How is the carbon cycle important in understanding global warming and everything?

Answer 1

Short version:

Carbon, in the form of carbon dioxide (CO2), moves between the land, the oceans and the atmosphere in the carbon cycle.This is a natural process. Plants remove CO2 from the air through photosynthesis, and release it when they are consumed.

Humans, however, have been putting extra carbon dioxide into the atmosphere by burning fossil fuels (coal, oil and natural gas). This carbon dioxide has been hidden away for hundreds of millions of years, so releasing it now is proving too much for the carbon cycle. It manages to remove about half this extra CO2, but the rest is building up, capturing more and more of the sun's heat, and causing global warming.

A:To understand global warming we have to look deeper than polar bears and glaciers. Carbon is what we have to look at first.

Carbon is just about everywhere. The "lead" in lead pencils is carbon, diamonds are carbon. The "dry weight" of a human, after taking out the water, is two thirds carbon. Whales, dandelions, trees, everything is largely made of carbon.

Carbon atoms attach easily to other atoms. They connect in all sorts of ways. And carbon grips tightly. Even after the creature is dead, the carbon bonds stay strong. This is important with fossil fuels. Millions of years ago in the Middle East there were zooplankton in the sea, rather like jellyfish, all filled with carbon atoms. The trillions and trillions of zooplankton died, sank to the bottom of the sea and over time compressed themselves into a mixture that turned into, yes, oil, and full of carbon.

All the carbon bonds contain energy, and that energy can be released in several ways. Burning breaks the bonds and releases the energy. When we start a car engine, the spark ignites the gasoline and releases energy. This energy drives the vehicle. When we eat a carrot, digestive juices in our stomachs break the bonds and release the energy which we then use.

When the first man discovered how to harness fire, and used that energy for heating and cooking, that was the start of our civilization!

Burning fossil fuel is so easy, and so powerful, that most countries in the world do it. There are other atoms that produce energy, of course. Uranium releases a lot of energy, but it also makes people nervous. Hydrogen is another. Perhaps we will drive hydrogen-powered vehicles in the future.

A few countries have broken away somewhat from fossil fuel dependency.

• France gets 80% of its energy from nuclear power plants.
• Denmark gets 20% of its energy from the wind.
• 85% of Iceland's houses are heated with geothermal energy.
• In the first few weeks of the summer of 2011, Germany's one million rooftop solar panels pumped 13.2 gigawatts into the grid - the equivalent output of up to a dozen nuclear power plants.

Whenever we burn anything, gasoline, paper, trees, the carbon bonds are broken, and the carbon atom is released. It immediately latches on to a convenient and stable atom, oxygen. And it takes two oxygen atoms and bonds firmly to them. It is now carbon dioxide (C+O+O, or CO2).

What happens to this new CO2? It floats up into the atmosphere. Some is caught by falling rain, turning the rain to acid (carbonic acid, as used in soda). Much of it is absorbed into the oceans. Other CO2 is absorbed by trees.

Man is adding so much CO2 to the atmosphere, the trees and the oceans can't cope any more. So the extra CO2 goes into the greenhouse gases in the atmosphere where the sun heats it up. This is causing the accelerated greenhouse effect, which in turn is causing global warming.

What can we do about this? We can't change carbon. Carbon will always grab onto oxygen atoms and form carbon dioxide.

We can stop using so much of it. We have to find other ways of producing energy. Uranium, hydrogen, solar, wind, water, geothermal, bio-fuel, and other ways not discovered yet.

Scientists hope they can capture the CO2 as it leaves the fossil fueled power station and pipe it safely underground. This is called carbon sequestration. It is expensive and hasn't been managed successfully yet on a large scale.

How much are we prepared to pay, or how much are we prepared to change? It's our choice.

Source: The excellent PBS short Animations at the link below.