1.1 Trends in global greenhouse gas concentrations

Last Updated: 
June 2, 2015

This indicator reports on global atmospheric concentrations of important long-lived greenhouse gases (GHGs) during the last 2,000 years.

This information is summarized from the Fifth Assessment Report of the International Panel on Climate Change - Climate Change 2013 - The Physical Science Basis published by the World Meteorological Organization and the United Nations Environment Programme. Current global carbon-dioxide (CO2) concentration is obtained from US National Oceanic and Atmospheric Administration.

Environment Canada Air Quality Lab at Alert, Nunavut. Photo credit: US National Oceanic Administration
Environment Canada Air Quality Lab at Alert, Nunavut. Photo credit: US National Oceanic Administration

NWT focus

Increases in global GHG concentrations, partly responsible for the noticeable changes in the NWT’s climate during the past three decades, are having complex effects on the NWT environment.

Current view: status and trend

Concentrations of carbon dioxide (CO2), methane (CH4) and nitrogen dioxide (N20) now subtaintially exceed the highest concentrations recorded in ice cores during the past 800,000 years. The mean rates of increase in atmospheric concentrations over the past century are, with very high confidence, unprecedented in the last 22,000 years. ~ Quote from the Fifth Assessment Report of the International Panel on Climate Change - Climate Change 2013 - The Physical Science Basis - Summary for Policy Makers1.

Photo credit: Ed Dlugokencky and Pieter Tans, NOAA/ESRL 
Photo credit: Ed Dlugokencky and Pieter Tans, NOAA/ESRL 

    The graph shows recent monthly mean carbon dioxide globally averaged over marine surface sites. The Global Monitoring Division of NOAA/Earth System Research Laboratory has measured carbon dioxide and other greenhouse gases for several decades at a globally distributed network of air sampling sites. A global average is constructed by first fitting a smoothed curve as a function of time to each site then the smoothed value for each site is plotted as a function of latitude for 48 equal time steps per year. A global average is calculated from the latitude plot at each time step.

    Concentrations of Greenhouse Gases from 0 to 2005. Source courtesy of: IPCC WG1-2007 "The Physical Science Basis" Report; FAQ 2.1. Data from various sources, including from glaciers.
    Concentrations of Greenhouse Gases from 0 to 2005. Source courtesy of: IPCC WG1-2007 "The Physical Science Basis" Report; FAQ 2.1. Data from various sources, including from glaciers.

    Atmospheric concentrations of important long-lived greenhouse gases during the last 2,000 years. Increases since about 1750 are attributed to human activities in the industrial era. Concentration units are parts per million (ppm) or parts per billion (ppb), indicating the number of molecules of the greenhouse gas per million or billion air molecules, respectively, in an atmospheric sample.

    While there are no long-term records of atmospheric CO2 measurements for the NWT, there are measurements for Alert, NU.

    CO2 concentration from Alert, NU. Data courtesy Doug Worthy, Environment Canada.
    CO2 concentration from Alert, NU. Data courtesy Doug Worthy, Environment Canada.

      Looking forward

      "Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased."

      "Continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system. Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions."

      "The Arctic region will warm more rapidly than the global mean, and mean warming over land will be larger than over the ocean." 

      Quotes from the Fifth Assessment Report of the International Panel on Climate Change - Climate Change 2013 - The Physical Science Basis: Summary for Policy Makers.1

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      Found an error or have a question? Contact the team at NWTSOER@gov.nt.ca.