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Biofuels could potentially play a significant part in efforts to combat climate change. Besides offering a replacement to fossil fuels, they also absorb carbon dioxide as they grow. Significantly increasing our reliance on biofuels could however be overtaxing on land and water resources. To maximize the effectiveness of biofuels, we must first understand the proper balance between production and impacts on land and water. Nowhere is this energy-water-land nexus more evident than in Brazil, the world’s second largest producer and exporter of biofuels. The country aims to increase its biofuel production by 18% over the next decade. Researchers found that there is a clear difference between irrigated and rainfed ethanol production. In addition, the study revealed that analyzing water and land scarcity produces significant differences. This information will be useful as Brazil expands its bioenergy sector. “Clearly, biofuels can play an important part in reducing our dependence on fossil fuels,” explains Laixiang Sun, a researcher in the IIASA Water Program. "By evaluating the trade-offs across the energy-water- land nexus at the state level and taking into account the local stress levels of water and land resources, our research reveals more options for planning sustainable bioenergy production in Brazil." The western US depends heavily on water for hydroelectric generation and the cooling of thermoelectric power plants. During droughts, water resources in the region are scarce, leading to increased emissions. The impact is so severe that droughts in the western part of the country also affect emissions at the national level. Given that power sector CO2 emissions account for roughly one third of all emissions in the US, it is imperative to understand the significance of drought-induced changes in power sector emissions. Research showed that emissions induced by droughts in California, Idaho, Oregon, and Washington amounted to 7–12% of total CO2 emissions from their respective power sectors. The yearly rates were 8–15% of their respective 2030 annual targets outlined in the Clean Power Plan. Researchers hope the results can be used to influence mitigation targets for pollutant emissions, not just in the US, but worldwide. “We have illustrated yet another interaction between climate change, air pollution, and water,” explains Fabian Wagner, a IIASA researcher and an author of the study. “Some of these nexus relations are subtle, and it was important to use systems analysis to reveal some of the hidden consequences that are likely to play a role in the future.” / AMERICAS The impact of drought conditions in the western US Further info: Herrera-Estrada J, Diffenbaugh N, Wagner F, Craft A, & Sheffield J (2018). Response of electricity sector air pollution emissions to drought conditions in the western United States. Environmental Research Letters 13 (12): e124032. [pure.iiasa.ac.at/15693] Fabian Wagner: wagnerf@iiasa.ac.at Further info: Munoz Castillo R, Feng K, Sun L, Guilhoto J, Pfister S, Miralles-Wilhelm F, & Hubacek K (2019). The land-water nexus of biofuel production in Brazil: Analysis of synergies and trade-offs using a multiregional input-output model. Journal of Cleaner Production 214: 52-61. [pure.iiasa.ac.at/15653] Laixiang Sun: sun@iiasa.ac.at Understanding environmental impacts of biofuel production in Brazil Regional impacts www.iiasa.ac.at 21OptionsSummer 2019