JP

Global Health and Economic Impacts of Future Ozone Pollution

We assess the human health and economic impacts of projected 2000–2050 changes in ozone pollution using the MIT Emissions Prediction and Policy Analysis - Health Effects (EPPA-HE) model, in combination with results from the GEOS-Chem global tropospheric chemistry model of climate and chemistry effects of projected future emissions. We use EPPA-HE to assess the human health damages (including mortality and morbidity) caused by ozone pollution, and quantify their economic impacts in sixteen world regions. We compare the costs of ozone pollution under scenarios with 2000 and 2050 ozone precursor and greenhouse gas emissions (using the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B scenario). We estimate that health costs due to global ozone pollution above pre-industrial levels by 2050 will be $580 billion (year 2000$) and that mortalities from acute exposure will exceed 2 million. We find that previous methodologies underestimate costs of air pollution by more than a third because they do not take into account the long-term, compounding effects of health costs. The economic effects of emissions changes far exceed the influence of climate alone.

© 2009 Institute of Physics and IOP Publishing Limited

Global Health and Economic Impacts of Future Ozone Pollution

We assess the human health and economic impacts of projected 2000-2050 changes in ozone pollution using the MIT Emissions Prediction and Policy Analysis-Health Effects (EPPA-HE) model, in combination with results from the GEOS-Chem global tropospheric chemistry model that simulated climate and chemistry effects of IPCC SRES emissions. We use EPPA to assess the human health damages (including acute mortality and morbidity outcomes) caused by ozone pollution and quantify their economic impacts in sixteen world regions. We compare the costs of ozone pollution under scenarios with 2000 and 2050 ozone precursor and greenhouse gas emissions (SRES A1B scenario). We estimate that health costs due to global ozone pollution above pre-industrial levels by 2050 will be $580 billion (year 2000$) and that acute mortalities will exceed 2 million. We find that previous methodologies underestimate costs of air pollution by more than a third because they do not take into account the long-term, compounding effects of health costs. The economic effects of emissions changes far exceed the influence of climate alone.

Global passenger travel: Implications for CO2 emissions

Humans spend, on average, a constant fraction of their time and expenditure on travel. These and a few other constraints allow a new model for projecting regional and world travel, which we use to develop a scenario for carbon emissions from passenger transport. Globally, carbon emissions rise from 0.8 GtC in 1990 to 2.7 GtC in 2050. In every industrialized region aircraft and high-speed trains become the dominant mode; unable to satisfy the rising demand for mobility within a fixed travel time budget, automobile travel declines by 2050. Passenger transport carbon emissions stabilize by 2020 without any further policy intervention. But in developing countries automobile travel is still rising and becomes the dominant source of carbon dioxide from passenger transport. Fear of global warming may require stabilization of these emissions by mid-century. We show that without some action to accelerate an improvement in energy efficiency starting in the next decade, the goal of stabilization is a technically impossible task, unless zero-carbon technologies become available.

© 1999 Elsevier B.V.

Global Thermohaline Circulation. Part I: Sensitivity to Atmospheric Moisture Transport

A global ocean general circulation model of idealized geometry, combined with an atmospheric model based on observed transports of heat, momentum, and moisture, is used to explore the sensitivity of the global conveyor belt circulation to the surface freshwater fluxes, in particular the effects of meridional atmospheric moisture transports. The numerical results indicate that the equilibrium strength of the North Atlantic Deep Water (NADW) formation increases as the global freshwater transports increase. However, the global deep water formation, i.e., the sum of the NADW and the Southern Ocean Deep Water formation rates, is relatively insensitive to changes of the freshwater flux.
      Perturbations to the meridional moisture transports of each hemisphere identify equatorially asymmetric effects of the freshwater fluxes. The equilibrium NADW formation is primarily controlled by the magnitude of the Southern Hemisphere freshwater flux. The Northern Hemisphere freshwater flux only has a significant impact on the transient behavior of the North Atlantic overturning. Increasing this flux leads to a collapse of the conveyor belt circulation, but the collapse is delayed if the Southern Hemisphere flux also increases. The perturbation experiments also illustrate that the rapidity of collapse is affected by random fluctuations in the wind stress field.

© 1999 American Meteorological Society

Global thermohaline circulation. Part II: Sensitivity with interactive atmospheric transports

A hybrid coupled ocean-atmosphere model is used to investigate the stability of the thermohaline circulation (THC) to an increase in the surface freshwater forcing in the presence of interactive meridional transports in the atmosphere. The ocean component is the idealized global general circulation model used in Part I (below). The atmospheric model assumes fixed latitudinal structure of the heat and moisture transports, while the amplitudes are calculated separately for each hemisphere from the large-scale sea surface temperature (SST) and SST gradient, using parameterizations based on baroclinic stability theory. The ocean-atmosphere heat and freshwater exchanges are calculated as residuals of the steady-state atmospheric budgets.
        Owing to the ocean component's weak heat transport, the model has too strong a meridional SST gradient when driven with observed atmospheric meridional transports. When the latter are made interactive, the conveyor belt circulation collapses. A flux adjustment is introduced in which the efficiency of the atmospheric transports is lowered, to match the too low efficiency of the ocean component.
        The feedbacks between the THC and both the atmospheric heat and moisture transports are positive, whether atmospheric transports are interactive in the Northern Hemisphere, the Southern Hemisphere, or both. However, the feedbacks operate differently in the Northern and Southern Hemispheres, because the THC upwells and causes equatorward heat transport in the latter. The feedbacks in the two hemispheres do not necessarily reinforce each other because they have opposite effects on low-latitude temperatures. The model is qualitatively similar in stability to one with conventional "additive" flux adjustment, but quantitatively more stable.

© 1999 American Meteorological Society

Global Warming

I believe that what we know now about global warming justifies imposition of a modest tax on carbon emissions by the U.S. and other developed nations. This is a first step toward assuring that future generations will not find the concentration of atmospheric gases increased so much that it cannot be practically reversed before changes in the Earth’s climate cause calamitous damage. [...] The U.S. should propose a small carbon tax as an alternative to the current national emission targets on the table for Kyoto. It is a first step that is more consistent with the state of scientific knowledge and the extent of international consensus; and it is a first step that is more likely to be politically acceptable in the U.S. today.

Global Warming Projections: Sensitivity to Deep Ocean Mixing

The climatological impact of increases in greenhouse gas concentrations in the atmosphere, despite being a subject of intensive study in recent years, is still very uncertain. One major uncertainty affecting possible climate change that has not received enough attention is the uncertainty in heat uptake by the deep ocean. We analyze the influence of this process and its uncertainty on climate predictions by means of numerical simulations with a 2-dimensional climate model. In the case of high climate sensitivity, as a result of uncertainty in deep ocean heat uptake, there is more than a factor of two uncertainty in the predicted increase of surface temperature. The corresponding uncertainty in the sea level rise due to thermal expansion is much larger than the uncertainty in the predicted temperature change and is significant even in the case of low climate sensitivity.

Greenhouse Gas Markets, Carbon Dioxide Credits and Biofuels

The biofuels sector is in the midst of turmoil, and many people are asking whether biofuels will be able to deliver on their climate change, energy security and rural development objectives.

Whether biofuels will emerge from the current deadlock will depend on the policies and strategies that countries adopt, says The Biofuels Market: Current Situation and Alternative Scenarios.

The new UNCTAD report discusses "alternative decision paths" governments may consider in relation to biofuels and provides insights on the global repercussions those different choices may imply. The scenarios are linked to the following specific issues:

* The role of government targets for biofuel use.
* Links between biofuels and the greenhouse gas markets.
* Prospects offered by the unfolding of new biofuel technologies and the related intellectual property rights issues.
* Trade potential available to developing countries.
* Possible changes that could occur in current production and trade patterns, should alternative biofuel feedstocks become commercially available.

The report represents a new contribution by UNCTAD to the analysis of this dynamic and complex sector of the world economy.

This activity was made possible by the generous financial contribution of the Ministry of Environment, Land and Sea of Italy. UNCTAD has been working on the trade and development implications of biofuels since 2005, through its Biofuels Initiative.

© 2009 United Nations

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