Warming our planet

What's in our atmosphere?

Take a deep breath. We need the oxygen in the air to help our body function and for us to survive. Changing what's in the atmosphere will do more than just affect our breathing.

The air we breathe is approximately 20% oxygen, 79% nitrogen and 1% carbon dioxide and other gases. 3.8 billion years ago, the air was quite different and very toxic. Blue-green algae changed all that by taking in carbon dioxide from the toxic air and changing it to oxygen. Plants do the same thing to create oxygen, in a process called photosynthesis.

Warming our planet

By changing what is in our atmosphere, humans are helping to warm the planet. Gasses such as carbon dioxide, methane and nitrous oxide are known as greenhouse gases, because they trap and hold a blanket of warm air around the earth. Without these gases, the earth would be about 30 degrees Celsius colder. Imagine winter in Brisbane at minus 20 degrees!

Human activities, such as using electricity from fossil fuels, driving cars that run on petrol or diesel, chopping down trees that would take in carbon dioxide, are all helping to increase the levels of carbon dioxide in the atmosphere. By increasing carbon dioxide and other greenhouse gases we are trapping even more heat and making our planet warmer.

Changing our climate

The earth's climate in the past has experienced changes. But humans are increasing greenhouse gas levels so fast that we are causing the climate to change much faster than it would if we didn't exist. In Queensland, we can expect to see more extremes of weather, such as storms, cyclones and droughts. Natural processes affect climate change but human impact such as burning fossil fuels, burning biomass, deforestation, changes in land use and industry have a real and observable effect.

Carbon cycle

Every living thing is made up of carbon. Carbon is essential for life. The carbon cycle is the process through which carbon is cycled through the air, ground, plants, animals and fossil fuels. In the carbon cycle there has been a balance of carbon in the various reservoirs, all helping maintain the earth's temperatures within relatively narrow ranges. Humans are upsetting the carbon balance by increasing carbon dioxide in the atmosphere through burning fossil fuels, deforestation and industry.

Taking in carbon

Plants use the sun's energy to convert carbon dioxide in the air into carbon (carbohydrates) and oxygen. The carbon is stored in the plants. Animals eat these plants and their stored carbon. Other animals come along and eat these animals.

Giving out carbon

All living things breathe out carbon dioxide (a waste product from chemical reactions in the body), returning carbon to the atmosphere. Dead plants and animals decay, leaving their carbon in the soil. Soil organisms break down the carbon and return carbon dioxide to the atmosphere.

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