Carbon Credits-CDM & JI

Purpose

Why Do Rising Carbon Dioxide Levels Matter?

If carbon dioxide did nothing at all, we probably wouldn't need to care how much we are adding to the atmosphere. However, CO2 is an energy absorber or 'greenhouse gas' and causes the temperature of the Earth's surface to slowly rise. The effect, called 'global warming', is now measurable and biological changes because of the temperature rise are starting to be noted. Scientists are still trying to find out if observed weather pattern changes are also a result of global warming or are part of normal climate variation.

There is general agreement that something needs to be done to keep balance in the atmosphere. However, politicians, scientist and environmentalists cannot agree on how. The US government wants to increase the number of carbon sinks to get rid of the excess. However, many scientists and other governments think that it is more effective to get rid of some of the carbon sources, since car exhaust and factory smoke, add a lot more pollutants than just carbon dioxide. Acid rain is one side effect of industry.

Unfortunately cutting down on cars and other industrialization requires considerable lifestyle changes from people in the first world. There is a huge amount of money and time invested in the current infrastructure. Consequently, change toward a 'greener' lifestyle is very slow. In the meantime, there is little incentive for developing nations to invest in the more-expensive 'clean' technologies that put out fewer pollutants, so the problem grows. Energy policy, pollution control and finding environmental balance are major world issues for the 21st century.

Carbon In and Out of the Atmosphere

Carbon dioxide is one of the important atmospheric gases in the despite Earth only having 0.035% of carbon dioxide actually in the atmosphere. This is because carbon dioxide is a greenhouse gas that warms the Earth's surface by about 50º Fahrenheit. However, Earth actually has an incredibly small amount of carbon dioxide (or CO2) in its atmosphere. Venus, which is a very similar planet to Earth in size and composition, has a thicker atmosphere with a massive amount of CO2, over 200,000 times the amount that is in Earth's atmosphere. The greenhouse warming makes the surface temperature of Venus a whopping 870º Fahrenheit!

So why does Venus have so much carbon dioxide and warming while Earth has so little? Well, Earth has three important features that Venus does not: plate tectonics, liquid water, and lots of life.

Plants use carbon dioxide to make their food and their physical bodies. Animals eat plants for food to make their own physical bodies. The result is that massive amounts of carbon is taken out of the atmosphere and made into flesh, bone and shell. Some carbon goes back to the atmosphere every day when we breathe out, other carbon goes back to the atmosphere when life forms die and decay. However, even more is taken up by yet more life-forms, so that much of the Earth's carbon has been converted from CO2 into living things.

A lot of carbon is in the form of 'calcium carbonate', the material that makes seashells. Coral and shellfish make their shells from CO2 dissolved in water. When they die, the coral reefs turn into limestones. Other sediments bury the limestones and so the carbon leaves the atmosphere permanently. A similar thing happens in swamps, where animals and planets die without decaying back to carbon dioxide. Instead, their carbon becomes buried and turns into oil deposits. Limestones and oil keep carbon stored out of the atmosphere for millions of years.

If all the carbon on Earth were turned into limestone and oil deposits, then there would be too little CO2 in our atmosphere to keep warming us and Earth would cool down to an icebox like Mars. However, the buried rocks are carried away by plate tectonics. When one plate dives down below another, it takes lots of sedimentary rocks with it. The deposits of trapped carbon end up being taken deep within the Earth and melted down. The carbon converts back to carbon dioxide inside the liquid rock, the liquid rock erupts as volcanoes and the CO2 is slowly pumped back into the atmosphere, during eruptions. The whole action of carbon removal, storage, and return is called the Carbon Cycle.