The Value of Emissions Trading

Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).This paper estimates the value of international emissions trading, focusing attention on a here-to-fore neglected component: its value as a hedge against uncertainty. Much analysis has been done of the Kyoto Protocol and other potential international greenhouse gas mitigation policies comparing the costs of achieving greenhouse gas emission targets with and without trading. These studies often show large cost reductions for all Parties under trading compared to a no trading case. We investigate the welfare gains of including emissions trading in the presence of uncertainty in economic growth rates, using both a partial equilibrium model based on marginal abatement cost curves and a computable general equilibrium model that allows consideration of the interaction of emissions trading with existing energy taxes and changes in terms of trade. We find that the hedge value of international trading is small relative to its value in reallocating emissions reductions when, as in the Kyoto Protocol, the burden-sharing scheme does not resemble a least-cost allocation. The Kyoto Protocol also allocated excess allowances to Russia, so-called “hot air,” and much of the value often attributed to emissions trading stems from other Parties having access to these extra allowances, which has the effect of lowering the aggregate emissions target. We also find that the effects of preexisting tax distortions and terms of trade dominate the hedge value of trading. We conclude that the primary value of emissions trading in international agreements is as a burden-sharing or wealth transfer mechanism and should be judged accordingly.We gratefully acknowledge helpful comments from A.D. Ellerman. This research was supported by the US Department of Energy (DE-FG02-02ER63468, DE-FG04-04ER63929), US Environmental Protection Agency, US National Science Foundation, US National Aeronautics and Space Administration, US National Oceanographic and Atmospheric Administration; and the Industry and Foundation Sponsors of the MIT Joint Program on the Science and Policy of Global Change

Antenna design for microwave hepatic ablation using an axisymmetric electromagnetic model

BACKGROUND: An axisymmetric finite element method (FEM) model was employed to demonstrate important techniques used in the design of antennas for hepatic microwave ablation (MWA). To effectively treat deep-seated hepatic tumors, these antennas should produce a highly localized specific absorption rate (SAR) pattern and be efficient radiators at approved generator frequencies. METHODS AND RESULTS: As an example, a double slot choked antenna for hepatic MWA was designed and implemented using FEMLAB™ 3.0. DISCUSSION: This paper emphasizes the importance of factors that can affect simulation accuracy, which include boundary conditions, the dielectric properties of liver tissue, and mesh resolution

Uncertainty in Greenhouse Emissions and Costs of Atmospheric Stabilization

Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).We explore the uncertainty in projections of emissions, and costs of atmospheric stabilization applying the MIT Emissions Prediction and Policy Analysis model, a computable general equilibrium model of the global economy. Monte Carlo simulation with Latin Hypercube Sampling is applied to draw 400 samples from probability distributions for 100 parameters in the EPPA model, including labor productivity growth rates, energy efficiency trends, elasticities of substitution, costs of advanced technologies, fossil fuel resource availability, and trends in emissions factors for urban pollutants. The resulting uncertainty in emissions and global costs is explored under a scenario assuming no climate policy and four different targets for stabilization of atmospheric greenhouse gas concentrations. We find that most of the IPCC emissions scenarios are outside the 90% probability range of emissions in the absence of climate policy, and are consistent with atmospheric stabilization scenarios. We find considerable uncertainty in the emissions prices under stabilization. For example, the CO2 price in 2060 under an emissions constraint targeted to achieve stabilization at 650 ppm has a 90% range of $14 to$88 per ton CO2, and a 450 ppm target in 2060 has a range of $241 to$758. We also explore the relative contribution of uncertainty in different parameters to the resulting uncertainty in emissions and costs and find that, despite the significant uncertainty in future energy supply technologies, the largest drivers of uncertainty in costs of atmospheric stabilization are energy demand parameters, including elasticities of substitution and energy efficiency trends.The authors gratefully acknowledge the financial support for this work provided by the MIT Joint Program on the Science and Policy of Global Change through a consortium of industrial sponsors and Federal grants

Allocation of Communications to Reduce Mental Workload

As the United States Department of Defense continues to increase the number of Remotely Piloted Aircraft (RPA) operations overseas, improved Human Systems Integration becomes increasingly important. Manpower limitations have motivated the investigation of Multiple Aircraft Control (MAC) configurations where a single pilot controls multiple RPAs simultaneously. Previous research has indicated that frequent, unpredictable, and oftentimes overwhelming, volumes of communication events can produce unmanageable levels of system induced workload for MAC pilots. Existing human computer interface design includes both visual information with typed responses, which conflict with numerous other visual tasks the pilot performs, and auditory information that is provided through multiple audio devices with speech response. This paper extends previous discrete event workload models of pilot activities flying multiple aircraft. Specifically, we examine statically reallocating communication modality with the goal to reduce and minimize the overall pilot cognitive workload. The analysis investigates the impact of various communication reallocations on predicted pilot workload, measured by the percent of time workload is over a saturation threshold

Community dynamics of Pleistocene coral reefs during alternative climatic regimes

Reef ecosystems built during successive periods of Pleistocene sea level rise have shown remarkable persistence in coral community structure, but little is known of the ecological characteristics of reef communities during periods of low sea stands or sea level falls. We sampled the relative species abundance of coral, benthic foraminifera, and calcareous red algae communities from eight submerged coral reefs in the Huon Gulf, Papua New Guinea, which formed during successive sea level fall and lowstand periods over the past 416 kyr. We found that dissimilarity in coral species composition increased significantly with increasing time between reef-building events. However, neither coral diversity nor the taxonomic composition of benthic foraminifera and calcareous red algae assemblages varied significantly over time. The taxonomic composition of coral communities from lowstand reefs was significantly different from that of highstand reefs previously reported from the nearby Huon Peninsula. We interpret the community composition and temporal dynamics of lowstand reefs as a result of shifting energy regimes in the Huon Gulf, and differences between low and highstand reefs as a result of differences in the interaction between biotic and environmental factors between the Huon Gulf and Huon Peninsula. Regardless of the exact processes driving these trends, our study represents the first glimpse into the ecological dynamics of coral reefs during low sea level stands when climatic conditions for reef growth were much different and less optimal than during previously studied highstand periods. Copyright ESA. All rights reserved

Recent Pollen Deposition in Miller\u27s Bay, Lake Okoboji, Iowa

Proportional counts (200/ sample) of pollen present in nine samples of surface sediments from a settling basin in Miller\u27s Bay, Lake Okoboji, Iowa, are summarized. In order of decreasing abundance the types of pollen listed are Compositae, Quercus, Gramineae, Pinus, Ulmus, Picea, Carya, Tilia, ]uglans, Ostrya, Fraxinus, Betula, Salix, Acer negundo, fem (spores), Celtis, Myriophyllum, Sparganium, Typh,i Alnus, and Potamogeton. The period of pollen rain for Tilia americana was determined to be from June 27 to July 14 (in 1964). Pollen found in algal mats collected during this period contained 15 types of pollen, of which Tilia pollen was the most abundant

Analysis of Climate Policy Targets under Uncertainty

Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).Although policymaking in response to the climate change is essentially a challenge of risk management, most studies of the relation of emissions targets to desired climate outcomes are either deterministic or subject to a limited representation of the underlying uncertainties. Monte Carlo simulation, applied to the MIT Integrated Global System Model (an integrated economic and earth system model of intermediate complexity), is used to analyze the uncertain outcomes that flow from a set of century-scale emissions targets developed originally for a study by the U.S. Climate Change Science Program. Results are shown for atmospheric concentrations, radiative forcing, sea ice cover and temperature change, along with estimates of the odds of achieving particular target levels, and for the global costs of the associated mitigation policy. Comparison with other studies of climate targets are presented as evidence of the value, in understanding the climate challenge, of more complete analysis of uncertainties in human emissions and climate system response.This study received support from the MIT Joint Program on the Science and Policy of Global Change, which is funded by a consortium of government, industry and foundation sponsors

The Responses of Young Sheep to Chronic High Intake of Sodium Chloride

High intakes of NaCl by sheep especially in the arid and semi-arid grazing areas of Australia contribute to deaths and reduced production. The performance of sheep exposed to high intakes of NaCl is well documented but the basis of the tolerances shown are not well understood especially in young sheep. Homeostasis is maintained by integration of body systems that is determined by an animal's genotype. Studies presented were undertaken to evaluate the productive performance of young sheep exposed to high intakes of NaCl from an early age. Information to aid in the understanding of the complex homeostatic mechanisms was obtained. Young sheep were given a fixed daily oral dose of NaCl to standardize the challenge and a number of variables measured over a period of several months. ... Detrimental effects on growth and wool production were observed when young sheep received chronic high intake of NaCl from an early age. Body water, Na+ and Cl- pools and fluxes were changed and this affected food intake-water intake relationships. Renal responses were efficient when lambs were subjected to NaCl challenges. No permanent modifications of function appeared to occur. Changes of rates of function of the renal and gastrointestinal system and body water, Na+ and Cl- pools and fluxes appear to be the mechanisms that sheep utilise to tolerate NaCl loads. An integration of body systems and functions occur to enable sheep to tolerate a high intake of NaCl. Other factors such as behavioural responses, circadian rhythms, climate and weather conditions also affect the tolerance to NaCl. Genotype-phenotype interactions determine the levels of tolerance that enable maintenance of homeostasis. Research in areas where knowledge is lacking would provide a better understanding of osmoregulation during stresses such as a NaCl load

Arctic rock coast responses under a changing climate

It has been widely reported that Arctic sea ice has decreased in both extent and thickness, coupled with steadily rising mean annual temperatures. These trends have been particularly severe along the rock coast of southern Svalbard. Concerns have been raised over the potential for higher energy storms and longer ice-free open water seasons to increase the exposure of Arctic coasts, and consequently the concentration of infrastructure critical to Arctic community survival, to enhanced rates of erosion. Here we present and apply innovative remote sensing, monitoring and process analyses to assess the impact of recent coastal climatic changes. High resolution analyses demonstrate that the small scale (<0.001 m3) changes that are rarely considered quantitatively exhibit geomorphic responses distinct from those of larger, more readily detected cliff failures. We monitor temperature depth profiles in both the shore platform and the cliff face to show rock sensitivity over time to both global and local influences. The results demonstrate the efficacy of thermal processes on Arctic rock cliffs relative to platforms, and may hold implications for understanding strandflat development rates. New three-dimensional thermography (thermal mapping) and process zone characterisation has been used to spatially assess the sensitivity of Arctic rock coast responses to contemporary processes on deglaciating coasts. Through the spatial and temporal analyses of key geomorphic behaviour zones and comparison over a range of sites, the complex and changing interplay between subaerial weathering and cryogenic and intertidal processes has been highlighted. These data challenge long standing assumptions over the future of Arctic rock coasts and identify new, focused lines of enquiry on the decline in cryogenic processes and understanding the sensitivity of Arctic rock coasts to climatic changes