Martin A

The resolution of the Marcott et al ensemble is 120 years in duration and +/- 0.1C.

The instrument record show an increase of 1C in 135 years. If this had occured earlier in the Holocene it would have shown up clearly, being well above the detection threshold of the Marcott data.

Some of the individual proxies in the ensemble have better time resolution, but higher temperature noise levels .part of the purpose of an ensemble is to improve the signal to noise ratio. This allows you to identify genuine spikes which show in most proxies, as opposed to noise which shows up at random.

An earlier event as large and prolonged as the 1C in 135 post 1880 warming would have been picked up as a spike of at least 0.4C at 120 year resolotion. That is twice the 95% confidence limits. There are no spikes in the earlier data even as large as 0.1C.

"it is dishonest to claim that such events did not occur in the period covered by the other section merely because that section reveals no trace of such events."

On the contrary. It is dishonest to claim the possibility of events when the methodology is quite capable of detecting the events, but shows no evidence of their existance. One event was detected, at the end of the sequence, and independently validated. On the evidence no others occurred at all.

I cannot precis McIntyre and in vany way improve on his explanation. Go to climateaudit.org and search Marcott. Read the various posts. If you can't see it after that I despair.

EM, the excuse about acid rain ruining the evidence for recent warmth being exceptional in the tree-proxies leaves me strongly unpersuaded for several reasons.

Firstly, much industrial air pollution was being cleaned up during and after the 1960's, so on that count the more recent treemometer proxy data might be as good or better than that which obtained shortly before the data was truncated.

Secondly, acid is rain is very local and much of it was exaggerated or simply non-existent due to other temporary causes being misattributed by environmentalists (where have we heard that before?).

Thirdly, places like the Yamal Peninsular, site of the most influential tree in the modern world, and scene of the murder of science, is bloody miles from anywhere even by Russian standards.

Fourthly, dendro-thermatology is based on selecting a few trees from the many on the basis of simple correlation. (How this is done is also the scene of other crimes against science and statistics committed by Michael Mann.) There is often no a priori good reason for why some otherwise appropriately-situated trees correlate with temperature while others don't, or when and why a given tree starts/stops correlating with temperature. At such times, other, previously ignored but salient, factors affecting tree growth suddenly become important? How very convenient.

If the multiple offenders (they who know who they are) had confidence in their technique showing unprecedented warmth in the modern proxy record, they could have found a way to show it. Instead, they chose to go with the 'We need to get rid of the medieval Warm Period' approach and "Mike's Nature trick" etcetera.

The resolution of the Marcott et al ensemble is 120 years in duration and +/- 0.1C.

Marcott et al conceded that because of their averaging process a 100 year spike on its own would not show up - ie it would have to be something enduring centuries to be detected by their methods.

You and I have previously discussed how, if you are doing a moving average (or similar lowpass filtering) then you can't make use of the output from the past N years, if your smoothing function has an effective duration of N years. So any conclusions they reach about the twentieth century cannot be from their data smoothed over 100 year periods.

In their paper they discuss temperatures from 1900 - 1909 and from 2000 - 2009 - ie averaging over decades, not centuries. Then they immediately state "... Global temperature, therefore, has risen from near the coldest to the warmest levels of the Holocene within the past century...". So their conclusion about unprecedented temperature increases (that one hit the headlines) was clearly derived from thermometer records with high temporal resolution.

One event was detected, at the end of the sequence, and independently validated.

EM - You have greater faith than Marcott et al than they themselves had. Or the Met Office. Marcott, in his thesis, evidently made no claim to detect rapid recent warming. Only in the paper. But, after publication, news headlines, and then criticism, they themselves conceded that this result was "not robust" and the Met Office removed their reference to the result from their web site. Obviously it was an embarrassment to them.

Martin A, and that is why I consider Marcott only slightly above a charlatan on the make.

A reasonable person with only a modest insight into academia would know that his academic committee would drag his ass over hot coals for claiming that (maybe they did? we shall probably never know). But he found one of the highest profile scientific journals was willing to publish it. That journal is straying from the path of science in pursuit of politics, money, or both.

michael hart - It was pretty clear at the time that hitting the headlines with "recent temperature rise unprecedented for 11,000 years" was their objective. Which they achieved 100%.

The fact that within weeks they admitted that their result was "not robust"* was neither here not there; their objective had been achieved.

robust . . . . not obviously wrong
not robust . . . . obviously wrong
[The Dictionary of Climate Science (Ed. Martin A) - in preparation]

"Obviously it was an embarrassment to them."

Nov 6, 2015 at 10:38 PM | Unregistered CommenterMartin A

Given past performance it is most unlikely that was the motivation.

http://www.bishop-hill.net/blog/2013/5/27/met-office-admits-claims-of-significant-temperature-rise-unt.html

So is the so-called GHE still a matter of dispute?

So is the so-called GHE still a matter of dispute?

Was it ever? (Skydragon slayers excepted)

A disgruntled reluctance to accept it is not the same thing as it being disputed, Dung.

Martin A

You can independently calculate the energy accumulating in the oceans by calculating a) the energy needed to increase the average temperature or b)the amount of energy needs to produce the observed thermal expansion.

I've put the figures here before. Either way you get 3*10^22 J/year. This is equivalent to 0.7W/M^2.

The satellite imbalance is 0.7W/M^2 +/- 0.7.

One reason why I am convinced that we are warming is that these three independent calculations give the same result.

Michael hart

Much of the 1950's air pollution in the UK originally came from local power stations like Battersea with low chimneys which polluted their local area.

In the 1960s they were replaced with larger power stations outside towns. Their high chimneys dumped their sulphur higher in the troposphere.Regrettably they did not solve the problem, just moved it. Instead of dropping locally it washed out as acid rain a thousand miles downwind.

Instead of dropping locally it washed out as acid rain a thousand miles downwind.

No. It didn't. It is washed out too rapidly. China's current pollution stays mainly in China. Even James Hansen thinks it stays fairly local and is responsible of fertilising the biosphere. He used this as his 2013 excuse about why land-based carbon sinks are expanding faster than thought. And by that, I assume he means trees.

Michael hart

Links, please.

In the 1960s they were replaced with larger power stations outside towns. Their high chimneys dumped their sulphur higher in the troposphere. Regrettably they did not solve the problem, just moved it. Instead of dropping locally it washed out as acid rain a thousand miles downwind.
Nov 10, 2015 at 5:43 PM | Unregistered CommenterEntropic man

That's incorrect.

The installation of electrostatic precipitators, which were certainly in widespread use by the 1960's, made a huge reduction in power station emission of solid matter.

One reason why I am convinced that we are warming is that these three independent calculations give the same result.
Nov 10, 2015 at 5:31 PM | Unregistered CommenterEntropic man

EM - I'm not sure what you are replying to. I don't think there is any dispute that we have been warming off and on since the end of the last ice age. And also off and on since the end of the little ice age. And I don't think anybody disputes that sea levels have risen pretty well continuously as well.

The satellite imbalance is 0.7W/M^2 +/- 0.7.

Last time I looked, Hansen (?) had said that this figure came from models estimating the imbalance as the difference between measure incoming and outgoing radiation was too great to be believable. Has that situation changed recently? If not, then the figure is just somebody's hypothesis as to what the imbalance is.

Michael hart

Links, please.

Nov 10, 2015 at 9:28 PM | Unregistered CommenterEntropic man

I have discussed and given you links before on Hansen's last paper before he left office at NASA. Are you telling me you didn't read it? Why should I think you will this time?

EM - I said "that's incorrect".

But you are no doubt right. In my haste to post something before being 403'd, I forgot that SO2 in flue gas is not exactly solid matter.

Mike Jackson

"No. It didn't. It is washed out too rapidly. "

This is what I wanted confirmation for.

Why do you demand detailed information from me, but refuse to give links yourself?

Martin AA

"If not, then the figure is just somebody's hypothesis as to what the imbalance is."

Isn't this how science works? One puts forward a hypothesis and then confirms it by observation?

EM, we've been here before (and probably will do again, I suspect).

However much you dislike it, I have the null hypothesis on my side. You need to supply evidence supporting an assertion that the growth of a tree is substantially affected by a power station thousands of mile away.