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Energy for water for food Declan Conway [email protected] Overview • Why is this of interest? • How significant are GHG emissions from water use? • Case study: Energy for water for food production in China Collaborative work with CAAS Integrating climate change, water availability and socio-economic scenarios • • • • Climate Change CO2 fertilization effects Water Availability Agricultural land conversion • All drivers together Xiong et al., 2009 Chinese Academy of Agricultural Sciences The need for integration Change in total cereal production with different combinations of drivers Only climate change: Without CO2, modest negative impacts by 2050s Change in total cereal production with different combinations of drivers Climate change and water: Water is a significant limiting factor for future cereal production How significant are GHG emissions from water use? • Water is heavy……… • Water and wastewater often requires treatment….. • Water has high specific heat capacity: end use heating is energy intensive….. What is energy required for? Energy use is high…… • UK roughly 3% of electricity used by water industry. • Water-related energy use in the US accounts for nearly 5% of total GHG emissions. • Proportion is even higher in the UK mostly associated with end uses of water, such as heating. • In countries with extensive irrigation energy use for abstraction and conveyance can be high: – Estimates for India suggest emissions from lifting water for irrigation as much as 6% of total national emissions. • In the US, agriculture is the largest business consumer of electricity, annual cost of almost US$1.2 billion Energy use is under-recognised • Poor definition of system boundaries – – – – LCA studies of specific processes, technologies and sites Range of units / lack of data Failure to include end use such as heating Few comprehensive ‘system’ scale assessments • Very few peer reviewed publications – – – – Grey literature from water industry No discussion in IPCC Gap between research community and industry/practionners Increasing recognition in US (California) of water-energy connections – Little attention to mitigation-adaptation linkages Energy for water for food – Irrigation and energy use – Globally, irrigation accounts for around 20% of the arable land area, but contributes 40% of the global harvest China’s waterenergy nexus: Greenhouse-gas emissions from groundwater use for agriculture Figure 1 | Methodological steps and data input for the estimate of GHG emissions Figure 2 | Location of the 11 survey provinces and 366 survey villages Many villages are located near each other and may appear as one point on the map Location of the 11 survey provinces and 366 survey villages Provincial level results GHG emission rates reflect the mix of pump lift and power source Considerable differences with a range of 0.15 – 0.60kgCO2e/m3 Total GHG emissions = 33.1MtCO2e (0.58% of national total) Key points • Important to link food-water-energy • Energy use is under-recognised – System boundaries, lack of data – Disparate communities: water resources/climate research water industry/practionners • Energy use is high…… – Water is heavy, and has high specific heat capacity • Energy for water for food – Irrigation and energy use – Food production policy targets: integrate adaptation and energy use Thank you Figures taken from: Rothausen, G. and Conway, D. Greenhouse gas emissions from energy use in the water sector. Nature Climate Change 1, 210–219.(2011) Wang, J., Rothausen, G., Conway, D. et al. China’s water energy nexus: greenhouse gas emissions from irrigated agriculture. Environmental Research Letters (In press) Xiong, W. et al Future cereal production in China: The interaction of climate change, water availability and socio-economic scenarios. Global Environmental Change 19, 3444. (2009) Implications for policy….. • GW abstraction is an important source of GHG emissions; rapidly increasing and largely unregulated • Water scarcity in China is already driving policies to improve water conservation; – potential exists to promote co-benefits of water and energy saving to meet national planning targets Factors affecting energy use for groundwater irrigation