Valerie J. Karplus

A Rice Glutamate Receptor–Like Gene Is Critical for the Division and Survival of Individual Cells in the Root Apical Meristem

Glu receptors are known to function as Glu-activated ion channels that mediate mostly excitatory neurotransmission in animals. Glu receptor–like genes have also been reported in higher plants, although their function is largely unknown. We have identified a rice (Oryza sativa) Glu receptor–like gene, designated GLR3.1, in which mutation by T-DNA insertion caused a short-root mutant phenotype. Histology and DNA synthesis analyses revealed that the mutant root meristematic activity is distorted and is accompanied by enhanced programmed cell death. Our results supply genetic evidence that a plant Glu receptor–like gene, rice GLR3.1, is essential for the maintenance of cell division and individual cell survival in the root apical meristem at the early seedling stage.

Proposed Vehicle Fuel Economy Standards in the United States for 2017 to 2025: Impacts on the Economy, Energy, and Greenhouse Gas Emissions

Increases in the U.S. Corporate Average Fuel Economy (CAFE) standards for light-duty vehicles for the 2017 to 2025 model years are currently under consideration. This analysis used an economywide model with detail in the passenger vehicle fleet to evaluate the impacts of economic, energy use, and greenhouse gas (GHG) emissions associated with year-on-year increases in new targets for vehicle fuel economy of 3%, 4%, 5%, and 6%, which corresponded to the initially proposed rates of increase for the 2017 to 2025 CAFE rulemaking. The results revealed that, across the range of targets proposed, the average welfare cost of a policy constraint increased nonlinearly with target stringency because the proposed policy targets would require increasingly costly changes to vehicles in the near term. Further, the results showed that the impacts on the economy and GHG emissions of combining a fuel tax with fuel economy standards could be positive or negative, as those impacts would depend on underlying technology costs. Finally, the results suggested that over the period from 2015 to 2030, a 5% CAFE policy could reduce gasoline use by about 25 billion gal/year, reduce CO2 emissions by approximately 190 million metric tons per year, and cost

Markets versus Regulation: The Efficiency and Distributional Impacts of U.S. Climate Policy Proposals

25 billion per year (net present value in 2004 dollars), relative to a no-policy baseline.

Modeling Regional Transportation Demand in China and the Impacts of a National Carbon Policy

We acknowledge support of the MIT Joint Program on the Science and Policy of Global Change through a combination of government, industry, and foundation funding, the MIT Energy Initiative, and additional support for this work from a coalition of industrial sponsors. This work is also supported by the DOE Integrated Assessment Grant (DE-FG02-94ER61937). For development of the USREP-ReEDS model, the authors further acknowledge the support of the Joint Institute for Strategic Energy Analysis, which is operated by the Alliance for Sustainable Energy, LLC, on behalf of the U.S. Department of Energy’s National Renewable Energy Laboratory, the University of Colorado-Boulder, the Colorado School of Mines, the Colorado State University, the Massachusetts Institute of Technology, and Stanford University.

Analysis on energy–water nexus by Sankey diagram: the case of Beijing

Chinas climate and energy policy commitments are stated at the national level, but they may have uneven impacts on the countrys regionally heterogeneous transport system. This work quantifies the expected provincial-level response of freight transport to an economywide policy targeting reductions in carbon emissions intensity. The analysis applies the China Regional Energy Model, a multisector, static, global, computable general equilibrium (CGE) model representing 30 individual provinces with physical accounts of energy and greenhouse gas emissions. The structure of road and nonroad freight (and passenger) sectors, the preparation of transport activity data, and a policy similar to announced goals that specify a 17% reduction in the carbon dioxide emissions intensity of gross domestic product are described. In the national aggregate and in most provinces, the road freight sector is most affected by the emissions intensity cap. The road freight sector contributes 24%–-versus 18% from nonroad freight and 51% from nontransport sectors–-of a 5.1% reduction in national refined oil demand. Significant regional differences are found in the impacts of a national-level, economywide policy. Steep reductions in freight activity occur in some of the poorest provinces, partly because they offer low-cost abatement opportunities, and the resulting adjustments across the economy affect transport demand. This research contributes a new tool capable of capturing the transport impact of sector- and province-specific policies in detail and providing a rigorous foundation for future dynamic CGE analyses. Potential impacts of energy and climate policy on regional transport systems are important inputs to policy and infrastructure investment decisions at the central and local levels.

Plant Biology Research Comes of Age in China

Abstract We visualize water utilization in Beijing from source to service and onwards to destination using Sankey diagram to analyze the energy–water nexus at the city level. First, we describe the methodology, definition, and data and apply the Sankey diagram approach. Beijing faces highly constrained water resources and relies heavily on water that is energy-intensive to supply (such as underground water or water that must be conveyed over long distances. We find that the electricity required for water supply, treatment, utilization, and post-use utilization comprised about 5–7% of total electricity consumption in Beijing in 2009. We further find that water used in the energy-related sub-sectors accounted for about one-fourth of the water used in the whole industrial sector and about of 3% of the total fresh water used in Beijing in 2009. Among the energy related sub-sectors, the electricity sub-sector was found to be the largest contributor.

Regulatory control of vehicle and power plant emissions: how effective and at what cost?

A modern plant biology research enterprise is developing rapidly in mainland China. The cohort of well-trained young scientists has expanded, the prevalence of international research collaborations has risen, and the number of publications in international journals has surged over the past 10 years

China's War on Air Pollution: Can Existing Governance Structures Support New Ambitions?

Passenger vehicles and power plants are major sources of GHG emissions. While economic analyses generally indicate that a broader market-based approach to GHG reduction would be less costly and more effective, regulatory approaches have found greater political success. We evaluate a global regulatory regime that replaces coal with natural gas in the electricity sector and imposes technically achievable improvements in the efficiency of personal transport vehicles. Its performance and cost are compared with other scenarios of future policy development including a no-policy world, achievements under the Copenhagen Accord, and a price-based policy to reduce global emissions by 50% by 2050. The assumed regulations applied globally achieve a global emissions reduction larger than projected for the Copenhagen agreements, but they do not prevent global GHG emissions from continuing to grow. The reduction in emissions is achieved at a high cost compared to a price-based policy. Diagnosis of the reasons for the limited yet high-cost performance reveals influences including the partial coverage of emitting sectors, small or no influence on the demand for emissions-intensive products, leakage when a reduction in fossil use in the covered sectors lowers the price to others, and the partial coverage of GHGs. If these regulatory measures are in part correcting other barriers or behavioural limitations consumers face, the benefits of overcoming these could offset at least some of the costs we estimate. The extent of any efficiency gap – the difference between engineering estimates of best practice and what actually happens – is highly contested, and offers an important avenue for future research. Policy relevance While analysts concerned with national cost of GHG control have long advocated a GHG pricing policy, by a cap-and-trade system or a tax, covering all emissions sources and gases, governments more often pursue sectoral policies and technology standards. Given these political realities, the regulations represent a more politically practical approach to GHG reductions, focusing on solutions that are within reach and that do not depend on technological breakthroughs. If regulations are imposed as a way to get started on larger emissions reductions, and then combined with a broader GHG pricing policy pursuing a deep global cut in emissions, its requirements will eventually be overtaken by the pricing policy. The remaining higher costs of the regulatory targets become diluted so that in later years the difference in average cost per ton between a least-cost approach and one preceded by a period of regulatory action becomes very small.

China’s emissions trading takes steps towards big ambitions

Unprecedented and highly visible degraded air quality in Chinas urban centres has prompted a step change in central government control efforts in recent years. This “War on Air Pollution” has included a mixture of administrative controls, regulatory clampdowns, economic incentives and public education campaigns. A critical constraint on how policies are designed and implemented is the central governments capacity to access accurate cost information, and monitor, evaluate and enforce the policies at subordinate levels of government. We examine in detail the directives and arrangements that underpin Chinas “War on Air Pollution” at the provincial level, taking Hebei province as a case study. Located upwind of Beijing, Hebeis heavy industries have been a particular focus of the environmental policies. The current approach, which requires highly specific and costly local actions, yet allocates funds centrally, suffers from misaligned incentives and does not address longstanding weaknesses in local policy monitoring, evaluation and enforcement.

Quantifying coal power plant responses to tighter SO2 emissions standards in China

China recently announced its national emissions trading scheme, advancing market-based approaches to cutting greenhouse gas emissions. Its evolution over coming years will determine whether it becomes an effective part of China’s portfolio of climate policies.