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Atmospheric nitrous oxide: patterns of global change during recent decades
and centuries
Khalil, MAK | Rasmussen, RA | Shearer, MJ
Chemosphere [Chemosphere]. Vol. 47, no. 8, pp. 807-821. Jun 2002.

Science 15 August 2003:
Vol. 301. no. 5635, pp. 945 - 948
DOI: 10.1126/science.1085293
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Reports
Ice Core Records of Atmospheric N2O Covering the
Last 106,000 Years
Todd Sowers,* Richard B. Alley, Jennifer Jubenville
Paleoatmospheric records of trace-gas concentrations recovered from ice cores provide
important sources of information on many biogeochemical cycles involving carbon,
nitrogen, and oxygen. Here, we present a 106,000-year record of atmospheric nitrous
oxide (N2O) along with corresponding isotopic records spanning the last 30,000 years,
which together suggest minimal changes in the ratio of marine to terrestrial N2O
production. During the last glacial termination, both marine and oceanic N2O emissions
increased by 40 ± 8%. We speculate that our records do not support those hypotheses that
invoke enhanced export production to explain low carbon dioxide values during glacial
periods.
Department of Geosciences and the EMS Environment Institute, Pennsylvania State University,
UniversityPark, PA 16802, USA.

GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L14810, 4 PP., 2006
doi:10.1029/2006GL026152
Law Dome CO2, CH4 and N2O ice core records extended to 2000 years BP
C. MacFarling Meure
Marine and Atmospheric Research, Commonwealth Scientific and Industrial Research
Organisation, Aspendale, Victoria, Australia
D. Etheridge
Marine and Atmospheric Research, Commonwealth Scientific and Industrial Research
Organisation, Aspendale, Victoria, Australia
C. Trudinger
Marine and Atmospheric Research, Commonwealth Scientific and Industrial Research
Organisation, Aspendale, Victoria, Australia
P. Steele
Marine and Atmospheric Research, Commonwealth Scientific and Industrial Research
Organisation, Aspendale, Victoria, Australia
R. Langenfelds
Marine and Atmospheric Research, Commonwealth Scientific and Industrial Research
Organisation, Aspendale, Victoria, Australia
T. van Ommen
Department of the Environment and Heritage, Australian Antarctic Division, and
Antarctic Climate and Ecosystems CRC, Hobart, Tasmania, Australia
A. Smith
Australian Nuclear Science and Technology Organisation, Menai, New South Wales,
Australia
J. Elkins
NOAA, Earth System Research Laboratory, Boulder, Colorado, USA
New measurements of atmospheric greenhouse gas concentrations in ice from Law
Dome, Antarctica reproduce published Law Dome CO2 and CH4 records, extend them
back to 2000 years BP, and include N2O. They have very high air age resolution, data
density and measurement precision. Firn air measurements span the past 65 years and
overlap with the ice core and direct atmospheric observations. Major increases in CO2,
CH4 and N2O concentrations during the past 200 years followed a period of relative
stability beforehand. Decadal variations during the industrial period include the
stabilization of CO2 and slowing of CH4 and N2O growth in the 1940s and 1950s.
Variations of up to 10 ppm CO2, 40 ppb CH4 and 10 ppb N2O occurred throughout the
preindustrial period. Methane concentrations grew by 100 ppb from AD 0 to 1800,
possibly due to early anthropogenic emissions.
Received 26 February 2006; accepted 16 May 2006; published 21 July 2006.
Citation: MacFarling Meure, C., D. Etheridge, C. Trudinger, P. Steele, R. Langenfelds,
T. van Ommen, A. Smith, and J. Elkins (2006), Law Dome CO2, CH4 and N2O ice core
records extended to 2000 years BP, Geophys. Res. Lett., 33, L14810,
doi:10.1029/2006GL026152.
Nature 360, 449 - 451 (03 December 1992); doi:10.1038/360449a0
Ice-age atmospheric concentration of nitrous oxide from
an Antarctic ice core
Markus Leuenberger & Ulrich Siegenthaler
Physics Institute, University of Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
INCREASING anthropogenic emissions of greenhouse gases are expected to
influence the Earth's climate, but the mechanisms for this are not yet fully
understood. One way to determine the effect of such gases on climate is to study
their atmospheric concentrations during periods of past climate change, such as
glacial to interglacial transitions. Previous studies on polar ice cores showed that the
concentrations of the greenhouse gases CO2 and CH4 were significantly reduced
during the last glacial period relative to Holocene values1–5. But no comparable
studies have been reported for nitrous oxide (N2O), which is the next most
important greenhouse gas and also affects stratospheric ozone6,7 and, potentially, the
oxidative capacity of the troposphere8. Here we report results from Antarctic ice
cores, showing that the atmospheric N2O concentration was about 30% lower
during the Last Glacial Maximum than during the Holocene epoch. Our data also
show that present-day N2O concentrations are unprecedented in the past 45 kyr,
and hence provide evidence that recent increases in atmospheric N2O are of
anthropogenic origin.

Title:
Nitrous oxide: trends and global mass balance over the last 3000 years Authors:
Khalil, M. A. K.; Rasmussen, R. A. Publication:
Annals of Glaciology, vol.10, pp.73-79 Publication Date:
00/1988 Origin:
WEB Bibliographic Code:
1988AnGla..10...73K
http://earthobservatory.nasa.gov/Features/Paleoclimatology_IceCores/
http://www.agu.org.proxy.library.carleton.ca/journals/gl/gl0614/2006GL026152/
(accessed through Carleton University account to this article:
GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L14810, doi:10.1029/
2006GL026152, 2006
Law Dome CO2, CH4 and N2O ice core records extended to 2000 years BP
C. MacFarling Meure, D. Etheridge, C. Trudinger, P. Steele, and R. Langenfelds
Marine and Atmospheric Research, Commonwealth Scientific and Industrial Research
Organisation,
Aspendale, Victoria, Australia)