Kennaook / Cape Grim Baseline Air Pollution Station

Understanding our atmosphere

Earth's climate is changing due to changes in the composition of the atmosphere.

At Kennaook / Cape Grim, the Bureau operates a scientific observatory to measure the composition of some of the world's cleanest air. The station is on Tasmania's west coast, near the north-west tip of the island.

When conditions are right, the air at Kennaook / Cape Grim is representative of the well-mixed atmosphere, unaffected by local pollution.

What is measured

At the station we measure atmospheric composition to chronicle how it has changed over time. This includes measuring:

• greenhouse gases that drive climate change
• substances that cause the hole in the ozone layer (stratospheric ozone depletion)
• other features of the atmosphere that affect climate, directly or indirectly.

Why Kennaook / Cape Grim data is important

Scientists use data from this station to:

• understand the life cycle and impacts of various parts of the atmosphere, and how their influence changes over time
• calculate emissions of harmful substances, nationally and globally.

The station contributes to the Cape Grim Science Program, which we manage with CSIRO.

Clean air from across the Southern Ocean

Westerly to south-westerly winds blow across the Southern Ocean. They deliver pristine air to the station's precise monitoring equipment.

This air is representative of the well-mixed atmosphere of the southern hemisphere. Unpolluted by local sources, it's called 'baseline air'.

Some measurements are made in non-baseline conditions. These give insight into the processes of the atmosphere. The data also helps refine Australian emissions estimates, for example, greenhouse gases.

Global significance

Several sites around the world measure elements of atmospheric composition. Few of these, and none in the southern hemisphere, do this as comprehensively as at Kennaook / Cape Grim.

This station and the related science program are guided by the World Meteorological Organization's Global Atmosphere Watch Programme. Kennaook / Cape Grim data is stored in the World Data Centres coordinated by the program.

Updates on station activities and more

We report the station's activities, data and research results in Baseline. You'll find this publication on Trove, an archive service managed by the National Library of Australia.

Measurements at Kennaook / Cape Grim

Measuring greenhouse gases

Greenhouse gas measurements began at this station in 1976. It started with carbon dioxide and various halocarbons – potent synthetic greenhouse gases.

Carbon dioxide at that time was recorded at 330 parts per million (ppm). Nearly half a century later, it has increased by about 25%.

The station now captures valuable data on more than 80 gases, for example:

• carbon dioxide, CO₂
• methane, CH₄
• nitrous oxide, N₂O.

It also includes synthetic gases such as:

• chlorofluorocarbons (CFCs)
• hydrochlorofluorocarbons (HCFCs)
• hydrofluorocarbons (HFCs)
• perfluorocarbons (PFCs)
• sulphur hexafluoride (SF₆).

Monitoring ozone depleting substances

Ozone in Earth's stratosphere protects our planet from some of the Sun's harshest radiation.

Ozone depleting substances are chemicals responsible for the ozone hole. They destroy ozone in the stratosphere. Many of these are also potent greenhouse gases.

Concerns about the impact of these chemicals led to the Vienna Convention for the Protection of the Ozone Layer in 1985. This was followed by the Montreal Protocol on Substances that Deplete Ozone in 1987. It sought to curb production and called for ongoing monitoring of these chemicals in the atmosphere.

At the station we routinely measure all of the significant ozone depleting substances. This is possible through a collaboration with the international Advanced Global Atmospheric Gases Experiment (AGAGE) network.

Other measurements at Kennaook / Cape Grim

Measurements of greenhouse gases and ozone depleting substances are an important part of the work at Kennaook / Cape Grim, but there is much more.

The composition of the Earth's atmosphere is changing in complex and subtle ways. These changes influence how the atmosphere and climate respond. For example:

• Atmospheric particles can influence how light from the sun passes through the atmosphere. Particles are also critical in cloud formation.
• Reactive gases such as nitric oxides and ozone influence the chemistry of the atmosphere. They are also involved in particle formation.
• Radon measurements tell us if the air we are measuring has recently been over land, so works as a tracer.

We take detailed and precise measurements of these and more. This enables us to chronicle the influence of all these factors and understand changes over time.

Sample archives

Collections for the Cape Grim Air Archive have been made since 1978. It is the world's longest, complete archive of such pristine samples.

Using this archive, researchers can analyse samples as they were, as far back as 1978. They can use new techniques or look for recently-identified species in older samples. Samples are collected several times a year.

Particle samples from baseline air have been collected since 1985. The samples are collected with a high volume sampler through a PM₁₀ size-selective inlet. They are captured on a filter and analysed at CSIRO.

CSIRO manages the curated collections, used by researchers around the world.

Australian and international partners

Australian partners

CSIRO

With CSIRO, we manage the Cape Grim Science Program:

• The Bureau funds and operates the baseline air pollution station. We're responsible for chronicling how baseline atmospheric composition changes over time.
• CSIRO invests in staff who provide expertise in the measurement process. This collaboration enables CSIRO to progress scientific understanding of climate change drivers.

Australian Nuclear Science and Technology Organisation

The Australian Nuclear Science and Technology Organisation has expertise in radioactive substances. Their work at this station focuses on radon gas.

Radon occurs naturally in the atmosphere after being mainly emitted from land, and is short-lived.

Radon measurements help us understand whether the air we're measuring has recently been over land and whether it may have been recently polluted by urban activity.

University of Wollongong and University of Southern Queensland

The University of Wollongong and University of Southern Queensland focus on solar radiation. This informs understanding of:

• chemical processes of the clean baseline air
• impacts on the global heat budget
• long-term changes in UV radiation.

International partners

The Cape Grim Science Program collaborates with the Advanced Global Atmospheric Gases Experiment. This work focuses on the synthetic greenhouse gases and ozone depleting substances.

Other international agencies collect samples from Kennaook / Cape Grim for global sampling networks. This includes organisations such as the:

• Scripps Institution of Oceanography
• National Oceanic and Atmospheric Administration's Global Monitoring Laboratory.

How Kennaook / Cape Grim data is used

Kennaook / Cape Grim data is freely available. It is widely used to quantify global, regional and Australian emissions of greenhouse gases. The data is available from the World Data Centres.

Climate change research and assessments

The data and related analyses have been used in hundreds of research papers on climate change and ozone depletion. The data have been cited in all United Nations:

• Framework Convention on Climate Change Intergovernmental Panel on Climate Change Assessment Reports
• Environment Programme and World Meteorological Organization Scientific Assessment of Ozone Depletion Reports.

Reporting for international obligations

Kennaook / Cape Grim data is used in reporting Australia's status on various international obligations, such as the:

• Vienna Convention for the Protection of the Ozone Layer (1985)
• Montreal Protocol on Substances that Deplete the Ozone layer (1987) and later amendments
• Kyoto Protocol (2005) and Paris Agreement (2016), both under the United Nations Framework Convention on Climate Change.

This also includes verifying parts of Australia's National Greenhouse Gas Inventory. The inventory is how Australia reports its annual emissions to the United Nations Framework Convention on Climate Change.

Understanding national climate

Measurements from Kennaook / Cape Grim are also vital to the State of the Climate report. We publish this report with the CSIRO every 2 years.

The data:

• contributes to understanding of climate in Australia
• includes new information about Australia’s climate of the past, present and future
• informs a range of economic, environmental and social decision-making by governments, industries and communities.