Introduction

Greenhouse gases are gases such as Carbon Dioxide (CO₂) and Methane (CH₄) that absorb and re-emit infrared radiation. In the atmosphere, their interaction with infrared radiation ultimately leads to a warming of the atmosphere and surface.

Atmospheric concentrations of greenhouse gases reflect a balance between emissions from human activities (such as the burning of fossil fuels), natural sources, and sinks in the biosphere and ocean. Increasing levels of greenhouse gases in the atmosphere due to human activities have been the major driver of climate change since the mid-twentieth century. Global average mole fractions of greenhouse gases (as shown in the figures) are calculated from in situ observations made at multiple sites in the Global Atmosphere Watch (GAW) Programme of WMO and partner networks.

The ocean is a sink for CO₂. Some of the excess CO₂ in the atmosphere is absorbed by the ocean. CO₂ reacts with seawater and lowers its pH. This process is known as ocean acidification.

What the IPCC says

A 1.1 Observed increases in well-mixed greenhouse gas (GHG) concentrations since around 1750 are unequivocally caused by human activities. Since 2011 (measurements reported in AR5), concentrations have continued to increase in the atmosphere, reaching annual averages of 410 parts per million (ppm) for carbon dioxide (CO₂), 1866 parts per billion (ppb) for methane (CH₄), and 332 ppb for nitrous oxide (N₂O) in 2019. Land and ocean have taken up a near-constant proportion (globally about 56% per year) of CO₂ emissions from human activities over the past six decades, with regional differences (high confidence).

Key messages

Atmospheric concentration of carbon dioxide

In 2021, greenhouse gas mole fractions reached new highs, with globally averaged surface mole fractions of carbon dioxide (CO₂) at 415.7 ± 0.2 parts per million (ppm), methane (CH₄) at 1908 ± 2 parts per billion (ppb) and nitrous oxide (N₂O) at 334.5 ± 0.1 ppb, respectively 149%, 262% and 124% of pre-industrial (1750) levels.

Dataset and processing details

Carbon dioxide

Carbon dioxide (CO₂) is one of the most important greenhouse gases. The concentration of CO₂ in the atmosphere is measured at stations around the world which are combined to provide a globally representative value.

The data in the above plot are available in a zip file containing a csv file for each data set.

Data file: Carbon_dioxide_data_files.zip
Checksum: 3f5ed6475290bb13b77d800af6b0e348 Copy
Format: BADC CSV format

WDCGG

Original data file (external link)

Citation: WMO Greenhouse Gas Bulletin, No.18, 2022. 26 October 2022 ISSN 2078-0796.

To produce the plot, the following processing steps were performed:

• Data set created from file ['co2_monthly_20221026.csv'] downloaded from ['https://gaw.kishou.go.jp/static/publications/global_mean_mole_fractions/2022/co2_monthly_20221026.csv'] at ['2023-02-27 09:20:00']

Methane

Methane (CH₄) is an important greenhouse gas. The concentration of CH₄ in the atmosphere is measured at stations around the world which are combined to provide a globally representative value.

The data in the above plot are available in a zip file containing a csv file for each data set.

Data file: Methane_data_files.zip
Checksum: 0f1b697150223b7b84fc954c06811925 Copy
Format: BADC CSV format

WDCGG

Original data file (external link)

Citation: WMO Greenhouse Gas Bulletin, No.18, 2022. 26 October 2022 ISSN 2078-0796.

To produce the plot, the following processing steps were performed:

• Data set created from file ['ch4_monthly_20221026.csv'] downloaded from ['https://gaw.kishou.go.jp/static/publications/global_mean_mole_fractions/2022/ch4_monthly_20221026.csv'] at ['2023-02-27 09:19:55']

Nitrous Oxide

Nitrous oxide (N₂O) is an important greenhouse gas. The concentration of N₂O in the atmosphere is measured at stations around the world which are combined to provide a globally representative value.

The data in the above plot are available in a zip file containing a csv file for each data set.

Data file: Nitrous_Oxide_data_files.zip
Checksum: c517527d576f699c3d372ad4769cd436 Copy
Format: BADC CSV format

WDCGG

Original data file (external link)

Citation: WMO Greenhouse Gas Bulletin, No.18, 2022. 26 October 2022 ISSN 2078-0796.

To produce the plot, the following processing steps were performed:

• Data set created from file ['n2o_monthly_20221026.csv'] downloaded from ['https://gaw.kishou.go.jp/static/publications/global_mean_mole_fractions/2022/n2o_monthly_20221026.csv'] at ['2023-02-27 09:20:10']

Carbon dioxide growth rate

The data in the above plot are available in a zip file containing a csv file for each data set.

Data file: Carbon_dioxide_growth_rate_data_files.zip
Checksum: 5b2c2d55063781699c31ba5017f6a1cc Copy
Format: BADC CSV format

WDCGG

Original data file (external link)

Citation: WMO Greenhouse Gas Bulletin, No.18, 2022. 26 October 2022 ISSN 2078-0796.

To produce the plot, the following processing steps were performed:

• Data set created from file ['co2_annual_20221026.csv'] downloaded from ['https://gaw.kishou.go.jp/static/publications/global_mean_mole_fractions/2022/co2_annual_20221026.csv'] at ['2023-02-27 09:20:06']

Methane growth rate

The data in the above plot are available in a zip file containing a csv file for each data set.

Data file: Methane_growth_rate_data_files.zip
Checksum: 2b35a4d02f6e944f9d89bbd4aad04fa4 Copy
Format: BADC CSV format

WDCGG

Original data file (external link)

Citation: WMO Greenhouse Gas Bulletin, No.18, 2022. 26 October 2022 ISSN 2078-0796.

To produce the plot, the following processing steps were performed:

• Data set created from file ['ch4_annual_20221026.csv'] downloaded from ['https://gaw.kishou.go.jp/static/publications/global_mean_mole_fractions/2022/ch4_annual_20221026.csv'] at ['2023-02-27 09:19:59']

Nitrous oxide growth rate

The data in the above plot are available in a zip file containing a csv file for each data set.

Data file: Nitrous_oxide_growth_rate_data_files.zip
Checksum: 70b9cc4f97a20c3f2904358aee66d82b Copy
Format: BADC CSV format

WDCGG

Original data file (external link)

Citation: WMO Greenhouse Gas Bulletin, No.18, 2022. 26 October 2022 ISSN 2078-0796.

To produce the plot, the following processing steps were performed:

• Data set created from file ['n2o_annual_20221026.csv'] downloaded from ['https://gaw.kishou.go.jp/static/publications/global_mean_mole_fractions/2022/n2o_annual_20221026.csv'] at ['2023-02-27 09:20:13']