New greenhouse gas (GHG) standards for cars and light trucks are taking effect for model year 2017, progressing towards an anticipated sales-weighted average level of 173 g/mile C0 2 for model year 2025, and fuel economy standards increasing each year to the Corporate Average Fuel Economy (CAFE) target of 51.4 mpg fleet-wide by 2025 (for a projected vehicle sales mix). As a result, vehicle manufacturers are looking for solutions that can meet these goals without sacrificing marketable vehicle attributes (Nehuis et al., 2014;U.S. EPA, 2012aU.S. EPA, , 2014. Reducing mass enables vehicles to operate more efficiently during the use phase because energy demands (e.g., acceleration, rolling friction) on the powertrain are reduced. This reduction in mass can have major benefits on the total life-cycle impacts of vehicles because the current use phase accounts for 84-88% of the total life-cycle energy consumption and GFIG emissions for conventional light-duty vehicles. Comparatively, the manufacturing contributes approximately 4-7% of the energy consumption over the life of a light-duty vehicle (Keoleian and Sullivan, 2012;Mcauley, 2003; Sullivan and Cobas-Flores, 2001; Sullivan et al., 1998). Because of this dominant contribution of impacts from the use phase, mass reduction efforts and other use-phase efficiency measures provide an effective means to reduce the total life-cycle impacts. Flowever, the share of life-cycle impacts between the production and use phase for vehicles is likely to shift away from the use phase with increasing efficiency and with reduced light-duty vehicle GFIG emissions standards, as shown in the example comparison in Fig. 1

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Thermoelectric power production comprised 41% of total freshwater withdrawals in the U.S., surpassing even agriculture. This review highlights scenarios of the electric sector's future demands for water, including scenarios that limit both CO 2 and water availability. A number of studies show withdrawals decreasing with retirement of existing electricity generating units. Consumption, the evaporative losses, also decreases in many scenarios. However, climate mitigation scenarios relying heavily on nuclear and carbon capture technologies may induce increases in water consumption. These increases in consumption represent a potential tradeoff between climate mitigation and adaptation of the electric sector to climate-related changes in water resources. It also points to the need for both analyses and technological solutions from the chemical engineering community.

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