Climate gases in Svalbard

Last updated 10 March 2023

The most important greenhouse gases emitted by human activity are carbon dioxide (CO₂), methane (CH₄), a combined group of gases called halocarbons, and nitrous oxide (N₂O). These are gases that contribute to an increase in temperature and where the concentration in the atmosphere is affected by human activities such as deforestation and fossil combustion.

Status and trend

Carbon dioxide (CO₂)

In 2015, a mean CO₂ concentration of over 400 ppm was measured at the Zeppelin Observatory for the first time. Carbon dioxide is an end product of organic compounds which are oxidised in the atmosphere, and levels have risen by no less than 50% since the pre-industrial age. This is mainly due to the anthropogenic combustion of fossil fuels and land use. Measurements taken at the Zeppelin Observatory show that CO₂ concentrations are rising by around 2.5ppm per year.

Global CO₂ emissions from fossil fuels and cement production rose by 2.3% from 2012 to 2013, with a total of 9.9 ± 0.5 GtC (gigatonnes carbon). This is equivalent to the emission of 36 Gt CO₂ into the atmosphere, which is 61% higher than the emissions which occurred in 1990 (the reference year for the Kyoto Protocol).

Methane (CH₄)

The atmospheric concentration of methane rose sharply during the 20th century, but its concentration was relatively stable during the period 1998 – 2006, when the global mean increase was virtually zero. However, a recent increase in CH₄ levels over the past decade is apparent from NILU (Norwegian Institute for Air Research) observations at both the Zeppelin Observatory and other stations.

Methane measurements at the Zeppelin Observatory began in 2001, and the trend over the whole measurement period has been determined. The analyses show that the mean increase in methane is 6.5ppb per year. The global methane concentration has risen from 722ppb in the pre-industrial age to 1889ppb in 2020, an increase of 145%.

Nitrous oxide (N₂O)

The global concentration of nitrous oxide has risen from around 270ppb before industrialisation to a global mean of 333ppb in 2020. N₂O measurements at the Zeppelin Observatory began in 2010, and the and the trend calculations show a mean N2O increase of 0.98ppb per year. The annual N₂O mean for the Zeppelin station in 2020 was 333.4ppb. According to WMO, the global mean increase since 2014 is 1.1ppb, a slightly sharper rise than before 2014.

Causal factors

Carbon dioxide (CO₂)

Carbon dioxide is considered to be the most important man-made greenhouse gas, both in Norway and globally. In Norway, over 80% of total emissions of greenhouse gases consist of carbon dioxide.

The burning of fossil fuels is the main source of carbon dioxide. Land use is also an important source. In this case, CO₂ emissions take place through deforestation, the clearance of land for agricultural use and soil degradation. In the same way that these soil and forest areas can contribute to increases in CO₂ concentrations, they can also remove carbon dioxide from the atmosphere through reforestation, for example.

Methane (CH₄)

The main sources of methane include

• boreal and tropical wetlands
• rice paddies
• emission from ruminant animals
• biomass burning
• waste
• termites
• extraction and combustion of fossil fuels

Furthermore, methane is the principal constituent of natural gas, and leakage from pipelines and offshore and onshore installations is a known source of atmospheric methane. The distribution between natural and man-made sources is approximately 40% natural and 60% man-made sources. With regard to natural sources, there is major potential source of methane beneath the seabed, known as ‘methane hydrates’. In addition, there are large but unknown quantities of carbon bound up in the permafrost layer in Siberia and North America, which could be released as methane if the permafrost layer were to melt as a result of climate change.

The observed increase in methane concentrations in recent years is not fully understood.

Leaks from gas installations, world-wide, both onshore and offshore might be an increasing source. Hence, it is essential to find out if the increase since 2005 is due to emissions from large point sources, or if it is caused by newly initiated processes releasing methane to the atmosphere e.g. the thawing of the permafrost layer.

Recent scientific studies point to increased emissions from wetlands in both tropical and arctic regions.

Nitrous oxide (N₂O)

Nitrous oxide is a greenhouse gas with both natural and anthropogenic sources. The sources include

• oceans
• tropical forests
• soil
• biomass burning
• cultivated soil
• use of particular synthetic fertilizers
• various industrial processes

There is considerable uncertainty associated with the quantity estimates of N₂O contributions from soil, agriculture, combustion and marine sources. Frozen peat in the Arctic tundra has also been reported as a possible source, but recent studies led by NILU have identified tropical and sub-tropical regions as the largest source areas.

Consequences

An increase in greenhouse gases in the atmosphere is directly related to climate change and increasing temperatures globally. The rise in temperature in the Arctic is greater than the rise in the global mean, which is consistent with current climate models.

Carbon dioxide (CO₂)

Carbon dioxide is the most important greenhouse gas with a radiative forcing of 1.82 W/m² since the year 1750, and an increase since the previous IPCC report (AR4, 2007) of 0.16 W/m². The increase in radiative forcing is due to the rise in CO₂ concentrations in recent years.

Methane (CH₄)

The measurements from 2014 reveal a pronounced new record in the observed methane level at Zeppelin. Methane is the second most important greenhouse gas from human activity after carbon dioxide (CO₂). Radiative forcing was 0.48 W/m² from 1750 through until 2011, but is as high as 0.97 W/m² if other atmospheric effects initiated by methane are included.

In addition to being a dominant greenhouse gas, methane also plays central role in the atmospheric chemistry. The atmospheric lifetime of methane is approx. 12 years, when indirect effects are included.

Nitrous oxide (N₂O)

Nitrous oxide is an important greenhouse gas with a radiative forcing of 0.17 W/m² since 1750. It contributes about 6% of the total radiative forcing through the industrial age. Nitrous oxide is also the major source of the ozone-depleting nitric oxide (NO) and nitrogen dioxide (NO₂) in the stratosphere, thus the component is also influencing the stratospheric ozone layer.

About the monitoring

The atmospheric monitoring programme “Monitoring of greenhouse gases and aerosols at the Zeppelin Observatory, Svalbard, and Birkenes Observatory, Aust-Agder, Norway” focuses on the level of greenhouse gases and aerosols properties relevant for the interaction of aerosols and radiation in the Norwegian background air and in the Arctic. The main objectives are to quantify the levels of greenhouse gases including ozone depleting substances, describe the relevant optical and physical properties of aerosols, and document the development over time.

Measurements of greenhouse gases and aerosol properties provide key data for studies and evaluations of climate change, and are also vital for assessing strategies for emission reductions and evaluating whether measures are effective. The Norwegian monitoring stations are located in areas where the influence of local sources is minimal, with the result that the stations are representative of a wider region and can demonstrate long-term changes in the composition of the atmosphere.