why would you smooth the modern temperature data?

you will lose 15 years of warming.

so if you leave out tree rings, use a 30 years smooth to get rid of the last 15 years of warming, assume a rather large error, you come to the conclusion that the MWP was only slightly colder than today.

if you don t smooth, use GISS data and a small error bar, you will notice that it is WARMER today. fact.

1st) In climate history, it doesn’t make sense to document smaller resolution than 30 years. So if you smooth the medieval warm period, you also have to smooth the latest data. Otherwise it is cherry picking. The “peak cherries” of the MWP are eaten already.

no. i use an apple peeler on apples, not on oranges. why should i use the same tool on different objects?

2nd) Even if we “lose” 15 years of warming (in terms of annual mean temperature), we will also lose some of the warming that occured between 1917 and 1935, in the above graph

i don t think that you understand either the smooth or the splice.
you will NOT lose any warming around 1935, as the end point is irrelevant (or should be made so by the method used for the splice)

anyway, losing parts here and there would NOT compensate each other!

This statement is not correct. Today is 28 January 2008. With which date within the 700 years of MWP do you want to compare today?

that is silly.
feel free to compare to any 28 january, if you have the data to so.
if not, feel free to assume that i was talking of recently measured years.

Sod. You seem to have a Masters in Statistics. Can you explain to me what slicing means in the particular exemple I used? You certainly noticed very well that I compare a period with a period, not a date with a period. I am sure you read my text

i would say that my understanding of statistics is rather mediocre.

but i can of course tell you what “sPlicing” is. “to splice” (verbinden) one graph to another one, is what we are doing when we are combining the proxy data with measured temperature data.
one can either do it in a good, complicated, scientific way (Mann s hockeystick is a good example of this) or in an easy way, for example by just adding a certain number to the last proxy data to get up to today.

i haven t seen anyone who would compare a date with a period. did you?

For you I say it more precisely. 29-year peiord with end point 12.1935 and end point 12.2007.

why would you compare those periods?
that is completely useless!

I am sure you are also familiar with the idea that comparing “today” with “a period “in the past is “cherry picking”, especially if “today” is probably a peak of a spike.

i don t know a single real publication, that assumes that we have just experienced just a “spike” in temperature.
surely you can name a few, when making such claims?

Yeah, not “recently measured years” - because the warmers know that you would - again - lose some of the publicity effect.

it is warmer in summer. so surely if i had any interest in comparing “dates”, i would have chosen one in summer…
can we try to be serious now?

REPORT UPDATE:
Source: CO2 Science which incidentally is on the Exxpose Exxon black list just because they at least partly depend on private and corporate funding.

In reference to the new results, Loehle and McCulloch report that the peak value of the MWP (which represents a 29-year-mean) is 0.526°C above the mean of the entire period, which places it 0.412°C above the last reported 29-year-mean value of 0.114°C at 1935 (which includes data through 1949). They then state that “while instrumental data are not strictly comparable, the rise in 29-year-smoothed global data from NASA GISS from 1935-1992 (with data from 1978 to 2006) is 0.34°C,” and that “adding this rise to the 1935 reconstructed value, the MWP peak remains 0.07°C above the end of the 20th-century values, though the difference is not significant.”

Reviewed 30 January 2008

Take that!

So this is the way how to professionally splice the Loehle data with GISS tempereture records of recent years. What has escaped my attention is that 1935 represents the middle of the last 29-year period of proxy reconstructions, not the end point. The projected (?) end point is 1949 according to Loehle, which means that the starting point of the splice period is 1935 and its end point 1992 according to Loehle (2*29 years).

Knowing this methodology, it is now possible to use NCDC (or GISS) data after each month and update the relative temperature with regard to the peak of the early MWP. At the time, the Loehle 2008 update was published, the final temperature statements of 2007 were not yet available.

I will post an updated (an hopefully somewhat more professionally looking graph) some time after the January 2008 NCDC global temperature data being updated. As it looks now, January 2008 will be close to the 1979-2007 mean.

Unfortunately for those who want to state that “today” is definitely warmer than during the MWP, well, we are going to “lose” even more of the warming when using professional splicing and smoothing.

Sod. Who is most people please? I am just reading what is free on the net. (I am not going to pay 30 $ or so for each paper). Are you referring to the community of earth scientists, physicists, athmospheric scientists, climatologists, meteorogists, climate programmers? Or does it also include politicians, NGOs, earth singers, gaia worshippers, philosophers, esotherics?

Anyway, I can just read the abstract from your link and can’t judge the CO2-Science interpretation. But thank you. I’ll check things out well before I post. Anyway, according to the Metoffice, 2008 is likely to be a cool year. That would boost energy demand, I am afraid. It’s an energy and pollution problem, rather than a climate problem after all.

Yeah. There I agree with you. I don’t like it that CO2-science doesn’t give links. They just say they receive an e-mail from such and such. That’s why my favorite source is Roger Pielke Sr.

Most people will tell you, that the current warming period started in the 70s. Applying a 30year smooth to a 36year period is IDIOTIC.

Actually, there must be at least somebody in the universe who can professionally splice that. To splice a smoothed proxy with unsmoothed temperature data is at least as IDIOTIC. But I don’t see the smooth claimed to be exactly what you quote it for. And Mann et al. doesn’t seem to have published his methodology of splicing. You never see the proxy seperately in his graphs. It is always spliced already with the modern temperature records. There is interesting discussion going on at Climateaudit about that… Anyway and never mind all that discussion. Its about as warm now than during the early peak of the MWP.

Yes. The current warming started in the 70s. For that part I don’t have to ask people. The graphs indead tell me that alright. What I will try to find out in the future is
1) - how strong the human signal is in this 30 year period 1978-2007.
2) - Is it the reduction of anthropogenic aerosols that caused a reduction of low clouds and as a consequence more solar radiation that heated up the ocean, especially during the nineties?
3) - How much is the delay of the cooling after a solar maximum
4) - Where does the warming occur? If it is mainly during cold winter nights - as the ground radiation signal of CO2 in dry athmosphere tells us, then this is positive. But if it causes more heat waves that kill more people than the cold waves would, If it negatively affects the distribution of precipitable moisture in lower latitudes, then it is a matter of concern.

In fact there are so many questions that remain open, especially when it comes to mitigation. Does it require global governance? Should we put our trust into such global governace? Will it make things better? Will it make it rather worse? Questions upon questions. that I want to address in future posts if I have the time.

And no, I don’t have evidence of some real cooling but according to established science it actually should be cooling now according to what can be expected from solar output. I hope the cooling will not be to strong during the coming decades. Otherwise , we’ll have a real energy crisis. We should not artificially make energy more expensive. it is already going to be hard enough.

End off topic rambling from my side. Bottom line: There is no evidence that does convince me that the warming between 1978 and 2007 as seen in the above graph is more than 50% human induced. This remains my skeptical position.

@ thanks a lot for the Buentgen paper. I just printed it out since it is from the Swiss Federal Research Institute. I ll check. CO2-science is okay as long one has the original papers. This last sentence under ‘conclusions’ fits very well to the description of CO2-science:

Although, reconstructed temperature variations mimic natural forcing agents reasonably well, their quantification is still vague, and the twentieth-century contribution of anthorpogenic greenhouse gases and aerosol remains insecure.

And look at page 5617:
The offset in ~1970 likely refers to a cooling due to industrial sulfate aerosol emissions (Anderson et al. 2003), with the sun’s contribution to the recent warmth remaining an open question (Crowley 2000; Damon and Peristykh 2005; Foukal et al. 2004: Hansen 2000: Meehl et al. 2003: Solanki et al. 2004; Usoskin et al. 2003; Wild et al. 2005).

If you look at the graph on papge 5616, you’ll see that the sun TSO was never as high as in the 20th century.

Moreover, the paper reconfirms the MWP and the LIA which is - on a global scale - still being disputed by people like Mann et al.

My conclusion: It is still unclear if the 80s’ warmth was due to a record high TSO and the 90s’ continued warmth mainly the result of diminished anthropogenic aerosols. That explains the decreased lower clouds and the warming of the oceans.

Thank you, luminous beauty. I will center it. So it is in phase:-). I will probably take commenter Sod’s imput regarding the smooth of the splice (centering 1935) and then centering 1992 as you said. Meanwhile I checked the original dataset. The last proxy was indeed in 1935 and not 14-15 years later as apparently some people thought it to be. I am somehow temped to include the El-Nina outlier January 2008. No, that would be cherry picking:-). Yeah and then I can also replace the 1-year smooth line along the 10 year graph “global warming stopped or paused?”.