"Earl Evleth" <evleth@[EMAIL PROTECTED]
> wrote in message
news:C43A8547.12163C%evleth@[EMAIL PROTECTED]
>I don't see anything "new" in this item. The factor of
> 14,000 is new to me however. We "chicken littles" have
> long claimed that man is screwing things up.
And you've been wrong for a very long time then.
> Human warming hobbles ancient climate cycle
> Sun Apr 27, 2008 1:07pm EDT
> By Deborah Zabarenko, Environment Correspondent
> WA****NGTON (Reuters) - Before humans began burning fossil fuels, there
> was
> an eons-long balance between carbon dioxide emissions and Earth's
> ability to
> absorb them, but now the planet can't keep up, scientists said on
> Sunday.
Atmospheric CO2 Increases, Due To Ocean, Rather Than Mankind
Roy W. Spencer
25 Jan 2008
http://wattsupwiththat.wordpress.com/2008/01/25/double-whammy-friday-roy-spencer-on-how-oceans-are-driving-co2/#more-611
This is probably the most provocative hypothesis I have ever
(and will ever) advance: The long-term increases in carbon dioxide
concentration that have been observed at Mauna Loa since 1958 could be
driven more than by the ocean than by mankind's burning of fossil fuels.
Most, if not all, experts in the global carbon cycle will at
this point think I am totally off my rocker. Not being an expert in the
global carbon cycle, I am admittedly sticking my neck out here. But, at
a minimum, the results I will show make for a fascinating story - even
if my hypothesis is wrong. While the evidence I will show is admittedly
empirical, I believe that a physically based case can be made to sup****t
it.
But first, some acknowledgements. Even though I have been
playing with the CO2 and global temperature data for about a year, it
was the persistent queries from a Canadian engineer, Allan MacRae, who
made me recently revisit this issue in more detail. Also, the writings
of Tom V. Segalstad, a Norwegian geochemist, were also a source of
information and ideas about the carbon cycle.
First, let's start with what everyone knows: that
atmospheric carbon dioxide concentrations, and global-averaged surface
temperature, have risen since the Mauna Loa CO2 record began. These are
illustrated in the next two figures.
Both are on the increase, an empirical observation that is qualitatively
consistent with the "consensus" view that increasing anthropogenic CO2
emissions are causing the warming. Note also that they both have a
"bend" in them that looks similar, which might also lead one to
speculate that there is a physical connection between them.
Now, let's ask: "What is the empirical evidence that CO2 is driving
surface temperature, and not the other way around?" If we ask that
question, then we are no longer trying to explain the change in
temperature with time (a heat budget issue), but instead we are dealing
with what is causing the change in CO2 concentration with time (a carbon
budget issue). The distinction is im****tant. In mathematical terms, we
need to analyze the sources and sinks contributing to dCO2/dt, not
dT/dt.
So, let us look at the yearly CO2 input into the atmosphere based upon
the Mauna Loa record, that is, the change in CO2 concentration with time
(Fig. 3).
Here I have expressed the Mauna Loa CO2 concentration changes in million
metric tons of carbon (mmtC) per year so that they can be compared to
the human emissions, also shown in the graph.
Now, compare the surface temperature variations in Fig. 2 with the Mauna
Loa-derived carbon emissions in Fig. 3. They look pretty similar, don't
they? In fact, the CO2 changes look a lot more like the temperature
changes than the human emissions do. The large interannual fluctuations
in Mauna Loa-derived CO2 "emissions" roughly coincide with El Nino and
La Nina events, which are also periods of globally-averaged warmth and
coolness, respectively. I'll address the lag between them soon.
Of some additional interest is the 1992 event. In that case, cooling
from Mt. Pinatubo has caused the surface cooling, and it coincides in a
dip in the CO2 change rate at Mauna Loa.
These results beg the question: are surface temperature variations a
surrogate for changes in CO2 sources and/or sinks?
First, let's look at the strength of the trends in temperature and
CO2-inferred "emissions". If we compare the slopes of the regression
lines in Figs. 2 and 3, we get an increase of about 4300 mmt of carbon
at Mauna Loa for every degree C. of surface warming. Please remember
that ratio (4,300 mmtC/deg. C), because we are now going to look at the
same relation****p for the interannual variability seen in Figs. 2 and 3.
In Fig. 4 I have detrended the time series in Figs. 2 and 3, and plotted
the residuals against each other. We see that the interannual
temperature-versus-Mauna Loa-inferred emissions relation****p has a
regression slope of about 5,100 mmtC/deg. C.
There is little evidence of any time lag between the two time series,
give or take a couple of months.
So, what does this all show? A comparison of the two slope
relation****ps (5100 mmtC/yr for interannual variability, versus 4,700
mmtC/yr for the trends) shows, at least empirically, that whatever
mechanism is causing El Nino and La Nina to modulate CO2 concentrations
in the atmosphere is more than strong enough to explain the long-term
increase in CO2 concentration at Mauna Loa. So, at least based upon
this empirical evidence, invoking mankind's CO2 emissions is not even
necessary. (I will address how this might happen physically, below).
In fact, if we look at several different temperature averaging areas
(global, N. H. land, N.H. ocean, N.H. land + ocean, and S.H. ocean), the
highest correlation occurs for the Southern Hemisphere ocean , and with
a larger regression slope of 7,100 mmtC/deg. C. This suggests that the
oceans, rather than land, could be the main driver of the interannual
fluctuations in CO2 emissions that are being picked up at Mauna Loa -
especially the Southern Ocean.
Now, here's where I'm really going to stick my neck out - into the
mysterious discipline of the global carbon cycle. My postulated
physical explanation will involve both fast and slow processes of
exchange of CO2 between the atmosphere and the surface.
The evidence for rapid exchange of CO2 between the ocean and atmosphere
comes from the fact that current carbon cycle flux estimates show that
the annual CO2 exchange between surface and atmosphere amounts to 20% to
30% of the total amount in the atmosphere. This means that most of the
carbon in the atmosphere is recycled through the surface every five
years or so. From Segalstad's writings, the rate of exchange could even
be faster than this. For instance, how do we know what the turbulent
fluxes in and out of the wind-driven ocean are? How would one measure
such a thing locally, let alone globally?
Now, this globally averaged situation is made up of some regions
emitting more CO2 than they absorb, and some regions absorbing more than
they emit. What if there is a region where there has been a long-term
change in the net carbon flux that is at least as big as the human
source?
After all, the human source represents only 3% (or less) the size of the
natural fluxes in and out of the surface. This means that we would need
to know the natural upward and downward fluxes to much better than 3% to
say that humans are responsible for the current upward trend in
atmospheric CO2. Are measurements of the global carbon fluxes much
better than 3% in accuracy?? I doubt it.
So, one possibility would be a long-term change in the El Nino / La Nina
cycle, which would include fluctuations in the ocean upwelling areas off
the west coasts of the continents. Since these areas represent
semi-direct connections to deep-ocean carbon storage, this could be one
possible source of the extra carbon (or, maybe I should say a decreasing
sink for atmospheric carbon?).
Let's say the oceans are producing an extra 1 unit of CO2, mankind is
producing 1 unit, and nature is absorbing an extra 1.5 units. Then we
get the situation we have today, with CO2 rising at about 50% the rate
of human emissions.
If nothing else, Fig. 3 illustrates how large the natural interannual
changes in CO2 are compared to the human emissions. In Fig. 5 we see
that the yearly-average CO2 increase at Mauna Loa ends up being anywhere
from 0% of the human source, to 130%.
It seems to me that this is proof that natural net flux imbalances are
at least as big as the human source.
Could the long-term increase in El Nino conditions observed in recent
decades (and whatever change in the carbon budget of the ocean that
entails) be more responsible for increasing CO2 concentrations than
mankind? At this point, I think that question is a valid one.
« Warming Trend: PDO And Solar Correlate Better Than CO2 How not to
measure temperature, part 49. Alaska's COOP Stations »
Warmest Regards
Bonzo
"In scientific circles, C02 is referred to as a `trace gas' that, for
hundreds of thousands of years, has remained at or below five
ten-thousandths of the atmosphere by volume. Even among the so-called
`greenhouse gases' (GHG), C02 accounts for less than 4%, with water
vapour being by far the most significant GHG. C02 is clearly a
miniscule component of the massive mechanisms that create climate and
cause climate change."
Dr. Timothy Ball, Chairman of the Natural Resources Steward****p Project
(NRSP.com), Former Professor Of Climatology, University of Winnipeg
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