Engelbeen on why he thinks the CO2 increase is man made (part 3)

Mike Edwards says:
September 16, 2010 at 9:08 am

There is no doubt that human burning of fossil fuels has dumped a vast quantity of CO2 into the atmosphere and into the oceans. And the changes in isotope ratios found in the atmosphere and the oceans bear testimony to that.

No, it does not bear testimony to that as methane degradation causes exactly the same changes in isotope ratios and appears to be sufficient unto itself to explain it.
Dig it: the industrial revolution began coincident with the end of the Little Ice Age circa 1800. The earth began warming at that time quite naturally unless one can somehow blame the LIA on human activity. A warming earth would naturally release methane from thawing permafrost and with a significant lag time also from the ocean floor. Combine that natural increase in methane emission with the explosive growth in the cattle industry (both beef and milk production) and you have a timeframe that matches the growth in manmade CO2 emission and where the isotope signature is the same for both CO2 contributors.

Interesting piece of science. I’ve been following this and related topics for about 2 years and have not seen the corresponding calculation check. That is to estimate the tons per year of CO2 being produced in various human endeavors, and compare to the total mass of atmosphere. It should be possible to get within a factor of two. In the US, the Energy Information Administration (EIA) keeps track of fuel use, and we know that a typical 1000 MWe power plant emits about 20,000 tons/day CO2. I can do this estimate unless somebody here points out why it would be useless.
Also – “Marko says: September 16, 2010 at 8:00 am
Roger. If methane is a “fossil fuel” and Saturn’s moon Titan is a big ball of methane it must mean one of two things. Since the scientific concensus claims hydrocarbons are based on organic matter, and who can argue against scientific concensus, Titan was obviously a life bearing moon.”
I have heard astronomer Sir Fred Hoyle argue this is exactly how methane formed on the other planets and moons.

Vince Causey says:
September 16, 2010 at 7:48 am
D. Patterson,
[….]
I think the article is saying that d13 is decreasing not increasing.

Yes, and the rate of sea level rise potentially affecting the d13C levels has been declining. To put it briefly, there are a plethora of confounding factors whose existence has been denied in favor of assuming anthropogenic sources of combustion emissions. Contrary to the article, excursions of isotopic balances have long predated the Industrial Age, and science has barely even begun to acquire the data necessary to untangle the results, much less the causes and effects.

O-C Strat, Oxygen-Carbon Isotope Stratigraphy
The carbon isotope composition of marine limestone fluctuates on a shorter time scale than 87Sr/86Sr ratios (see SrStrat) and the pattern of fluctuation tends to be confined to individual basins. Such relatively short term excursions in marine carbonate d13C values may reflect changes in organic productivity and burial rates of organic carbon. e.g. in the Jurassic and Cretaceous positive d13C “anomalies” may correspond with higher levels of carbon storage in organic-rich mudstone and rising sea levels, while negative d13C excursions may correspond with lower sea levels and/or sub-aerial exposure of shelf areas. This secular variation has been used to correlate limestone strata on a local scale where the original marine carbonate d13C signature has been preserved (e.g. Vahrenkamp 1996).
http://www.isotopic.co.uk/carbonstrat.html

One of the potential anthropogenic effects is the exposure of more mudflats and soils by the human efforts to eradicate mosquitos and malaria by draining vast areas of swamp.

George E. Smith:
“The NASA map certainly puts the Kibosh on the notion that CO2 in the atmospehre is well mixed; and that appears to be a starting assumption in climate models.”
It’s not a starting assumption in climate models.
“It clearly isn’t even approximately well mixed. To me; well mixed would eman that no matter where or when I took a sample of the atmosphere and analysed it, I would get the same composition on a molecular species (and isotopic) basis; at least within limits of differences that are of no consequence to any climate argument;”
And that is precisely what we see in the map. The colour scale ranges from about 365 to 385ppm – a global variation of no more than 3% either side of the mean. This is of no consequence to any climate argument.

I have a bath with a running tap and an open plug hole. There’s one guy controlling the tap, according to unknown rules that depend amongst other things on the water level, and another guy adjusting the flow out through the plug hole, similarly.
We pour a few cubic centimetres of ink into the bath, and the water turns blue.
The water level also rises. Has the colour change proved that the rise in level is caused by the addition of the ink, and not the two guys controlling tap and plug? If the water level had fallen but the water still turned blue, what would you have deduced?
Personally, I am of the opinion that the source of the CO2 is indeed mankind – but I don’t believe this argument proves it. All it shows is that an increasing proportion of the CO2 in the air is fossil-sourced (scarcely surprising), but doesn’t say anything about the cause of the change in overall level. Still, it’s excellent to see the argument/evidence set out and debated. If only the IPCC did the same.

Doug Proctor says:
September 16, 2010 at 9:04 am
HelmutU says:
September 16, 2010 at 6:58 am :
[….]
The recyling of fossil fuel CO2 is certainly a concern.

Is the “recyling of fossil fuel CO2…certainly a concern,” or is the deprivation of CO2 merely a means for meddling humans to unwittingly commit mass suicide as a consequence of CO2 concentrations falling too low to support photosynthesis by the Plant Kingdom?

Let’s assume for a second that there are no equilibrium processes which would have CO2 at current levels, even if humans didn’t exist.
Humans do produce some amount of CO2, and added to the net CO2 from all other processes, the total is higher than it would have been, meaning that humans have produced the incremental CO2.
So now, granted all this, what is your point?!

” Pamela Gray says: September 16, 2010 at 11:29 am
I could be all wet here. So take this with a grain of salt. I had a hard time finding the answer. I found one source that talk about it. Humans respire 13CO2. Has anyone calculated the increase in this isotope as a function of the increasing animal population?”
Pamela: The carbon isotope ratio that you respire is identical to the isotope ratio of the carbon in the food you eat. The human body is a chemical reactor, not a nuclear reactor. Both 13C and 12C are stable, but 14C is radioactive and Beta decays with a 5730 year half life, too slow to change the isotopic ratio inside your body. When you die, the 14C decays and the ratio can tell us when you died, up to about 60,000 years, or 10 half-lives.

So if we are breathing out more 13CO2 along with more 12CO2 due to population growth, and the greening of the planet prefers 12CO2, human population growth could be causing at least some of the extra 13CO2 in the atmosphere.
Wonder what restrictions and taxes will be placed on that issue.

899 says:
September 16, 2010 at 6:00 am
This is all very interesting, but so what?
The level of CO2 in the atmosphere has been far higher than present, and things were copacetic then.
____________
If you believe what GCM’s say about the 40% increase in CO2 since the 1700’s, then the “so what” becomes the significant changes that are climate is undergoing and will be undergoing. If you don’t believe what the GCM’s are saying, then who cares if the CO2 levels are higher than they’ve been for hundreds of thousands of years.
Only an extreme minority currently would ever seriously no doubt that human activity has caused the 40% increase in CO2 since the 1700’s. So while this is an interesting, and mostly accurate post, it is hardly earth-shattering or particularily interesting. The core issue really is how sensitive is the climate system to this anthropogenic based increase in CO2. And of course the next step that some are working on already is some sort of geoengineering efforts to reduce the CO2 levels or mitigate their effects.

http://ethomas.web.wesleyan.edu/ees123/clathrate.htm

Unique features of clathrates as part of the carbon cycle
Methane hydrates are part of the carbon cycle with unique features: they serve as a possible large source of isotopically extremely light carbon, but NOT as a sink. The carbon in methane hydrate was originally stored in the sediments (lithosphere, out of contact with the ocean and atmosphere) as organic carbon. Thus only carbon with the isotopic signature of organic carbon is taken out of the ocean-atmosphere reservoir – influencing the carbon isotopic value of the remainder in the well-known way (ratio of organic carbon to carbonate of sediments). Within the lithosphere, isotopically light carbon is strongly enriched in the methane in gas hydrates by bacterial action. The isotopically heavier remainder is isotopically not much heavier than ‘normal’ carbonate, and ends up in carbonate in the lithosphere. As long as both the methane hydrates and the remainder remain in the sediments there is no effect on the exospheric carbon reservoirs, but when the methane hydrates dissociate, material strongly depleted in the heavy isotopes escapes from the lithosphere into the ocean-atmospheric reservoir – making that reservoir lighter. The effect on the large sediment reservoir is not noticeable.
This means that the carbon that is stored in the methane hydrates was taken from the ocean-atmosphere system as carbon with an average isotopic composition of about -25‰, but the carbon returning to the ocean atmosphere system through the methane hydrate loop is isotopically ~ -60‰. Overall decreasing methane hydrate reservoirs (e.g., as a result of fluctuating sea levels during glacial -interglacial alternation) thus lead to a secular trend towards a lighter carbon isotopic signature of the ocean-atmosphere reservoir.