Brian:
According to your post the amount of  CO2 emitted by man annualy  is 15
billion tonnes (I assume that is metric tons).  You should check your
sources.
Doing a bit of digging I found a few references to anthropogenic
emissions of CO2

 From "Trends in Global Emissions: Carbon, Sulfur and Nitrogen" by
Arnolf Grubler (International Institute for Applied Systems Analysis,
Laxenberg Austria
in the Encyclopedia of Global Environmental Change (ISBN 0-471-97796-9)
published in 2002

Page 2
"Compared to the size of annual fluxes that characterize the carbon
cycle and its inter-annual variations, anthropogenic altrerations to the
carbon cycle are comparatively small and hence impossible to measure
directly. Emmission estimates need therefore  to be based on inventory
data linking socio-economic activity data such as fossil fuel use  or
land use changes ..."

"Currently (AD 2000), human-induced alterations to carbon flows include
emissions of some 6.6 (+/_ 0.6) Pg C year from industrial activities
(mostly the burning of fossil fuels) that constitute a net addition to
natural carbon fluxes, albeit not necessarily in the same year. In
addition, estimates indicate a net additional flux of about one
(uncertainty range: 0-2.8)Pg C year from the burning of biomass and
changes in soil carbon in conjunction with land use changes."

Source:
http://www.iiasa.ac.at/Research/TNT/WEB/Publications/Trends_in_Global_Emissions/egec_sulfur.pdf

So what he is saying is that they really cannot determine actual amounts
so they have to make estimates based on economic factors such as amount
of  fuels consumed. OK, I'll go along with that, but Brubler says that
the amount is ONLY 6.6 Pg C (i.e. 6.6 billion metric tons) per year.
 Quite a bit less than 15 billion.

I also found, at http://www.fao.org/clim/docs/1-3.HTM

XI WORLD FORESTRY CONGRESS
Antalya, Turkey, 13 to 22 October 1997

VOLUME 1, TOPIC 4

FORESTS AND CLIMATE CHANGE: ROLE OF FOREST LANDS AS CARBON SINKS
Sandra Brown (US Environmental Protection Agency, National Health and
Environmental Effects Research Laboratory, Western Ecology Division)


"The estimated net C flux from the world's forests is a source of 0.9 ±
0.5 Pg/yr, or about 16% of the amount produced by burning fossil fuels
and cement manufacture. The error terms associated with the C flux
estimate are basically derived from the range of values resulting from
the use of different assumptions in the C budgets for a given country or
region. They do not represent errors derived from statistical
procedures. Error enters the flux estimation procedure through
uncertainties and biases in the primary data and these compound as the
data are combined to draw inferences (Robinson 1989). Many estimates for
components of the forest sector C budget are probably known no better
than ± 30% of their mean and others may be known no better than >± 50%
of their mean (Robinson 1989). These errors are compounded in making
global estimates of C flux, perhaps to large proportions, but to what
extent is presently unknown.

The average annual global C budget for the 1980s is estimated as follows
(Schimel et al. 1995):

   Pg C yr
Emissions from fossil fuel and cement production    5.5 +/- 0.5
Emissions from change in tropical land use             1.6 +/- 1/0
Total emissions                                                     7.1
+/- 1.1


So Brown estimates emissions at ONLY 5.5 Pg C (i.e. 5.5 billion metric
tons) per year.

Chuck


>
> Brian Ellis wrote:
>
>> What you are saying is that the annual 15 billion tonnes of CO2 that are
>> spewing out of our chimneys and exhaust pipes, year in, year out, is for
>> nought? PLEEEEEEZE! Nor the 6 billion tonnes that are not absorbed
>> because of deforestation.
>>
>> Yes, the ocean surface waters contain 1000 billion tonnes of carbon,
>> some in life forms, some in dissolved CO2, but the annual carbon
>> emissions from the oceans are 90 billion tonnes, whereas the absorption
>> by the oceans is 92 billion tonnes. In fact, the annual increase of
>> carbon in the surface oceans is only 1 billion tonnes, because there are
>> other interchanges into deep waters and, eventually into sedimentation.
>> [figures from Sundquist, Trabalka, Bolin and Siegenthaler, IPCC 1990]
>>
>> Sorry, if your hypothesis were correct, we would be in a positive
>> feedback cycle, snowballing into ever-increasing GHG emissions, causing
>> more global climate change, causing more ocean heating... Hopefully, we
>> are not there - yet.
>>
>> No, I'm sorry, it is you and I who are responsible, not some quirk of
>> nature. This is now definite and no apologetics of bad science will
>> diminish our responsibilty. Even GWB is admitting it!
>>
>> Brian
>
>
>