Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Greenhouse Gases”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed2006

Integrated model shows that atmospheric brown clouds and greenhouse gases have reduced rice harvests in India.

Previous studies have found that atmospheric brown clouds partially offset the warming effects of greenhouse gases. This finding suggests a tradeoff between the impacts of reducing emissions of aerosols and greenhouse gases. Results from a statistical model of historical rice harvests in India, coupled with regional climate scenarios from a parallel climate model, indicate that joint reductions in brown clouds and greenhouse gases would in fact have complementary, positive impacts on harvests. The results also imply that adverse climate changes due to brown clouds and greenhouse gases contributed to the slowdown in harvest growth that occurred during the past two decades.

Air Pollutants↗
PubMed2005

[Regional simulation of rice yield change under two emission scenarios of greenhouse gases].

Based on the newest emission scenarios of SO2 and greenhouse gases, i. e., the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emission Scenarios (SRES) A2 and B2 scenarios, and by using RCM (Regional Climate Model)-PRECIS and CERES-Rice model, this paper simulated the rice yield change in 2080 at 50 x 50 km scale. The results showed that there was a great range of yield change across whole China. The yield would increase along the Changjiang River and in South China, and decrease in North and Northeast China. Because of the direct effect of CO2 on rice growth, the SRES A2 scenario would be more positive to the increase of rice yield than B2. In 2080, the total rice yield in whole China would increase under A2 emission scenario, while decrease under B2 emission scenario.

Biomass↗
PubMed2001

Keeping Mars warm with new super greenhouse gases.

Our selection of new super greenhouse gases to fill a putative "window" in a future Martian atmosphere relies on quantum-mechanical calculations. Our study indicates that if Mars could somehow acquire an Earth-like atmospheric composition and surface pressure, then an Earth-like temperature could be sustained by a mixture of five to seven fluorine compounds. Martian mining requirements for replenishing the fluorine could be comparable to current terrestrial extraction.

Journal Article↗
PubMed2002

Path-radiance correction by polarization observation of Sun glint glitter for remote measurements of tropospheric greenhouse gases.

High-accuracy remote measurement of greenhouse gases is hampered by contamination of the field of view by the path radiance of solar radiation scattered from clouds and aerosols. A method is proposed for eliminating the effect of path radiance by differentiating two components of polarized light. The polarization of path radiance is measured directly at the wave-number region of strong water-vapor absorption. Using this measurement, we eliminate the components of path radiance involved in other bands, which are used for greenhouse gas measurements, by differentiating two components of the polarized light. It is shown that the effect of path radiance on retrieving the column amount of gases potentially can be reduced to below 0.1%.

Journal Article↗
PubMed2004

[The research on the law of greenhouse gases emission from warm temperate forest soils in Beijing region].

In situ measurements by closed chamber technique were done to investigate the law of greenhouse gases (Methane, carbon dioxide and Nitrous Oxide) fluxes emission from different warm temperate forest soils (Broad-leaved forest, Form. Quercus liaotungensis and Form. Pinus tabulae) of Dongling mountain in Beijing region. Results show that the all representative types forest soils were sink of CH4 and source of CO2 and N2O. Different type of vegetables and soils result of different fluxes range of the main greenhouse gases. The fluxes range of CH4, CO2 and N2O emission from the three types forest soils were: 42-103 micrograms/(m2.h), 15-344 mg/(m2.h) and -61-101 micrograms/(m2.h); 13-182 micrograms CH4/m2.h, 23-380 mg/(m2.h) and -15-183 micrograms/(m2.h); 12-128 ug CH4/m2.h, 15-292 mg/(m2.h) and -94-153 micrograms/(m2.h); respectively. The mean fluxes of CH4, CO2 and N2O emission from the three types forest soils during the observation period were: -66 micrograms/(m2.h), 145 mg/(m2.h) and 22 micrograms/(m2.h); -67 micrograms/(m2.h), 146 mg/(m2.h) and 45 micrograms/(m2.h); -79 micrograms/(m2.h), 150 mg/(m2.h) and 31 micrograms/(m2.h), respectively. The total amounts of CH4 CO2 and N2O emission from the three types forest soils were -5.34 kg/(hm2.a), 13.9 Mg/(hm2.a) and 2.58 kg/(hm2.a); -6.20 kg/(hm2.a), 14.07 Mg/(hm2.a) and 4.19 kg/(hm2.a); -6.85 kg/(hm2.a), 15.71 Mg/(hm2.a) and 4.30 kg/(hm2.a), respectively.

Carbon Dioxide↗
PubMed2002

Evaluation of the potentialities to reduce greenhouse gases (GHG) emissions resulting from various treatments of municipal solid wastes (MSW) in moist tropical climates: application to Yaounde.

The authors here analyse the emission of greenhouse gases (GHG) resulting from the various treatment of municipal solid waste found in the town of Yaounde. Four management systems have been taken as the basis for analyses. System 1 is the traditional collection and landfill disposal, while in system 2 the hiogas produced in the landfill is recuperated to produce electricity. In systems 3 and 4, in addition to the collection, we have introduced a centralised composting or biogas plant before the landfilling disposal of refuse. A Life Cycle Inventory (LCI) of the four systems was made; this enable us to quantify the flux of matter and of energy, consumed or produced by the systems. Following this, only the greenhouse effect was taken into account to evaluate the ecological consequences of the MSW management systems. The method used to evaluate this impact takes into consideration on the one hand, GHG emissions or avoided emission following the substitution of fuel with methane recovered from landfills or produced in the digesters, and on the other hand, sequestrated carbon in the soil following the regular deposit of compost. Landfilling without recuperation of methane is the most emitting solution for greenhouse gas: it leads to the emission of 1.7 ton of carbon dioxide equivalent (tCO2E) per ton of household waste. Composting and methanisation allow one to have a comparable level of emission reduction, either respectively 1.8 and 2 tCO2E/t of MSW. In order to reduce the emission of GHG in the waste management systems, it is advisable to avoid first of all the emissions of methane coming from the landfills. System 2 seems to be a solution that would reduce the emissions of GHG at low cost (2.2 to 4 $/tCO2E). System 2 is calculated as the most effective at the environmental and economic level in the context of Yaounde. Therefore traditional collection, landfill disposal and biogas recuperation to produce electricity is preferable in moist tropical climates.

Air Pollution↗
PubMed2005

Anaerobic digestion: impact of future greenhouse gases mitigation policies on methane generation and usage.

The debate as to whether carbon dioxide, methane, nitrous oxide and other greenhouse gas emissions will become subject to increasing regulation, increased restrictions, and probably to some form of carbon tax, has moved from a simple "yes" or "no" to "when". Wastewater treatment plants will be significantly impacted by increased energy costs and by specific regulations and/or penalties associated with emissions of methane and nitrous oxide. In this paper, the greenhouse gases emissions of different wastewater process options are estimated. The paper outlines the increasing need for wastewater treatment plants to factor greenhouse gas mitigation issues into their medium- as and long-term strategies, and identifies anaerobic enhouse as processes as being at the core of such strategies. Further, the paper identifies a number of key research challenges to be addressed if such strategies are to play a larger role in attenuating the likely impacts of GHG mitigation requirements on wastewater treatment plant design and operation.

Air Pollutants↗
PubMedDate not supplied

Cattle feedlot soil moisture and manure content: I. Impacts on greenhouse gases, odor compounds, nitrogen losses, and dust.

Beef cattle feedlots face serious environmental challenges associated with manure management, including greenhouse gas, odor, NH3, and dust emissions. Conditions affecting emissions are poorly characterized, but likely relate to the variability of feedlot surface moisture and manure contents, which affect microbial processes. Odor compounds, greenhouse gases, nitrogen losses, and dust potential were monitored at six moisture contents (0.11, 0.25, 0.43, 0.67, 1.00, and 1.50 g H2O g(-1) dry matter [DM]) in three artificial feedlot soil mixtures containing 50, 250, and 750 g manure kg(-1) total (manure + soil) DM over a two-week period. Moisture addition produced three microbial metabolisms: inactive, aerobic, and fermentative at low, moderate, and high moisture, respectively. Manure content acted to modulate the effect of moisture and enhanced some microbial processes. Greenhouse gas (CO2, N2O, and CH4) emissions were dynamic at moderate to high moisture. Malodorous volatile fatty acid (VFA) compounds did not accumulate in any treatments, but their persistence and volatility varied depending on pH and aerobic metabolism. Starch was the dominant substrate fueling both aerobic and fermentative metabolism. Nitrogen losses were observed in all metabolically active treatments; however, there was evidence for limited microbial nitrogen uptake. Finally, potential dust production was observed below defined moisture thresholds, which were related to manure content of the soil. Managing feedlot surface moisture within a narrow moisture range (0.2-0.4 g H2O g(-1) DM) and minimizing the accumulation of manure produced the optimum conditions that minimized the environmental impact from cattle feedlot production.

Animal Husbandry↗
PubMed2000

Greenhouse gases in intensive agriculture: contributions of individual gases to the radiative forcing of the atmosphere

Agriculture plays a major role in the global fluxes of the greenhouse gases carbon dioxide, nitrous oxide, and methane. From 1991 to 1999, we measured gas fluxes and other sources of global warming potential (GWP) in cropped and nearby unmanaged ecosystems. Net GWP (grams of carbon dioxide equivalents per square meter per year) ranged from 110 in our conventional tillage systems to -211 in early successional communities. None of the annual cropping systems provided net mitigation, although soil carbon accumulation in no-till systems came closest to mitigating all other sources of GWP. In all but one ecosystem, nitrous oxide production was the single greatest source of GWP. In the late successional system, GWP was neutral because of significant methane oxidation. These results suggest additional opportunities for lessening the GWP of agronomic systems.

Journal Article↗
PubMed2006

Investigation of a new approach to decompose two potent greenhouse gases: photoreduction of SF(6) and SF(5)CF(3) in the presence of acetone.

In this paper, we addressed the utilization of photochemical method as an innovative technology for the destruction and removal of two potent greenhouse gases, SF(6) and SF(5)CF(3). The destruction and removal efficiency (DRE) of the process was determined as a function of excitation wavelength, irradiation time, initial ratio of acetone to SF(5)X (X represented F or CF(3)), initial SF(5)X concentration, additive oxygen and water vapor concentration. A complete removal was achieved by a radiation period of 55min and 120min for SF(6)-CH(3)COCH(3) system and SF(5)CF(3)-CH(3)COCH(3) system respectively under 184.9nm irradiation. Extra addition of water vapor can enhance DRE by approximately 6% points in both systems. Further studies with GC/MS and FT-IR proved that no hazardous products such as S(2)F(10), SO(2)F(2), SOF(2), SOF(4) were generated in this process.

Acetone↗
PubMed2004

Changes in the regional emissions of greenhouse gases and ozone-depleting compounds.

In the wake of the Kyoto and Montreal Protocols, there is a need to verify whether policies to reduce emissions are working. We present data showing that emissions of ozone-depleting compounds, such as the chlorofluorocarbons and methyl chloroform, are decreasing from some regions of the United States but emissions of the greenhouse gases do not appear to be declining.

Air Pollutants↗
PubMed2005

Adsorption of super greenhouse gases on microporous carbons.

Grand canonical Monte Carlo simulations are reported for low molecular weight perfluorocarbons (C2F6 and CF4) and their dilute (10% molar) mixtures in N2 adsorbing unto slitlike graphite pores. Adsorption isotherms and selectivity plots are shown for various temperatures, pressures, and pore widths. It is shown how selectivities on the order of thousands may be obtained when appropriate pore widths and thermodynamic conditions are used. Selective entrapment of these super greenhouse gases onto carbon nanopores is shown to be a promising alternative in the remediation of air streams.

Adsorption↗
PubMed2002

Renewable energies in electricity generation for reduction of greenhouse gases in Mexico 2025.

This study presents 4 scenarios relating to the environmental futures of electricity generation in Mexico up to the year 2025. The first scenario emphasizes the use of oil products, particularly fuel oil, and represents the historic path of Mexico's energy policy. The second scenario prioritizes the use of natural gas, reflecting the energy consumption pattern that arose in the mid-1990s as a result of reforms in the energy sector. In the third scenario, the high participation of renewable sources of energy is considered feasible from a technical and economic point of view. The fourth scenario takes into account the present- and medium-term use of natural-gas technologies that the energy reform has produced, but after 2007 a high and feasible participation of renewable sources of energy is considered. The 4 scenarios are evaluated up to the year 2025 in terms of greenhouse gases (GHG) and acid rain precursor gases (ARPG).

Acid Rain↗