EPA document supports ~3% of atmospheric carbon dioxide is attributable to human sources

WUWT doesn’t “disappear” posts, and shouldn’t.
There is a nearly infinite capacity for the biosphere to absorb ANY conceivable amount of CO2 that human activity could possibly release. It’s automatic. The naive and, frankly, obtuse belief that there is some sort of “limit” on this is just ridiculous and bizarre, not to mention completely unscientific.
If CO2 levels get high enough, an entirely new level of plant life will remove all that is possible.
CO2 levels DO NOT control temperature. That is backward. But hey, go ahead and continue believing the fiction.

As others have pointed out this claim rests on considering annual emissions. Half of what is man made emissions this year becomes ‘natural’ the following year as the biosphere keeps expanding.

Oh brother, yet another thread wasted on trying to explain the obvious.
Here is a 5-year old paraphrase from David J. C. MacKay, professor of natural philosophy in the Department of Physics at the University of Cambridge,
The burning of fossil fuels sends seven gigatons (3.27 %) of carbon dioxide into the atmosphere each year, while the biosphere and oceans account for 440 (55.28 %) and 330 (41.46 %) gigatons, respectively. Total human emissions have jumped sharply since the Industrial Revolution; and it is this added atmospheric carbon that worries many. Yes, carbon is emitted naturally into the atmosphere but the atmosphere also sends carbon back to the land and oceans and these carbon flows have canceled each other out for millennia. Burning fossil fuels, in contrast, creates a new flow of carbon that, though small, is not cancelled.

Geocraft had it at 3.225% – http://www.geocraft.com/WVFossils/greenhouse_data.html
Given the small percentage, I suspect both are in the ball park

Johan says:
July 29, 2014 at 4:14 am
markstoval says: July 29, 2014 at 4:04 am
This post and the comments that follow bring up some questions.
You have every right to ask those questions.
But when citing / quoting a paper, one should at the very least correctly convey what the authors’ claims are.

I made no claim at all as to what the cited paper said. Why would you suggest that I had incorrectly conveyed the author’s claims?

Of course, on a somewhat different and even more important note; what e.g. Nick Stokes has missed (or is perhaps unaware of) is that; for the stated rate and retention of anthropogenic (fossil-derived) CO2 in the atmosphere claimed by IPCC in AR4 to have caused the small drop observed in atmospheric δ13C, the initial atmosphere CO2 concentration would have been 2,913.9 GtC, some 3.8 times the figure used by IPCC. This is equivalent to 1,453 ppm of CO2 instead of 380 ppm!
The atmospheric 13C mass balance will agree with the measurements only if the atmosphere retains much less than 50% of the estimated anthropogenic emissions. The necessary retention is 13.1%, a factor of 3.8 less than the ~50% supplied by IPCC in AR4. The IPCC AR4 Figure 2.3(b) ‘Keeling Plot’ is fraudulent. They quoted Battle et al. (2000) but they didn’t botgher to read it.
The surge in CO2 seen in the last century was not caused by man (although it may well have been caused by global warming). The CO2 added to the atmosphere is far heavier than the weight attributed to anthropogenic CO2. The isotopic ratio for fossil fuel would have had to be considerably heavier; -13.657‰PDB instead of -29.4‰PDB, for the increase in atmospheric CO2 to have been caused by man. IPCC can’t even get their isotopic geochemistry right. Dig and ye shall find ‘curious’ literature contortions with the 13C data have continued right up into the last decade! Settled science…..not.
.

The headline is mis-leading, alarmist claim most if not all of the increase in CO2 is man-made. The table presented shows that human contributions are ~3% of total CO2, then shows the effective increase is ~1.5%.
As wrong as the headline is, the alarmist claim that there would be little to no increase to the total CO2 without man-made CO2 contributions is equally wrong. The global system is dynamic not static with the only variable being humanity.
I do not think alrmist claims would even pass as circumstantial evidence in a court of law. If petty crime went up since Michael Mann was hired by his university, could Michael Mann be arrested as the cause?

Although the conclusions drawn by the Hockey Schtick were a load of junk, the table produced by the IPCC is quite reliable. It gives the relative contributions of CO2 to the atmosphere from natural and human-made sources. This shows that the human contribution was about 3% during the 1990s. The figures are a little out of date, but won’t have changed much.
It is easy to see that, without the human contribution, the natural CO2 sinks on the planet could cope with CO2 naturally produced but when human-made CO2 is included these sinks are overloaded and there is an excess of 11,700 tonnes of CO2 left in the atmosphere each year.
So how does this increase of 11,700 tonnes per year compare to the increasing CO2 levels measured by the Mauna Loa Observatory each year?
The Mauna Loa figures show that CO2 concentrations are increasing at a rate of about 2 parts per million(by volume) per year.
Now the mass of the Earth’s atmosphere is about 5.1*10^15 tonnes so, in proportion, an increase of 11,700 tonnes per year represents an increase of 2.29 parts per million (by mass). So we can see that this is in the right ball park and conclude that the rise in CO2 levels of 2 ppmv per year is consistent with the human-made contribution of atmospheric CO2.
From another perspective, we know that a CO2 concentration of about 280 ppm is normal during interglacial periods like this one and this was the level before the industrial era. See ice core records…http://commons.wikimedia.org/wiki/File:Vostok-ice-core-petit.png
The level is now 400 ppm, the highest level for 800,000 years. In the absence of any other theories to the contrary, it is reasonable to suppose that the current enhanced CO2 levels are due to human activity.
This is not to say that there is a problem. Oil and Gas will run out long before we can double the current level ( at 2ppm per annum it will take 200 years) and, as the ‘pause’ indicates the sensitivity of the climate to CO2 is probably much less than the IPCC would have us believe. So increasing CO2 is as likely to be beneficial as it is harmful.

here we go again……man emits a special CO2 that’s cumulative….plants, oceans, and chemistry can’t touch it
“CO2 levels can be expected to drop below 200 ppm and approach levels that will limit plant growth.”
Our current CO2 level is limiting to plants now….increase it in a greenhouse and plants grow faster