Science Forums 2

[InfiniteNow]

Hi eDude,

Here's a good link with an intro on the topic:

Ch 7. Carbon Cycle

The flow of carbon throughout the biosphere, atmosphere, hydrosphere, and geosphere is one of the most complex, interesting, and important of the global cycles. More than any other global cycle, the carbon cycle challenges us to draw together information from biology, chemistry, oceanography, and geology in order to understand how it works and what causes it to change. The major reservoirs for carbon and the processes that move carbon from reservoir to reservoir are shown in Figure 7.00 below. We will discuss these processes in more detail below and then we will construct and experiment with various renditions of the carbon cycle, but first, we will explore some of the history of carbon cycle studies.

A guy from another forum I freqent put it pretty well. I'm going to quote him here, but it's not my intention to use this as a source or citation, just an explanation:

Ok, for starters, lets take a greenhouse gas molecule like, say, carbon dioxide:




Take a good look at it. Let it sink in.

Ok, now that particular molecule can absorb mostly infrared radiation. Now, how does it do this. Well, when a beam of infrared radiation strikes that molecule, it causes it to vibrate. It is then released , where the particular beam now has less energy. It moves on, where it would either strike the ground or will hit yet another greenhouse molecule. As it turns out, all greenhouse gases have this property, absorbing different wavelengths of course.

Now, lets take a look at a chart which displays what exactly the sun emits:



(SOURCE: Greenhouse Effect: Background Material)

As you can see, the sun emits mostly visible light, infrared radiation, and UV radiation. 43% of it is visible light in particular, BUT the atmosphere is mostly transparent to visible light. About 7-8% of it is UV, and about the same amount of it is infrared, both of which is absorbed by the atmosphere before it hits the ground. These may seem like small numbers, but they are pretty significant given the amount of energy that hits Earth on a daily basis.

Now, lets get back to this carbon dioxide molecule here. Because it has this intrinsic property, that means it can retain heat and consequentially raise the temperature (which by the way is a measure of the average energy). Our atmosphere may contain less than 0.04% of it in our atmosphere, but as we can see this small amount is more than enough to heat the planet up to allow it to have a temperate climate. And, given the trillions upon trillions of tons of gases that make up our atmosphere in total, 0.04% isn't that small a number.

Now, you may ask, what is the point of all this. Well then, because of this property, and given the BILLIONS of tons of greenhouse gases we are dumping into the atmosphere (among other things) every year, we know for certain that we do, indeed, contribute to climate change to some degree. And, we also know that we are releasing more and more greenhouse gases every year too, more so than the year before that.

That explains most of the "how." Now, you just need to recognize the scope of our contributions to atmospheric CO₂. It is NOT an easy topic, so please ask questions. That's the only way you can learn, and it helps us to view the issue in new ways.