Greenhouse Gases
Greenhouse gases (GHGs) in the atmosphere trap infrared radiation from the Earth, warming it up. This is known as the greenhouse effect. The three main long-lived greenhouse gases are carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O). There are many other greenhouse gases, for example, Sulphur hexafluoride (SF₆), and together these have a significant influence on the climate.
426.8 ppm
in 2025, an observed record high.
Explanation
The concentration of CO₂ in the atmosphere reflects a balance between sources and sinks. CO₂ is released into the atmosphere through natural processes and human activities, including fossil fuel burning, cement production and land-use changes such as deforestation. CO2 is removed from the atmosphere of uptake by vegetation and the ocean. CO₂ concentrations are measured through a globally coordinated network of monitoring stations. The human-caused increase in its atmospheric concentration is the largest driver of climate change.
Methodology
The indicator is based on high-precision measurements from a global network of atmospheric monitoring stations representing background atmospheric conditions, with the global series beginning in 1984 and continuous instrumental records at some locations extending back several decades.
2.8 ppm/year
from 2024 to 2025
Explanation
The concentration of CO₂ in the atmosphere reflects a balance between sources and sinks. CO₂ is released into the atmosphere through natural processes and human activities, including fossil fuel burning, cement production and land-use changes such as deforestation. CO2 is removed from the atmosphere of uptake by vegetation and the ocean. CO₂ concentrations are measured through a globally coordinated network of monitoring stations. The human-caused increase in its atmospheric concentration is the largest driver of climate change.
Methodology
The indicator is based on high-precision measurements from a global network of atmospheric monitoring stations representing background atmospheric conditions, with the global series beginning in 1984 and continuous instrumental records at some locations extending back several decades.
Kennaook/Cape Grim: 422.9 ppm
Mauna Loa: 427.4 ppm
in 2025
Explanation
The concentration of CO₂ in the atmosphere reflects a balance between sources and sinks. CO₂ is released into the atmosphere through natural processes and human activities, including fossil fuel burning, cement production and land-use changes such as deforestation. CO2 is removed from the atmosphere of uptake by vegetation and the ocean. CO₂ concentrations are measured through a globally coordinated network of monitoring stations. The human-caused increase in its atmospheric concentration is the largest driver of climate change.
Methodology
The series here are from two individual sites, one in the northern hemisphere and one in the southern hemisphere.
The Mauna Loa site was chosen because it surrounded by a large area of bare lava without vegetation or soil that might emit or absorb carbon dioxide. This means that the observatory measured "background" air that is representative of the northern hemisphere.
The Kennaook / Cape Grim site is on a peninsula in the northwest of Tasmania. In the predominantly westerly winds, the air sampled at the site has passed over the Southern Ocean and the air is representative of large areas of the southern hemisphere. Travelling due west from the site, the first land you would encounter would be the southern tip of South America.
1948 ppb
in 2025
Explanation
Methane (CH₄) is the second most important long-lived greenhouse gas influenced by human activities. It is emitted from natural sources, such as wetlands, and human activities, including agriculture, fossil fuel production and use, and landfills. Methane is removed mainly through chemical reactions in the atmosphere. Its atmospheric lifetime is much shorter than that of CO₂.
Methodology
The indicator is based on high-precision measurements from a global network of atmospheric monitoring stations representing background atmospheric conditions, with the global series beginning in 1984 and continuous instrumental records at some locations extending back several decades.
6 ppb/year
from 2024-2025, lower than the previous year.
Explanation
Methane (CH₄) is the second most important long-lived greenhouse gas influenced by human activities. It is emitted from natural sources, such as wetlands, and human activities, including agriculture, fossil fuel production and use, and landfills. Methane is removed mainly through chemical reactions in the atmosphere. Its atmospheric lifetime is much shorter than that of CO₂.
Methodology
The indicator is based on high-precision measurements from a global network of atmospheric monitoring stations representing background atmospheric conditions, with the global series beginning in 1984 and continuous instrumental records at some locations extending back several decades.
339.1 ppb
in 2025
Explanation
Nitrous oxide (N₂O) is the third most important long-lived greenhouse gas influenced by human activities. It is emitted from natural sources, including soils and oceans, as well as human activities such as fertilizer use, biomass burning, and industrial processes. N₂O is removed mainly through photochemical processes in the stratosphere. N₂O also contributes to stratospheric ozone depletion.
Methodology
The indicator is based on high-precision measurements from a global network of atmospheric monitoring stations representing background atmospheric conditions, with the global series beginning in 1984 and continuous instrumental records at some locations extending back several decades.
26% increase
from 2024-2025
Explanation
Nitrous oxide (N₂O) is the third most important long-lived greenhouse gas influenced by human activities. It is emitted from natural sources, including soils and oceans, as well as human activities such as fertilizer use, biomass burning, and industrial processes. N₂O is removed mainly through photochemical processes in the stratosphere. N₂O also contributes to stratospheric ozone depletion.
Methodology
The indicator is based on high-precision measurements from a global network of atmospheric monitoring stations representing background atmospheric conditions, with the global series beginning in 1984 and continuous instrumental records at some locations extending back several decades.
12.24 ppt
in 2024
Explanation
Sulphur hexafluoride (SF₆) is a synthetic, long-lived and potent greenhouse gas. It is used primarily in electricity systems. SF₆ is released through industrial activities and is highly stable in the atmosphere, with a lifetime exceeding 1 000 years.
Methodology
To produce the plot, the following processing steps were performed:
- Data set created from file ['sf6_annmean_gl.txt'] downloaded from ['https://gml.noaa.gov/webdata/ccgg/trends/sf6/sf6_annmean_gl.txt'] at ['2026-02-19 14:51:35']