JP

Measuring Loss in Human Welfare Caused by Air Pollution: A CGE Analysis

To evaluate the socio-economic impacts of air pollution, we develop an integrated approach based on computable general equilibrium (CGE). Applying our approach to 18 western European countries shows that even there, where air quality is relatively high compared with other parts of the world, health- related damages caused by air pollution may be substantial. We estimate that as of 2005, Europe experienced an annual loss in consumption of about 220 billion Euro in year 2000 prices (about 3% of total consumption) with a range based on 95% high and low epidemiological response functions of 107–335 billion Euro and a total welfare loss of about 370 billion Euro (range of 209–550) including both consumption and broader welfare losses (around 2% of welfare level) due to the accumulated effects of three decades of air pollution in Europe. In addition, we estimate that a set of air quality improvement policy scenarios as proposed in the 2005 CAFE program would bring 18 European countries as a whole a welfare gain of 37–49 billion Euro (year 2000 prices) in year 2020 alone.

© 2010 Elsevier

Measuring Welfare Loss Caused by Air Pollution in Europe: A CGE Analysis

To evaluate the socio-economic impacts of air pollution, we develop an integrated approach based on computable general equilibrium (CGE). Applying our approach to Europe shows that even there, where air quality is relatively high compared with other parts of the world, health-related damages caused by air pollution are substantial. We estimate that in 2005, air pollution in Europe caused a consumption loss of around 220 billion Euro (year 2000 prices, around 3 percent of consumption level) and a social welfare loss of around 370 billion Euro, measured as the sum of lost consumption and leisure (around 2 percent of welfare level). In addition, we estimated that a set of 2020-targeting air quality improvement policy scenarios, which are proposed in the 2005 CAFE program, would bring 18 European countries as a whole a welfare gain of 37 to 49 billion Euro (year 2000 prices) in year 2020 alone.

Mechanistic, Sensitivity, and Uncertainty Studies of the Atmospheric Oxidation of Dimethylsulfide

The global-scale emissions and reactivity of dimethylsulfide (CH3SCH3, DMS) make it an integral component in the atmospheric sulfur cycle. DMS is rapidly oxidized in the atmosphere by a complex gas-phase mechanism involving many species and reactions. The resulting oxidized sulfur-bearing products are hygroscopic and interact with aerosols through condensation and secondary aerosol formation. Predictions of the impacts of DMS chemistry on aerosols and climate are inhibited by the poorly understood DMS oxidation mechanism. This thesis diagnoses the gas-phase connections between DMS and its oxidation products by simulating comprehensive DMS chemistry (approximately 50 reactions and 30 species) using three atmospheric models of varying size and complexity.

A diurnally-varying box model of the DMS cycle in the remote marine boundary layer is used to identify important DMS-related parameters and propagate parameter uncertainties to the sulfur-containing species. This analysis shows that the concentrations of DMS and sulfur dioxide (SO2) are sensitive to relatively few parameters. Moreover, the concentrations of DMS and SO2 are found to have factor of 2 uncertainties caused primarily (more than 60% of the variance) by uncertainties in DMS emissions and heterogeneous removal, respectively. In contrast, the concentrations of other products, such as sulfuric acid (H2SO4) and methanesulfonic acid (CH3SO3H, MSA), are found to be sensitive to many parameters and have larger uncertainties (factors of 2 to 7) resulting from multiple uncertain chemical and non-photochemical processes.

The DMS oxidation mechanism is quantitatively assessed using a one-dimensional column model constrained by high-frequency aircraft measurements from the First Aerosol Characterization Experiment (ACE-1). From this analysis, the baseline mechanism predicts DMS and SO2 concentrations in statistical agreement with the observations, yet it underestimates MSA concentrations by a factor of 104 to 105. These differences for MSA are statistically very significant and indicative of missing gas-phase reactions in the DMS mechanism. To reconcile these differences, five hypothetical MSA production paths are individually tested which greatly improve the model predictions to within a factor of 2 to 3 of the observations. Overall, the best improvement occurs when MSA is produced from the oxidation of methanesulfinic acid (CH3S(O)OH). Furthermore, the boundary layer model predictions of H2SO4 show improvement after an SO2-independent sulfuric acid production channel is added to the mechanism.

The DMS cycle is simulated in a global three-dimensional chemical transport model using, for the first time, comprehensive DMS oxidation chemistry. Four model cases are considered, which include two new comprehensive mechanisms and two parameterized schemes of 4 to 5 reactions taken from previous global sulfur models. The mole fractions of DMS, SO2, H2SO4, and MSA are compared between these four cases and with observations from the ACE-1 and PEM-Tropics A campaigns. Among the four cases, the calculated mole fractions of DMS and SO2 are largely invariant, while those for H2SO4 and MSA exhibit order-of-magnitude differences. These results indicate that H2SO4 and MSA are sensitive to the details of the mechanism, while DMS and SO2 are not. The comparisons between the model predictions and observations in the lower troposphere show reasonable agreement for DMS and SO2 (within a factor of 5), but larger disagreements for H2SO4 and MSA (factors of 5 to 30) due to the difficulty in constraining their sources and sinks. The four model cases, however, bound the H2SO4 and MSA measurements. Moreover, the comprehensive mechanisms provide a better match to the MSA observations.

Methane fluxes between terrestrial ecosystems and the atmosphere at northern high latitudes during the past century: A retrospective analysis with a process-based biogeochemistry model

We develop and use a new version of the Terrestrial Ecosystem Model (TEM) to study how rates of methane (CH4) emissions and consumption in high-latitude soils of the Northern Hemisphere have changed over the past century in response to observed changes in the region's climate. We estimate that the net emissions of CH4 (emissions minus consumption) from these soils have increased by an average 0.08 Tg CH4 yr-1 during the 20th century. Our estimate of the annual net emission rate at the end of the century for the region is 51 Tg CH4 yr-1. Russia, Canada, and Alaska are the major CH4 regional sources to the atmosphere; responsible for 64%, 11%, and 7% of these net emissions, respectively. Our simulations indicate that large inter-annual variability in net CH4 emissions occurred over the last century. If CH4 emissions from the soils of the pan-Arctic region respond to future climate changes as our simulations suggest they have responded to observed climate changes over the 20th century, a large increase in high latitude CH4 emissions is likely and could lead to a major positive feedback to the climate system. © 2004 American Geophysical Union

Methane Fluxes Between Terrestrial Ecosystems and the Atmosphere at Northern High Latitudes During the Past Century: A Retrospective Analysis with a Process-based Biogeochemistry Model

We develop and use a new version of the Terrestrial Ecosystem Model (TEM) to study how rates of methane (CH4) emissions and consumption in high-latitude soils of the Northern Hemisphere have changed over the past century in response to observed changes in the region's climate. We estimate that the net emissions of CH4 (emissions minus consumption) from these soils have increased by an average 0.08 Tg CH4 yr-1 during the 20th century. Our estimate of the annual net emission rate at the end of the century for the region is 51 Tg CH4 yr-1. Russia, Canada, and Alaska are the major CH4 regional sources to the atmosphere; responsible for 64%, 11%, and 7% of these net emissions, respectively. Our simulations indicate that large inter-annual variability in net CH4 emissions occurred over the last century. If CH4 emissions from the soils of the pan-Arctic region respond to future climate changes as our simulations suggest they have responded to observed climate changes over the 20th century, a large increase in high latitude CH4 emissions is likely and could lead to a major positive feedback to the climate system.

Mitigation of greenhouse gas emissions from land use: creating incentives within greenhouse gas emissions trading systems

Terrestrial carbon sinks and sources were introduced into climate change mitigation related policy relatively late in the design of the architecture of those policies. Much literature addresses how terrestrial sources and sinks differ from emissions from fossil fuel combustion and, hence, is a possible justification for differential treatment of them in policy design. Late introduction in climate policy discussions and perceived differences appear to have resulted in very different policy approaches for sinks versus fossil emission sources. The attempt to differentiate has generated complexity in policy design and likely inefficiency in the operation of these policies. We review these issues and find that the characteristics claimed to apply to sinks apply as well to fossil sources, and differences that do exist are often more a matter of degree than of kind. Because cap-and-trade has gained momentum as the instrument of choice to control fossil emissions, we use as a starting point, how such a cap-and-trade system could be altered to include terrestrial carbon sinks and sources.

© 2007 Springer Science+Business Media

Model Estimates of the Mass Balance of the Greenland & Antarctic Ice Sheets

The six possible combinations of two climate models and three methods for calculating the melting of snow and ice are used to estimate current values of accumulation and ablation on the Greenland and Antarctic ice sheets. This allows the contrasting of high vs. low resolution climate input and to assess the reliability of simple temperature based parameterizations of melting when compared to a physical model of the seasonal evolution of the snow cover. In contrast to past efforts at modelling the mass balance of Greenland and Antarctica, the latter model allows an explicit calculation of the formation of meltwater, of the fraction of meltwater which refreezes and of runoff in the ablation region, this is not the case for the other two melt models. While the higher resolution GCM (ECHAM 4) does bring the estimation of accumulation closer to observations, it fails to give accurate results in its predictions of runoff. The simpler climate model (MIT 2D LO) overestimates accumulation in Antarctica but produces satisfactory estimates of runoff from the Greenland ice sheet. Both models reproduce some of the characteristics of the extent of the wet snow zone observed with satellite remote sensing, but the MIT model is closer to observations in terms of areal extent and intensity of the melting. The temperature dependent melting parameterizations generally require an accuracy in the climatic input beyond what is currently achieved to produce reliable. Because it is based on physical principles and relies on the surface energy balance as input, the snow cover model is believed to have the capability to respond adequately to the current climatic forcing as well as to future changes in climate.

Modeling climate feedbacks to electricity demand: The case of China

This paper is an empirical investigation of the effects of climate on the use of electricity by consumers and producers in urban and rural areas within China. It takes advantage of an unusual combination of temporal and regional data sets in order to estimate temperature, as well as price and income elasticities of electricity demand. The estimated positive temperature/electric power feedback implies a continually increasing use of energy to produce electric power which, in China, is primarily based on coal. In the absence of countervailing measures, this will contribute to increased emissions, increased atmospheric concentrations of greenhouse gases, and increases in greenhouse warming.
© 2007 Elsevier B.V.

Modeling climate feedbacks to energy demand: The case of China

This paper is an empirical investigation of the effects of climate on the use of electricity by consumers and producers in urban and rural areas within China. It takes advantage of an unusual combination of temporal and regional data sets in order to estimate temperature, as well as price and income elasticities of electricity demand. The estimated positive temperature/electric power feedback implies a continually increasing use of energy to produce electric power which, in China, is primarily based on coal. In the absence of countervailing measures, this will contribute to increased emissions, increased atmospheric concentrations of greenhouse gases, and increases in greenhouse warming. © 2007 Elsevier B.V.

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