The word 'carbon' is used a lot. This article explains why carbon is a hot topic.
Let's start at the beginning
Everything that's alive or has been alive on the planet is made of carbon. For example, plants are almost 50% carbon and you are approximately 15% carbon (give or take a few kilos...). That's not pure carbon, rather it's combined with other elements to form compounds.
So how does carbon get into the atmosphere?
In simple terms, when animals and plants die, their carbon is absorbed into the earth. This in turn has created deposits of fossil fuels (aha... fuels made from their fossils). Fossil fuels are oils, natural gases and coal. We are now digging up and using those carbon deposits to power our world. In powering our world and burning the fossil fuels, we release carbon dioxide, heat and water into the atmosphere, as well as solid carbon in the form of stuff like soot.
Carbon dioxide is natural and it is released from decaying and living things, and from volcanos. When we exhale, aaaah; we exhale carbon dioxide. Plants absorb carbon dioxide, keep the carbon and release the oxygen. As we remove more and more plant life to make way for cities and farming, we reduce the number of plants that can process our carbon dioxide.
In terms of functionality, carbon dioxide does a very good job of letting sunlight through to the earth's surface whilst retaining the sun's heat close to earth - preventing us from having an ice age. It has a good purpose in small doses. In large doses carbon dioxide retains too much heat close to earth.
Carbon dioxide is only one of a few greenhouse gases that can trap heat for us - the others are methane (carbon+hydrogen), nitrous oxide, chloroflurocarbons, water vapour (think clouds and steam) and ozone. Of these greenhouse gases, carbon dioxide is the leading human contributor to global warming, so it's of highest concern.
When coal and oil are burnt, they release carbon dioxide in large quantities. If you burn 2.8 kilograms of gasoline, it releases 9 kilograms of carbon dioxide (broken down in detail here). That's proportionately a lot!
Is this just a climate phase?
It is normal for the earth to pass through different climate phases. For example, we go through cycles of el nina and la nino. Climate critics (and deniers) point to the cyclical nature of climate to explain the heating atmosphere. However, there is concrete evidence and scientific consensus that we are in hot water (excuse the pun) and this isn't a natural ebb and flow of climate. NASA has a lot of collated evidence readily available for the public to read - check it out at this link.
Cold water can absorb and store more carbon than warm water. The Arctic ocean acts as a carbon sink - it is very cold and absorbs 58 megatons of carbon each year (see NSIDC article). The carbon sink is not stable and varies. The part of the Arctic ocean near Greenland is warmer and is actually omitting carbon dioxide. As the Arctic ocean heats up, it will no longer be as effective at processing the same large quantities of carbon. Read more on this particular aspect here.
And the ice caps
In very simplistic terms, as the earth warms, the oceans warm. As the oceans warm, the ice caps and ice shelves melt. According to NASA, Antartica holds about 60% of earth's fresh water deposits within its ice. So that is all at risk of being released as the ice melts.
The ice has been sequestering carbon for the earth. As ice melts, carbon is released into the atmosphere and the earth gets even hotter. (That's a simplistic description of a complicated cycle, so check out this article if you want to read more.)
Scary. Yes. Time for action.
How can you reduce your carbon contributions immediately?
Consider an electric or hybrid car. Cycle or walk instead if it's possible.
Compost paper and food scraps. If you put food scraps and paper in landfill, it releases carbon into the atmosphere because it doesn't provide the right environment for biodegrading. Placing it into compost piles or burying them straight into your garden instead deposits the carbon into the soil.
Turn off lights and use energy efficient light bulbs. Buy energy efficient household appliances and use cold water for the laundry.
Reduce, reuse, recycle.
Buy from companies that have eco-friendly policies and that use recycled plastic packaging.
Across the world, cities are trying to reduce their carbon outputs. Copenhagen is racing to become the first carbon neutral city, as is the city of Adelaide. The EU is hoping to make 100 cities carbon neutral by 2030. Some cities are doing carbon challenges, such as the Brisbane City Council. Check out your local government website for more information and get involved in your local community's efforts to reduce carbon.