It’s the air we breathe, it protects us from the sun, and it controls the earth’s temperature. The atmosphere makes life possible, but human activities have tipped the balance towards pollution, global warming and depleted ozone – burning issues for New Zealanders.
Full story by Bill Allan, Katja Riedel, Richard McKenzie, Sylvia Nichol and Tom Clarkson
Main image: The sun’s ultraviolet radiation
The Short Story
A quick, easy summaryRead the Full Story
What is the atmosphere?
The atmosphere is the cover of gases, including oxygen, that lies between earth and outer space. It reaches hundreds of kilometres above the earth. The atmosphere protects us from the sun’s rays, and controls the temperature around us. Without it, life could not exist. The layer of atmosphere where we live, and where the weather happens, is the troposphere.
What is an aurora?
An aurora is a beautiful display of coloured lights in the night sky. This occurs in the upper atmosphere. In the northern hemisphere it is called the aurora borealis, and in the southern hemisphere, the aurora australis. New Zealanders are most likely to see an aurora from the southern South Island.
What is the greenhouse effect?
This is the way the earth is warmed by the sun. Energy from the sun travels down through the atmosphere to the earth’s surface, where much of it is absorbed as heat. The surface then sends the heat back up. But some of this is held in the atmosphere by gases, keeping the earth warm enough for living things to survive – like a gardener’s greenhouse.
Why are greenhouse gases bad?
The gases that hold the earth’s warmth are called greenhouse gases. They include carbon dioxide and methane. In recent times human activities have upset the balance of these gases in the atmosphere. Cars and factories produce carbon dioxide, and so does burning down forests. Farm animals such as cows and sheep produce methane by burping, and New Zealand’s many farms produce a huge amount of methane. All the extra carbon dioxide and methane in the atmosphere is holding a lot more heat. This causes global warming. If it continues, life as we know it will be in danger.
The ozone layer
Ozone is a type of oxygen which forms a layer in the atmosphere. It protects us from the sun’s ultraviolet (UV) radiation, which can cause skin cancer. Ozone can be destroyed by chemicals released into the atmosphere from old fridges and other causes.
New Zealand: ozone and air pollution
New Zealand has very high UV levels in summer, and many Kiwis die from skin cancer. It is important to cover up in the sun, especially in the middle of the day.
The air is cleaner than in many countries. But Auckland’s traffic causes pollution, and Christchurch has smog in winter. To protect air quality, there are now rules about car exhausts and other pollutants.
The Kyoto Protocol
The Kyoto Protocol is an international agreement to deal with global warming. It was signed in 1997 in Kyoto, Japan. New Zealand and many other countries have agreed to reduce the greenhouse gases they are putting into the atmosphere.