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jose.bailen@gmail.com
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 Posted: Thu Apr 05, 2007 11:03 pm Post subject: Re: Mars surface warmed at close to same rate as Earth |
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On Apr 5, 7:23 pm, "darkness39" <darknes...@yahoo.com> wrote:
| Quote: |
On Apr 5, 1:53 pm, "jose.bai...@gmail.com" <jose.bai...@gmail.com
wrote:
On Apr 5, 12:15 pm, "David" <d...@wilkinson6337.freeserve.co.uk
wrote:
What makes you think you know enough to even assess the evidence?
Climate change is a very complex scientific field where the layman has
no worthwhile view. For instance as a very simple example, how
accurately can the flow of water at moderate speed and room
temperature through a pipe with a right-angled bend in it be
predicted? What are the governing equations? Can they be solved
exactly and if not, why not? Ignore possible cavitation and evolution
of disolved air.
Of course I don't know enough about climate change. What I know is 1/
There is strong evidence about global warming. There is scientific
consensus in this area;
You've missed a trick. The usual method at this point is to attack
the Mann Diagram as being a statistical artefact.
2/ There is no consensus regarding the causes
of global warming.
Except the meeting of over 1000 climate scientists, and their
governments, including just about every practising climate scientist
in the world. This was called the IPCC, and signed by every world
government (not sure if North Korea is a signatory).
3/ There are scientific studies that show that
global warming could be fully explained through natural causes.
None reputable. And most not even credible. Certainly not ones
subject to peer review. And by the same people, by and large, who are
attacking the Mann diagram.
A lot of work has been done to isolate the sources of the observed
forcing. The best that we can come up with is that solar forcing is
likely less than 20%. There isn't even any observed trend in solar
flux (plus or minus) for the period that we have data for.
Cosmic rays is even further out. $10m is being spent on investigating
that one.
It's unlikely you will invent a new denialist claim that we all
haven't seen before, on the internet.
But turn it round another way.
CO2 and water vapour block infra-rad. This you learned in your high
school chemistry lab.
The concentrations of CO2 are now 130ppm above what they were at the
dawn of the industrial age and are rising at 3pm (250 to 380).
Concentrations of other gases with known greenhouse effects are also
much higher than they were at that time (some of those gases didn't
even exist). Atmospheric water vapour is higher.
What would you expect to happen to the average temperature of a planet
that was experiencing such dramatic and quick rises in CO2
concentrations?
|
The fact that CO2 emissions have increased and the average Earth
temperature has also increased doesn't imply causality, just
correlation. In Mars, there are no SUVs issuing CO2, yet the
temperature has increased just at about the same rate as in the Earth.
If global warming can happen in a planet like Mars for natural causes,
why it can't happen here??? |
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PeterL
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| Posted: Fri Apr 06, 2007 2:06 am Post subject: Re: Mars surface warmed at close to same rate as Earth |
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On Apr 5, 1:26 am, "jose.bai...@gmail.com" <jose.bai...@gmail.com>
wrote:
| Quote: |
On Apr 5, 9:21 am, "David" <d...@wilkinson6337.freeserve.co.uk> wrote:
On Apr 4, 11:19 pm, "jose.bai...@gmail.com" <jose.bai...@gmail.com
Why so puzzled that we don't take your views on climate change
seriously? Why would we prefer your view over that of the consensus
view of hundreds of climate change scientists, meteorologists and
fluid dynamicists? It's a no contest between the scientists and a semi-
retired economist with no training or experience in climate change or
any other scientific field.
I don't care about the consensus view about anything. Someone who
follows the herd and thinks that something is right just because many
people think is right is an idiot. I like to see both sides of an
argument on every issue (there are always two sides, even if one is
followed by 90% of the community), see what are their reasons, and
then take a position. In the case of the global warming debate, while
global warming is undisputed -as the empirical evidence shows- the
argument is whether it is man-made or due to other reasons. I haven't
seen any conclusive evidence that shows that it is man-made, and given
what we see in other planets in the solar system like Mars with no
human activity at all, most likely the warming is caused by natural
processes.
|
Just because the warming at Mars may not be caused by human actvities
does not mean the erath's warming is not caused, at least in part, by
human activities. |
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jose.bailen@gmail.com
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| Posted: Fri Apr 06, 2007 2:49 am Post subject: Re: Mars surface warmed at close to same rate as Earth |
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On Apr 5, 11:06 pm, "PeterL" <po.n...@gmail.com> wrote:
| Quote: |
Just because the warming at Mars may not be caused by human actvities
does not mean the erath's warming is not caused, at least in part, by
human activities.
|
It may, or it may not be. The point is that the causality human
activity ==> global warming is far from proven. Governments around the
world are going to enforce (or they are already enforcing) very
costly regulation to correct something that is not evident. Needless
to say, the cost of all of this will be paid by taxpayers and by the
companies' shareholders (corporate earnings always suffer because of
wasteful regulation). |
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darkness39
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| Posted: Fri Apr 06, 2007 12:23 pm Post subject: Re: Mars surface warmed at close to same rate as Earth |
|
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On Apr 5, 7:03 pm, "jose.bai...@gmail.com" <jose.bai...@gmail.com>
wrote:
| Quote: |
On Apr 5, 7:23 pm, "darkness39" <darknes...@yahoo.com> wrote:
On Apr 5, 1:53 pm, "jose.bai...@gmail.com" <jose.bai...@gmail.com
wrote:
On Apr 5, 12:15 pm, "David" <d...@wilkinson6337.freeserve.co.uk
wrote:
What makes you think you know enough to even assess the evidence?
Climate change is a very complex scientific field where the layman has
no worthwhile view. For instance as a very simple example, how
accurately can the flow of water at moderate speed and room
temperature through a pipe with a right-angled bend in it be
predicted? What are the governing equations? Can they be solved
exactly and if not, why not? Ignore possible cavitation and evolution
of disolved air.
Of course I don't know enough about climate change. What I know is 1/
There is strong evidence about global warming. There is scientific
consensus in this area;
You've missed a trick. The usual method at this point is to attack
the Mann Diagram as being a statistical artefact.
2/ There is no consensus regarding the causes
of global warming.
Except the meeting of over 1000 climate scientists, and their
governments, including just about every practising climate scientist
in the world. This was called the IPCC, and signed by every world
government (not sure if North Korea is a signatory).
3/ There are scientific studies that show that
global warming could be fully explained through natural causes.
None reputable. And most not even credible. Certainly not ones
subject to peer review. And by the same people, by and large, who are
attacking the Mann diagram.
A lot of work has been done to isolate the sources of the observed
forcing. The best that we can come up with is that solar forcing is
likely less than 20%. There isn't even any observed trend in solar
flux (plus or minus) for the period that we have data for.
Cosmic rays is even further out. $10m is being spent on investigating
that one.
It's unlikely you will invent a new denialist claim that we all
haven't seen before, on the internet.
But turn it round another way.
CO2 and water vapour block infra-rad. This you learned in your high
school chemistry lab.
The concentrations of CO2 are now 130ppm above what they were at the
dawn of the industrial age and are rising at 3pm (250 to 380).
Concentrations of other gases with known greenhouse effects are also
much higher than they were at that time (some of those gases didn't
even exist). Atmospheric water vapour is higher.
What would you expect to happen to the average temperature of a planet
that was experiencing such dramatic and quick rises in CO2
concentrations?
The fact that CO2 emissions have increased and the average Earth
temperature has also increased doesn't imply causality, just
correlation. In Mars, there are no SUVs issuing CO2, yet the
temperature has increased just at about the same rate as in the Earth.
If global warming can happen in a planet like Mars for natural causes,
why it can't happen here???
|
Jose
I have posted 2 articles regarding the 'Mars global warming' thesis,
in this thread.
They explain the scientific view, the last time this story came around
(about 2 years ago). We'll see what the scientists say this time.
As I said, your high school chemistry taught you that CO2 and water
vapour block infra red radiation.
So, if you increase the CO2 and water vapour concentrations in an
atmosphere, you would expect to increase the average temperature.
This is, in fact, why the average temperature on the surface of the
Earth is not minus 30 degrees C, because of that greenhouse effect.
Alter the atmospheric concentration of CO2, increasing it by about 40%
from its norm, and enter onto a track to (more than) double it within
another 50 years, and you would expect to increase the greenhouse
effect.
Mars is a whole different kettle of fish, as the articles explain:
1. we don't have accurate measurements, taken over a long period of
time, at different locations and altitudes
2. we have modelled Mars' climate, and there are a number of factors
which don't play a role in the case of the Earth (chiefly dust storms)
3. if solar flux is causing planetary warming (which it has been
estimated, with great labour in the Earth's case to be 0-20%) then
3a. we would have to observe that solar flux -- so far, with accurate
data, there has been no sustained increase in solar flux
3b. every planet would be showing warming, not just Mars. But again,
we haven't observed that
In the end, the skeptics claim that glacial melt on Mars is a sign
that Mars is not warming. 20 similar phenomena on Earth, are claimed
to be *not* signs that the Earth is warming.
I am going to leave you on this one. You were trolling for a fight,
we've given you one, and I have cited what was said the last time
about the 'Mars is warming therefore humans and CO2 are not causing
global warming on Earth' thesis.
You don't know much about this area, you've stepped outside your area
of expertise, and you've brought your preconceptions to it. I
recommend reading a good textbook on climate science.
I'm happy to discuss, by email, with any interested 3rd Party about
what the scientists are saying about these 'critiques' of global
climate change theory.
One more cite, though, about the 'CO2 correlation' thesis.
http://www.realclimate.org/index.php?p=13
3 Dec 2004
What does the lag of CO2 behind temperature in ice cores tell us about
global warming?
Filed under:
* Paleoclimate
* Greenhouse gases
* FAQ
- group @ 9:42 am - (fr flag)
This is an issue that is often misunderstood in the public sphere and
media, so it is worth spending some time to explain it and clarify it.
At least three careful ice core studies have shown that CO2 starts to
rise about 800 years (600-1000 years) after Antarctic temperature
during glacial terminations. These terminations are pronounced warming
periods that mark the ends of the ice ages that happen every 100,000
years or so.
Does this prove that CO2 doesn't cause global warming? The answer is
no.
The reason has to do with the fact that the warmings take about 5000
years to be complete. The lag is only 800 years. All that the lag
shows is that CO2 did not cause the first 800 years of warming, out of
the 5000 year trend. The other 4200 years of warming could in fact
have been caused by CO2, as far as we can tell from this ice core
data.
The 4200 years of warming make up about 5/6 of the total warming. So
CO2 could have caused the last 5/6 of the warming, but could not have
caused the first 1/6 of the warming.
It comes as no surprise that other factors besides CO2 affect climate.
Changes in the amount of summer sunshine, due to changes in the
Earth's orbit around the sun that happen every 21,000 years, have long
been known to affect the comings and goings of ice ages. Atlantic
ocean circulation slowdowns are thought to warm Antarctica, also.
| Quote: |
From studying all the available data (not just ice cores), the
probable sequence of events at a termination goes something like this. |
Some (currently unknown) process causes Antarctica and the surrounding
ocean to warm. This process also causes CO2 to start rising, about 800
years later. Then CO2 further warms the whole planet, because of its
heat-trapping properties. This leads to even further CO2 release. So
CO2 during ice ages should be thought of as a "feedback", much like
the feedback that results from putting a microphone too near to a
loudspeaker.
In other words, CO2 does not initiate the warmings, but acts as an
amplifier once they are underway. From model estimates, CO2 (along
with other greenhouse gases CH4 and N2O) causes about half of the full
glacial-to-interglacial warming.
So, in summary, the lag of CO2 behind temperature doesn't tell us much
about global warming. [But it may give us a very interesting clue
about why CO2 rises at the ends of ice ages. The 800-year lag is about
the amount of time required to flush out the deep ocean through
natural ocean currents. So CO2 might be stored in the deep ocean
during ice ages, and then get released when the climate warms.]
To read more about CO2 and ice cores, see Caillon et al., 2003,
Science magazine
Guest Contributor: Jeff Severinghaus
Professor of Geosciences
Scripps Institution of Oceanography
University of California, San Diego. |
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jose.bailen@gmail.com
Guest
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| Posted: Fri Apr 06, 2007 12:55 pm Post subject: Re: Mars surface warmed at close to same rate as Earth |
|
|
On Apr 6, 9:23 am, "darkness39" <darknes...@yahoo.com> wrote:
| Quote: |
On Apr 5, 7:03 pm, "jose.bai...@gmail.com" <jose.bai...@gmail.com
wrote:
On Apr 5, 7:23 pm, "darkness39" <darknes...@yahoo.com> wrote:
On Apr 5, 1:53 pm, "jose.bai...@gmail.com" <jose.bai...@gmail.com
wrote:
On Apr 5, 12:15 pm, "David" <d...@wilkinson6337.freeserve.co.uk
wrote:
What makes you think you know enough to even assess the evidence?
Climate change is a very complex scientific field where the layman has
no worthwhile view. For instance as a very simple example, how
accurately can the flow of water at moderate speed and room
temperature through a pipe with a right-angled bend in it be
predicted? What are the governing equations? Can they be solved
exactly and if not, why not? Ignore possible cavitation and evolution
of disolved air.
Of course I don't know enough about climate change. What I know is 1/
There is strong evidence about global warming. There is scientific
consensus in this area;
You've missed a trick. The usual method at this point is to attack
the Mann Diagram as being a statistical artefact.
2/ There is no consensus regarding the causes
of global warming.
Except the meeting of over 1000 climate scientists, and their
governments, including just about every practising climate scientist
in the world. This was called the IPCC, and signed by every world
government (not sure if North Korea is a signatory).
3/ There are scientific studies that show that
global warming could be fully explained through natural causes.
None reputable. And most not even credible. Certainly not ones
subject to peer review. And by the same people, by and large, who are
attacking the Mann diagram.
A lot of work has been done to isolate the sources of the observed
forcing. The best that we can come up with is that solar forcing is
likely less than 20%. There isn't even any observed trend in solar
flux (plus or minus) for the period that we have data for.
Cosmic rays is even further out. $10m is being spent on investigating
that one.
It's unlikely you will invent a new denialist claim that we all
haven't seen before, on the internet.
But turn it round another way.
CO2 and water vapour block infra-rad. This you learned in your high
school chemistry lab.
The concentrations of CO2 are now 130ppm above what they were at the
dawn of the industrial age and are rising at 3pm (250 to 380).
Concentrations of other gases with known greenhouse effects are also
much higher than they were at that time (some of those gases didn't
even exist). Atmospheric water vapour is higher.
What would you expect to happen to the average temperature of a planet
that was experiencing such dramatic and quick rises in CO2
concentrations?
The fact that CO2 emissions have increased and the average Earth
temperature has also increased doesn't imply causality, just
correlation. In Mars, there are no SUVs issuing CO2, yet the
temperature has increased just at about the same rate as in the Earth.
If global warming can happen in a planet like Mars for natural causes,
why it can't happen here???
Jose
I have posted 2 articles regarding the 'Mars global warming' thesis,
in this thread.
They explain the scientific view, the last time this story came around
(about 2 years ago). We'll see what the scientists say this time.
As I said, your high school chemistry taught you that CO2 and water
vapour block infra red radiation.
So, if you increase the CO2 and water vapour concentrations in an
atmosphere, you would expect to increase the average temperature.
This is, in fact, why the average temperature on the surface of the
Earth is not minus 30 degrees C, because of that greenhouse effect.
Alter the atmospheric concentration of CO2, increasing it by about 40%
from its norm, and enter onto a track to (more than) double it within
another 50 years, and you would expect to increase the greenhouse
effect.
Mars is a whole different kettle of fish, as the articles explain:
1. we don't have accurate measurements, taken over a long period of
time, at different locations and altitudes
2. we have modelled Mars' climate, and there are a number of factors
which don't play a role in the case of the Earth (chiefly dust storms)
3. if solar flux is causing planetary warming (which it has been
estimated, with great labour in the Earth's case to be 0-20%) then
3a. we would have to observe that solar flux -- so far, with accurate
data, there has been no sustained increase in solar flux
3b. every planet would be showing warming, not just Mars. But again,
we haven't observed that
In the end, the skeptics claim that glacial melt on Mars is a sign
that Mars is not warming. 20 similar phenomena on Earth, are claimed
to be *not* signs that the Earth is warming.
I am going to leave you on this one. You were trolling for a fight,
we've given you one, and I have cited what was said the last time
about the 'Mars is warming therefore humans and CO2 are not causing
global warming on Earth' thesis.
You don't know much about this area, you've stepped outside your area
of expertise, and you've brought your preconceptions to it. I
recommend reading a good textbook on climate science.
I'm happy to discuss, by email, with any interested 3rd Party about
what the scientists are saying about these 'critiques' of global
climate change theory.
One more cite, though, about the 'CO2 correlation' thesis.
http://www.realclimate.org/index.php?p=13
3 Dec 2004
What does the lag of CO2 behind temperature in ice cores tell us about
global warming?
Filed under:
* Paleoclimate
* Greenhouse gases
* FAQ
- group @ 9:42 am - (fr flag)
This is an issue that is often misunderstood in the public sphere and
media, so it is worth spending some time to explain it and clarify it.
At least three careful ice core studies have shown that CO2 starts to
rise about 800 years (600-1000 years) after Antarctic temperature
during glacial terminations. These terminations are pronounced warming
periods that mark the ends of the ice ages that happen every 100,000
years or so.
Does this prove that CO2 doesn't cause global warming? The answer is
no.
The reason has to do with the fact that the warmings take about 5000
years to be complete. The lag is only 800 years. All that the lag
shows is that CO2 did not cause the first 800 years of warming, out of
the 5000 year trend. The other 4200 years of warming could in fact
have been caused by CO2, as far as we can tell from this ice core
data.
The 4200 years of warming make up about 5/6 of the total warming. So
CO2 could have caused the last 5/6 of the warming, but could not have
caused the first 1/6 of the warming.
It comes as no surprise that other factors besides CO2 affect climate.
Changes in the amount of summer sunshine, due to changes in the
Earth's orbit around the sun that happen every 21,000 years, have long
been known to affect the comings and goings of ice ages. Atlantic
ocean circulation slowdowns are thought to warm Antarctica, also.
From studying all the available data (not just ice cores), the
probable sequence of events at a termination goes something like this.
Some (currently unknown) process causes Antarctica and the surrounding
ocean to warm. This process also causes CO2 to start rising, about 800
years later. Then CO2 further warms the whole planet, because of its
heat-trapping properties. This leads to even further CO2 release. So
CO2 during ice ages should be thought of as a "feedback", much like
the feedback that results from putting a microphone too near to a
loudspeaker.
In other words, CO2 does not initiate the warmings, but acts as an
amplifier once they are underway. From model estimates, CO2 (along
with other greenhouse gases CH4 and N2O) causes about half of the full
glacial-to-interglacial warming.
So, in summary, the lag of CO2 behind temperature doesn't tell us much
about global warming. [But it may give us a very interesting clue
about why CO2 rises at the ends of ice ages. The 800-year lag is about
the amount of time required to flush out the deep ocean through
natural ocean currents. So CO2 might be stored in the deep ocean
during ice ages, and then get released when the climate warms.]
To read more about CO2 and ice cores, see Caillon et al., 2003,
Science magazine
Guest Contributor: Jeff Severinghaus
Professor of Geosciences
Scripps Institution of Oceanography
University of California, San Diego.- Hide quoted text -
- Show quoted text -
|
Thanks, the articles are pretty interesting. There are two issues here
1/ if the observed increase in the atmospheric concentration in CO2
can explain the bulk of the greenhouse effect, or if it is just a
minor cause and there are other factors at play, 2/ in the case in
which the main reason of global warming is the increase in CO2
concentration, in the past, we had that CO2 was released to the
atmosphere for natural -still unknown- reasons, as it happened at the
end of the ice age. It is far from proven that the reason of
increased CO2 is human activity.
If we answer first issue one (depending on the model, you may have
that increased CO2 explains most of global warming, or you have
factors such as cosmic rays explaining this); then we need to answer
issue two: that the main reason for the increase in CO2 concentrations
has been human activity and no other -natural- causes. As we see, as
of now, it is far from proven that global warming is because of human
activity. |
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Evojeesus
Guest
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| Posted: Fri Apr 06, 2007 4:59 pm Post subject: Re: Mars surface warmed at close to same rate as Earth |
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|
On Apr 5, 8:03 pm, "jose.bai...@gmail.com" <jose.bai...@gmail.com>
wrote:
| Quote: |
The fact that CO2 emissions have increased and the average Earth
temperature has also increased doesn't imply causality, just
correlation.
|
Increased CO2 in the atmosphere creates a warming effect. That's
elementary and I don't think anyone sane is denying that (if you
disagree, I'll happily check your references). Now, the CO2 is only
one part in the puzzle, other effects might counteract that warming,
at least for now (although statistics show that things are warming up
here already). |
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Evojeesus
Guest
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| Posted: Fri Apr 06, 2007 6:29 pm Post subject: Re: Mars surface warmed at close to same rate as Earth |
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On Apr 5, 11:49 pm, "jose.bai...@gmail.com" <jose.bai...@gmail.com>
wrote:
| Quote: |
It may, or it may not be. The point is that the causality human
activity ==> global warming is far from proven.
|
How would one prove causality in this case? |
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darkness39
Guest
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| Posted: Fri Apr 06, 2007 8:11 pm Post subject: Re: Mars surface warmed at close to same rate as Earth |
|
|
On Apr 6, 8:55 am, "jose.bai...@gmail.com" <jose.bai...@gmail.com>
wrote:
| Quote: |
Thanks, the articles are pretty interesting. There are two issues here
1/ if the observed increase in the atmospheric concentration in CO2
can explain the bulk of the greenhouse effect, or if it is just a
minor cause and there are other factors at play,
|
http://www.ipcc.ch/SPM2feb07.pdf
page 4. Note the last column 'Level of Scientific Understanding'
associated with each estimate.
The short answer is CO2 is about 60%, other GHG and black carbon
particles about 40%. However there are bands of uncertainty.
CO2 is one of the longest lived CO2 gases.
2/ in the case in
| Quote: |
which the main reason of global warming is the increase in CO2
concentration, in the past, we had that CO2 was released to the
atmosphere for natural -still unknown- reasons,
|
Actually we have some pretty good mechanisms. Not the least of which
is that ice kills plant life, and a drier colder world would have less
green cover, and therefore retain less CO2.
as it happened at the
| Quote: |
end of the ice age. It is far from proven that the reason of
increased CO2 is human activity.
|
Except we have radioisotope tests showing that it comes from coal, oil
and natural gas, because we know the age of tye carbon isotopes in
those molecules.
The other major factor is tropical deforestation: also a man-made
activity.
| Quote: |
If we answer first issue one (depending on the model, you may have
that increased CO2 explains most of global warming, or you have
factors such as cosmic rays explaining this);
|
But CO2 we have a clear, provable link in chemistry and physics to
higher atmospheric temperatures. These can be demonstrated in a lab.
In the case of Cosmic Rays, we have a contentious theory, and no
scientific evidence for it.
http://www.realclimate.org/index.php/archives/2006/10/taking-cosmic-rays-for-a-spin/
we're spending $10m finding out, so we'll know, as best we can know,
fairly soon, one hopes.
then we need to answer
| Quote: |
issue two: that the main reason for the increase in CO2 concentrations
has been human activity and no other -natural- causes.
|
The statement below is factually incorrect, due to radio-isotope work.
As we see, as
| Quote: |
of now, it is far from proven that global warming is because of human
activity.
|
http://illconsidered.blogspot.com/2006/03/co2-rise-is-natural.html
http://www.grida.no/climate/ipcc_tar/wg1/109.htm on estimating the
global discharge of CO2
http://www.realclimate.org/index.php?p=87 on sourcing the atmospheric
CO2:
One way that we know that human activities are responsible for the
increased CO2 is simply by looking at historical records of human
activities. Since the industrial revolution, we have been burning
fossil fuels and clearing and burning forested land at an
unprecedented rate, and these processes convert organic carbon into
CO2. Careful accounting of the amount of fossil fuel that has been
extracted and combusted, and how much land clearing has occurred,
shows that we have produced far more CO2 than now remains in the
atmosphere. The roughly 500 billion metric tons of carbon we have
produced is enough to have raised the atmospheric concentration of CO2
to nearly 500 ppm. The concentrations have not reached that level
because the ocean and the terrestrial biosphere have the capacity to
absorb some of the CO2 we produce.* However, it is the fact that we
produce CO2 faster than the ocean and biosphere can absorb it that
explains the observed increase.
Another, quite independent way that we know that fossil fuel burning
and land clearing specifically are responsible for the increase in CO2
in the last 150 years is through the measurement of carbon isotopes.
Isotopes are simply different atoms with the same chemical behavior
(isotope means "same type") but with different masses. Carbon is
composed of three different isotopes, 14C, 13C and 12C. 12C is the
most common. 13C is about 1% of the total. 14C accounts for only about
1 in 1 trillion carbon atoms.
CO2 produced from burning fossil fuels or burning forests has quite a
different isotopic composition from CO2 in the atmosphere. This is
because plants have a preference for the lighter isotopes (12C vs.
13C); thus they have lower 13C/12C ratios. Since fossil fuels are
ultimately derived from ancient plants, plants and fossil fuels all
have roughly the same 13C/12C ratio - about 2% lower than that of the
atmosphere. As CO2 from these materials is released into, and mixes
with, the atmosphere, the average 13C/12C ratio of the atmosphere
decreases.
Isotope geochemists have developed time series of variations in the
14C and 13C concentrations of atmospheric CO2. One of the methods used
is to measure the 13C/12C in tree rings, and use this to infer those
same ratios in atmospheric CO2. This works because during
photosynthesis, trees take up carbon from the atmosphere and lay this
carbon down as plant organic material in the form of rings, providing
a snapshot of the atmospheric composition of that time. If the ratio
of 13C/12C in atmospheric CO2 goes up or down, so does the 13C/12C of
the tree rings. This isn't to say that the tree rings have the same
isotopic composition as the atmosphere - as noted above, plants have a
preference for the lighter isotopes, but as long as that preference
doesn't change much, the tree-ring changes wiil track the atmospheric
changes.
Sequences of annual tree rings going back thousands of years have now
been analyzed for their 13C/12C ratios. Because the age of each ring
is precisely known** we can make a graph of the atmospheric 13C/12C
ratio vs. time. What is found is at no time in the last 10,000 years
are the 13C/12C ratios in the atmosphere as low as they are today.
Furthermore, the 13C/12C ratios begin to decline dramatically just as
the CO2 starts to increase -- around 1850 AD. This is exactly what we
expect if the increased CO2 is in fact due to fossil fuel burning.
Furthermore, we can trace the absorption of CO2 into the ocean by
measuring the 13C/12C ratio of surface ocean waters. While the data
are not as complete as the tree ring data (we have only been making
these measurements for a few decades) we observe what is expected: the
surface ocean 13C/12C is decreasing. Measurements of 13C/12C on corals
and sponges -- whose carbonate shells reflect the ocean chemistry just
as tree rings record the atmospheric chemistry -- show that this
decline began about the same time as in the atmosphere; that is, when
human CO2 production began to accelerate in earnest.***
In addition to the data from tree rings, there are also of
measurements of the 13C/12C ratio in the CO2 trapped in ice cores. The
tree ring and ice core data both show that the total change in the 13C/
12C ratio of the atmosphere since 1850 is about 0.15%. This sounds
very small but is actually very large relative to natural variability.
The results show that the full glacial-to-interglacial change in 13C/
12C of the atmosphere -- which took many thousand years -- was about
0.03%, or about 5 times less than that observed in the last 150 years.
For those who are interested in the details, some relevant references
are:
Stuiver, M., Burk, R. L. and Quay, P. D. 1984. 13C/12C ratios and the
transfer of biospheric carbon to the atmosphere. J. Geophys. Res. 89,
1731-1748.
Francey, R.J., Allison, C.E., Etheridge, D.M., Trudinger, C.M.,
Enting, I.G., Leuenberger, M., Langenfelds, R.L., Michel, E., Steele,
L.P., 1999. A 1000-year high precision record of d13Cin atmospheric
CO2. Tellus 51B, 170-193.
Quay, P.D., B. Tilbrook, C.S. Wong. Oceanic uptake of fossil fuel CO2:
carbon-13 evidence. Science 256 (1992), 74-79 |
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darkness39
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| Posted: Fri Apr 06, 2007 9:58 pm Post subject: Re: Mars surface warmed at close to same rate as Earth |
|
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On Apr 6, 2:29 pm, "Evojeesus" <evojee...@mailinator.com> wrote:
| Quote: |
On Apr 5, 11:49 pm, "jose.bai...@gmail.com" <jose.bai...@gmail.com
wrote:
It may, or it may not be. The point is that the causality human
activity ==> global warming is far from proven.
How would one prove causality in this case?
|
If one could prove humans had increased CO2 levels in the atmosphere,
say by radioisotope analysis of atmospheric CO2, and one could show
that CO2 and water vapour in the atmosphere behaves in the same way as
they do in the lab (ie by absorbing wavelengths of infrared light)
then one would have pretty good proof that humans were raising the
average temperature? |
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Evojeesus
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| Posted: Sat Apr 07, 2007 6:27 am Post subject: Re: Mars surface warmed at close to same rate as Earth |
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On Apr 5, 10:26 am, "jose.bai...@gmail.com" <jose.bai...@gmail.com>
wrote:
| Quote: |
The long term wisdom of my
investment decisions is shown by the fact that I'm actually semi
retired (the few hours I work every week is just because I like the
work, not because I need the $$$). How many people can do this, at my
age???
|
That's good but be careful, retirement is bad for the mind and
longevity too. Maybe you'll get lucky and find something that you
really _love_ to do, what could be more interesting than that? |
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jose.bailen@gmail.com
Guest
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| Posted: Sat Apr 07, 2007 1:54 pm Post subject: Re: Mars surface warmed at close to same rate as Earth |
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On Apr 7, 3:27 am, "Evojeesus" <evojee...@mailinator.com> wrote:
| Quote: |
That's good but be careful, retirement is bad for the mind and
longevity too. Maybe you'll get lucky and find something that you
really _love_ to do, what could be more interesting than that?
|
I'm not old and I'm far from being inactive. I bike 2-3 hours a day
almost every day -the weather here is very pleasant (except in the
summertime, when it gets too warm, but by then I will be on vacations
somewhere in the mountains) and there are enough routes to explore
almost a new bike route each day-. On the intellectual side, I'm
teaching a course on stock market investment at a private university
near the place where I live in, next year I will teach in a newly
created master of finance at the same university. By the way, I'm
reading a very interesting book right now that may also interest you
and all the posters in this forum:
"The Quest for Value"
Author: Stern, Joel M. Stewart, G. Bennett
Published By: Harper Collins
Category: Business & Economics - Entrepreneurship |
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