Friday, 16 October 2015

Indonesian Fires

Typically During El Nino years we see forest fires that will raise the CO2 concentration levels in the atmosphere.

These Indonesian fires will contribute towards this effect although the causes of the fires are not completely natural as explained in the post above.

Contrarians in the past and undoubtedly in the future will use the data (CO2 concentrations increased due to these CO2 pulses) to arrive at false conclusions.

These fires cause atmospheric CO2 concentrations to rise more than would be expected from emissions alone. It is this extra rise in CO2 that LAGs variations in SST that have led Humlum, here and led Spencer, here, in the past to wrongly assume that SST are the cause of CO2 rise in the overall trend of CO2 rise. The overall trend in CO2 rise is of course caused by human emissions.

It was to be expected that something similar would happen during an El Nino as discussed, here, It is also likely that we will see more events globally in the short term(over the next few months) that will further contribute to short term variations in this upward direction.

Inevitably these anomalous upward variations in SST will decline, La Nina will return, global rainfall over land will increase, plant growth will increase and the trend in CO2 concentrations will rise less steeply. (This offset due to this reduction of CO2, however, will not fully compensate for the rise in CO2 during El Nino in the case of these Indonesian fires as explained in the news article at the top of this page). Again the variations in CO2 will lag the SST to be misinterpreted by climate contrarians. 

Wednesday, 7 October 2015

Roy Spencer’s “model”

Carbon dioxide and Sea surface temperature.

Roy Spencer plays with data in a failed attempt here.  He attempts to explain that the rise in atmospheric CO2 has mainly come from rising sea surface temperature, SST.

 I only recently came across Spencer's blog though it was written back in 2009 and thought it relevant to discuss this in light of the present El Nino of 2015. The relevance is discussed here.

A coherent and consistent explanation is generally accepted for the rise of CO2 since the start of the industrial revolution. This explanation includes the causes for the trend in CO2 and different causes for the variations in CO2. There is little doubt that the trend is caused by human activity and in particular the burning of fossil fuels.

There is continual movement back and forth between the atmosphere, biosphere and oceans; however these are net fluxes that are indicated.

In spite of the oceans warming, the oceans are net absorbers because of the extra CO2 pressure from the atmosphere

Roy Spencer challenges this and while not stating his conclusions explicitly he makes strong implications:-

According to Spencer something is causing SST to increase and this is most likely to be due to changes in cloud cover for reasons unknown and the cloud cover conveniently changes at a level too small to measure. Spencer suggests this change in SST is the main cause of CO2 to rise in our atmosphere. To arrive at this viewpoint Spencer uses a circular argument assuming it is true in the attempt to show it is true. This logical fallacy on its own shows his argument to be false but Spencer also requires mutually exclusive arguments in an attempt to justify his arguments. Playing with data, Spencer makes a “model”, (it is hoped he is not equating this to resemble anything like a climate model) which is nothing more than an algebraic equation to which he quickly finds a solution.

Confusing the causes of trends with the causes in natural variation and confusing correlation with cause, Spencer then makes a provocative claim that if scientists don’t take this incredulous flawed argument seriously then they must be politically motivated for doing so.

Perhaps Spencer’s main flaw (although all the flaws are in fact fatal to a coherent argument) is that any dubious conclusion he makes as to causes in natural variations he assumes are applicable to the causes for the trends. While attempting to consider some of the intricacies of natural variation he makes simple fatal errors on explaining the simple basics. The complexities of the variations are interesting and well worth investigating. (A repeat of the link above is given here which contrasts much with Spencer and explains the significance of the lag that Spencer refers to). Rather than trying to clarify these complexities Spencer uses them to obfuscate the simpler basics.

Spencer’s mutually exclusive arguments.
Roy Spencer disagrees with the diagram above. He doesn’t dispute the fact that the atmosphere has been increasing in CO2 and presumably he doesn’t disagree that we have been burning fossil fuels. So the top line in figure 1 is not disputed, give or take a little uncertainty.  What Spencer disagrees with is the net fluxes represented by arrows b and c into the biosphere and oceans and furthermore he disagrees with their direction.
He cannot make up his mind if arrow b or c should be reversed. For obvious reasons both cant be reversed or the atmosphere would gain more than humans emitted.

He would like to argue the “Coke-Fizz” effect ( arrow c reversed), the argument that warming oceans would give up their CO2 due to them being warmer, but he knows this argument is flawed so he jumps to the other argument that the biosphere could be net sources of CO2 to the atmosphere but knowing this is also flawed he leaves it vague which of these mutually exclusive arguments he proposes.

If the oceans were net sources of CO2 (arrow c reversed) then we would require more greening (arrow b to be most of the 10 Gt /year) and the oceans to be increasing in pH (or becoming more alkaline, which is not observed)
 The evidence of carbon 13 isotopes falling excludes the possibility that the oceans are the sources of CO2 to the atmosphere. Plants preferentially take up C12 and the oceans being the source would prevent the C13/C12 ratio in the atmosphere falling to the extent for which there is observational evidence. Aware of this Spencer “pre-empts” this argument by switching to the biosphere as a net source. He states that “the C13 change is not a unique signature of fossil fuel source”. This is true but is an example of a half truth. Spencer fails to acknowledge that the reduction in C13/C12 ratio completely destroys his previous argument that the oceans via the “Coke-Fizz effect“could be the source of the atmospheric CO2.

The biosphere being a source for the CO2 could explain the C13/C12 ratio; however he doesn’t dwell on this for long. This would mean the biosphere was ungreening ( he has argued on other posts that a benefit of burning fossil fuels is that it is causing greening of the atmosphere) and the oceans would be gaining most of the 10Gt/year of CO2. 

It would appear that you are to momentarily believe that the oceans could be the source for CO2 and if you find a flaw in that argument you can perhaps believe the biosphere is the source. Not only are both these arguments flawed but they are mutually exclusive unless you think that mass can somehow not be conserved.

Spencers Circular arguments.  Spencers Model.
Spencers “Model”
delta[CO2]/delta[t] = a*SST + b*Anthro
This claims that the CO2 gradient correlates linearly on a combination of SST anomalies and an anthropogenic component.
Is Spencer implying that his “model” based on a simple algebraic equation is supposed to be a replacement for sophisticated climate models that use scientific laws and data coded into computer language to obtain emergent weather patterns? One gets the feeling he is hoping climate contrarians will infer this.

It is inconceivable that CO2 concentrations are proportional to an anomaly based on differences compared to a 1961 to 1990 average.

The value for SST anomaly depends on what years we compare SST to. SST’s are compared to the average of years 1960 to 1990. So the solutions for the co-ordinate values that fit a narrowly defined period with a start and end date depend on this choice. This means that Spencer decides how much is SST (which he calls natural) and how much is anthropogenic based on this arbitrary choice.

If the model is extended into the future, as long as CO2 emissions occur and absolute values of SST increase, then the gradient of CO2 concentrations will increase. This will mean an inevitable exponential increase in CO2 concentrations that would indeed imply drastic positive carbon feedbacks to carbon emissions. Any SST would mean that CO2 concentrations would rise without any emissions. Thankfully the model is flawed; the exponential effect is seen in the graph above.

The observed CO2 and the model are made to fit in year 1958 and then this formula is used to calculate how the model changes over the time period. The coefficients a and b are “solved” to give the best fit. The solution favoured by Spencer results in the atmosphere at the present time gaining about 1Gt/year (10%) from anthropogenic sources and hence 3.5GT from “natural sources” due to SST rise. He doesn’t really explain where the other 9GT of human emissions goes.

In his original graphs the anthropogenic component didn’t seem to fit well because he decided to plot the rate of change of CO2 against time and depending on how little the data is smoothed you can get wild fluctuations with this technique. This is a common technique used by an obfuscator when they want to show something that is well correlated not to be so.  He didn’t use that technique when he wanted his 90% “natural” plus 10% anthropogenic to fit well.

For an explanation of the variations of CO2 associated with ENSO cycles along with references see here.

Tuesday, 23 June 2015

Variations On the rate of change of sea level rise

Global warming due to the build up of greenhouse gases, primarily carbon dioxide (CO2), causes the sea level to rise.

Here I will describe a flawed attempt by Nir Shaviv at attributing global warming on changes in solar activity. This case by looking at sea level rises rather than surface temperatures.

Shaviv posted to the Financial Post on June 16 2015 claiming “the sun raises the seas”. In that post (link to follow) he claims he has evidence to show that it is changes in solar activity that is the major factor in present day sea level rise. However his arguments do not disprove the consensus view that this sea level rise is primarily due to the enhanced Greenhouse Effect (GHE) due to human activities. It is however reasonable to consider sea level rises as most of the energy built up due to Global Warming is taken up by the oceans. It is this energy absorption that results in sea level rises.(figure 1)

Figure 1 Sea level rises CSIRO

If this sea level rise could be attributed to changes in the sun rather than greenhouse gases then this would be a way of undermining the GHE.
Previous attempts at showing that it is changes in the solar activity that has caused surface temperatures to change have failed:-

To raise the sea levels requires extra energy; energy obtained via the GHE. Most of this energy raises the temperature of the sea and cause the seas to expand. Some of the energy also results in net melting of land ice that also raises sea levels. This explains the trend in rising sea levels. The short term variations, however, may be due to natural variations such as changes in solar activity or in oceanic circulation patterns such as El Nino and La Nina; the later resulting in changes of rainfall and snowfall over land changing the amount of water removed from the oceans.

However Shaviv claims that the sea level data shows.....the rate of change of sea level “follows the sun”.....and then concludes that it the sun that it is the cause of sea level rise.

I will argue that the first point is very dubious but also show that even if it where the case the calculations he shows about rates of changes of sea level does not support the conclusion. Shaviv doesn’t explicitly say he has made the conclusion from that evidence, however in his post that is the only evidence he presents and so the very strong inference is made.

Figure 2 Shaviv

The lower graph in figure 2 shows sea level rises without uncertainties but otherwise similar to that of figure 1.

The upper graph shows the rate of change of sea level (blue line) and variations in solar flux (black line). We see these two superimposed graphs overlap well with similar amplitude phase and frequency and so superficially it may seem that the conclusion follows.

Let us assume for the moment that the rate of change of sea level follows the sun as in the upper diagram of fig 2 is true. Why does the conclusion not follow?

When manipulating data to tease out underlying causes, it is important that your conclusions are not really a result of the manipulations and not the data itself.

Shaviv manipulates the data by effectively removing the trend in sea level (explained later) and smoothing out the sea level to omit seasonal changes so he is only left with other natural variations. Nothing wrong so far. However one can no longer make conclusions about the solar activity and the trend in sea level rise but this is precisely what he seems to do.

Shaviv does not actually remove the trend; he simply hides it. If he were to remove the trend and the seasonal cycles we would be left with variations that would be more obviously related to ENSO cycles. Instead he finds the rate of change of sea level suitably smoothed so that a linear trend will be seen as a horizontal offset so when compared and plotted with another graph showing the solar cycle with an independent scale and origin he has effectively removed the trend for comparison purposes.

Perhaps simpler examples can clarify this and this is good reason to look at what is regarded as the main cause of modern day sea level rise.
Keeling curve:-

Figure 3 CO2 levels

This diagram plots the CO2 smoothed out to show the monthly changes (red curve) and yearly changes (blue curve). The monthly changes are due to the seasonal cycle whereby CO2 is absorbed by plants during the growing season in the NH and CO2 is released by decay over the winter months. The trend is due to the build up of from human activities mainly in the burning of fossil fuels.

When focussing on the rates of change, the annual rate of change of CO2 is completely dominated by the monthly rate of change clearly because the slow annual trend is smaller than the swings in concentration over each single year. A graph of the rate of change of the monthly concentration of CO2 would show positive and negative swings across the time axis off-set slightly due to the long term trend. (Similar to figure 4).

This Keeling curve can be approximately modelled by a straight line with a long term trend rate (given the value k) modulated by a sinusoidal wave.

CO2 = kt + asinwt + a constant

Rate of change of CO2 (wrt to t) =  k+awcoswt

Figure 4 rate of change of idealized CO2 concentration against time.

Figure 4 shows a sinusoidal wave with an average value k, that is offset by a value k, the long term trend rate. The higher the frequency, w, of noise or short term variations then the more the long term trend k is obscured by the amplitude, aw.

From the Keeling curve we can see that the rate of change of the CO2 concentration (as seen by the changing slope of the red graph) mainly follows the seasons but this is totally independent of the causes of CO2 build up due to human activities as seen by the long term trend.

Back to sea level rise:-
 Shaviv has smoothed and sampled the sea level data at appropriate intervals, just enough but not too much, ensuring the short term variations dominate the trend when looking at rates of change. (....too little and other variations would dominate the solar cycle....too much and variations over frequencies comparable to the solar cycle would disappear).

However what about the similar frequency and amplitude of the rate of change of sea level rise and solar flux as in the upper diagram of figure 2?

The frequencies are similar partly because they are chosen to be so by deciding how much smoothing is employed and partly because there may be some albeit small connection. However I can see about two or three times per decade (when looking at the sea level rise as in the lower graph of figure 2)  when the rate of change of sea level rise should swing between positive and negative which is not reflected in the upper graph.

The amplitudes are equally similar because again they are chosen to be so....the two graphs have independent scales and further the origin of each graph is changed so that the long term trend (k, of about 2 or 3 mm/year as seen in the average of the rate of change of sea graph) is overlapped by the solar flux.

The important conclusion I make here is that any resemblance of the rate of change of sea level rise to the solar variations have no bearing on the long term trend of sea level rise just as in the case of the CO2 variations. The causes of the short term variations and the long term trend in each of these graphs are different.

There is an obvious correlation here of course, and that is the consensus view, that the long term trend in CO2 is not only the cause of the long term trend in sea level but the correlation between them is excellent (graphs 1 and 3). Shaviv has discarded the obvious and made claims or inferences that could lead the reader to a false conclusion.