Nitrous Oxide: Trends and Global Mass Balance Over the Last 3000 Years

1988 ◽  
Vol 10 ◽  
pp. 73-79 ◽  
Author(s):  
M.A.K. Khalil ◽  
R.A. Rasmussen
Keyword(s):  
Nitrous Oxide ◽  
Fossil Fuels ◽  
Ice Cores ◽  
Average Concentration ◽  
Rate Of Change ◽  
Nitrogen Fertilizers ◽  
Anthropogenic Sources ◽  
Polar Regions ◽  
Atmospheric Concentration ◽  
Slow Increase

We analyzed ice cores from both northern and southern polar regions to determine the concentrations of nitrous oxide in the pre-industrial and ancient atmospheres from about 150 years to 3000 yearsB.P.We found that the pre-industrial concentration of nitrous oxide remained constant over the period we studied and that the average atmospheric concentration was 285 ± 1 ppb volume (90% confidence limits), representing about 2100 Tg (2100 × 1012g) of N20 in the atmosphere, whereas the average concentration in 1984 was about 307 ppb volume or 2260 Tg. This is a change of 22 ppb volume (160 Tg), or about 8%, between pre-industrial and present times. Now the rate of change is between 0.7 and 0.9 ppb volume/year or 5 and 6.5 Tg/year, which is a slow increase of about 0.3% per year. The changes observed are probably caused by increasing use of fossil fuels, particularly coal and oil, and perhaps to a lesser extent by the use of nitrogen fertilizers in recent years. The atmospheric lifetime of N2O is probably between 100 and 150 years. The pre-industrial concentrations, present levels, and a lifetime of 100 years are consistent with natural sources, mostly soils and oceans, of about 22 Tg/year and the present anthropogenic sources of about 8.7 Tg/year. In the next 50 years we expect nitrous oxide levels to reach 360–390 ppb volume, or about 16–25% more than present.

scholarly journals Nitrous Oxide: Trends and Global Mass Balance Over the Last 3000 Years

1988 ◽  
Vol 10 ◽  
pp. 73-79 ◽  
Author(s):  
M.A.K. Khalil ◽  
R.A. Rasmussen
Keyword(s):  
Nitrous Oxide ◽  
Fossil Fuels ◽  
Ice Cores ◽  
Average Concentration ◽  
Rate Of Change ◽  
Nitrogen Fertilizers ◽  
Anthropogenic Sources ◽  
Polar Regions ◽  
Atmospheric Concentration ◽  
Slow Increase

We analyzed ice cores from both northern and southern polar regions to determine the concentrations of nitrous oxide in the pre-industrial and ancient atmospheres from about 150 years to 3000 yearsB.P.We found that the pre-industrial concentration of nitrous oxide remained constant over the period we studied and that the average atmospheric concentration was 285 ± 1 ppb volume (90% confidence limits), representing about 2100 Tg (2100 × 1012g) of N20 in the atmosphere, whereas the average concentration in 1984 was about 307 ppb volume or 2260 Tg. This is a change of 22 ppb volume (160 Tg), or about 8%, between pre-industrial and present times. Now the rate of change is between 0.7 and 0.9 ppb volume/year or 5 and 6.5 Tg/year, which is a slow increase of about 0.3% per year. The changes observed are probably caused by increasing use of fossil fuels, particularly coal and oil, and perhaps to a lesser extent by the use of nitrogen fertilizers in recent years. The atmospheric lifetime of N2O is probably between 100 and 150 years. The pre-industrial concentrations, present levels, and a lifetime of 100 years are consistent with natural sources, mostly soils and oceans, of about 22 Tg/year and the present anthropogenic sources of about 8.7 Tg/year. In the next 50 years we expect nitrous oxide levels to reach 360–390 ppb volume, or about 16–25% more than present.

scholarly journals Variations in global methane sources and sinks during 1910–2010

2014 ◽  
Vol 14 (20) ◽  
pp. 27619-27661 ◽  
Author(s):  
A. Ghosh ◽  
P. K. Patra ◽  
K. Ishijima ◽  
T. Umezawa ◽  
A. Ito ◽  
...  
Keyword(s):  
Air Temperature ◽  
General Circulation ◽  
Transport Model ◽  
Circulation Model ◽  
Ice Cores ◽  
Growth Period ◽  
Rate Of Change ◽  
Anthropogenic Sources ◽  
Biogeochemical Model ◽  
Bottom Up

Abstract. Atmospheric methane (CH4) increased from ~900 ppb (parts per billion, or nanomoles per mole of dry air) in 1900 to ~1800 ppb during the 2000s at a rate unprecedented in any observational records. However, the causes of the CH4 increase are poorly understood. Here we use initial emissions from bottom-up inventories for anthropogenic sources, emissions from wetlands and rice paddies simulated by a terrestrial biogeochemical model, and an atmospheric general circulation model (AGCM)-based chemistry-transport model (i.e. ACTM) to simulate atmospheric CH4 concentrations for 1910 to 2010. The ACTM simulations are compared with the CH4 concentration records reconstructed from Antarctic and Arctic ice cores and firn air samples, and from direct measurements since the 1980s at multiple sites around the globe. The differences between ACTM simulations and observed CH4 concentrations are minimized to optimize the global total emissions using a mass balance calculation. During 1910–2010, the global total CH4 emission increased from ~290 Tg yr−1 to ~580 Tg yr−1. Compared to optimized emission the bottom-up emission dataset underestimates the rate of change of global total CH4 emissions by ~30% during the high growth period of 1940–1990, while it overestimates by ~380% during a~low growth period of 1990–2010. Further, using the CH4 stable carbon isotopic data (δ13C), we attribute the emission increase during 1940–1990 primarily to enhancement of biomass burning. The total lifetime of CH4 shortened from 9.4 yr during 1910–1919 to 9 yr during 2000–2009 by the combined effect of increasing abundance of atomic chlorine radicals (Cl) and increases in average air temperature. We show that changes of CH4 loss rate due to increased tropospheric air temperature and CH4 loss due to Cl in the stratosphere are important sources of uncertainty to more accurately estimate global CH4 budget from δ13C observations.

scholarly journals Greenhouse Gases from Agriculture

2021 ◽  
pp. 1-10
Author(s):  
M. Zaman ◽  
K. Kleineidam ◽  
L. Bakken ◽  
J. Berendt ◽  
C. Bracken ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Greenhouse Gases ◽  
Fossil Fuels ◽  
Management Practices ◽  
Global Climate ◽  
Terrestrial Ecosystems ◽  
Animal Manure ◽  
Anthropogenic Sources ◽  
Natural Sources ◽  
Animal Excreta

AbstractThe rapidly changing global climate due to increased emission of anthropogenic greenhouse gases (GHGs) is leading to an increased occurrence of extreme weather events such as droughts, floods, and heatwaves. The three major GHGs are carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). The major natural sources of CO2 include ocean–atmosphere exchange, respiration of animals, soils (microbial respiration) and plants, and volcanic eruption; while the anthropogenic sources include burning of fossil fuel (coal, natural gas, and oil), deforestation, and the cultivation of land that increases the decomposition of soil organic matter and crop and animal residues. Natural sources of CH4 emission include wetlands, termite activities, and oceans. Paddy fields used for rice production, livestock production systems (enteric emission from ruminants), landfills, and the production and use of fossil fuels are the main anthropogenic sources of CH4. Nitrous oxide, in addition to being a major GHG, is also an ozone-depleting gas. N2O is emitted by natural processes from oceans and terrestrial ecosystems. Anthropogenic N2O emissions occur mostly through agricultural and other land-use activities and are associated with the intensification of agricultural and other human activities such as increased use of synthetic fertiliser (119.4 million tonnes of N worldwide in 2019), inefficient use of irrigation water, deposition of animal excreta (urine and dung) from grazing animals, excessive and inefficient application of farm effluents and animal manure to croplands and pastures, and management practices that enhance soil organic N mineralisation and C decomposition. Agriculture could act as a source and a sink of GHGs. Besides direct sources, GHGs also come from various indirect sources, including upstream and downstream emissions in agricultural systems and ammonia (NH3) deposition from fertiliser and animal manure.

scholarly journals Variations in global methane sources and sinks during 1910–2010

2015 ◽  
Vol 15 (5) ◽  
pp. 2595-2612 ◽  
Author(s):  
A. Ghosh ◽  
P. K. Patra ◽  
K. Ishijima ◽  
T. Umezawa ◽  
A. Ito ◽  
...  
Keyword(s):  
Air Temperature ◽  
General Circulation ◽  
Ice Cores ◽  
Growth Period ◽  
Rate Of Change ◽  
Anthropogenic Sources ◽  
Biogeochemical Model ◽  
Data Set ◽  
Bottom Up ◽  
Sources And Sinks

Abstract. Atmospheric methane (CH4) increased from ~900 ppb (parts per billion, or nanomoles per mole of dry air) in 1900 to ~1800 ppb in 2010 at a rate unprecedented in any observational records. However, the contributions of the various methane sources and sinks to the CH4 increase are poorly understood. Here we use initial emissions from bottom-up inventories for anthropogenic sources, emissions from wetlands and rice paddies simulated by a~terrestrial biogeochemical model, and an atmospheric general circulation model (AGCM)-based chemistry-transport model (i.e. ACTM) to simulate atmospheric CH4 concentrations for 1910–2010. The ACTM simulations are compared with the CH4 concentration records reconstructed from Antarctic and Arctic ice cores and firn air samples, and from direct measurements since the 1980s at multiple sites around the globe. The differences between ACTM simulations and observed CH4 concentrations are minimized to optimize the global total emissions using a mass balance calculation. During 1910–2010, the global total CH4 emission doubled from ~290 to ~580 Tg yr−1. Compared to optimized emission, the bottom-up emission data set underestimates the rate of change of global total CH4 emissions by ~30% during the high growth period of 1940–1990, while it overestimates by ~380% during the low growth period of 1990–2010. Further, using the CH4 stable carbon isotopic data (δ13C), we attribute the emission increase during 1940–1990 primarily to enhancement of biomass burning. The total lifetime of CH4 shortened from 9.4 yr during 1910–1919 to 9 yr during 2000–2009 by the combined effect of the increasing abundance of atomic chlorine radicals (Cl) and increases in average air temperature. We show that changes of CH4 loss rate due to increased tropospheric air temperature and CH4 loss due to Cl in the stratosphere are important sources of uncertainty to more accurately estimate the global CH4 budget from δ13C observations.

Modeling nitrous oxide mitigation potential of enhanced efficiency nitrogen fertilizers from agricultural systems

2021 ◽  
pp. 149342
Author(s):  
Ram B. Gurung ◽  
Stephen M. Ogle ◽  
F. Jay Breidt ◽  
William J. Parton ◽  
Stephen J. Del Grosso ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Nitrogen Fertilizers ◽  
Agricultural Systems ◽  
Mitigation Potential ◽  
Nitrous Oxide Mitigation

scholarly journals Glaciological Investigations of the Tropical Quelccaya Ice Cap, Peru

1980 ◽  
Vol 25 (91) ◽  
pp. 69-84 ◽  
Author(s):  
Lonnie G. Thompson
Keyword(s):  
Rainy Season ◽  
Ice Core ◽  
Ice Cores ◽  
Dry Season ◽  
Radioactive Material ◽  
Polar Regions ◽  
Near Surface ◽  
Ice Cap ◽  
Activity Measurements ◽  
Quelccaya Ice Cap

AbstractGlaciological results of the continuing investigations of the Quelccaya ice cap located at lat. 13° 56’ S., long. 70° 50’ W., in the Cordillera Oriental of southern Peru are presented. Ice cores to a depth of 15 m have been retrieved from the summit dome (5650 m), middle dome (5543 m), and south dome (5480 m) and sampled in detail for microparticle, oxygen-isotope, and total-β-activity measurements. Results of these core analyses indicate that although the summit of this ice cap is only 300 m above the annual snow line and the firn is temperate, an interpretable stratigraphic record is preserved. The marked seasonal ice stratigraphy is produced by the marked seasonal variation in regional precipitation. High concentrations of microparticles and β- radioactive material occur during the dry season (May-August). Microparticles deposited during the rainy season are larger than those deposited during the dry season. On the Quelccaya ice cap the most negative δ18O values occur during the warmer rainy season (the opposite occurs in polar regions). The near-surface mean δ value of – 21‰ is remarkably low for this tropical site where the measured mean annual air temperature is – 3°C The seasonality of the microparticles, total β activity, and isotope ratios offers the prospect of a climatic ice-core record from this tropical ice cap.

Effects of Nitrogen Fertilizer on Switchgrass Productivity and Soil Trace Gas Production

2016 ◽  
Author(s):  
Serra Buchanan
Keyword(s):  
Nitrogen Fertilizer ◽  
Fossil Fuels ◽  
Cost Benefit Analysis ◽  
Cost Benefit ◽  
Gas Production ◽  
Nitrogen Fertilizers ◽  
Bioenergy Crops ◽  
N2o Production ◽  
Switch Grass ◽  
Ch4 Production

Atmospheric greenhouse gas (GHG) concentrations continue to increase and one of the major culprits is the continued elevation and use of fossil fuels for energy. Using bioenergy, a renewable and sustainable source of natural energy, could help to reduce the effect that fossil fuels are having on the planet by slowing the rate of input of atmospheric GHG’s. Perennial crops such as switch grass can be grown and used as a bioenergy crop. In some cases, nitrogen fertilizers are used to increase the growth of bioenergy crops with potential negative environmental consequences. For example, nitrogen fertilizer can impact soil chemical processes and lead to an increase in the production of greenhouse gases, mainly N2O and CH4. Production of these gases would negate some of the benefits achieved by substituting bioenergy crops for fossil fuels. When I examined the amount of gas flux being produced by switchgrass fields, with 0 lbs/acre, 50 lbs/acre and 150lbs/acre fertilizer treatments we observed, as predicted, an increase in N2O production with more fertilization. In some cases the increase in N2O production in the 150lbs/acre treatment was as extreme as being over 200% larger compared with no fertilization. I also observed some very interesting results with methane production, which has been showing production of methane, along with after around 30 minutes of gas collection in a chamber. Based on the results of my research, I have created a cost benefit analysis of using nitrogen fertilizer on switchgrass crops.

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