Engineering topics

Edmonds, James A

Publications and source records attributed to Edmonds, James A.

11 records

DOE OSTI2013

Sensitivity of Multi-gas Climate Policy to Emission Metrics

Multi-gas greenhouse emission targets require that different emissions be combined into an aggregate total. The Global Warming Potential (GWP) index is currently used for this purpose, despite various criticisms of the underlying concept. It is not possible to uniquely define a single metric that perfectly captures the different impacts of emissions of substances with widely disparate atmospheric lifetimes, which leads to a wide range of possible index values. We examine the sensitivity of emissions and climate outcomes to the value of the index used to aggregate methane emissions using a technologically detailed integrated assessment model. We find that the sensitivity to index value is of order 4-14% in terms of methane emissions and 2% in terms of total radiative forcing, using index values between 4 and 70 for methane, with larger regional differences in some cases. The sensitivity to index value is much higher in economic terms, with total 2-gas mitigation cost decreasing 4-5% for a lower index and increasing 10-13% for a larger index, with even larger changes if the emissions reduction targets are small. The sensitivity to index value also depends on the assumed maximum amount of mitigation available in each sector. Evaluation of the maximum mitigation potential for major sources of non-CO2 greenhouse gases would greatly aid analysis

Smith, Steven J↗

DOE OSTI2013

Implications of simultaneously mitigating and adapting to climate change: Initial experiments using GCAM

Historically climate impacts research and climate mitigation research have been two separate and independent domains of inquiry. Climate mitigation research has investigated greenhouse gas emissions assuming that climate is unchanging. At the same time climate mitigation research has investigated the implications of climate change on the assumption that climate mitigation will proceed without affecting the degree of climate impacts or the ability of human and natural systems to adapt. The Global Change Assessment Model (GCAM) has largely been employed to study climate mitigation. Here we explore the development of capabilities to assess climate change impacts and adaptation within the GCAM model. These capabilities are being developed so as to be able to simultaneously reconcile the joint implications of climate change mitigation, impacts and adaptive potential. This is an important step forward in that it enables direct comparison between climate mitigation activities and climate impacts and the opportunity to understand interactions between the two.

Calvin, Katherine V↗

DOE OSTI2013

Scenarios of Global Municipal Water-Use Demand Projections over the 21st Century

This paper establishes three future projections of global municipal water use to the end of the 21st century: A reference business-as usual (BAU) scenario, a High Technological Improvement (High Tech) scenario and a Low Technological Improvement (Low Tech) scenario. A global municipal water demand model is constructed using global water use statistics at the country-scale, calibrated to the base year of 2005, and simulated to the end of the 21st century. Since the constructed water demand model hinges on socioeconomic variables (population, income), water price, and end-use technology and efficiency improvement rates, projections of those input variables are adopted to characterize the uncertainty in future water demand estimates. The water demand model is linked to the Global Change Assessment Model (GCAM), a global change integrated assessment model. Under the reference scenario, the global total water withdrawal increases from 466 km3/year in 2005 to 941 km3/year in 2100,while withdrawals in the high and low tech scenarios are 321 km3/ year and 2000 km3/ year, respectively. This wide range (321-2000 km3/ year) indicates the level of uncertainty associated with such projections. The simulated global municipal demand projections are most sensitive to population and income projections, then to end-use technology and efficiency projections, and finally to water price. Thus, using water price alone as a policy measure to reduce municipal water use may substantiate the share of municipal water price of people’s annual incomes.

climate policy↗

DOE OSTI2013

An integrated assessment of global and regional water demands for electricity generation to 2095

Electric power plants currently account for approximately one-half of the global industrial water withdrawal. While continued expansion of the electric sector seems likely into the future, the consequent water demands are quite uncertain, and will depend on highly variable water intensities by electricity technologies, at present and in the future. Using GCAM, an integrated assessment model of energy, agriculture, and climate change, we first establish lower-bound, median, and upper-bound estimates for present-day electric sector water withdrawals and consumption by individual electric generation technologies in each of 14 geopolitical regions, and compare them with available estimates of regional industrial or electric sector water use. We then explore the evolution of global and regional electric sector water use over the next century, focusing on uncertainties related to withdrawal and consumption intensities for a variety of electric generation technologies, rates of change of power plant cooling system types, and rates of adoption of a suite of water-saving technologies. Results reveal that the water withdrawal intensity of electricity generation is likely to decrease in the near term with capital stock turnover, as wet towers replace once-through flow cooling systems and advanced electricity generation technologies replace conventional ones. An increase in consumptive use accompanies the decrease in water withdrawal rates; however, a suite of water conservation technologies currently under development could compensate for this increase in consumption. Finally, at a regional scale, water use characteristics vary significantly based on characteristics of the existing capital stock and the selection of electricity generation technologies into the future.

electric power↗

DOE OSTI2013

Influence of Climate Change Mitigation Technology on Global Demands of Water for Electricity Generation

Globally, electricity generation accounts for a large and potentially growing water demand, and as such is an important component to assessments of global and regional water scarcity. However, the current suite—as well as potential future suites—of thermoelectric generation technologies has a very wide range of water demand intensities, spanning two orders of magnitude. As such, the evolution of the generation mix is important for the future water demands of the sector. This study uses GCAM, an integrated assessment model, to analyze the global electric sector’s water demands in three futures of climate change mitigation policy and two technology strategies. We find that despite five- to seven-fold expansion of the electric sector as a whole from 2005 to 2095, global electric sector water withdrawals remain relatively stable, due to the retirement of existing power plants with water-intensive once-through flow cooling systems. In the scenarios examined here, climate policies lead to the large-scale deployment of advanced, low-emissions technologies such as carbon dioxide capture and storage (CCS), concentrating solar power, and engineered geothermal systems. In particular, we find that the large-scale deployment of CCS technologies does not increase long-term water consumption from hydrocarbon-fueled power generation as compared with a no-policy scenario without CCS. Moreover, in sensitivity scenarios where low-emissions electricity technologies are required to use dry cooling systems, we find that the consequent additional costs and efficiency reductions do not limit the utility of these technologies in achieving cost-effective whole-system emissions mitigation.

Climate policy↗

DOE OSTI2012

Exploring the Future Role of Asia Utilizing A Scenario Matrix Architecture and Shared Socio-Ecosystem Pathways

We explore the implications of alternative pathways for human population and economic development for the role of Asia in both reference, no-climate-policy, scenarios and scenarios in which climate forcing is limited. We consider three different reference scenarios, which we refer to as Shared Socio-ecosystem Pathways (SSPs) and four different levels of limitation on climate forcing, which we refer to as Shared Policy Assumptions (SPAs). SSPs are differentiated by population and economic growth assumptions, while SPAs are differentiated on the level of radiative forcing in the year 2100. Regardless of the scenarios we examined Asia plays a central role in shaping the world’s future with nearly half of the world’s people and more than half of the world’s economic activity and energy consumption. The future of Asian and world are dramatically different across the various combinations of SSPs and SPAs. High population worlds place significant stress on Asian resources and ecosystems. In high population SSPs the poorest members of the population face high energy and food prices and the more stringent the level of emissions mitigation, the more stress poor populations experience, though the more stringent the emissions mitigation, the larger the area of unmanaged ecosystems that are preserved.

Emissions Mitigation↗

DOE OSTI2012

Energy and technology lessons since Rio

The 1992 Framework Convention on Climate Change created the basic international architecture for addressing climate change. That treaty was negotiated at a time when the research literature examining emissions mitigation and the role of energy technology was relatively limited. In the two subsequent decades a great deal has been learned. The problem of stabilizing the concentration of greenhouse gases in the atmosphere has proved far more difficult than envisioned in 1992 and the role of technology appears even more important when emissions mitigation strategies are co-developed in the context of multiple competing ends.

Energy, economics, climate change↗

DOE OSTI2012

Global irrigation demand - A holistic approach

To develop a research track on global irrigation demand and the use of future water resources to help feed the world, we need to adopt a holistic approach to understand inter-dependencies and the main drivers of the global water system and unravel positive (reinforcing) and negative (balancing) feedback loops that can lead to cascading consequences. Thus, there needs to be more research dedicated to 1) the modeling of the agricultural and water systems as components within an integrated assessment human-Earth modeling framework, 2) the understanding of the linkages between the physical processes and the human system, and to integrate them in an economic framework to capture the dynamics of market price, and institutional regulations. This editorial discusses the importance of tackling the global irrigation problem in an integrated assessment modeling framework.

irrigation, global, integrated assessment modeling↗

DOE OSTI2012

A proposal for a new scenario framework to support research and assessment in different climate research communities

In this paper, we propose a scenario framework that could provide a scenario thread through the different climate research communities (climate change vulnerability, impact, and adaptation (VIA) and mitigation) in order to provide assessment of mitigation and adaptation strategies and other VIA challenges. The scenario framework is defined across two main axes. One is defined by the radiative forcing levels (climate signal) of the Representative Concentration Pathways (RCPs). The second axis is defined by socio-economic development and comprises elements that affect the capacity for adaptation and mitigation but also exposure to climate impacts. The proposed set of scenarios derived from this framework are limited in number, allow for comparison across various mitigation and adaptation levels, address a range of vulnerability characteristics, provide information across climate forcing and vulnerability states and spans a full century time scale. Scenario assessment based on the proposed framework would strengthen cooperation between integrated-assessment modelers, climate modelers and the VIA research community, and most importantly, facilitate the development of more consistent and comparable research within and across communities.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2011

A special issue on the RCPs

This paper provides an editors' introduction to the special issue of Climatic Change on the RCPs. Scenarios form a crucial element in climate change research. They allow researchers to explore the long-term consequences of decisions today, while taking account of the inertia in both the socio-economic and physical system. Scenarios also form an integrating element among the different research disciplines of those studying climate change, such as economists, technology experts, climate researchers, atmospheric chemists and geologists. In 2007, the IPCC requested the scientific community to develop a new set of scenarios, as the existing scenarios (published in the Special Report on Emissions Scenarios, (Nakicenovic and Swart 2000), and called the 'SRES scenarios') needed to be updated and expanded in scope (see Moss et al. (2010) for a detailed discussion). Researchers from different disciplines worked together to develop a process to craft these new scenarios, as summarized by Moss, et al. (2010). The Integrated Assessment Modeling Consortium (IAMC), founded in response to the IPCC call, played a key role in this process.1 The scenario development process aims to develop a set of new scenarios that facilitate integrated analysis of climate change across the main scientific communities. The process comprises 3 main phases: (1) an initial phase, developing a set of pathways for emissions, concentrations and radiative forcing, (2) a parallel phase, comprising both the development of new socio-economic storylines and climate model projections, and (3) an integration phase, combining the information from the first phases into holistic mitigation, impacts and vulnerability assessments. The pathways developed in the first phase were called 'Representative Concentration Pathways (RCPs)'. They play an important role in providing input for prospective climate model experiments, including both the decadal and long-term projections of climate change. The RCPs also provide an important reference point for new research within the integrated assessment modeling (IAM) community by standardizing on a common set of year-2100 conditions, and exploring alternative pathways and policies that could produce these outcomes. By design, the RCPs, as a set, cover the range of radiative forcing levels examined in the open literature and contain relevant information for climate model runs. This Special Issue documents the main assumptions and characteristics of the RCPs, and, in particular, the various steps that were involved in their development. A number of collaborative activities were initiated and finalized during the last 2-3 years to develop the RCPs. This required the cooperation of researchers from various disciplines involved in climate research, including emission experts, climate modelers, atmospheric chemistry modelers, land use modelers and experts involved in integrated assessment. The four RCPs together reflect the range of year-2100 radiative forcing values found in the literature, i.e. from 2.6 to 8.5 W/m{sup 2}. The papers in this Special Issue describe the individual RCPs, but also the various integrative steps that were necessary within the RCP development process to provide a harmonized set of pathways, that show a smooth transition from the past and extend far into the future for very long-term experiments. Important outcomes of this process included, for instance, the development of new emission inventories, new methods for the harmonization of spatial land use patterns, as well as extensions of the RCP trends beyond 2100. They briefly discuss the content of the individual papers.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2011

The Representative Concentration Pathways: An Overview

This paper summarizes the development process and main characteristics of the Representative Concentration Pathways (RCPs), a set of four new scenarios developed for the climate modeling community as a basis for long-term and near-term modeling experiments. The four RCPs together span the range of year 2100 radiative forcing values found in the open literature, i.e. from 2.6 to 8.5 W/m2. The RCPs are the product of an innovative collaboration between integrated assessment modelers, climate modelers, terrestrial ecosystem modelers and emission inventory experts. The resulting product forms a comprehensive data set with high spatial and sectoral resolutions for the period extending to 2100. Land use and emissions of air pollutants and greenhouse gases are reported mostly at a 0.5 x 0.5 degree spatial resolution, with air pollutants also provided per sector (for well-mixed gases, a coarser resolution is used). The underlying integrated assessment model outputs for land use, atmospheric emissions and concentration data were harmonized across models and scenarios to ensure consistency with historical observations while preserving individual scenario trends. For most variables, the RCPs cover a wide range of the existing literature. The RCPs are supplemented with extensions (Extended Concentration Pathways, ECPs), which allow climate modeling experiments through the year 2300. The RCPs are an important development in climate research and provide a potential foundation for further research and assessment, including emissions mitigation and impact analysis.

54 ENVIRONMENTAL SCIENCES↗