Optimal Carbon Taxes for Emissions Targets in the Electricity Sector

The most dangerous effects of anthropogenic climate change can be mitigated by using emissions taxes or other regulatory interventions to reduce greenhouse gas (GHG) emissions. This paper takes a regulatory viewpoint and describes the Weighted Sum Bisection method to determine the lowest emission tax rate that can reduce the anticipated emissions of the power sector below a prescribed, regulatorily-defined target. This bi-level method accounts for a variety of operating conditions via stochastic programming and remains computationally tractable for realistically large planning test systems, even when binary commitment decisions and multi-period constraints on conventional generators are considered. Case studies on a modified ISO New England test system demonstrate that this method reliably finds the minimum tax rate that meets emissions targets. In addition, it investigates the relationship between system investments and the tax-setting process. Introducing GHG emissions taxes increases the value proposition for investment in new cleaner generation, transmission, and energy efficiency; conversely, investing in these technologies reduces the tax rate required to reach a given emissions target

Birth cohort and the black-white achievement gap: the role of health soon after birth

A large literature documents the significant gap in average test scores between blacks and whites, while a related literature finds a substantial narrowing of the gap during the 1980’s, and a stagnation in convergence during the 1990’s. We use two data sources the Long Term Trends NAEP and AFQT scores for the universe of applicants to the U.S. military between 1976 and 1991 to show that most of the racial convergence in the 1980’s is explained by relative improvements across successive cohorts of blacks born between 1963 and the early 1970’s and not by a secular narrowing in the gap over time. Furthermore, these across-cohort test score gains occurred almost exclusively among blacks in the South. We then examine the potential causes of these large composition effects in the test score gap and their significant variation across U.S. states. We demonstrate that the timing of the cohort-based AFQT convergence closely tracks the convergence in measures of black and white infant health for those cohorts. For example, the cohort- specific AFQT gaps (adjusted for age and year effects and selection into test taking) and the racial gaps in post- neonatal mortality rates deaths between one month and one year of birth exhibit very similar patterns across states and birth cohorts. We show that the black-white convergence in AFQT scores appears to have been more closely linked with post- neonatal mortality rates than with earlier health measures such as neonatal mortality (deaths within one month of birth) and low birthweight. We also find little evidence that other potential confounders (e.g., schooling desegregation, family background) can explain these patterns in AFQT scores. Investments in health at very early ages after birth appear to have large, long-term effects on human capital accumulation. We also discuss preliminary evidence that the staggered timing of hospital integration across the South is consistent with the patterns of gains in black test scores 17 to 18 years after birth more so than other hypotheses for progress in black infant health (e.g., Food Stamps, AFDC, Medicaid).Newborn infants - Mortality ; Racially mixed children

REGIONAL ECONOMIC INTEGRATION: THE CANADA-U.S. EXPERIENCE

This paper assesses the nature and degree of bilateral economic integration preceding and following the implementation of the Canada- U.S. Free Trade Agreement (CUSTA). Various price-based and quantity- based indicators of economic integration are assessed. Results vary depending upon the indicator; however, on balance, the results provide only modest evidence of incremental integration in the post-CUSTA period. The findings serve as a caution against managers and policymakers assuming that regional integration is an inevitable dynamic and basing strategies and policies around this assumption.economic integration; free trade agreements; trade, foreign direct investment; price convergence

REGIONAL ECONOMIC INTEGRATION: THE CANADA-U.S. EXPERIENCE

This paper assesses the nature and degree of bilateral economic integration preceding and following the implementation of the Canada- U.S. Free Trade Agreement (CUSTA). Various price-based and quantity- based indicators of economic integration are assessed. Results vary depending upon the indicator; however, on balance, the results provide only modest evidence of incremental integration in the post-CUSTA period. The findings serve as a caution against managers and policymakers assuming that regional integration is an inevitable dynamic and basing strategies and policies around this assumption.economic integration; free trade agreements; trade, foreign direct investment; price convergence.

Adaptive multichannel control of time-varying broadband noise and vibrations

This paper presents results obtained from a number of applications in which a recent adaptive algorithm for broadband multichannel active noise control is used. The core of the algorithm uses the inverse of the minimum-phase part of the secondary path for improvement of the speed of convergence. A further improvement of the speed of convergence is obtained by using double control filters for elimination of adaptation loop delay. Regularization was found to be necessary for robust operation. The regularization technique which is used preserves the structure to eliminate the adaptation loop delay. Depending on the application at hand, a number of extensions are used for this algorithm. For an application with rapidly changing disturbance spectra, the core algorithm was extended with an iterative affine projection scheme, leading to improved convergence rates as compared to the standard nomalized lms update rules. In another application, in which the influence of the parametric uncertainties was critical, the core algorithm was extended with low authority control loops operating at high sample rates. In addition, results of other applications are given, such as control of acoustic energy density and control of time-varying periodic and non-periodic vibrations

Comparing the Copenhagen emissions targets

Following the Copenhagen climate Accord, developed and developing countries have pledged to cut their greenhouse gas emissions, emissions intensity or emissions relative to baseline. This analysis puts the targets for the major countries on a common footing, and compares them across different metrics. Targeted changes in absolute emissions differ markedly between countries, with continued strong increases in some developing countries but significant decreases in others including Indonesia, Brazil and South Africa, provided reasonable baseline projections are used. Differences are smaller when emissions are expressed in per capita terms. Reductions in emissions intensity of economies implicit in the targets are remarkably similar across developed and developing countries, with China's emissions intensity target spanning almost the same range as the implicit intensity reductions in the United States, EU, Japan, Australia and Canada. Targeted deviations from business-as-usual are also remarkably similar across countries, and the majority of total global reductions relative to baselines may originate from China and other developing countries. The findings suggest that targets for most major countries are broadly compatible in important metrics, and that while the overall global ambition falls short of a two degree trajectory, the targets by key developing countries including China can be considered commensurate in the context of what developed countries have pledged.Copenhagen Accord, emissions targets, emissions intensity, business-as-usual, cross-country comparison., Environmental Economics and Policy, Resource /Energy Economics and Policy,

Four-dimensional variational data assimilation for inverse modeling of atmospheric methane emissions: Analysis of SCIAMACHY observations

Recent observations from the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) instrument aboard ENVISAT have brought new insights in the global distribution of atmospheric methane. In particular, the observations showed higher methane concentrations in the tropics than previously assumed. Here, we analyze the SCIAMACHY observations and their implications for emission estimates in detail using a four-dimensional variational (4D-Var) data assimilation system. We focus on the period September to November 2003 and on the South American continent, for which the satellite observations showed the largest deviations from model simulations. In this set-up the advantages of the 4D-Var approach and the zooming capability of the underlying TM5 atmospheric transport model are fully exploited. After application of a latitude-dependent bias correction to the SCIAMACHY observations, the assimilation system is able to accurately fit those observations, while retaining consistency with a network of surface methane measurements. The main emission increments resulting from the inversion are an increase in the tropics, a decrease in South Asia, and a decrease at northern hemispheric high latitudes. The SCIAMACHY observations yield considerable additional emission uncertainty reduction, particularly in the (sub-)tropical regions, which are poorly constrained by the surface network. For tropical South America, the inversion suggests more than a doubling of emissions compared to the a priori during the 3 months considered. Extensive sensitivity experiments, in which key assumptions of the inversion set-up are varied, show that this finding is robust. Independent airborne observations in the Amazon basin support the presence of considerable local methane sources. However, these observations also indicate that emissions from eastern South America may be smaller than estimated from SCIAMACHY observations. In this respect it must be realized that the bias correction applied to the satellite observations does not take into account potential regional systematic errors, which - if identified in the future - will lead to shifts in the overall distribution of emission estimates

What Has Happened to Wages in Mexico since NAFTA?

In this paper, I examine the impacts of trade and investment liberalization on the wage structure of Mexico. Part one of the paper surveys recent literature on the labor-market consequences of Mexico's economic reforms in the 1980?s. Mexico's policy reforms appear to have raised the demand for skill in the country, reduced rents in industries that prior to reform paid their workers high wages, and raised the premium paid to workers in states along the U.S. border. These changes have resulted in an increase in wage dispersion in the country. Part two of the paper examines changes in Mexico's wage structure during the 1990's. In the last decade, Mexico has experienced rising returns to skill, which mirror closely wage movements in the United States. There is, however, little evidence of wage convergence between the two countries. Regional wage differentials in Mexico have widened and appear to be explained largely by variation in regional access to foreign trade and investment and in regional opportunities for migration to the United States. I discuss implications of Mexico's experience for the rest of Latin America in the event a Free Trade Agreement of the Americas is enacted.

Equidistribution Rates, Closed String Amplitudes, and the Riemann Hypothesis

We study asymptotic relations connecting unipotent averages of $Sp(2g,\mathbb{Z})$ automorphic forms to their integrals over the moduli space of principally polarized abelian varieties. We obtain reformulations of the Riemann hypothesis as a class of problems concerning the computation of the equidistribution convergence rate in those asymptotic relations. We discuss applications of our results to closed string amplitudes. Remarkably, the Riemann hypothesis can be rephrased in terms of ultraviolet relations occurring in perturbative closed string theory.Comment: 15 page

Rapidly converging multichannel controllers for broadband noise and vibrations

Applications are given of a preconditioned adaptive algorithm for broadband multichannel active noise control. Based on state-space descriptions of the relevant transfer functions, the algorithm uses the inverse of the minimum-phase part of the secondary path in order to improve the speed of convergence. A further improvement of the convergence rate is obtained by using double control filters for elimination of adaptation loop delay. Regularization was found to be essential for robust operation. The particular regularization technique preserves the structure to eliminate the adaptation loop delay. Depending on the application at hand, a number of extensions are used for this algorithm, such as for applications with rapidly changing disturbance spectra, applications with large parametric uncertainty, applications with control of time-varying acoustic energy density