Data represented in the movies was obtained from the following sources. It represents many years work by an international community of scientists. The original sources should be cited when reusing any data from this collection.
Climate Change 2001: The Scientific Basis . J.T. Houghton, Y. Ding, D. J. Griggs, M. Noguer, P. J. van der Linden, X. Da, K. Maskell, and C. A. Johnson for the Intergovernmental Panel on Climate Change.
Global Gridded Pliocene and Late Quaternary Sea Level
U.S. Geological Survey Open-File Report 96-000 by Peter N. Schweitzer and Robert S. Thompson.
Images depicting the largest changes in global eustatic sea level that have been inferred from geological studies. The light blue color shows an estimate of the coastline of the eastern United States during the last glacial maximum, about 20,000 years ago. The dark green shows the modern coastline, and the lighter shades of green show the coastlines that may have existed during the warm climatic interval of the middle Pliocene epoch, about 3 million years ago. Expected global coastlines with eustatic sea-level of -120, 0, 35, and 60 meters from present (not accounting for ice loading) are shown.
Midwestern US 16,000 Years Ago
Maps based on A.S. Dyke and V.K. Prest, Late Wisconsinan and Holocene history of the Laurentide ice sheet, Geographie Physique et Quaternaire, 41: 237-264, 1987, trace the retreat of the glaciers of the last Ice Age. They begin with the glaciers at their maximum extent (18,000 years ago) . Maps are drawn for 18,000; 14,000; 12,000; 10,000; and 8,000 years ago. By 8,000 years ago, glaciers were no longer present in the midwestern United States. In addition, the maps show the extent and location of some of the lakes that formed as a result of the melting of the glaciers. The final map is present day.
The movie is derived from maps found at
For more information on why ice ages occur, see
Sea Level Data
Permanent Service for Mean Sea Level, Proudman Oceanographic Laboratory, UK
Since 1933, the Permanent Service for Mean Sea Level (PSMSL) has been responsible
for the collection, publication, analysis and
interpretation of sea level data from the global network of tide gauges. The database of the PSMSL contains almost 49000 station-years of monthly and annual mean values of sea level from over 1800 tide gauge stations around the world received from almost 200 national authorities. On average, approximately 2000 station-years of data are entered into the database each year.
The Wolf Sunspot Index
National Geophysical Data Center Solar-Terrestrial Physics division
In 1848 Rudolph Wolf devised a daily method of estimating solar activity by counting the number of individual spots and groups of spots on the face of the sun. Wolf chose to compute his sunspot number by adding 10 times the number of groups to the total count of individual spots, because neither quantity alone completely captured the level of activity. Today, Wolf sunspot counts continue, since no other index of the sun's activity reaches into the past as far and as continuously. An avid astronomical historian and an unrivaled expert on sunspot lore, Wolf confirmed the existence of a cycle in sunspot numbers. He also more accurately determined the cycle's length to be 11.1 years by using early historical records. Wolf, who became director of the Zurich Observatory, discovered independently the coincidence of the sunspot cycle with disturbances in the earth's magnetic field.
An observer computes a daily sunspot number by multiplying the number of groups he/she sees by ten and then adding this product to his total count of individual spots, same way that Wolf did. Many refer to the sunspot number as a Wolf number or count (or as a Zurich Sunspot Number). Results, however, vary greatly, since the measurement strongly depends on observer interpretation and experience and on the stability of the Earth's atmosphere above the observing site. Moreover, the use of Earth as a platform from which to record these numbers contributes to their variability, too, because the sun rotates and the evolving spot groups are distributed unevenly across solar longitudes. To compensate for these limitations, each daily international number is computed as a weighted average of measurements made from a network of cooperating observatories.
Indices of solar activity such as sunspots have led to several efforts
to connect various climatic fluctuations with solar variations.
Hoyt, D. V. 1979. "Variations In Sunspot Structure And Climate." Climatic Change 2:79-92.
Hoyt, D. V. 1979. "An Empirical Determination Of The Heating Of The Earth By The Carbon Dioxide Greenhouse Effect." Nature 282:388-390.
Atmospheric solar transmission at Mauna Loa
Dutton, E.G. 1994. Atmospheric solar transmission at Mauna Loa. In Trends: A Compendium of Data on Global Change. ORNL/CDIAC-65. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tenn., U.S.A.
Direct solar irradiance has been measured at the same location at Mauna Loa since 1958. The record from Mauna Loa is unique because of its long duration and essential completeness (data are missing for only 10 months since 1958) and because of the site's clear-sky and high-altitude location. The most prominent features of the record are the dramatic decreases in atmospheric transmission after the major explosive volcanic eruptions of Agung in 1963, El Chichón in 1982, and Pinatubo in 1991. A number of other smaller eruptions (e.g., Awu in 1965 and De Fuego in 1974) have also visibly affected the record (Mendonca et al. 1978). In addition, the data show an annual cycle: a statistically significant decrease in transmission from March through June (with a minimum in May) and a second, statistically insignificant, minimum in October. The spring minimum has been attributed primarily to an influx of tropospheric aerosols that are carried over Mauna Loa from Asia by seasonal winds (Dutton 1992). Other fluctuations, potentially random, are evident in the data; however, there is no evidence of a linear trend extending over the entire period of record.
-Ellis, H. T. and Pueschel, R. F. 1971. Solar radiation: absence of air
pollution trends at Mauna Loa, Science, 172, 845-846.
Dutton, E. G., J. J. DeLuisi, and A. P. Austring, 1985. Interpretation of Mauna Loa Atmospheric Transmission Relative to Aerosols, Using Photometric Precipitable Water Amounts. J. Atmos. Chem., 3, 53-68.
-Dutton, E.G., 1992. A Coherence Between the QBO and the Amplitude of the Mauna Loa Atmospheric Transmission Annual Cycle. International J. Climatology 12, 383-396.
-Dutton, E.G., P. Reddy, S. Ryan, and J.J. DeLuisi, 1994. Features and effects of aerosol optical depth observed at Mauna Loa, Hawaii: 1982-1992. J. Geophys. Res. 99, 8295- 8306.
-Dutton, E.G. and B.A. Bodhaine, 2001: Solar irradiance anomalies caused by clear-sky transmission variations above Mauna Loa 1957-1999. J. Clim., 14, 3255-3262.
Climate Change 2001: The Scientific Basis . J.T. Houghton, Y. Ding, D. J. Griggs, M. Noguer, P. J. van der Linden, X. Da, K. Maskell, and C. A. Johnson for the Intergovernmental Panel on Climate Change.
The ALE/GAGE/AGAGE Network
R. Prinn, Massachusetts Institute of Technology; D. Cunnold, Georgia Institute of Technology; P. Fraser, Commonwealth Scientific and Industrial Research Organisation; R. Weiss, Scripps Institution of Oceanography; P. Simmonds, Bristol University; S. O'Doherty, Bristol University; L.P. Steele, Commonwealth Scientific and Industrial Research Organisation; P. Salameh, Scripps Institution of Oceanography; and R.H.J. Wang, Georgia Institute of Technology
In the ALE/GAGE/AGAGE global network program, continuous high frequency gas chromatographic measurements of two biogenic/anthropogenic gases (methane, CH4; nitrous oxide, N2O; and six anthropogenic gases (chlorofluorocarbons CFCl3, CF2Cl2, and CF2ClCFCl2; methyl chloroform, CH3CCl3; chloroform, CHCl3; and carbon tetrachloride, CCl4) are carried out at five globally distributed sites. Additional important species (H2, CO, HFC-134a, HCFC-141b, and HCFC-142b) have been added at select sites in recent years.
The program, which began in 1978, is divided into three parts associated with three changes in instrumentation: the Atmospheric Lifetime Experiment (ALE), which used Hewlett Packard HP5840 gas chromatographs; the Global Atmospheric Gases Experiment (GAGE), which used HP5880 gas chromatographs; and the present Advanced GAGE (AGAGE). AGAGE uses two types of instruments: a gas chromatograph with multiple detectors (GC-MD), and a gas chromatograph with mass spectrometric analysis (GC-MS). The GC-MD is a new fully automated system produced at the Scripps Institution of Oceanography containing a custom-designed sample module and HP5890 and Carle Instruments gas chromatographic components. The GC-MS is a fully automated system produced at the University of Bristol and comprised of an adsorption-desorption preconcentration module and HP5973 gas chromatographic and mass spectrometric module.
The current station locations are Cape Grim, Tasmania (41° S, 145° E), Cape Matatula, American Samoa (14° S, 171° E), Ragged Point, Barbados (13° N, 59° W), Mace Head, Ireland (53° N, 10° W), and Trinidad Head, California (41° N, 124° W). Stations also previously existed at Cape Meares, Oregon (45° N, 124° W), and Adrigole, Ireland (52° N, 10° W). The current Mace Head station replaced the Adrigole station and the station at Trinidad Head replaced the Cape Meares station.
-Prinn, R.G., R.F. Weiss, P.J. Fraser, P.G. Simmonds, D.M. Cunnold, F.N. Alyea, S. O'Doherty, P. Salameh, B.R. Miller, J. Huang, R.H.J. Wang, D.E. Hartley, C. Harth, L.P. Steele, G. Sturrock, P.M. Midgely, and A. McCulloch. 2000. A history of chemically and radiatively important gases in air deduced from ALE/GAGE/AGAGE. Journal of Geophysical Research 115: 17751-92.
http://cdiac.ornl.gov/ftp/ale_gage_Agage/AGAGE/gc-md/monthly/ (November 5, 2003)
http://cdiac.ornl.gov/ftp/ale_gage_Agage/AGAGE/gc-ms/monthly/ (November 5, 2003)
http://cdiac.ornl.gov/ftp/ale_gage_Agage/ALE/monthly/ (July 13, 2000)
http://cdiac.esd.ornl.gov/ftp/ale_gage_Agage/GAGE/monthly/ (July 12, 2000)
Climate Monitoring and Diagnostics Laboratory (CMDL)
National Oceanic and Atmospheric Administration (NOAA)
Carbon Cycle Greenhouse Gases Cooperative Air Sampling Network
The NOAA CMDL CCGG cooperative air sampling network effort began in 1967 at Niwot Ridge, Colorado. Today, the network is an international effort which includes regular samples from the South Pole, Samoa, Mauna Loa, and Barrow baseline observatories. Samples are analyzed (see photo) in Boulder. Carbon dioxide (CO2) in air samples is detected using a non-dispersive infrared (NDIR) analyzer. Methane (CH4) is separated from other sample constituents by gas chromatography using packed columns and detected using flame ionization (FID). Carbon monoxide (CO) and molecular hydrogen (H2) are separated from other sample constituents using dualcolumns. CO and H2 are reacted with a hot HgO bed to produce mercury (Hg) which is then determined photometrically.Sampling frequencies are approximately weekly.
CO2 ftp://ftp.cmdl.noaa.gov/ccg/co2/flask/month/ (November 28, 2003)
CH4 ftp://ftp.cmdl.noaa.gov/ccg/ch4/flask/month/ (October 2, 2003)
CO ftp://ftp.cmdl.noaa.gov/ccg/co/flask/month/ (October 2, 2003)
H2 ftp://ftp.cmdl.noaa.gov/ccg/h2/flask/month/ (October 2, 2003)
Climate Monitoring and Diagnostics Laboratory (CMDL)
National Oceanic and Atmospheric Administration (NOAA)
Halocarbon and other Atmospheric Trace Species
HATS has been analyzing air samples collected in flasks since 1977. This program originally involved the analysis of flask samples from Point Barrow, Alaska (BRW), Niwot Ridge, Colorado (NWR), Mauna Loa, Hawaii (MLO), American Samoa (SMO), and the South Pole (SPO). Electropolished, stainless-steel flasks (300 ml) were collected weekly in pairs, filled to 1.5 atm with a metal bellows pump to minimize contamination of CFC's by plastics or other elastomers, and shipped to Boulder for analysis. All samples were analyzed for N2O, CFC-11, and CFC-12 on a Hewlett Packard 5710A, electron-capture gas chromatograph (GC/ECD) equipped with a Porasil A column. In 1986, when GMCC became the Climate Monitoring and Diagnostics Laboratory within the Environmental Research Laboratories (ERL/CMDL) and HATS was formed, efforts were initiated to increase the number of gases measured from each flask. Larger flasks (850 ml) were obtained and KNF Neuberger diaphragm pumps were sent to the sampling sites so that the flasks could be pressurized to 4 atm absolute pressure. This allowed for the cryotrapping of larger quantities of air for detection of low concentration or weakly responding gases. Measurement of Halons by GC/ECD was begun in 1988 and analysis of flask samples for CFC's, N2O, CH3CCl3, and CCl4 was fully automated by 1992. In late 1991, HATS began analyzing flask samples for hydrochlorofluorocarbons (HCFC's), hydrofluorocarbons (HFC's), and other atmospheric halogens by gas chromatography with detection by mass spectrometry (GC/MS). Because of the need for additional air for some measurements, HATS has introduced 2.4 l flasks into the network. Also in 1991, two cooperative sites were added to the sampling network -- Cape Grim Baseline Air Pollution Station, Tasmania (CGO) and Alert, Northwest Territories (ALT). Cooperative sampling sites are currently being set up at Harvard Forest, Massachusetts (HFM) and Grifton, North Carolina (ITN). Today, flasks are filled at nine sites, six of which are considered remote locations (ALT, BRW, NWR, MLO, SMO, CGO, SPO) and two of which were established to sample both polluted/source and clean air (ITN, HFM). HATS analyzes pairs of flasks collected weekly from these sites for over 20 gases.
CFC11 ftp://ftp.cmdl.noaa.gov/hats/cfcs/cfc11/flasks/monthly/otto/ (June 3, 2003)
CFC12 ftp://ftp.cmdl.noaa.gov/hats/cfcs/cfc12/flasks/monthly/otto/ (November 8, 2002)
CFC113 ftp://ftp.cmdl.noaa.gov/hats/cfcs/cfc113/flasks/GCMS/113_MS2004a.dat (May 5, 2004)
Halon 1211 ftp://ftp.cmdl.noaa.gov/hats/halons/flasks/H1211_MS2004a.dat (May 5, 2004)
Halon 1301 ftp://ftp.cmdl.noaa.gov/hats/halons/flasks/H1301 (Station Data) through2002 (030210).txt (February 13, 2003)
Halon 2402 ftp://ftp.cmdl.noaa.gov/hats/halons/flasks/h2402_(GCMS)_1998.dat (January 15, 1998)
HCFC 22 ftp://ftp.cmdl.noaa.gov/hats/hcfcs/hcfc22/flasks/22_MS2004a.dat (May 5, 2004)
HCFC 141b ftp://ftp.cmdl.noaa.gov/hats/hcfcs/hcfc141b/141b_MS2004a.dat (May 5, 2004)
HCFC 142b ftp://ftp.cmdl.noaa.gov/hats/hcfcs/hcfc142b/Flasks/142b_MS2004a.dat (May 5, 2004)
HFC 134a ftp://ftp.cmdl.noaa.gov/hats/hfcs/hfc134a/134A_MS2004a.dat (May 5, 2004)
CH3Br ftp://ftp.cmdl.noaa.gov/hats/methylhalides/ch3br/flasks/CH3Br_MS2004a.dat (May 5, 2004)
N2O ftp://ftp.cmdl.noaa.gov/hats/n2o/insituGCs/CATS/monthly/ (November 21, 2003)
SF6 ftp://ftp.cmdl.noaa.gov/hats/sf6/flasks/ (April 21, 2003)
C2Cl4 ftp://ftp.cmdl.noaa.gov/hats/solvents/C2Cl4/flasks/C2Cl4_MS2001.dat (June 26, 2001)
CCl4 ftp://ftp.cmdl.noaa.gov/hats/solvents/CCl4/insituGCs/CATS/monthly/ (November 21, 2003)
CH2Cl2 ftp://ftp.cmdl.noaa.gov/hats/solvents/CH2Cl2/flasks/CH2Cl2_MS2001.dat (January 8, 2001)
CH3CCl3 ftp://ftp.cmdl.noaa.gov/hats/solvents/CH3CCl3/flasks/GCMS/CH3CCl3_MS2004a.dat (May 5, 2004)
CH3CCl3 ftp://ftp.cmdl.noaa.gov/hats/solvents/CH3CCl3/insituGCs/CATS/monthly/ (November 21, 2003)
Commonwealth Scientific and Industrial Research Organization (CSIRO)
Atmospheric Research GASLAB air sampling network, Aspendale, Victoria, Australia
Data are obtained from flask air samples returned to the CSIRO GASLAB for analysis. CO2 Samples were analysed by gas chromatography with flame ionization detection after methanization to CH4. Methane samples were analysed by gas chromatography with flame ionization detection (FID). Hydrogen samples were analyzed by gas chromatography with a mercuric oxide reduction gas detector. H2 reduces HgO to Hg vapor which is detected by UV absorption. Carbon monoxidesamples were analyzed by gas chromatography with a mercuric oxide reduction gas detector. CO reduces HgO to Hg vapor which is detected by UV absorption.
(December 18, 2002)
CH4 http://cdiac.esd.ornl.gov/trends/atm_meth/csiro/csiro_gaslabch4.html (Januray 9, 2003)
CO http://cdiac.esd.ornl.gov/trends/otheratg/csiro-co/csiro_gaslabco.html (February 21, 2003)
H2 http://cdiac.esd.ornl.gov/trends/otheratg/csiro-h2/csiro_gaslabh2.html (March 24, 2003)
Atmospheric Methane at Cape Meares, Oregon, U.S.A.
M. A. K. Khalil and R. A. Rasmussen
This data base presents continuous automated atmospheric methane (CH4) measurements taken at the atmospheric monitoring facility in Cape Meares, Oregon, by the Oregon Graduate Institute of Science and Technology. The Cape Meares data represent some 119,000 individual atmospheric methane measurements carried out during 1979-1992. Analysis of ambient air (collected 12 to 72 times daily) was carried out by means of an automated sampling and measurement system, using the method of gas chromatography and flame ionization detection. Despite the long course of the record and the large number of individual measurements, these data may all be linked to a single absolute calibration standard.
-Khalil, M.A.K., R.A. Rasmussen, and F. Moraes. 1993. Atmospheric methane at Cape Meares: Analysis of a high resolution data base and its environmental implications. Journal of Geophysical Research 98:14,753-14,770.
Atmospheric Fluoroform (CHF3, HFC-23) at Cape Grim, Tasmania
Air samples were taken from the archive of Cape Grim, Tasmania (41oS,
145oE) air samples collected from 1978 through 1995. Comparisons
of CFC-11, CFC-12, CFC-113, CH3CCl3, and CH4
data between archive samples and corresponding
-Oram, D.E., W.T. Sturges, S.A. Penkett, A. McCulloch, and P.J. Fraser. 1998. Growth of fluoroform (CHF3, HFC-23) in the background atmosphere. Geophysical Research Letters 25:35-38.
http://cdiac.esd.ornl.gov/trends/otheratg/oram/oram.html (December 14, 2000)
The Global Distribution of Atmospheric Methyl Chloride
M.A. Khalil and R.A. Rasmussen
Methyl chloride is the most abundant chlorine containing gas in the Earth’s atmosphere. Samples were collected in 0.8-L internally electropolished stainless steel canisters at Pt. Barrow, Alaska (71.16ºN, 156.5ºW); Cape Meares, Oregon (45.5ºN, 124ºW); Cape Kumukahi and Mauna Loa, Hawaii (19.3ºN, 154.5ºW); Cape Matatula, Samoa (14.1ºS, 170.6ºW); Cape Grim, Tasmania (42ºS, 145ºE); and Antarctica (South Pole at 90ºS and Palmer Station at 65.46ºS, 64.05ºW). These containers preserve the concentrations of most trace gases for periods much longer than the time between sample collection and analysis. Measurements of methyl chloride and other gases were done using a gas chromatograph equipped with an electron capture detector.
Trifluoromethyl Sulfur Pentafluoride (SF5CF3) and Sulfur Hexafluoride (SF6) from Dome Concordia
Air samples were pumped from consolidated deep snow (firn) at Dome Concordia (eastern Antarctica) in December 1998 and January 1999, from the surface to a depth of approximately 100 m. Air samples were analyzed with a gas chromatograph - mass spectrometer, with a detection limit of about 0.001 parts per trillion (ppt).
-Sturges, W.T., T.J. Wallington, M.D. Hurley, K.P. Shine, K. Sihra, A. Engel, D.E. Oram, S.A. Penkett, R. Mulvaney, and C.A.M. Brenninkmeijer 2000. A potent greenhouse gas identified in the atmosphere: SF5CF3. Science 289:611-613.
http://cdiac.esd.ornl.gov/trends/otheratg/sturges/sturges.html (September 29, 2000)
Low-Latitude Ice Cores & Polar Ice Cores Slide Sets
Wooden trays with ice cores photo by Kendrick Taylor, DRI, University of
Ice Core sample taken from drill photo by Lonnie Thompson, Byrd Polar Research Center, Ohio State University.
Historical carbon dioxide record from the Siple Station ice core 1734-1983
A. Neftel, H. Friedli, E. Moor, H. Lötscher, H. Oeschger, U. Siegenthaler,
Physics Institute, University of Bern, CH-3012 Bern, Switzerland
Determinations of ancient atmospheric CO2 concentrations for Siple Station, located in West Antarctica, were derived from measurements of air occluded in a 200-m core drilled at Siple Station in the Antarctic summer of 1983-84. The core was drilled by the Polar Ice Coring Office in Nebraska and the Physics Institute at the University of Bern. The ice could be dated with an accuracy of approximately ±2 years to a depth of 144 m (which corresponds to the year 1834) by counting seasonal variations in electrical conductivity. Below that depth, the core was dated by extrapolation (Friedli et al. 1986). The gases from ice samples were extracted by a dry-extraction system, in which bubbles were crushed mechanically to release the trapped gases, and then analyzed for CO2 by infrared laser absorption spectroscopy or by gas chromatography (Neftel et al. 1985). After the ice samples were crushed, the gas expanded over a cold trap, condensing the water vapor at -80°C in the absorption cell. The analytical system was calibrated for each ice sample measurement with a standard mixture of CO2 in nitrogen and oxygen. For further details on the experimental and dating procedures, see Neftel et al. (1985), Friedli et al. (1986), and Schwander and Stauffer (1984).
Historical CO2 record from the Law Dome DE08, DE08-2, and DSS ice cores
D.M. Etheridge, L.P. Steele, R.L. Langenfeld, R.J. Francey, J.-M. Barnola, V.I. Morgan
The CO2 records presented here are derived from three ice cores obtained
at Law Dome, East Antarctica from 1987 to 1993. The Law Dome site satisfies
many of the desirable characteristics of an ideal ice core site for atmospheric
CO2 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
Air bubbles were extracted using the "cheese grater" technique. Ice core samples weighing 500-1500 g were prepared by selecting crack-free ice and trimming away the outer 5-20 mm. Each sample was sealed in a polyethylene bag and cooled to -80°C before being placed in the extraction flask where it was evacuated and then ground to fine chips. The released air was dried cryogenically at -100°C and collected cryogenically in electropolished stainless steel "traps", cooled to about -255°C.
Concentrations of CH4 from the Law Dome (East Side,"DE08" Site) Ice Core
D.M. Etheridge, G.I. Pearman, P.J. Fraser
http://cdiac.esd.ornl.gov/ftp/trends/methane/lawdome.259 (February 18, 1998)
Concentrations of N2O from the Law Dome (Summit, "BHD" Site) Ice Core
D.M. Etheridge, G.I. Pearman, P.J. Fraser
Commonwealth Scientific and Industrial Research Organisation
Aspendale, Victoria, Australia
http://cdiac.esd.ornl.gov/ftp/trends/n2o/lawdome.393 (February 18, 1998)
Data from the Vostok Ice Core (3623 meter core, 420,000 years)
Vostok Carbon Dioxide Data
J.M. Barnola, D. Raynaud, C. Lorius
Laboratoire de Glaciologie et de Géophysique de l'Environnement, CNRS, BP96, 38402 Saint Martin d'Heres Cedex, France
Arctic and Antarctic Research Institute, Beringa Street 38, 199397, St. Petersburg, Russia
In January 1998, the collaborative ice-drilling project between Russia, the United States, and France at the Russian Vostok station in East Antarctica yielded the deepest ice core ever recovered, reaching a depth of 3,623 m (Petit et al. 1997, 1999). Ice cores are unique with their entrapped air inclusions enabling direct records of past changes in atmospheric trace-gas composition. Preliminary data indicate the Vostok ice-core record extends through four climate cycles, with ice slightly older than 400 kyr (Petit et al. 1997, 1999). Because air bubbles do not close at the surface of the ice sheet but only near the firn-ice transition (that is, at ~90 m below the surface at Vostok), the air extracted from the ice is younger than the surrounding ice (Barnola et al. 1991). Using semiempirical models of densification applied to past Vostok climate conditions, Barnola et al. (1991) reported that the age difference between air and ice may be ~6000 years during the coldest periods instead of ~4000 years, as previously assumed. Ice samples were cut with a bandsaw in a cold room (at about -15°C) as close as possible to the center of the core in order to avoid surface contamination (Barnola et al. 1983). Gas extraction and measurements were performed with the "Grenoble analytical setup," which involved crushing the ice sample (~40 g) under vacuum in a stainless steel container without melting it, expanding the gas released during the crushing in a pre-evacuated sampling loop, and analyzing the CO2 concentrations by gas chromatography (Barnola et al. 1983). The analytical system, except for the stainless steel container in which the ice was crushed, was calibrated for each ice sample measurement with a standard mixture of CO2 in nitrogen and oxygen. For further details on the experimental procedures and the dating of the successive ice layers at Vostok, see Barnola et al. (1987, 1991), Lorius et al. (1985), and Petit et al. (1999).
- Barnola, J.-M., D. Raynaud, A. Neftel, and H. Oeschger. 1983. Comparison
of CO2 measurements by two laboratories on air from bubbles
in polar ice. Nature 303:410-13.
- Barnola, J.-M., D. Raynaud, Y.S. Korotkevich, and C. Lorius. 1987. Vostok ice core provides 160,000-year record of atmospheric CO2. Nature 329:408-14.
- Barnola, J.-M., P. Pimienta, D. Raynaud, and Y.S. Korotkevich. 1991. CO2-climate relationship as deduced from the Vostok ice core: A re-examination based on new measurements and on a re-evaluation of the air dating. Tellus 43(B):83-90.
- Delmas, R.J., J.-M. Ascencio, and M. Legrand. 1980. Polar ice evidence that atmospheric CO2 20,000 yr BP was 50% of present. Nature 284:155-57.
- Jouzel, J., C. Lorius, J.R. Petit, C. Genthon, N.I. Barkov, V.M. Kotlyakov, and V.M. Petrov. 1987. Vostok ice core: A continuous isotopic temperature record over the last climatic cycle (160,000 years). Nature 329:403-8.
- Lorius, C., J. Jouzel, C. Ritz, L. Merlivat, N.I. Barkov, Y.S. Korotkevich, and V.M. Kotlyakov. 1985. A 150,000-year climatic record from Antarctic ice. Nature 316:591-96.
-Neftel, A., H. Oeschger, J. Schwander, B. Stauffer, and R. Zumbrunn. 1982. Ice core measurements give atmospheric CO2 content during the past 40,000 yr. Nature 295:220-23.
- Pepin, L., D. Raynaud, J.-M. Barnola, and M.F. Loutre. 2001. Hemispheric roles of climate forcings during glacial-interglacial transitions as deduced from the Vostok record and LLN-2D model experiments. Journal of Geophysical Research 106 (D23): 31,885-31,892.
- Petit, J.R., I. Basile, A. Leruyuet, D. Raynaud, C. Lorius, J. Jouzel, M. Stievenard, V.Y. Lipenkov, N.I. Barkov, B.B. Kudryashov, M. Davis, E. Saltzman, and V. Kotlyakov. 1997. Four climate cycles in Vostok ice core. Nature 387: 359-360.
- Petit, J.R., J. Jouzel, D. Raynaud, N.I. Barkov, J.-M. Barnola, I. Basile, M. Benders, J. Chappellaz, M. Davis, G. Delayque, M. Delmotte, V.M. Kotlyakov, M. Legrand, V.Y. Lipenkov, C. Lorius, L. Pépin, C. Ritz, E. Saltzman, and M. Stievenard. 1999. Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica. Nature 399: 429-436.
- Raynaud, D., and J.-M. Barnola. 1985. An Antarctic ice core reveals atmospheric CO2 variations over the past few centuries. Nature 315:309-11.
Historical Isotopic Temperature Record from the Vostok Ice Core
J.R. Petit, D. Raynaud, and C. Lorius
Laboratoire de Glaciogie et Géophysique de l'Environnement, CNRS, Saint Martin d'Hères Cedex, France
J. Jouzel and G. Delaygue
Laboratoire des Sciences du Climat et de l'Environnement (LSCE), CEA/CNRS, L'Orme des Merisiers, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
Arctic and Antarctic Research Institute, Beringa Street 38, 199397 St. Petersburg, Russia
Institute of Geography, Staromonetny, per 29, Moscow 109017, Russia
Because isotopic fractions of the heavier oxygen-18 (18O) and deuterium (D) in snowfall are temperature-dependent and a strong spatial correlation exists between the annual mean temperature and the mean isotopic ratio (18O or D) of precipitation, it is possible to derive ice-core climate records. The record presented by Jouzel et al. (1987) was the first ice core record to span a full glacial-interglacial cycle. That record was based on an ice core drilled at the Russian Vostok station in central east Antarctica. The 2083-m ice core was obtained during a series of drillings in the early 1970s and 1980s and was the result of collaboration between French and former-Soviet scientists. Drilling continued at Vostok and was completed in January 1998, reaching a depth of 3623 m, the deepest ice core ever recovered (Petit et al. 1997, 1999). The resulting core allows the ice core record of climate properties at Vostok to be extended to ~420 kyr BP.
The first isotopic analysis of the Vostok ice core was described in Lorius et al. (1985). Sampling of ice for 18O and deuterium was done in the field during the 1982-83 austral summer by cutting a continuous slice from the length of ice after careful cleaning. Sampling was performed on 1.5- to 2-m increments of ice. Samples were sent in solid form to Grenoble, France, and then melted before isotopic analysis in Saclay, France. Two independent series of samples were obtained. For the discontinuous series, duplicated to check reproducibility, one sample was taken at each 25-m interval from the surface down to the bottom of the core. For the continuous series, samples were collected between 1406 and 2083 m. Oxygen-18 and deuterium determinations were simultaneously performed on all the samples, and the 18O results were discussed in Lorius et al. (1985).
The 420-kyr Vostok temperature record presented here was reconstructed from the continuous deuterium profile measured along the core. The new measurements were taken along ice in increments between 0.5 and 2 m in length to a depth of 2080 m and then every 1 m for the remainder of the upper 3310-m of the ice core. Isotopic analysis was again performed by the Geochemistry team at LSCE at Saclay. Further details on the methodology are presented in Jouzel et al. (1987), Lorius et al. (1985), and Petit et al. (1999).
-Petit, J.R., D. Raynaud, C. Lorius, J. Jouzel, G. Delaygue, N.I. Barkov,
and V.M. Kotlyakov. 2000. Historical isotopic temperature record from
the Vostok ice core. In Trends: A Compendium of Data on Global Change.Carbon
Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S.
Department of Energy, Oak Ridge, Tenn., U.S.A.
-Barnola, J.M., D. Raynaud, Y. S. Korotkevich, and C. Lorius. 1987. Vostok ice core provides 160,000-year record of atmospheric CO2. Nature 329:408-14.
-Jouzel, J., C. Lorius, J.R. Petit, C. Genthon, N.I. Barkov, V.M. Kotlyakov, and V.M. Petrov. 1987.Vostok ice core: a continuous isotope temperature record over the last climatic cycle (160,000 years). Nature 329:403-8.
-Jouzel, J., J.R. Petit, and D. Raynaud. 1990.
Paleoclimatic information from ice cores--the Vostok records. Transactions of the Royal Society of Edinburgh-Earth Sciences 81:349-55.
-Jouzel, J., N.I. Barkov, J.M. Barnola, M. Bender, J. Chappellaz, C. Genthon, V.M. Kotlyakov, V. Lipenkov, C. Lorius, J.R. Petit, D. Raynaud, G. Raisbeck, C. Ritz, T.Sowers, M. Stievenard, F. Yiou, and P. Yiou. 1993.Extending the Vostok ice-core record of palaeoclimate to the penultimate glacial period. Nature 364:407-12.
-Jouzel, J., C. Waelbroeck, B. Malaize, M. Bender, J.R. Petit, M. Stievenard, N.I. Barkov, J.M. Barnola, T. King, V.M. Kotlyakov, V. Lipenkov, C. Lorius, D. Raynaud, C. Ritz, and T. Sowers. 1996. Climatic interpretation of the recently extended Vostok ice records. Climate Dynamics 12:513-521.
-Lorius, C., J. Jouzel, C. Ritz, L. Merlivat, N.I. Barkov, Y.S. Korotkevich, and V.M. Kotlyakov. 1985. A 150,000-year climatic record from Antarctic ice. Nature 316:591-96.
-Lorius, C., J. Jouzel, D. Raynaud, J. Hansen, H. Le Treut. 1990. The ice-core record: climate sensitivity and future greenhouse warming. Nature 347:139-45.
-Lorius, C., J. Jouzel, D. Raynaud, Y.S. Korotkevich, and V.M. Kotlyakov. 1991. Greenhouse warming, climate sensitivity, and Vostok data. Glaciers-Ocean-Atmosphere Interactions (Proceedings of the International Symposium held at St. Petersburg, September 1990), IAHS Publication Number 208.
-Petit, J.R., I. Basile, A. Leruyuet, D. Raynaud, C. Lorius, J. Jouzel, M. Stievenard, V.Y. Lipenkov, N.I. Barkov, B.B. Kudryashov, M. Davis, E. Saltzman, and V. Kotlyakov. 1997. Four climate cycles in the Vostok ice core. Nature 387:359.
-Petit, J.R., J. Jouzel, D. Raynaud, N.I. Barkov, J.-M. Barnola, I. Basile, M. Bender, J. Chappellaz, M. Davis, G. Delayque, M. Delmotte, V.M. Kotlyakov, M. Legrand, V.Y. Lipenkov, C. Lorius, L. Pépin, C. Ritz, E. Saltzman, and M. Stievenard. 1999. Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica. Nature 399: 429-436.
Vostok Methane Data
Trapped gas bubbles record the history of atmospheric methane concentrations
-Chappellaz et al, Nature 345,127-131 (1990)
Vostok Dust Data
Thousands of dust particles larger than .8 m per g of ice (Jouzel et al. 1996)
Vostok N2O Data
Trapped gas bubbles record the history of atmospheric N2O concentrations
-Sowers, T., JGR-Atmospheres, Vol. 106, No. D23, p. 31,903 (2001)
Central England Temperature
Hadley Centre for Climate Prediction and Research, Met Office, UK
The Central England Temperature series was originally constructed by the
late Professor Gordon Manley, and is now routinely updated by the Hadley
Centre. The monthly mean surface air temperatures, for a region representative
of the English Midlands, are expressed in degrees Celsius for the period
from 1659 to the present. The data are discussed in the following two papers:
G. Manley, "Central England Temperatures: monthly means 1659 to 1973",
Quarterly Journal of the Royal Meteorological Society, 1974, vol.
100, pp. 389-405. and D. E. Parker, T. P. Legg and C. K. Folland, "A
new daily Central England Temperature series, 1772-1991," International
Journal of Climatology, 1992, vol. 12, pp. 317-42. The 1990s decade
was nearly 0.6 deg C warmer than the 1961-90 average.
http://www.cru.uea.ac.uk/~mikeh/datasets/uk/cet.htm (December 8, 2003)
Global and Hemispheric Temperature Anomalies
Climate Research Unit, University of East Anglia, UK
Over land regions of the world over 3000 monthly station temperature time series are used. Coverage is denser over the more populated parts of the world, particularly, the United States, southern Canada, Europe and Japan. Coverage is sparsest over the interior of the South American and African continents and over the Antarctic. The number of available stations was small during the 1850s, but increases to over 3000 stations during the 1951-90 period. For marine regions sea surface temperature (SST) measurements taken on board merchant and some naval vessels are used. As the majority come from the voluntary observing fleet, coverage is reduced away from the main shipping lanes and is minimal over the Southern Oceans. Stations on land are at different elevations, and different countries estimate average monthly temperatures using different methods and formulae. To avoid biases that could result from these problems, monthly average temperatures are reduced to anomalies from the period with best coverage (1961-90). Annual values are approximately accurate to +/- 0.05°C (two standard errors) for the period since 1951. They are about four times as uncertain during the 1850s, with the accuracy improving gradually between 1860 and 1950 except for temporary deteriorations during data-sparse, wartime intervals.
-Christy, J.R., Parker, D.E., Stendel. M. and Norris, W.B., 2001: Differential
trends in tropical sea surface temperature and atmospheric temperatures
since 1979. Geophysical Research Letters 28, 183-186.
-Folland, C.K., Rayner, N.A., Brown, S.J., Smith, T.M., Shen, S.S.P., Parker, D.E., Macadam, I., Jones, P.D., Jones, R.N., Nicholls, N. and Sexton, D.M.H., 2001a: Global temperature change and its uncertainties since 1861. Geophysical Research Letters 28, 2621-2624.
-Folland, C.K., Karl, T.R., Christy, J.R., Clarke, R.A., Gruza, G.V., Jouzel, J., Mann, M.E., Oerlemans, J., Salinger, M.J. and Wang, S.-W., 2001b: Observed Climate Variability and Change. pp. 99-181 In: Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change (Houghton, J.T., Ding, Y., Griggs, D.J., Noguer, M., van der Linden, P.J., Dai, X., Maskell, K. and Johnson, C.A. Eds.). Cambridge University Press, Cambridge, UK, 881pp.
-Jones, P.D., Osborn, T.J. and Briffa, K.R., 1997: Estimating sampling errors in large-scale temperature averages. J. Climate 10, 2548-2568.
-Jones, P.D., New, M., Parker, D.E., Martin, S. and Rigor, I.G., 1999: Surface air temperature and its variations over the last 150 years. Reviews of Geophysics 37, 173-199.
-Jones, P.D., Osborn, T.J., Briffa, K.R., Folland, C.K., Horton, B., Alexander, L.V., Parker, D.E. and Rayner, N.A., 2001: Adjusting for sampling density in grid-box land and ocean surface temperature time series. J. Geophys. Res. 106, 3371-3380.
-Jones, P.D. and Moberg, A., 2003: Hemispheric and large-scale surface air temperature variations: An extensive revision and an update to 2001. J. Climate 16, 206-223.
-Rayner, N.A., Parker, D.E., Horton, E.B., Folland, C.K., Alexander, L.V, Rowell, D.P., Kaplan, A. and Kent, E.C., 2003: Globally complete analyses of sea surface temperature, sea ice and night marine air temperature, 1871-2000. J. Geophys. Res. (in press).
(December 14, 2003)
http://www.cru.uea.ac.uk/ftpdata/tavenh2v.dat Northern Hemisphere average temperature 1856 to 2003
http://www.cru.uea.ac.uk/ftpdata/tavesh2v.dat Southern Hemisphere average temperature 1856 to 2003
http://www.cru.uea.ac.uk/ftpdata/tavegl2v.dat Global average temperature 1856 to 2003
Temperature deviations derived from radiosonde records
National Oceanic and Atmospheric Administration-Air Resources Laboratory, Silver Spring, Maryland
Surface temperatures and thickness-derived temperatures from a 63-station, globally distributed radiosonde network have been used to estimate global, hemispheric, and zonal annual and seasonal temperature deviations. Most of the temperature values used were column-mean temperatures, obtained from the differences in height (thickness) between constant-pressure surfaces at individual radiosonde stations. The pressure-height data before 1980 were obtained from published values in Monthly Climatic Data for the World. Between 1980 and 1990, Angell used data from both the Climatic Data for the World and the Global Telecommunications System (GTS) Network received at the National Meteorological Center. Between 1990 and 1995, the data were obtained only from GTS, and since 1995 the data have been obtained from National Center for Atmospheric Research files. The data are evaluated as deviations from the mean based on the interval 1958-1977.
-Angell, J.K. 1988. Variations and trends in tropospheric and stratospheric
global temperatures, 1958-87. Journal of Climate 1:1296-1313.
-Angell, J.K. 1991. Changes in tropospheric and stratospheric global temperatures, 1958-88. pp. 231-47. In M.E. Schlesinger (ed.), Greenhouse-Gas-Induced Climatic Change: A Critical Appraisal of Simulations and Observations. Elsevier Science Publishers, Amsterdam, Netherlands.
-Angell, J.K. 1999. Comparison of surface and tropospheric temperature trends estimated from a 63-station radiosonde network, 1958-1998. Geophys. Res. Lett. 26:2761-2764.
-Angell, J.K. 2000. Tropospheric temperature variations adjusted for El Niño, 1958-1998. Journal of Geophysical Research 105:11841-11849.
-Angell, J.K., and J. Korshover. 1983. Global temperature variations in the troposphere and stratosphere, 1958-82. Monthly Weather Review 111:901-21.
-Christy, J.M., R.W. Spencer, and W.D. Braswell. 2000. MSU Tropospheric temperatures: Data set construction and radiosonde comparisons. J. Atmos. Oceanic Tech. 17:1153-1170.
- Jones, P.D., T.J. Osborn, K.R. Briffa, C.K. Folland, B. Horton, L.V. Alexander, D.E. Parker, and N.A. Rayner, 2001. Adjusting for sample density in grid-box land and ocean surface temperature time series. J. Geophys. Res. 106:3371-3380.
http://cdiac.esd.ornl.gov/trends/temp/angell/angell.html (February 4, 2005)
Global Surface Temperature Anomalies
National Climatic Data Center, National Oceanic and Atmospheric Administration, Asheville, North Carolina
NCDC's long-term mean temperatures for the Earth were calculated by processing data from thousands of world-wide observation sites on land and sea for the entire period of record of the data. Many parts of the globe are inaccessible and therefore have no data. The temperature anomaly time series presented here were calculated in a way that did not require knowing the actual mean temperature of the Earth in these inaccessible areas such as mountain tops and remote parts of the Sahara Desert where there are no regularly reporting weather stations. Using the collected data available, the whole Earth long-term mean temperatures were calculated by interpolating over uninhabited deserts, inaccessible Antarctic mountains, etc. in a manner that takes into account factors such as the decrease in temperature with elevation. By adding the long-term monthly mean temperature for the Earth to each anomaly value, one can create a time series that approximates the temperature of the Earth and how it has been changing through time.
(December 12, 2003)
United States Climate Summary
National Climatic Data Center, National Oceanic and Atmospheric Administration, Asheville, North Carolina
Monthly and annual temperature and precipitation records for the United States since 1895.
NASA's Earth Observatory
By precisely measuring the radiant energy emitted from Earth's surface, satellites can determine temperature at the surface-atmosphere boundary. Surface temperature influences the rate at which water evaporates, as well as wind and precipitation patterns and the formation of clouds.
Global, Regional, and National CO2 Emission Estimates from Fossil Fuel Burning, Cement Production, and Gas Flaring: 1751-2000
G. Marland, T. A. Boden, and R. J. Andres
Global, regional, and national annual estimates of CO2 emissions from fossil fuel burning, cement production, and gas flaring have been calculated through 2000, some as far back as 1751. These estimates, derived primarily from energy statistics published by the United Nations, were calculated using the methods of Marland and Rotty (1984). Cement production estimates from the U.S. Department of Interior's Bureau of Mines were used to estimate CO2 emitted during cement production. Emissions from gas flaring were derived primarily from U.N. data but were supplemented with data from the U.S. Department of Energy's Energy Information Administration, Rotty (1974), and with a few national estimates provided by G. Marland.
Carbon Flux to the Atmosphere from Land-Use Changes
R. A. Houghton and J. L. Hackler, Woods Hole Research Center, Woods Hole, Massachusetts
This database provides estimates of regional and global net carbon fluxes, on a year-by-year basis from 1850 through 2000, resulting from changes in land use (such as harvesting of forest products and clearing for agriculture), taking into account not only the initial removal and oxidation of the carbon in the vegetation, but also subsequent regrowth and changes in soil carbon. The net flux of carbon to the atmosphere from changes in land use from 1850 to 1990 was modeled as a function of documented land-use change and changes in aboveground and belowground carbon following changes in land use. The changes in carbon, with time, following land-use change are specified by region and ecosystem type.
The estimated global total net flux of carbon from changes in land use increased from 503 Tg C (1 teragram = 1012 gram) in 1850 to a maximum of 2376 Tg C (or 2.4 Pg C, where 1 petagram = 1015 gram) in 1991, then declined to 2081 Tg C (2.1 Pg C) in 2000. The global net flux during the period 1850-2000 was 156 Pg C, about 63% of which was from the tropics. During this period, the greatest regional flux was from Tropical Asia (48 Pg C), while the smallest regional flux was from North Africa and Middle East (3 Pg C). The global total flux averaged 2.0 Pg C yr-1 during the 1980s and 2.2 Pg C yr-1 during the 1990s (but generally declining during that latter decade), dominated by fluxes from tropical deforestation. For the U.S., the estimated flux is a net source to the atmosphere of 7 Pg C for the period 1850-2000, but a net sink of 1.2 Pg C for the 1980s and 1.1 Pg C for the 1990s.
-Houghton, R.A. 1999. "The annual net flux of carbon to the atmosphere
from changes in land use 1850-1990." Tellus 51B:298-313.
-Houghton, R.A. 2002. "Revised estimates of the annual net flux of carbon to the atmosphere from changes in land use and land management 1850-2000." Tellus
-Houghton, R.A., and J.L. Hackler. 1995. Continental Scale Estimates of the Biotic Carbon Flux from Land Cover Change: 1850-1980. ORNL/CDIAC-79, NDP-050, Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee.
-Houghton, R.A., and J.L. Hackler. 2001. Carbon Flux to the Atmosphere From Land-use Changes: 1850 to 1990. ORNL/CDIAC-79, NDP-050/R1, Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee.
-Houghton, R.A., J.E. Hobbie, J.M. Melillo, B. Moore, B.J. Peterson, G.R. Shaver, and G.M. Woodwell. 1983. "Changes in the carbon content of terrestrial biota and soils between 1860 and 1980: A net release of CO2 to the atmosphere." Ecological Monographs 53:235-262.
G-7 Countries: Transportation Highlights
Bureau of Transportation Statistics, U. S. Department of Transportation
Extent and use of the transportation networks, and selected statistics on trade and transportation, safety, and energy and environment for the United States, Canada, France, Germany, Italy, the United Kingdom and Japan.
Light-Duty Automotive Technology and Fuel Economy Trends
U. S. Environmental Protection Agency
The report summarizes key fuel economy and technology usage trends related to model year 1975 through 2003 light vehicles sold in the United States. The report finds that there has been a general overall declining trend in new light vehicle fuel economy since 1988.
http://www.epa.gov/otaq/cert/mpg/fetrends/r03006-e.pdf (data stratified by vehicle type)
Annual Estimates of Global Anthropogenic Methane Emissions: 1860-1994
D. I. Stern and R. K. Kaufman, Center for Energy and Environmental Studies, Boston University, Massachusetts
Estimates on a year-by-year basis of global emissions of methane from various
anthropogenic sources (flaring and venting of natural gas; oil and gas supply
systems, excluding flaring; coal mining; biomass burning; livestock farming;
rice farming and related activities; and landfills).
-Stern, D., and R. Kaufmann. 1995. Estimates of global anthropogenic methane emissions 1860-1993. Working Paper Series, Number 9504. Boston University, Center for Energy and Environmental Studies, Boston University, 675 Commonwealth Avenue, Boston, MA 02215, U.S.A.
-Stern, D.I., and R.K. Kaufmann. 1996. Estimates of global anthropogenic methane emissions 1860-1993. Chemosphere 33:159-76.
Release Estimates From Alternative Fluorocarbons Environmental Acceptability Study, AFEAS
Significant production of CFC-11 and CFC-12 began in the late 1930s for use in refrigeration. Production (and release) increased very slowly until after World War II, when CFCs began to be used as propellants for aerosol sprays. Very quickly, CFC-12 production for use in aerosols exceeded that for use in refrigeration. By the 1950s, the use of CFC-11 as the blowing agent in open-cell (foam rubber) and closed-cell (rigid polyurethane) foams and the use of CFC-12 as the blowing agent in closed-cell foams (mostly Styrofoam®) constituted an additional significant source of release. In 1975, fluorocarbon production and release began to decline after the U.S. ban on CFCs in aerosols. By the early 1980s, however, this decline reversed, partly because of growth in aerosol production in countries not participating in the ban. The use of CFC-11 as the blowing agent in rigid polyurethane foams grew unabatedly throughout the 1970s and 1980s. CFC-12 remained the preferred cooling agent in home refrigerators and, until very recently, in automobile air-conditioners. The recent decline in the release of CFC-11 and CFC-12 from all sources (primarily aerosols) has occurred largely in response to efforts to limit emissions of fully halogenated CFCs as prescribed by the 1987 Montreal Protocol and its subsequent revisions.
-Alternative Fluorocarbons Environmental Acceptability Study (AFEAS). 2003.
AFEAS, Washington, D.C., U.S.A.
-A. McCulloch, P. Ashford, and P.M. Midgley. "Historic Emissions of Fluorotrichloromethane (CFC-11) Based on a Market Survey," Atmos. Environ., 35, 4387-4397, 2001.
-A. McCulloch, P.M. Midgley, and P. Ashford. "Releases of Refrigerant Gases (CFC-12, HCFC-22, and HFC-134a) to the Atmosphere," Atmos. Environ., 37(7), 889-902, 2003.
http://afeas.org/prodsales_download.html (January 2003)
NASA Earth Probe TOMS Satellite
The TOMS is the first instrument to allow observation of aerosols (airborne
microscopic dust/smoke) as the particles cross the land/sea boundary. Using
these data it is possible to observe a wide range of phenomena such as desert
dust storms, forest fires and biomass burning.