Climate Change Indicators in the United States

This page contains reference links to external sites not hosted by EPA.

• References for Greenhouse Gases
• References for Weather and Climate
• References for Oceans
• References for Snow and Ice
• References for Society and Ecosystems

Greenhouse Gases

U.S. Greenhouse Gas Emissions

1. U.S. EPA (U.S. Environmental Protection Agency). 2010. Inventory of U.S. greenhouse gas emissions and sinks: 1990–2008. USEPA #EPA 430-R-10-006. www.epa.gov/climatechange/emissions/usinventoryreport.html
2. ibid.
3. ibid.
4. ibid.
5. ibid.

Global Greenhouse Gas Emissions

1. World Resources Institute. 2009. Climate Analysis Indicators Tool (CAIT). Version 6.0. Accessed January 2009. http://cait.wri.org
2. ibid.
3. ibid.
4. ibid.

Atmospheric Concentrations of Greenhouse Gases

1. IPCC (Intergovernmental Panel on Climate Change). 2007. Climate change 2007: The physical science basis (Fourth Assessment Report). Cambridge, United Kingdom: Cambridge University Press.
2. IPCC (Intergovernmental Panel on Climate Change). 2007. Climate change 2007: Synthesis report (Fourth Assessment Report). Cambridge, United Kingdom: Cambridge University Press.
3. ibid.
4. EPICA Dome C, Antarctica: 647,426 BC to 411,548 BC
   Siegenthaler, U., T. F. Stocker, E. Monnin, D. Lüthi, J. Schwander, B. Stauffer, D. Raynaud, J.M. Barnola, H. Fischer, V. Masson-Delmotte, and J. Jouzel. 2005. Stable carbon cycle-climate relationship during the late Pleistocene. Science 310(5752):1313–1317. ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/epica_domec/edc-co2-650k-390k.txt

   
   Vostok Station, Antarctica: 415,157 BC to 339 BC
   Barnola, J.M., D. Raynaud, C. Lorius, and N.I. Barkov. 2003. Historical CO₂ record from the Vostok ice core. In: Trends: A compendium of data on global change. Oak Ridge, TN: U.S. Department of Energy. http://cdiac.ornl.gov/trends/co2/vostok.html

   EPICA Dome C, Antarctica: 9002 BC to 1515 AD
   Flückiger, J., E. Monnin, B. Stauffer, J. Schwander, T.F. Stocker, J. Chappellaz, D. Raynaud, and J.M. Barnola. 2002. High resolution Holocene N₂O ice core record and its relationship with CH₄ and CO₂. Global Biogeochem. Cycles 16(1):10–11. ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/epica_domec/readme_flueckiger2002.txt

   Law Dome, Antarctica, 75-year smoothed: 1010 AD to 1975 AD
   Etheridge, D.M., L.P. Steele, R.L. Langenfelds, R.J. Francey, J.M. Barnola, and V.I. Morgan. 1998. Historical CO₂ records from the Law Dome DE08, DE08-2, and DSS ice cores. In: Trends: A compendium of data on global change. Oak Ridge, TN: U.S. Department of Energy. http://cdiac.ornl.gov/trends/co2/lawdome.html

   Siple Station, Antarctica: 1744 AD to 1953 AD
   Neftel, A., H. Friedli, E. Moor, H. Lötscher, H. Oeschger, U. Siegenthaler, and B. Stauffer. 1994. Historical CO₂ record from the Siple Station ice core. In: Trends: A compendium of data on global change. Oak Ridge, TN: U.S. Department of Energy. http://cdiac.ornl.gov/trends/co2/siple.html
   
   Mauna Loa, Hawaii: 1959 AD to 2009 AD
   NOAA (National Oceanic and Atmospheric Administration). 2010. Annual mean CO₂ concentrations for Mauna Loa, Hawaii. ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/co2_annmean_mlo.txt
   
   Barrow, Alaska: 1974 AD to 2008 AD
   Cape Matatula, American Samoa: 1976 AD to 2008 AD
   South Pole, Antarctica: 1976 AD to 2008 AD
   NOAA (National Oceanic and Atmospheric Administration). 2009. Monthly mean CO₂ concentrations for Barrow, Alaska, Cape Matatula, American Samoa, and the South Pole. http://cdiac.ornl.gov/ftp/ndp005a
   
   Cape Grim, Australia: 1992 AD to 2006 AD
   Shetland Islands, Scotland: 1993 AD to 2002 AD
   Steele, L.P., P.B. Krummel, and R.L. Langenfelds. 2007. Atmospheric CO₂ concentrations (ppmv) derived from flask air samples collected at Cape Grim, Australia, and Shetland Islands, Scotland. Aspendale, Victoria, Australia: Atmospheric, Research, Commonwealth Scientific, and Industrial Research Organisation. http://cdiac.esd.ornl.gov/ftp/trends/co2/csiro
   
   Lampedusa Island, Italy: 1993 AD to 2000 AD
   Chamard, P., L. Ciattaglia, A. di Sarra, and F. Monteleone. 2001. Atmospheric CO₂ record from flask measurements at Lampedusa Island. In: Trends: A compendium of data on global change. Oak Ridge, TN: U.S. Department of Energy. http://cdiac.ornl.gov/trends/co2/lampis.html

5. EPICA Dome C, Antarctica: 646,729 BC to 1888 AD
   Spahni, R., J. Chappellaz, T.F. Stocker, L. Loulergue, G. Hausammann, K. Kawamura, J. Flückiger, J. Schwander, D. Raynaud, V. Masson-Delmotte, and J. Jouzel. 2005. Atmospheric methane and nitrous oxide of the late Pleistocene from Antarctic ice cores. Science 310(5752):1317–1321. ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/epica_domec/edc-ch4-2005-650k.txt

   
   Vostok Station, Antarctica: 415,172 BC to 346 BC
   Petit, J.R., J. Jouzel, D. Raynaud, N.I. Barkov, J.M. Barnola, I. Basile, M. Bender, J. Chappellaz, M. Davis, G. Delaygue, M. Delmotte, V.M. Kotlyakov, M. Legrand, V. 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. ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/vostok/ch4nat.txt
   
   Greenland GISP2 ice core: 87,798 BC to 8187 BC
   Byrd Station, Antarctica: 85,929 BC to 6748 BC
   Greenland GRIP ice core: 46,933 BC to 8129 BC
   Blunier, T., and E.J. Brook. 2001. Timing of millenial-scale climate change in Antarctica and Greenland during the last glacial period. Science 291:109–112. ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/grip/synchronization/readme_blunier2001.txt
   
   EPICA Dome C, Antarctica: 8945 BC to 1760 AD
   Flückiger, J., E. Monnin, B. Stauffer, J. Schwander, T.F. Stocker, J. Chappellaz, D. Raynaud, and J.M. Barnola. 2002. High resolution Holocene N₂O ice core record and its relationship with CH₄ and CO₂. Global Biogeochem. Cycles 16(1):10–11. ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/epica_domec/readme_flueckiger2002.txt
   
   Law Dome, Antarctica: 1008 AD to 1980 AD
   Various Greenland locations: 1075 AD to 1885 AD
   Etheridge, D.M., L.P. Steele, R.J. Francey, and R.L. Langenfelds. 2002. Historical CH₄ records since about 1000 AD from ice core data. In: Trends: A compendium of data on global change. Oak Ridge, TN: U.S. Department of Energy. http://cdiac.ornl.gov/trends/atm_meth/lawdome_meth.html
   
   Greenland Site J: 1598 AD to 1951 AD
   WDCGG (World Data Centre for Greenhouse Gases). 2005. Atmospheric CH₄ concentrations for Greenland Site J. http://gaw.kishou.go.jp/wdcgg
   
   Cape Grim, Australia: 1984 AD to 2008 AD
   NOAA (National Oceanic and Atmospheric Administration). 2009. Monthly mean CH₄ concentrations for Cape Grim, Australia. ftp://ftp.cmdl.noaa.gov/ccg/ch4/flask/month/cgo_01D0_mm.ch4
   
   Mauna Loa, Hawaii: 1987 AD to 2008 AD
   NOAA (National Oceanic and Atmospheric Administration). 2009. Monthly mean CH₄ concentrations for Mauna Loa, Hawaii. ftp://ftp.cmdl.noaa.gov/ccg/ch4/in-situ/mlo/mlo_01C0_mm.ch4
   
   Shetland Islands, Scotland: 1993 AD to 2001 AD
   Steele, L.P., P.B. Krummel, and R.L. Langenfelds. 2002. Atmospheric CH₄ concentrations from sites in the CSIRO Atmospheric Research GASLAB air sampling network (October 2002 version). In: Trends: A compendium of data on global change. Oak Ridge, TN: U.S. Department of Energy. http://cdiac.esd.ornl.gov/trends/atm_meth/csiro/csiro-shetlandch4.html

6. Greenland GISP2 ice core: 104,301 BC to 1871 AD (Sowers et al., 2003)
   Taylor Dome, Antarctica: 30,697 BC to 497 BC (Sowers et al., 2003)
   Sowers, T., R.B. Alley, and J. Jubenville. 2003. Ice core records of atmospheric N₂O covering the last 106,000 years. Science 301(5635):945–948. www.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/taylor/taylor_n2o.txt

   
   EPICA Dome C, Antarctica: 9000 BC to 1780 AD
   Flückiger, J., E. Monnin, B. Stauffer, J. Schwander, T.F. Stocker, J. Chappellaz, D. Raynaud, and J.M. Barnola. 2002. High resolution Holocene N₂O ice core record and its relationship with CH₄ and CO₂. Global Biogeochem. Cycles 16(1):10–11. ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/epica_domec/readme_flueckiger2002.txt
   
   Antarctica: 1756 AD to 1964 AD
   Machida, T., T. Nakazawa, Y. Fujii, S. Aoki, and O. Watanabe. 1995. Increase in the atmospheric nitrous oxide concentration during the last 250 years. Geophys. Res. Lett. 22(21):2921–2924. ftp://daac.ornl.gov/data/global_climate/global_N_cycle/data/global_N_perturbations.txt
   
   Antarctica: 1903 AD to 1976 AD
   Battle, M., M. Bender, T. Sowers, P. Tans, J. Butler, J. Elkins, J. Ellis, T. Conway, N. Zhang, P. Lang, and A. Clarke. 1996. Atmospheric gas concentrations over the past century measured in air from firn at the South Pole. Nature 383:231–235. ftp://daac.ornl.gov/data/global_climate/global_N_cycle/data/global_N_perturbations.txt
   
   Cape Grim, Australia: 1979 AD to 2008 AD
   AGAGE (Advanced Global Atmospheric Gases Experiment). 2009. Monthly mean N₂O concentrations for Cape Grim, Australia. http://gaw.kishou.go.jp/wdcgg
   
   South Pole, Antarctica: 1998 AD to 2009 AD
   Barrow, Alaska: 1999 AD to 2009 AD
   Mauna Loa, Hawaii: 2000 AD to 2009 AD
   NOAA (National Oceanic and Atmospheric Administration). 2010. Monthly mean N₂O concentrations for Barrow, Alaska, Mauna Loa, Hawaii, and the South Pole. www.esrl.noaa.gov/gmd/hats/insitu/cats/cats_conc.html

7. IPCC (Intergovernmental Panel on Climate Change). 2007. Climate change 2007: Synthesis report (Fourth Assessment Report). Cambridge, United Kingdom: Cambridge University Press.
   
8. ibid.

Climate Forcing

1. NOAA (National Oceanic and Atmospheric Administration). 2009. The NOAA Annual Greenhouse Gas Index. Accessed April 2009. www.esrl.noaa.gov/gmd/aggi
2. IPCC (Intergovernmental Panel on Climate Change). 1995. Climate change 1995: The science of climate change (Second Assessment Report). Cambridge, United Kingdom: Cambridge University Press.
3. IPCC (Intergovernmental Panel on Climate Change). 2001. Climate change 2001: The scientific basis (Third Assessment Report). Cambridge, United Kingdom: Cambridge University Press.

Weather and Climate

U.S. and Global Temperature

1. NOAA (National Oceanic and Atmospheric Administration). 2010. National Climatic Data Center. www.ncdc.noaa.gov/oa/ncdc.html
2. ibid.
3. NOAA (National Oceanic and Atmospheric Administration). 2009. National Climatic Data Center. www.ncdc.noaa.gov/oa/ncdc.html

Heat Waves

1. Cheng, S., M. Campbell, Q. Li, L. Guilong, H. Auld, N. Day, D. Pengelly, S. Gingrich, J. Klaassen, D. MacIver, N. Comer, Y. Mao, W. Thompson, and H. Lin. 2005. Differential and combined impacts of winter and summer weather and air pollution due to global warming on human mortality in south-central Canada. Technical Report, Health Policy Research Program: Project Number 6795-15-2001/4400011.
2. CCSP (U.S. Climate Change Science Program). 2008. Synthesis and Assessment Product 3.3: Weather and climate extremes in a changing climate. www.climatescience.gov/Library/sap/sap3-3/final-report/sap3-3-final-Chapter2.pdf
3. CCSP (U.S. Climate Change Science Program). 2009. Updated version of a figure that originally appeared in U.S. Climate Change Science Program's 2008 report: Synthesis and Assessment Product 3.3: Weather and climate extremes in a changing climate. www.climatescience.gov/Library/sap/sap3-3/final-report/sap3-3-final-Chapter2.pdf
4. ibid.
5. ibid.

Drought

1. IPCC (Intergovernmental Panel on Climate Change). 2007. Climate change 2007: Synthesis report (Fourth Assessment Report). www.ipcc.ch/publications_and_data/ar4/syr/en/contents.html
2. Heim, R.R. 2002. A review of twentieth-century drought indices used in the United States. Bull. Amer. Meteor. Soc. 83(8):1149–1165.
3. National Drought Mitigation Center. 2010. U.S. Drought Monitor. Accessed April 2010. http://droughtmonitor.unl.edu 
4. National Drought Mitigation Center. 2010. Drought Monitor archives. Accessed April 2010. http://droughtmonitor.unl.edu/archive.html    
5. For example, see Heim, R.R. 2002. A review of twentieth-century drought indices used in the United States. Bull. Amer. Meteor. Soc. 83(8):1149–1165.

U.S. and Global Precipitation

1. NOAA (National Oceanic and Atmospheric Administration). 2010. National Climatic Data Center. www.ncdc.noaa.gov/oa/ncdc.html
2. ibid.
3. NOAA (National Oceanic and Atmospheric Administration). 2009. National Climatic Data Center. www.ncdc.noaa.gov/oa/ncdc.html

Heavy Precipitation

1. Tebaldi, C., K. Hayhoe, J.M. Arblaster, and G.A. Meehl. 2006. Going to the extremes: An intercomparison of model-simulated historical and future changes in extreme events. Climatic Change 79:185–211.
2. CCSP (U.S. Climate Change Science Program). 2008. Synthesis and Assessment Product 3.3: Weather and climate extremes in a changing climate. www.climatescience.gov/Library/sap/sap3-3/final-report/sap3-3-final-Chapter2.pdf
3. NOAA (National Oceanic and Atmospheric Administration). 2009. U.S. Climate Extremes Index. www.ncdc.noaa.gov/oa/climate/research/cei/cei.html
4. NOAA (National Oceanic and Atmospheric Administration). 2009. Standardized Precipitation Index data files. Accessed March 2009. ftp://ftp.ncdc.noaa.gov/pub/data/cirs

Tropical Cyclone Intensity

1. CCSP (U.S. Climate Change Science Program). 2008. Synthesis and Assessment Product 3.3: Weather and climate extremes in a changing climate. www.climatescience.gov/Library/sap/sap3-3/final-report/sap3-3-final-Chapter2.pdf
2. ibid.
3. ibid.
4. NOAA (National Oceanic and Atmospheric Administration). 2010. The 2009 North Atlantic hurricane season: A climate perspective. www.cpc.noaa.gov/products/expert_assessment/hurrsummary_2009.pdf
5. Emanuel, K.A. 2010 update of data originally published in: Emanuel, K.A. 2007. Environmental factors affecting tropical cyclone power dissipation. Journal of Climate 20(22):5497–5509.

Oceans

Ocean Heat

1. Bindoff, N.L., J. Willebrand, V. Artale, A, Cazenave, J. Gregory, S. Gulev, K. Hanawa, C. Le Quéré, S. Levitus, Y. Nojiri, C.K. Shum, L.D. Talley, and A. Unnikrishnan. 2007. Observations: Oceanic climate change and sea level. In: Climate change 2007: The physical science basis (Fourth Assessment Report).Cambridge, United Kingdom: Cambridge University Press.
2. Levitus, S., J. Antonov, and T. Boyer. 2005. Warming of the world ocean, 1955–2003. Geophys. Res. Lett. 32:L02604.
3. Domingues, C.M., J.A. Church, N.J. White, P.J. Gleckler, S.E. Wijffels, P.M. Barker, and J.R. Dunn. 2008. Improved estimates of upper-ocean warming and multi-decadal sea-level rise. Nature 453:1090–1093.
4. Ishii, M., and M. Kimoto. 2009. Reevaluation of historical ocean heat content variations with time-varying XBT and MBT depth bias corrections. J. Oceanogr. 65:287–299.
5. Levitus, S., J.I. Antonov, T.P. Boyer, R.A. Locarnini, H.E. Garcia, and A.V. Mishonov. 2009. Global ocean heat content
   1955–2008 in light of recently revealed instrumentation problems. Geophys. Res. Lett. 36:L07608.
6. Domingues, C.M., J.A. Church, N.J. White, P.J. Gleckler, S.E. Wijffels, P.M. Barker, and J.R. Dunn. 2008. Improved estimates of upper-ocean warming and multi-decadal sea-level rise. Nature 453:1090–1093.
7. Ishii, M., and M. Kimoto. 2009. Reevaluation of historical ocean heat content variations with time-varying XBT and MBT depth bias corrections. J. Oceanogr. 65:287–299.
8. Levitus, S., J.I. Antonov, T.P. Boyer, R.A. Locarnini, H.E. Garcia, and A.V. Mishonov. 2009. Global ocean heat content
   1955–2008 in light of recently revealed instrumentation problems. Geophys. Res. Lett. 36:L07608.

Sea Surface Temperature

1. NASA (National Aeronautics and Space Administration). 2008. NASA global sea surface temperature model. http://sos.noaa.gov/images/fullsize/Ocean/sstNASAModel.jpg
2. For example, see Ostrander, G.K., K.M. Armstrong, E.T. Knobbe, D. Gerace, and E.P. Scully. 2000. Rapid transition in the structure of a coral reef community: The effects of coral bleaching and physical disturbance. Proc. Natl. Acad. Sci. 97(10):5297–5302.
3. Pratchett, M.S., S.K. Wilson, M.L. Berumen, and M.I. McCormick. 2004. Sublethal effects of coral bleaching on an obligate coral feeding butterflyfish. Coral Reefs 23(3):352–356.
4. Trenberth, K.E., P.D. Jones, P. Ambenje, R. Bojariu, D. Easterling, A. Klein Tank, D. Parker, F. Rahimzadeh, J.A. Renwick, M. Rusticucci, B. Soden, and P. Zhai. 2007. Observations: Surface and atmospheric climate change. In: Climate change 2007: The physical science basis (Fourth Assessment Report). Cambridge, United Kingdom: Cambridge University Press.
5. NOAA (National Oceanic and Atmospheric Administration). 2010. Sea surface temperature (SST) datasets. National Climatic Data Center. www.ncdc.noaa.gov/oa/climate/research/sst/sst.html

Sea Level

1. Titus, J.G., E. K. Anderson, D. R. Cahoon, S. Gill, R.E. Thieler, and J.S. Williams. 2009. Coastal sensitivity to sea-level rise: A focus on the Mid-Atlantic region. U.S. Climate Change Science Program and the Subcommittee on Global Change Research. www.climatescience.gov/Library/sap/sap4-1/final-report/default.htm
2. University of Colorado at Boulder. 2009. Sea level change: 2009 release #2. http://sealevel.colorado.edu
3. CSIRO (Commonwealth Scientific and Industrial Research Organisation). 2009. Sea level rise. Accessed November 2009. http://www.cmar.csiro.au/sealevel
4. University of Colorado at Boulder. 2009. Sea level change: 2009 release #2. http://sealevel.colorado.edu
5. NOAA (National Oceanic and Atmospheric Administration). 2009 update to data originally published in: NOAA. 2001. Sea level variations of the United States 1854–1999. NOAA Technical Report NOS CO-OPS 36. http://tidesandcurrents.noaa.gov/publications/techrpt36.pdf

Ocean Acidity

1. Recreated from Environment Canada. 2008. The pH scale. www.ec.gc.ca/eau-water/default.asp?lang=En&n=FDF30C16-1
2. Wootton, J.T., C.A. Pfister, and J.D. Forester. 2008. Dynamic patterns and ecological impacts of declining ocean pH in a high-resolution multi-year dataset. Proc. Natl. Acad. Sci. 105(48):18848–18853.
3. Pacific Science Association. 2009. Task force on ocean acidification. www.pacificscience.org/tfoceanacidification.html
4. Bindoff, N.L., J. Willebrand, V. Artale, A. Cazenave, J. Gregory, S. Gulev, K. Hanawa, C. Le Quéré, S. Levitus, Y. Nojiri, C.K. Shum, L.D. Talley, and A. Unnikrishnan. 2007. Observations: Oceanic climate change and sea level. In: Climate change 2007: The physical science basis (Fourth Assessment Report).Cambridge, United Kingdom: Cambridge University Press.
5. Yool, A. 2007. Change in sea surface pH. Data from Global Ocean Data Analysis Project and analyzed using: R. Zeebe "csys" package. http://en.wikipedia.org/wiki/File:AYool_GLODAP_del_pH.png
6. Bates, N., A.C. Pequignet, R.J. Johnson, and N. Gruber. 2002. A short-term sink for atmospheric CO₂ in subtropical mode water of the North Atlantic Ocean. Nature 420:489–493.
7. Gruber, N., C.D. Keeling, N.R. Bates. 2002. Interannual variability in the North Atlantic Ocean carbon sink. Science 298:2374–2378.
8. Dore, J.E., R. Lukas, D.W. Sadler, and D.M. Karl. 2003. Climate-driven changes to the atmospheric CO₂ sink in the subtropical North Pacific Ocean. Nature 424:754–757.
9. Gonzalez-Davila, M., J.M. Santana-Casiano, M. Rueda, O. Llinas, and E. Gonzalez-Davila. 2003. Seasonal and interannual variability of sea-surface carbon dioxide species at the European Station for Time Series in the Ocean at the Canary Islands (ESTOC) between 1996 and 2000. Global Biogeochem. Cy. 17(3):1076.

Snow and Ice

Chapter Introduction

1. UNEP (United Nations Environment Programme). 2007. Global outlook for ice and snow. Cartographer: Hugo Ahlenius, UNEP/GRID-Arendal.
   
   Map based on the following data sources:
   
   Armstrong, R.L., and M.J. Brodzik. 2005. Northern Hemisphere EASE-Grid weekly snow cover and sea ice extent version 3. National Snow and Ice Data Center.
   
   Armstrong, R.L., M.J. Brodzik, K. Knowles, and M. Savoie. 2005. Global monthly EASE-Grid snow water equivalent climatology. National Snow and Ice Data Center.
   
   Brown, J., O.J. Ferrians, Jr., J.A. Heginbottom, and E.S. Melnikov. 2001. Circum-Arctic map of permafrost and ground-ice conditions. National Snow and Ice Data Center/World Data Center for Glaciology.
   
   National Geospatial-Intelligence Agency. 2000. Vector map level 0. http://geoengine.nima.mil/ftpdir/archive/vpf_data/v0soa.tar.gz
   
   Stroeve, J., and W. Meier. 2005. Sea ice trends and climatologies from SMMR and SSM/I. National Snow and Ice Data Center. http://nsidc.org/data/smmr_ssmi_ancillary/monthly_means.html

Arctic Sea Ice

1. NASA (National Aeronautics and Space Administration). 2009. Sea ice yearly minimum 1979–2007. NASA/Goddard Space Flight Center Scientific Visualization Studio. http://svs.gsfc.nasa.gov/vis/a000000/a003400/a003464/index.html
2. NSIDC (National Snow and Ice Data Center). 2009. Archived monthly sea ice data and images. Accessed November 2009. http://nsidc.org/data/seaice_index/archives/index.html
3. ibid.

Glaciers

1. Field, W.O. 1941. Muir Glacier. Glacier photograph collection. Boulder, Colorado: National Snow and Ice Data Center/World Data Center for Glaciology. http://nsidc.org/data/g00472.html
2. Molnia, B.F. 2004. Muir Glacier. Glacier photograph collection. Boulder, Colorado: National Snow and Ice Data Center/World Data Center for Glaciology. http://nsidc.org/data/g00472.html
3. Lemke, P., J. Ren, R.B. Alley, I. Allison, J. Carrasco, G. Flato, Y. Fujii, G. Kaser, P. Mote, R.H. Thomas, and T. Zhang. 2007. Observations: Changes in snow, ice and frozen ground. In: Climate change 2007: The physical science basis (Fourth Assessment Report).Cambridge, United Kingdom: Cambridge University Press.
4. Dyurgerov, M.B. 2010. Reanalysis of Glacier Changes: From the IGY to the IPY, 1960-2008. Data of Glaciological Studies 108:1–116.
5. USGS (U.S. Geological Survey). 2009. Water resources of Alaska—glacier and snow program, benchmark glaciers. Accessed November 2009. http://ak.water.usgs.gov/glaciology
6. GCRP (U.S. Global Change Research Program). 2009. Global climate change impacts in the United States. http://www.globalchange.gov/usimpacts
7. ibid.

Lake Ice

1. Magnuson, J.J., D.M. Robertson, B.J. Benson, R.H. Wynne, D.M. Livingstone, T. Arai, R.A. Assel, R.G. Barry, V. Card, E. Kuusisto, N.G. Granin, T.D. Prowse, K.M. Stewart, and V.S. Vuglinski. 2000. Historical trends in lake and river ice cover in the Northern Hemisphere. Science 289:1743–1746. Errata 2001. Science 1291:1254.
2. NSIDC (National Snow and Ice Data Center). 2009. Global lake and river ice phenology. http://nsidc.org/data/lake_river_ice
3. ibid.
4. ibid.

Snow Cover

1. Rutgers University Global Snow Lab. 2009. Area of extent data: North America (no Greenland). http://climate.rutgers.edu/snowcover
2. ibid.

Snowpack

1. Mote, P.W., A.F. Hamlet, M.P. Clark, and D.P. Lettenmaier. 2005. Declining mountain snowpack in Western North America. Bull. Amer. Meteor. Soc. 86(1):39–49.
2. Mote, P.W. 2009 update to data originally published in: Mote, P.W., A.F. Hamlet, M.P. Clark, and D.P. Lettenmaier. 2005. Declining mountain snowpack in Western North America. Bull. Amer. Meteor. Soc. 86(1):39–49.
3. Mote, P.W., A.F. Hamlet, M.P. Clark, and D.P. Lettenmaier. 2005. Declining mountain snowpack in Western North America. Bull. Amer. Meteor. Soc. 86(1):39–49.

Society and Ecosystems

Length of Growing Season

1. Easterling, W.E., P.K. Aggarwal, P. Batima, K.M. Brander, L. Erda, S.M. Howden, A. Kirilenko, J. Morton, J.-F. Soussana, J. Schmidhuber, and F.N. Tubiello. 2007. Food, fibre and forest products. In: Climate change 2007: Impacts, adaptation and vulnerability (Fourth Assessment Report). Cambridge, United Kingdom: Cambridge University Press.
2. Kunkel, K.E. 2009 update to data originally published in: Kunkel, K.E., D.R. Easterling, K. Hubbard, and K. Redmond. 2004. Temporal variations in frost-free season in the United States: 1895–2000. Geophys. Res. Lett. 31:L03201.
3. ibid.
4. ibid.
5. ibid.

Plant Hardiness Zones

1. Arbor Day Foundation. 2006. Differences between 1990 USDA hardiness zones and 2006 arborday.org hardiness zones reflect warmer climate. www.arborday.org/media/map_change.cfm
2. ibid.

Leaf and Bloom Dates

1. IPCC (Intergovernmental Panel on Climate Change). 2007. Climate change 2007: Synthesis report (Fourth Assessment Report). Cambridge, United Kingdom: Cambridge University Press.
2. Schwartz, M.D., R. Ahas, and A. Aasa. 2006. Onset of spring starting earlier across the Northern Hemisphere. Glob. Chang. Biol. 12:343–351.
3. For example, see: Schwartz, M.D., R. Ahas, and A. Aasa. 2006. Onset of spring starting earlier across the Northern Hemisphere. Glob. Chang. Biol. 12:343–351.
4. Schwartz, M.D. 2009 update to data originally published in: Schwartz, M.D., R. Ahas, and A. Aasa. 2006. Onset of spring starting earlier across the Northern Hemisphere. Glob. Chang. Biol. 12:343–351.
5. ibid.
6. Schwartz, M.D., R. Ahas, and A. Aasa. 2006. Onset of spring starting earlier across the Northern Hemisphere. Glob. Chang. Biol. 12:343–351.

Bird Wintering Ranges

1. National Audubon Society. 2009. Northward shifts in the abundance of North American birds in early winter: A response to warmer winter temperatures? www.audubon.org/bird/bacc/techreport.html
2. ibid.
3. ibid.
4. ibid.
5. ibid.
6. ibid.