production (2.6%), respectively. These model results suggest that decreasing radiation due to increasing aerosol concentration and other atmospheric pollutants has had a greater effect on crop production than warming trends in China. This underscores the need for crop–climate studies to resolve better the effects of radiation on crop yield and examine climate model projections of radiation in greater detail.

Cross-sectoral impacts of climate and socio-economic change in Scotland: implications for adaptation policy

Groundwater is a key resource for global agricultural production but is vulnerable to a changing climate. Given significant uncertainty about future impacts, bottom-up approaches for developing adaptive capacity are a more appropriate paradigm than seeking optimal adaptation strategies that assume a high ability to predict future risks or outcomes. This paper analyses the groundwater management practices adopted at multiple scales in East Anglia, UK, to identify wider lessons for developing adaptive capacity within groundwater management. Key elements are (1) horizontal and vertical integration within resource management; (2) making better use of water resources, at all scales, which vary in space and time; (3) embedding adaptation at multiple scales (from farm to national) within an adaptive management framework which allows strategies and management decisions to be updated in the light of changing understanding or conditions; (4) facilitating the ongoing formation through collective action of local Water Abstractor Groups; (5) promoting efficient use of scarce water resources by these groups, so as to increase their power to negotiate over possible short-term license restrictions; (6) controlling abstractions within a sustainable resource management framework, whether at national (regulatory) or at local (Abstractor Group) scales, that takes account of environmental water needs; and (7) reducing non-climate pressures which have the potential to further reduce the availability of usable groundwater.