Global greenhouse gas emissions

  • Image, Global greenhouse gas emissions.

    Greenhouse gas (GHG) emissions from human activities increase the concentration of these gases in the atmosphere. GHGs absorb heat radiating from Earth’s surface and warm the atmosphere. In turn, this warming changes our climate. Some GHG emissions are removed, primarily by forests. For this reason, we use net emission rather than gross emission values to represent the total amount of gas contributed to the atmosphere.

    We classified Global greenhouse gas emissions as a case study.

    Key findings

    Global net GHG emissions show an increasing trend. This trend is statistically significant.

    • In 2011, estimated global net GHG emissions were 33 percent higher than 1990 levels (an annual average increase of 1.4 percent or 591,240 Gg CO2-e units (gigagrams of equivalent carbon dioxide).
    • Brazil, China, the 28 European Union member countries, India, Indonesia, Japan, Russia, and the United States of America produce 66 percent of the world’s net emissions.
    • Between 1990 and 2011, New Zealand emitted an average of 0.1 percent of global net GHG emissions.


    Note: The United Nations Framework Convention on Climate Change is the preferred data source, but because some countries do not report on all years since 1990, the data are augmented with Climate Analysis Indicators Tool data. Emissions are in gigagrams of equivalent carbon dioxide (Gg CO2-e).

    Definition and methodology

    The estimate of GHG emissions includes country-by-country net emissions. These GHG emission totals include the effects of land use, land-use change, and forestry. Net emissions are used rather than gross emissions because they represent the amount of gas that human activities contribute to atmospheric concentrations of GHGs.

    The data are from two sources. The preferred source is the United Nations Framework Convention on Climate Change (UNFCCC). Because UNFCCC has different GHG data reporting requirements for Annex I and non-Annex I parties, not all countries’ data are available for all years since 1990. Where UNFCCC data are not available for the full 1990–2011 period, we use country-by-country data from the Climate Analysis Indicators Tool (CAIT).

    UNFCCC data are used for 44 of the 184 countries included in the estimated global net GHG emissions, and account for 36 percent of estimated net emissions in 2011.

    The GHG emission estimates comprise CO2-equivalent (CO2-e) totals. The totals exclude short-cycle biomass burning (such as planned burning of agricultural waste and savannah). The totals include other biomass burning (such as forest fires and peat fires) and all human-made sources of methane (CH4), nitrous oxide (N2O), and fluorinated gases (F-gases).

    We report GHGs in Gg CO2-e units (gigagrams of equivalent carbon dioxide), using the 100-year global warming potentials (GWPs) from the Intergovernmental Panel on Climate Change Second Assessment Report (IPCC, 1996). GWPs compare the potential for a gas to increase global temperatures with the equivalent CO2 potential to do the same thing (ie the CO2 equivalent). This means that GHG estimates can be reported consistently.

    See New Zealand’s greenhouse gas inventory 1990–2013.

    Data quality

    We classified Global greenhouse gas emissions as a case study.


     This case study is a direct measure of the ‘Global emissions of greenhouse gases and ozone-depleting substances’ topic.


     The accuracy of the data source is of medium quality.

    See Data quality information for more detail.

    Supporting information

    New Zealand’s greenhouse gas emissions


    Intergovernmental Panel on Climate Change (IPCC) (1996). Climate change 1995: The science of climate change. Contribution of Working Group I to the Second Assessment Report of the Intergovernmental Panel on Climate Change. Available from


    Updated 26 July 2016

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