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Originally posted by kennyb72
Fractional change HAS been factored into climate change models and the early assumptions are incorrect.
"The results run contrary to a significant body of recent research which expects that the capacity of terrestrial ecosystems and the oceans to absorb CO2 should start to diminish as CO2 emissions increase"
It would appear that this significant body of recent research is flawed as it runs contrary to this report
Therefore any climate models that have been using the assumption that the capacity of terrestrial ecosystems and the oceans to absorb CO2 should start to diminish as CO2 emissions increase, will also be flawed.
Originally posted by me
It raises some important questions, but it's not the only study of it's kind. Others show AF is changing. Indeed, the focus is on AF over the last few decades and near future rather than the trend over the last 150ish years. Easy to lose small changing trends in such an analysis.
For example, the study the author is actually criticising is Canadell et al (2007). In their paper they show an increase in Airborne Fraction (AF) of .25% per year (+/- 0.21%) at only a probability of .89 (11% of false positive). Using the error range for confidence intervals, the actual figure very likely lies between +0.4 to +4.6% per decade increases in AF.
In Knorr's paper he finds 0.7% (+/- 1.4%) per decade, Again, using error bars the confidence interval would be -0.7% to 2.1%. Due to the high error range, this data says probably no difference as it covers 0.
But the two datasets overlap considerably. When Knorr also accounts for ENSO (cf. Canadell et al., 2007), he also found an increase in AF of 1.2% (+/-.9%). Moroever, a second similar recent study (La Quere et al., 2009) shows an increase of 3% (+/-2) over the last 50 years.
Canadell's article is freely available on the PNAS website, worth a read. As it clearly points out that most models that even include variations in sink activity involve a negative trend in AF during the 20th century, and only turn positive during the 21st century.
And we don't really know for certain that will not be the case. The Knorr article doesn't even go there, being solely based on the carbon cycle in the past. Moreover, his data covers the potential for a large positive trend, and even has a mean which is positive (increasing AF).
Climate models that include a representation of carbon cycle
sinks estimate a proportional trend in the AF during the 21st
century of 0.41 +/- 0.23% y^-1 (mean standard deviation across
11 models) under a Special Report on Emission Scenarios
(SRES) A2 scenario (13). However, over the 1959–2006 time
period, 9 of the 11 models estimate a decrease in AF, and the
mean proportional trend is -0.27 +/- 0.36% y^-1 (11 models).
These results suggest that the observed carbon-cycle feedbacks
occur faster than expected by our current understanding of the
processes driving the sinks.
Without the inclusion of ENSO and VAI in the
analysis, the trend derived with data uncertainties is found
to be very small, only 0.7 ± 1.4 or 0.2 ± 1.7% per decade,
depending on whether the ice core record has been included
or not. This is not significantly different from zero and in
contrast to the previously published result [Canadell et al.,
2007] reporting an increase of 2.5 ± 2.1% per decade, but
obtained with de-trended VAI and ENSO index and without
accounting for data uncertainties. The equivalent result
reported here is 1.2 ± 0.9% per decade. The difference
between the last two probably reflects remaining differences
in the method chosen.
Originally posted by kennyb72
I understand what you are saying. In other words this report in your view is invalid.
I wouldn't for one minute question the data you threw at me because obviously your findings are gospel.
Did any of this data by any chance come from the University of East Anglia because I am afraid they are having a bit of a credibility crisis at the moment.
I am afraid that this has tainted the entire scientific argument, particularly more so since the whole issue of AGW has become politicized
I have noticed and I am sure many readers have also, that it is standard MO to discrediting those who are not convinced of AGW, to deride and mock those who are concerned that we are being lead down the garden path.
These tactics alone would lead the average reader to surmise that the argument for AGW must be tenuous for you to resort to this sort of behavior.
Please allow us to test your assumptions and please do not ask me to trust you.
There has been much revealed during this debate. More than half the population of the planet don't believe you. The more you mock, the more people will question your motives.