Global Greenhouse Effect Research Articles

Temporal variation in N 2O and N 2 fluxes from a permanent pasture in Switzerland in relation to management, soil water content and soil temperature

Nitrous oxide (N 2O) is an important greenhouse gas, and as such it contributes to the global greenhouse effect. Agro-ecosystems, including fertilized grasslands, represent a major source of N 2O, which is emitted together with N 2. In order to reduce the loss of fertilizer-N in the form of N 2O and N 2 by adjusting grassland management, it is important to understand the relationship between the emission of these gasses after fertilization and the conditions in the soil–plant system. This relationship was studied by determining the seasonal patterns of N 2O and N 2 fluxes, soil temperature, and soil water content based on weekly measurements between May and November in 1993, and between April and November in 1994. Measurements were carried out in fertilized and regularly cut pasture at a site located in the foothills of the Swiss Alps with a humus rich sandy loam Gleyic Cambisol. N fluxes were measured using soil cores incubated in the field either with or without acetylene inhibition. Highest N fluxes were measured from wet soil after plant cutting, and after N fertilizer application. For individual N applications, estimates of N loss relative to the amount of N applied ranged from 0.05% to 5.2% for N 2O and from 0% to 25.5% for N 2. The largest portion of the annual N loss as N 2O occurred during early spring (about 66%) and coincided with soil thawing, and as N 2 during autumn (44–62%) in combination with high soil water contents and advanced plant development. The magnitude of the fluxes of N 2O and N 2 were not directly correlated with soil temperature, but increased with increasing soil water content. N 2/N 2O ratio was largest at soil water contents above 60% water-filled pore space, and was further enhanced in the presence of a well developed plant canopy. The data suggest that in this managed grassland system soil moisture content and the stage of canopy development are the main factors regulating the seasonal pattern of N 2O and N 2 losses, and their ratio.

The aim of the symposium

The polar regions play a crucial role in global climate change. They are sensitive indicators of change and their snow and ice features are good integrators of change. They store long-term climatic records in their ice sheets, such as the Antarctic and Greenland ice sheets. They also affect the global climate directly through interactions between their atmospheres, ice cover, and oceans, and through feedback processes. Practically all climate models predict an amplification of the global greenhouse effect at high latitudes, but models as well as observations have produced results that are not easily interpreted.

Tropical and global scale interactions among water vapor, atmospheric greenhouse effect, and surface temperature

We employ a multitude of global data sets to extend recent analyses of atmospheric greenhouse effect and its dependence on surface temperature (Ts) and vertical water vapor distribution. The new data encompasses a global domain including both the continents and the oceans as well as both the ascending and descending branches of the Walker and Hadley cells and the extratropical storm track regions. We adopt the radiometric definition of the atmospheric greenhouse effect, Ga, which is the difference between the surface longwave emission and the outgoing longwave radiation. We derive the global average greenhouse effect over both oceans and land areas. The east to west variations of the normalized atmospheric greenhouse effect (ga) and precipitable water (w) are just as strong as the north to south variations, thus illustrating the strong role of the dynamics in w and ga. Between 60°N and 60°S the lowest values of ga (0.11–0.15) are found over the Saharan and other deserts; while the largest values (0.35–0.40) are found over the warm oceans with a deep convective atmosphere. The coupling between Ga, and the vertical distribution of atmospheric water vapor and temperature, is examined from monthly mean annual cycle. When averaged from the southern to the northern latitudes, these quantities exhibit a statistically significant annual cycle. The annual cycle of Ts, about 1 K for the tropics (30°N to 30°S) and about 4 K for the globe, is large enough to obtain a statistically significant estimate for the sensitivity parameter dGa/dTs. It is as large as 5.5–6 W m−2 K−1 for tropical mean conditions (30°N to 30°S) and reduces to a global mean value of 3.5 W m−2 K−1 (with a 2σ range of 2.9–4.1 W m−2 K−1). Consistent with earlier studies, the tropics exhibit a strong positive coupling between Ts, Ga, and water vapor distribution with large increases in the midtroposphere humidity. However, poleward of 30°N, water vapor increases are about half as much as that in the tropics, and the sensitivity parameter dGa/dTs decreases. This is because poleward of 30°, the annual cycle is dominated by land surface temperature changes which are not so effective as sea surface temperature changes in enhancing the water vapor greenhouse effect. Irrespective of the region (ocean or land) or the latitude domain (tropics or extratropics), the data presented here do not offer any support for the suggestion that increases in tropical or global mean surface temperature would lead to a decrease in water vapor greenhouse effect by drying the middle to upper troposphere. If any, the global scale sensitivity derived from the annual cycle is consistent with the magnitude of the positive feedback obtained by general circulation models.

The temporal and spatial characteristics of the surface air temperature variations over the Antarctic and its surrounding area

The characteristics of the spatial distribution, temporal variations trend and oscillation for the surface air temperature variations during 1957—1993 in the Antarctic and its surrounding area were analyzed. The results show that the short-time climate change in the Antarctic is complex both temporally and spatially. The Antarctic is by no means the strongest responding region to the global greenhouse effect. There is a distinguished difference in the trends of the temperature changes for the Antarctic and global mean, which could not be explained simply by the global greenhouse effect.

Volcanic sulfur emissions: Estimates of source strength and its contribution to the global sulfate distribution

Anthropogenic emission of SO2 and conversion into SO42− is argued to be the most important factor damping and modulating the global greenhouse effect. Recent estimates of the relative strength of the three important sources of volatile sulfur (SO2 from fossil fuel combustion ∼78 Tg S/yr, from biomass burning ∼2 Tg S/yr, and from natural sources ∼25 Tg S/yr) suggest an over‐whelming effect of the anthropogenic emissions for climate forcing. However, the radiauvely relevant product SO42− may have different patterns due to the distribution of the sources (some very dense areas near the surface for anthropogenic SO2, formation of SO2 from dimethylsulfide in the marine boundary layer, and emission of volcanic SO2 mostly in the free atmosphere in rural areas). In this paper we study the relative contribution of volcanic SO2 emissions to the atmospheric sulfur budget applying an atmospheric general circulation model including a full sulfur cycle and prescribed source distributions. An off‐line analysis tool is applied to determine the radiative forcing of sulfate aerosols. The results show that natural S sources are at least as important as the anthropogenic ones, even though their source strength is much smaller. The reasons are different lifetimes due to different production and emission processes. Therefore, we should improve our knowledge about the volcanic volatile sources and their time‐space variability.

Lateritic bauxite in central Germany and implications for Miocene palaeoclimate

Intense chemical weathering during middle Miocene times led to the formation of deep ferralitic weathering profiles on the Vogelsberg basaltic massif. Saprolite more than 50 m thick, was formed and, in its higher parts, bauxite concretions developed by absolute accumulation of aluminium. The tops of the profiles consist mostly of allochthonous, lateritic bauxite which has been mined intensively in the past. Similar high latitude bauxites occur on the Paleogene basalts of Ireland. These formed during a phase of recognized greenhouse conditions with a climatic optimum near the Paleocene-Eocene boundary, while during the Miocene the climate was already changing toward Quaternary icehouse conditions. However, the occurrence of deep weathering profiles with lateritic bauxite at the high palaeolatitude of 45°N may be interpreted as pointing to extreme climatic conditions also during the middle Miocene. The associated laterites and bauxites on middle Miocene basalts (17-15 Ma) provide evidence for a global climatic optimum around 17-14.5 Ma. Reduced uplift rates of the Himalayan-Tibetan Plateau and associated reduced CO2 consumption, coupled with additional volcanogenic CO2 production could have induced high atmospheric CO2 and an intensification of the global greenhouse effect. This may be reflected in accelerated chemical weathering and bauxite formation. Basalt volcanism has thus provided both a source (eruption) and a sink (via weathering) of CO2.

THE STUDY OF GAS HYDRATES AND ITS RELATION WITH GLOBAL CHANGES

Gas hydrates contains a large quantity of organic carbon which exceeds the total organic carbon from other sources. It is an important carbon reservoir in shallow geosphere. A slight variation of temperature/pressure would cause the formation/decomposition of gas hydrates,and subsequent consumption/release of methane. This exerts significant influence on global carbon cycle and greenhouse effect. The Polar regions differ from the mediate low latitudes on the feedback of gas hydrates to global climate change and galcial/interglacial alternation. Even in mediate low latitudes there exist two processes of opposite directions. The total effect of gas hydrates on global changes needs to be estimated in further researches. In China seas, there exist T P conditions suitable for the occurrence of gas hydrates. The BSR as an indication of gas hydrates has been reported in southern South China Sea. The total reserves of gas hydrates and their feedback to sea level changes in China seas may be assessed based on careful re interpretation of seismic profiles and computer simulations. This may provide an example for the marginal seas.

Non-CO2 emitting renewable energy sources in Nepal: Problems and prospects

The renewable energy sources of Nepal is highlighted. The huge hydro-power potential of Nepal is explained. The problems associated with its wide exploitation are given. Nepal's contribution to the global greenhouse effect through the emission of CO2, CH4 and CFSs from industrial emissions (cement, brick, and other factories), automotive vehicles, indoor biomass combustion, outdoor biomass combustion, petroleum products consumption and fuel based thermal plant generating 85 GWh is estimated. Equivalent CO2 saved by hydro and PV power is analyzed. Per capita consumption of CO2 is mentioned. Early precaution needed to be taken in reducing CO2 emissions from different sources is highlighted.

Affection of Livestock Farming to Global Environmental Burdens and Greenhouse Effect

Affection of Livestock Farming to Global Environmental Burdens and Greenhouse Effect

Carbon Taxes, Consumer Demand and Carbon Dioxide Emissions: A Simulation Analysis for the UK

In this paper we examine the effects of a carbon tax, one of the possible instruments for reducing carbon dioxide (CO2) emissions. Such taxes are currently being proposed as a means of reducing CO2 emissions, motivated by concerns about the global greenhouse effect and its potential impact on global climate and sea levels (Cline, 1991) and on global economies (Nordhaus, 1991). We therefore take as our problem the reduction of CO2 emissions by the UK economy by use of a carbon tax, and the corresponding effect of this tax on the purchasing power and economic behaviour of households. If they were introduced, carbon taxes would affect the price of fossil fuels in the UK, and thus UK consumer prices, both directly for fuels and indirectly for manufactured goods. These price changes would in turn affect the level and structure of UK final demand, and it is this post-tax UK final demand which will determine UK fossil fuel use, and thus CO2 emissions. In particular, we investigate the social effects of a carbon tax, by considering the distribution of the increased tax burden across consumers.

New safety issues when moving from liquid fuels to natural gas

Natural gas (NG) is produced whenever organic matter is decomposed in the absence of oxygen. The main constituent of natural gas is methane. In contrast to liquid fuels, methane has a boiling point far below normal ambient temperatures. Even the critical temperature is well below ambient. Therefore natural gas must be stored either as compressed natural gas (CNG) at very high pressures at ambient temperatures, or as liquefied natural gas (LNG) at very low temperatures. The basic safety issues are caused by loss of confinement of either CNG or LNG. In both cases the issues are: global greenhouse effects of natural gas (methane); local fire and explosion hazards; and local asphyxiation hazard due to reduced oxygen content in the atmosphere breathed when air is mixed with methane.

Automotive emissions in developing countries-relative implications for global warming, acidification and urban air quality

This paper attempts to assess the magnitude and scope of automotive pollutant emissions in developing countries and their role in global warming, regional scale air pollution and urban air quality. Greenhouse-gas emissions (CO 2 and CFCs) from motor vehicles in developing countries contribute less than 3% to the global greenhouse effect, compared to a 9 to 12% contribution from motor vehicles in OECD countries and Eastern Europe. The share of OECD countries in conventional pollutant emissions from motor vehicles exceeds the combined contribution of all developing countries by a factor of three to five. Acid deposition from motor vehicle emissions does not currently appear to be a problem in developing countries. The incidence of regional scale ozone is not known but could be potentially significant downstream from large urban centers. There is a need for more systematic monitoring and evaluation of acid deposition and regional ozone concentrations in developing countries. Urban air quality is the prime casualty of motorization in developing countries. The air pollution problem will intensify in developing countries with increasing urbanization and the rapid pace of motorization. Urban concentrations of carbon monoxide, airborne lead, particulate matter and sulfur oxides in many developing countries already exceed the levels in industrialized countries. Motor vehicles emit 30% to 85% of all man-made air pollutants in the large urban areas in developing countries, depending on the level of motorization. Without effective measures to control pollutant emissions, some 300 to 500 million city dwellers in developing countries will become exposed to unhealthy and dangerous levels of air pollution from motor vehicles by the year 2000.

Climate forcing by stratospheric aerosols

We illustrate how climate forcing by stratospheric aerosols depends on aerosol properties. The climate forcing is a function of aerosol size distribution, but the size dependence can be described well by a single parameter: the area‐weighted mean radius, reff.If reff is greater than about 2 μm, the global average greenhouse effect of the aerosols exceeds the albedo effect, causing a surface heating. The aerosol climate forcing is less sensitive to other characteristics of the size distribution, the aerosol composition, and the altitude of the aerosols. Thus stratospheric aerosol forcing can be defined accurately from measurements of aerosol, extinction over a broad wavelength range.

Cyclic voltammetric study on carbon dioxide reduction using Cu complexes as electrocatalysts

From the aspect of the global greenhouse effect, CO, reduction has received great interest recently. The electrochemical reduction of CO, has been studied extensively so far and is classified into three categories: (1) direct reduction on metal cathodes [l-9], (2) indirect reduction using metal electrocatalysts [l,lO-221, and (3) co-reduction with organic substrates [1,23-311. Although copper is a unique cathode metal which gives hydrocarbons (mainly CH, and C,H,) in high selectivity in the above category (1) [3], copper electrocatalysts in category (2) have rarely been used. In fact, it has been reported only that a copper-phthalocyanine electrocatalyst has a low catalytic activity [32,33]. Therefore, in this work the CO, reduction was examined by means of cyclic voltammetry using other copper-complex catalysts.

Influence of Global Greenhouse Effect on Seawall Wave Overtopping at Waterfront

In this paper, the following two subjects are investigated.1) Influence to global greenhouse effect on typhoon action.2) Increase of wave overtopping rate due to the combined effects of mean sea level rise, intensified typhoon, and beach erosion.The main conclusions obtained are1) The possibility of intensifying a typhoon due to mean sea level rise can not be neglected in the treatment of greenhouse effect.2) Coastal profile eroded by magnified waves can be predicted by eqs.(5), (6), and (7).3) Rate of wave overtopping is considerably increased by the effect of mean sea level rise and is further increased by beach erosion. the effect of intensifying a typhoon on wave overtopping rate is remarkably large.

International Business, Morality, and the Common Good

The author sets out a realist defense of the claim that in the absence of an international enforcement agency, multinational corporations operating in a competitive international environment cannot be said to have a moral obligation to contribute to the international common good, provided that interactions are nonrepetitive and provided effective signals of agent reliability are not possible. Examples of international common goods that meet these conditions are support of the global ozone layer and avoidance of the global greenhouse effect. Pointing out that the conclusion that multinationals have no moral obligations in these areas is deplorable, the author urges the establishment of an international enforcement agency.

Atmospheric CO estimates may be low

Carbon monoxide, an atmospheric gas that plays an important role in the chemical interactions involved in the global greenhouse effect, may have been underestimated by as much as 25% in some studies, according to a paper published in the Journal of Geophysical Research (vol. 96, D7, July 20, 1991).Paul C. Novelli and L. Paul Steele of the University of Colorado and James W. Elkins of NOAA developed a series of carbon monoxide reference mixtures for use in the calibration of measurements of atmospheric concentrations of CO. They compared various existing CO reference gases from the National Institute of Standards and Technology (NIST) and the Commonwealth Scientific and Industrial Research Organization (CSIRO), whose standards were referenced to those maintained by the Oregon Graduate Institute for Science and Technology (OGIST).

Solar‐generated construction material from sea water to mitigate global warming

The forced global greenhouse effect and consequently rising sea levels are discussed. A brief survey of biomineralization processes and laboratory/field work encompassing mineral accretion (MA) is given, which is performed by placing cathodic forms and anodes in sea water or other electrolytes. It is proposed to grow structures utilizing MA, autopias and substrates for the enhanced growth of coral reefs as an effective sink for carbon to reduce atmospheric carbon dioxide and thus mitigate global warming. The need for further research is emphasized.

Soil organic matter and the global carbon cycle

Abstract There is considerable concern over the annual global increase in CO2 in the atmosphere of around 1.5 ppm. Current thinking is that it is necessary to remove either from the atmosphere or prevent the release of three gigatons (GT) per year of carbon to avoid greenhouse warming of the earth. Suggested solutions have given little or no attention to the role that soil organic matter may have in decreasing atmospheric accumulation of CO2 . The world pool of soil organic matter carbon is around 3,000 GT, so for the foreseeable future, a 0.1 per cent increase to the present supply would be needed per year to remove three GT carbon from the atmosphere. If this could be accomplished, in addition to helping to curtail the possible global greenhouse effect, massive soil improvement could result, especially if the increased soil organic matter were concentrated on lands needing improvement. Indirectly, carbon would be transferred from fossil fuel to soil organic matter. Programs in biotechnology to improve b...

Methane leakage from natural gas

Carbon dioxide (CO 2) emissions from fossil fuels are a major cause of the global greenhouse effect. Fuel switching is one of the options to reduce emissions. However, CO 2 is not the only greenhouse gas. This paper addresses the question whether greenhouse effect mitigating strategies such as fuel switching would change if methane (CH 4) is taken into account, by calculating the global warming from current energy related CH 4 and CO (carbon monoxide) emissions as ‘CO 2 equivalents’.