Mark Hickey <
[email protected]> wrote in
news:
[email protected]:
<snip>
>
> I'll give you the same challenge as I did another poster recently:
>
> 1) How much of the total CO2 released into the air every year is
> caused by man?
> 2) How much would a reduction of 7% of the man-caused (as opposed to
> total) CO2 released into the atmosphere every year reduce the
> temperature of the planet?
>
> I would think you'd want to know these things in order to complement
> your obvious interest in the issue.
>
These questions suggest to me you have been reading only "climate
contrarian" websites because they demonstrate an incomplete understanding
of the global carbon cycle. The IPCC scientific assessments are
available free of charge for downloading, a quick google search will lead
you to them (try "ipcc climate scientific assessment" for starters).
They are scientifically impeccable, free of political bias, and will
explain inexcruciating detail the link between the natural carbon cycle,
and the effect of man's activities on it.
1) Nearly all of the CO2 released naturally gets reabsorbed by the
oceans and cycled by the terrestrial biosphere. That's why the CO2
concentration of the atmosphere fluctuates so slowly compared to the
rapid increase over the past 150 years due to anthropogenic activities.
So comparing the anthropogenic emissions to the global total is not the
right thing to look at. The parameter you need to use is the fraction of
the total average yearly increase in atmospheric CO2 that is due to
anthropogenic activities. That fraction, last time I checked, was around
100%.
2) A 7% reduction in yearly CO2 output would reduce the yearly increase
of atmospheric CO2 by about 3.5% (I am guessing a little here) since
approximately half of the CO2 released by mankind gets absorbed by the
oceans (there is excess carrying capacity for CO2 in the oceans, which is
why atmospheric CO2 concentrations are relatively stable (the ocean can
buffer a lot of carbonic acid, given enough time)). Nobody has a good
estimate for whether reducing the rate of increase of atmospheric CO2 by
3.5% would have any appreciable impact on global averaged temperatures.
But that really isn't the point of the Kyoto Protocol, which I suspect
you understand but just are eliding. The point of the Kyoto Accords is
to slow down the rate of increase so that the doubling of atmospheric CO2
levels is pushed farther out into the future. The reason for that, as I
think you know but I'll state anyway because I am a long-winded asshole
and nobody has read this far anyway, is that the doubling of atmospheric
CO2 is thought of as the canonical tipping point, beyond which nothing
much will mitigate the climatic impacts of altering the radiative
properties of the atmosphere. The reason pushing that horizon back is
desirable is because, as everyone knows, remediating atmospheric CO2
increase to stop climate change is horrendously expensive using current
technology. A delaying action, while itself costly, would perhaps allow
advanced technologies to be developed and brought to bear on the problem
so that the real mitigation could be considered as a practical matter (as
opposed to the semi-delusional schemes floating around now). The Kyoto
Accords won't do much and will be expensive, but you have to start
somewhere and this is going to be a serious problem.
Anyway, to get back to the carbon cycle (this is a cycling newsgroup
after all), the 600-lb gorilla in the corner is what might happen to
atmospheric CO2 levels if anthropogenic climate change messes up the
natural global carbon cycle. Increasing deep-water upwelling (which
releases lots of CO2) for instance, without a concomittant increase in
deep-water formation (which sequesters CO2), would dramatically increase
atmospheric CO2 levels. Another example is the acidification of the
oceans due to the increase in atmospheric CO2 (this has demonstrably
occurred now, do a web search for something like "sabine feely oceanic
alkalinity decrease" and you can find the reference). Plankton are
incredibly sensitive to changes in pH (a testament to the buffering
capacity of the ocean in that it is nearly constant) and if the ocean pH
decreases enough, you shift the balance of planktonic ecosystems, and the
global biological CO2 pump is a huge part of the global carbon cycle.
If you want to talk rationally about climate change, you really need to
read the unbiased scientific assessment of how the natural systems work.
The IPCC reports are a great place to start, they are not biased, despite
what the right-wing media might suggest.
--
Bill Asher