So, I was a bit restless last night. And, a bit irked. So, I went hunting. I found a post by a lady, Nancy Green, at WUWT. It was a rebuttal to Tamino’s insistence that Marcott’s idiotic graph would and could demonstrate spikes in temps like the one we’re seeing today. It’s a great post. But, it seemed missing a couple of things. To be sure, her thoughts were correct. And, I don’t mean this as a criticism. It’s just that I would try additional avenues to state the case. As I said, Nancy is correct. And this is, IMHO, her money quote…..
What needs to be understood is that adding a spike to the proxy data is not the same as adding a spike to the proxies. This is where people get confused.
The proxies are ocean cores or similar sitting in some repository. They are real, physical objects. To truly add a spike to the proxies you would need to travel back in time and change the temperature of the earth. This would then affect the proxies in some fashion, depending on the resolution of the proxies, how they respond regionally, including lags, gain or damping.
And, that’s the improvement of the post, if there were to be one. It’s just that some people are more receptive to illustrations, and others still more receptive to numbers. So, it got me to thinking, I should do what she’s stating. One can’t just slap extra numbers without context into a graph and think it means something….. as Tammy did. From his smearing post……
I created an artificial temperature signal consisting of a temperature spike like that of the 20th century, followed by a return to “normal.” The spike is a rise of 0.9 deg.C over a span of 100 years, followed by a return to zero over the next 100 years. I put in not just one, but three spikes, since the age uncertainties are different at different times so I wanted to know how spikes might be smoothed out at different times in the past. The spikes were centered at 7000 BC, 3000 BC, and 1000 AD.
I then took the proxy data sets used in Marcott et al. and added to them this artificial temperature signal. That enabled me to compute a temperature reconstruction (using the “difference method”) based on the Marcott proxies plus the artificial signal. Here it is:
You see what he did there? He added the artificial data outside the proxy data. If there was a spike, it would be in the proxy data. Not outside the proxy data. And, this is Tammy’s error. He added something independent of the data, when if it were to happen, it would be part of the data. This is what Nancy was trying to tell us. It would be in the rocks!!!
So, at this point, I already know how to proceed. Each proxy contains a temperature signal. So, you add a spike to each proxy signal and then see. Now, mind you, this is just a thought exercise. There’s nothing proper about this. In fact, we don’t know that we’re not adding a spike on top of what was already a spike. But, we do know, if there was a spike, it would be in the proxy data…… at this point, we’re going to pretend we’re as stupid as Tamino and not know how this would be manifested.
But, it was late. And I had already considered how much work it would be to do all of this. So, I figured I’d sleep on it. I did. And upon awakening I, immediately thought of Hank. Maybe he’d know an easy way to interject such temp spikes in the proxy data. I was going to email him this question. But, before I did, I was going to peruse the comments of Nancy’s post. I find that a fellow, Clive Best, has already done this! From Clive’s blog….
I simply increased all proxy temperatures within 100 years of a peak by DT = 0.009*DY, where DY=(100-ABS(peak year-proxy year)). Each spike is then a rise of 0.9 deg.C over a span of 100 years, followed by a return to zero over the next 100 years. The same three dates were used for the peaks as those used by Tamino.
Oddly, this is his results…….
They are smaller, but, noticeable peaks. What happened? Well, in so many words, Clive fell into a common trap. He bought into part of Tammy’s absurdity. He realized this …..
I believe we have been too generous by displacing the proxy data linearly upwards since the measurement standard deviation should be properly folded in. I estimate this would reduce the peaks by ~30%.
What I find very interesting is that there actually do appear to be smaller but similar peaks in the real data (blue arrows), one of which corresponds to the Medieval Warm Period !
New: Simulation of a 20% time resolution error in proxy measurement time.
And so this is his results…….
He should have shown it in red and then in black like the rest as to demonstrate it is indistinguishable from the rest of the proxy data.
Clive, like Nancy, is correct. I’m sure neither need confirmation from me, but I feel a need to state my affirmation. But, the approaches, IMHO, aren’t the kind which would typically convince people otherwise. And, adopting an approach one knows is errant simply begs for conflicting ideas.
Rather than restate what Nancy said, and rework the nice work that Clive did, allow me to just demonstrate a different approach which would be very similar to Clive’s final results. Please don’t take this post wrong, this isn’t a criticism of their fine posts, it is simply showing people a different view of a similar expression of the same or very similar things.
As Nancy stated, for this experiment to be valid (almost) we need to add the spike to the proxies, not outside and independent of the proxies. So, I’ll do just one and see if even one proxy could pick up on a 100 year spike. As fortune would have it. The very first proxy set serves our purposes. Proxy GeoB5844-2 is right here for us to look at. It runs from 15146.90 BP to 813.2 BP (BP = before present). Now for some reason Tammy didn’t conform to convention. He wanted to do BC/AD versus BP as the authors did. So, this puts his first spike (random?) at about 9000 BP. Now a person would notice that the proxy GeoB5844-2 runs at inconsistent intervals, but for this time period….. we go from 9264 BP to 9036 BP. For this proxy, for that time interval, it has a bit of a spike, going from 25.7 C to 25.9 over a 232 year period of time.
Let’s look at the graph of this proxy before we interject the spike.
I even altered the Excel default vertical axis to show more of the peaks and troughs.
So, what we want to do is to interject a 0.9C 100 year spike into this proxy. One would, naturally divide this time up into 3 parts. The start value, the 100 yr spike interlude, and then back to normal. This is what it looks like on a graph for the very small 232 year period of time. For the actual data, I added a step to move from the 25.7 to the 25.9. Because it’s a lot easier, I just went with a 1 C increase instead of the 0.9C increase over 100 years.
So, there it is. Series 1 is the stepping from temp A to B and Series2 is the same with a 1 degree increase over 100 years in the middle of the 232 year interval.
Now, let’s put it back into the whole proxy series. The mean for this interval was, obviously, 25.8 deg C. After putting the spike in it is 25.97457. I’ll be nice, again and just say 26 deg C. And, I’ll even let the proxy data end there instead of smoothing it down, as it should be . In other words, for that time interval on the proxy GeoB5844-2, we now have the values going from 25.7 deg to 26 deg.
Clearly, this won’t represent much of anything on a graph, but here it is…….. I’ll even scale the temps to the same difference Tammy uses….
The red line is the new proxy graph, the sliver of blue is the old one.
The answer is, “no”, Marcott’s graph cannot detect spikes of 100 years. Their individual proxies can’t much less the whole. But, team Marcott said this already.
Now, anyone with any experience or knowledge of this stuff would know I bent over backwards to show what ever spike would or could show. I could continue with each one, but, as I said, the results would look much like Clive’s.
It’s amazing. Marcott’s paper was an abomination of statistics. Who could possibly conceive that some other pinhead could come by and make it worse? Tamino managed.
Any reasonable, and rationale observations, questions and critiques would be welcome.