DATE RESOURCES AND MEASUREMENT
Credits: Ed Dlugokencky, NOAA/ESRL (www.esrl.noaa.gov/gmd/ccgg/trends_ch4/)
The methane ice core records for this time period are derived from three cores obtained from Law Dome, East Antarctica from 1987 to 1993, and samples from the Eurocore and GISP2 ice cores from the Summit region, Greenland. The Law Dome sites satisfy many of the desirable characteristics of an ideal ice core site for atmospheric reconstructions including negligible melting of the ice sheet surface, low concentrations of impurities, regular stratigraphic layering undisturbed at the surface by wind or at depth by ice flow, and high snow accumulation rate.
1000 years ago -
Etheridge, D.M., et al., 2002
Ice Core, Firn Air and Archived Air Atmospheric Methane Concentration Data
IGBP PAGES/World Data Center for Paleoclimatology
Data Contribution Series #2002-
NOAA/NGDC Paleoclimatology Program, Boulder CO, USA.
Etheridge, D. M., Steele, L. P., Francey, R. J., and Langenfelds, R. L., 1998, Atmospheric methane between 1000 A.D. and present: Evidence of anthropogenic emissions and climatic variability J. Geophys. Res. Vol. 103, No. D13, p. 15,979 (98JD00923)
800,000 YEARS AGO -
Changes in past atmospheric methane concentrations are determined by measuring the composition of air trapped in ice cores from Antarctica. So far, the Antarctic Vostok and EPICA Dome C ice cores have provided a composite record of atmospheric methane levels over the past 800,000 years.
Credits: Loulergue, L., A. Schilt, R. Spahni, V. Masson-
Orbital and millennial-
Nature, Vol. 453, pp. 383-
A hydrocarbon gas produced both through natural sources and human activities, including the decomposition of wastes in landfills, agriculture, and especially rice cultivation, as well as ruminant digestion and manure management associated with domestic livestock. On a molecule-
Air pollution consist of chemicals, particulate matter or biological materials that cause harm or discomfort to humans or other living organisms, or cause damage to the natural or built environment. There is great concern over deteriorating air quality as it can contribute to many health problems in our community….