[Flashman2]

I'd like to know where the carbon comes from, where it goes to, and does it stay there?

[tickle]

What carbon ?

Tick

[Flashman2]

The carbon that is released into the atmosphere and causes climate change

[ebaines]

That carbon comes primarily from the burning of organic matter - things like trees and fossil fuels. When you burn these things you get a lot of carbon dioxide as a byproduct - CO2. In the case of fossil fuels, this carbon had been sequestered underground in oil or gas deposits - and is now released as CO2 into the atmosphere. Some of this CO2 will in turn be taken up by plants, and some will be dissolved by the oceans, but much stays in the atmosphere, thereby raising the concentration of CO2 in the atmosphere. In the case of trees and plants - as they grow they absorb CO2 from the atmosphere, and then when they die and rot, or if you burn them, that CO2 is released again. So in a sense the world's inventory of plants is a large repository of carbon. If that repository shrinks - such as has happened with the Amazon rain forest - the concern is that this also leads to increased CO2 in the atmosphere.

[Flashman2]

Thanks ebaines, that sums it up beautifully. Is its density the same as the air we breathe or is it floating way above the air somewhere. Sorry to ask another question, but that's the trouble with good answers - they provoke more questions.

[tickle]

Carbon dioxide is denser then oxygen. That's why it is so dangerous. If we didn't have trees we would be in trouble, trees clean the air we breath. One reason why chopping down forests, and especially the destruction in the Amazon rain forest is no good for health, or any other living creature on earth.

Forestration must be encouraged.

Tick

Tick

[ebaines]

Yes, CO2 is denser than N2 or O2 (the principal constituents of air). But the CO2 in the atmosphere is pretty evenly mixed - because of winds. The actual percentage of air that is made up of CO2 is effectively the same no matter what altitude you are at - around 0.04%. Here's a web site that suggest that in perfectly calm air CO2 molecules would settle towards the ground at a rate of about 1 cm/hour - compare that with average wind speeds over the earth of around 5 miles/hour - almost a miilion times faster! So you can see why the CO2 stays well mixed. Re: Is the reason carbon dioxide does not settle-out is due to air currents?

[Flashman2]

Thanks ebaines and tickle. I said good answers generate more questions : So if the millions of tons of CO2 keep building up in the atmosphere does this mean our air pressure at sea level is increased accordingly ? And if a cubic metre, or a cubic foot, of air without CO2 weighs X, what does it weigh with CO2 ? (I feel like I'm getting a free education here !)

[ebaines]

Back of the envelope calculation:

If you model air as being 20% O2 and 80% N2, it's molecular weight is approximately 0.2*32 + 0.8*28 = 28.8. If you change the percentages to 19% O2, 1% CO2, and 80% N2 the molecular weight changes to 0.19*32 + 0.01*40 + 0.8 * 28 = 28.88, for a 0.28% increase in density. At today's CO2 level of 0.04%, the molecular weight is 28.8032, or 0.01% heavier than air with no CO2. This is clearly a small amount - probably not measurable.

[Flashman2]

Thanks again ebaines. Concise and informative.

[Unknown008]

No more questions? ;)

[1dam]

Carbon comes from the sun - that is, cosmic rays striking nitrogen in the upper atmosphere. There is a professor ? At Sandia National Laboratories in the US who lectures to scientists on this, but I forget his name - I read an article by him some time ago. Basically there is power involved - and to control power is to control public funds - such as for research. I will try to find his name, but my library is too large for a casual look - and a quick browse of the internet does not seem hopeful.

[1dam]

To add to my answer before - I remembered: It is Dr Russell Humphries, Sandia National Laboratories, US, lectured that carbon is made by cosmic rays striking nitrogen in the upper atmosphere.

Hope that answers the question.

Regards

[ebaines]

Dr Russell Humphries, Sandia National Laboratories, US, lectured that carbon is made by cosmic rays striking nitrogen in the upper atmosphere.

Incorrect, at least for the vast majority of carbon. Humphries was probably talking about radiocarbon dating methods. The reactions that are involved are:

1. A Carbon 14 atom is created from Nitrogen 14 through absorption of a neutron. The source of the neutron is cosmic rays.

2. The carbon 14 atom is radioactive, with a half-life of 5730 years. It decays to Nitrogen 14 through beta decay.

The amount of carbon 14 in the atmosphere is about 1 part per trillion. The vast majority of carbon non-radiaoactive Carbon 12, not Carbon 14. Hence the vast majority of carbon did not come from nitrogen.

Be skeptical about anything Russell Humphries says. He is a young earth creationist, and to support his view that the earth is only 6000 years old he tries to discredit radiocarbon dating methods. To do that he tries to show that the concentration of C14 in the atmosphere a few thousand years ago was much lower than today. But there is no evidence to support this hypothsis. Yes, he did work at Sandia National Labs for a time, but the majority of his career has been with the "Institute for Creation Research" and "Ceation Ministries International," so you can see where he's coming from. He does not "lecture to scientists."

[1dam]

He was talking about Carbon 14 - are you sure that the theory it reverts to Nitrogen has been checked by experiments or is it just a calculation on a desk (I have seen that all too often)? We should be careful to not see the world the way others want us to.

Regards

[Unknown008]

Hm... on another hand, he should have specified that he meant carbon-14 because saying merely 'carbon' implies most of the time that it's carbon-12 and not carbon-14.

[ebaines]

We should be careful to not see the world the way others want us to.

Especially if the "others" put forth theories that have not properly vetted. A major red flag is if the person pushing a new theory has not written peer-reviewed papers that have been published in reputable scientific journals. In science peer review is crucial - without it all you have is conjecture.

[tickle]

I went back on Flashmans previous posts and didn't find any posts where he was interested in carbonl4 testing. So, god only knows where the question came from, or what it means. I am familiar with carbonl4 testing because I have worked at ROM, a world class museum in Toronto where I was involved with this issue and carbonl4 testing to date organic material.

Unless he comes back, who knows what it all means.

[1dam]

Carbon 14 comes from cosmic rays interacting with nitgrogen in the upper atmosphere. There is a false claim that this decays to nitrogen in 5,730 years, but this is its half life - you should be careful of seeing the world the way others want you to.

Carbon 14 has been found in coal and diamonds. With the most accurate mass spectrometers, the oldest calculated age of items containing carbon-14 is about 80,000 years. Diamonds are assumed to be many billions of years old and should contain no detectable carbon-14 as it would have all decayed to nitrogen-14 long ago. The same is true of coal.

So we should be very careful.

Regards

[ebaines]

There is a false claim that this decays to nitrogen in 5,730 years, but this is its half life - you should be careful of seeing the world the way others want you to.

Right - it's the property of a radioactive half-life that makes C14 dating possible. I've not heard anyone make this error (certainly not in this thread) but I suppose some may miss this important point.

Carbon 14 has been found in coal and diamonds.

Right, though at incredibly low concentrations. This is why objects that are 60,000 or more years old can not be reliably dated using C14 dating methods. The concentration of C14 is so low for objects of this age that issues such as contamination of the sample and measuring at or below the lower limit of the lab instrument's range can cause errors. Also be aware that diamonds typically have impurities in them, including nitrogen, so it's possible that N14 in the crystal may be affected by naturally occurring radiation in the ground and become C14. Obviously this would be at a very low concentration - which is what's being measured here. Hence the age of objects >60K years old must be measured using other techniques (which would take us way off topic so I won't go further here).