Global Temperature Change, baseline in History

[Dancing David]

Sidestepping the issue of MWP and LIA (integral to hockey stick) noted.

? (+MWP+LIA+HS) or (-MWP-LIA-HS), take your pick.

Since I am new to the fray, perhaps a brief explanation would be in order. At least of the acronyms.

 

[Dancing David]

There here is the summary version.

At the earths distance from the Sun it receives ~1365 W/m^2 and this does vary with the number of sunspots but only by 0.5W/m^2. (1 W/m^ peek to peek)

This means an extra 9 X10^15 J of energy in the high half of the cycle and a loss of 9 X 10^15 J in the low half of the cycle. Peak to peak, that’s a swing of ~2X10^16 J.

However, the top 100m of the ocean (all that can really warm/cool in a given year) takes 2X10^18 J of energy to raise/cool by 1 deg C so you can’t get more then 0.01 deg cooling from the change in solar energy alone. Even with a 3X amplification due to water vapor feedback this is a really small value.

If you get a change that is sustained over the course of several decades it can become measurable, and this is precisely what happened in the early 1900’s. Even then, however, much lower greenhouse gas levels of that period are required to fully explain all the warming that occurred.

Thanks for the answer i am sure i will have questions like:

What about just the top 5 cm. or top 100 cm.?
What if it is just part of a tipping point?
We only really know about the soalr radiance for about 30 years right?

I tend to think something (very naive I am sure) that:
increased CO₂
lower albedo
increased solar radiance
low levels of volcanic reflection particles
high levels of 'greenhouse' emissions from volcanos
abosorbtion of CO₂ and lack thereof by the oceans
cloud cover
and lots and lots of other things will all play their part but then you reach a tipping point, the chaotic system bifurcates and hits a new stable configuration or starts flipping.

 

[Dancing David]

So here is the issue with scaling:
http://www.scotese.com/climate.htm

Which Travis linked to, at the bottom shows the temperature for 2 billion years, it looks bifucates with extremes where the 'global temperature' likes to hang out out with a couple of other places where it stabalizes.

The hotter of the two extremes would be difficult for me. A ten degree C higher temperature would make me miserable, unless I moved way north.

 

[CapelDodger]

So then it comes down to;
What is the baseline to decide what is a 'normal' cycle of climate change without human intevention?

It's a pretty blunt instrument, but the recent loss of permafrost demonstrates that what's going on now hasn't happened in the last eleven thousand years. Long before agriculture, and just after the ice-sheet exited. The chance of that coinciding with erroneous predictions based on established physics and with a normal, unexplained, and until recently unrecognised natural cycle vanished a while back.

 

[mhaze]

Since I am new to the fray, perhaps a brief explanation would be in order. At least of the acronyms.

Sure.

MWP Medieval Warm Period
LIA Little Ice Age
HS Hockey stick.

The general idea was that to get a pronounced hockey stick pattern, they had to "make the MWP and LIA go away". Which is really rather funny if you think about it, outside of "Climate Science"...





Why is it funny? The Mann 1998 papers (which build on the Hansen 1988 papers), plus some few straggle-on papers, together define and focus on "current historically unprecedented warming". Big problem with that thesis if you happen to have had simple natural periods of warming which exceeded the current period or equaled it. Similarly, if the planet recently emerged from a LIA, then it could be argued that current warming was the emergence out of the LIA back to a more temperate climate. In either case there is no "currently historically unprecedented warming".

By generating a statistical fiction that essentially lays all natural climatic variation into the level of statistical noise, the HS AlGorithm (yes, it is a pun snicker snicker) asserts that rise in temperatures past 1900 is due to man's dastardly infernal industrial operations and his greedy consumers generating trace atmospheric gases.

In so doing, Mann seemed to have generated a belief set that all natural cyclic variation could be disregarded - this included the 60-80 year climate cycles, the approximate 1500 year pattern, and the various sunspot and solar patterns which track the major planets' positions. As the chart shows, Mann and the others don't even calculate the rates of change correctly. After denouncing the very presence of repetitive patterns in climate, they see fit to start calculations at a trough and end at a peak (orange line). Hansen, also, picked the running start of a nice trough in 1988 (purple "Alarmist line" to start his campaign against CO2 emissions.



Short story, HS is the finest of junk science, good for a laugh or two. It's been abandoned by the mainstream, but there are stragglers that still believe in it. It's out of the IPCC 2007.

Underlying these issues, which I agree with you are not worth debating, as they are firmly settled, is the question of how do you define a statistical aberration from the "norm" of climate. Or is that at all possible. Many who would debate these subjects quite intensely have not actually even read the published papers on the subject, which shows how weak the belief structures are.

Today, 2008, it certainly is possible to take either Mann's 1998 algorithm, and critically review it as garbage. Trees in one small part of the USA supposedly tell us "global temperature" for a broad section of the global historical base - with those "teleconnection" signals. Uh....huh...



Similarly, we can take Hansen's 1988 algorithm, and do the same. But that only answers what isn't an adequate way of establishing a norm of climatic range - it does not answer the question of what that norm is, or how it could, would, or should be defined.

These may be very difficult questions, due to imprecise or incorrect wording, and thus may be not answerable. What is happening right now in the cooling of climate is related to the 60-80 year cycle with it's large PDO component, but also the quiet sun -



Which does not exactly look the same as....hmmm...



Soapbox now closed.

 

[a_unique_person]

So here is the issue with scaling:
http://www.scotese.com/climate.htm

Which Travis linked to, at the bottom shows the temperature for 2 billion years, it looks bifucates with extremes where the 'global temperature' likes to hang out out with a couple of other places where it stabalizes.

The hotter of the two extremes would be difficult for me. A ten degree C higher temperature would make me miserable, unless I moved way north.

Which is one of the concerns. If we kick off a large change, is that going to start another swing.

 

[lomiller]

Sure.

MWP Medieval Warm Period
LIA Little Ice Age
HS Hockey stick.

The general idea was that to get a pronounced hockey stick pattern, they had to "make the MWP and LIA go away". Which is really rather funny if you think about it, outside of "Climate Science"...

Actually the funny part is that there are people out using the little ice age as “proof” all the climate reconstructions are wrong because it only shows up strongly in Europe. Now think about that for a second, they are write off all, yes all, of the actual data and then talk with certainty about the LIA even though there is no data left to base that that opinion on.

 

[lomiller]

Short story, HS is the finest of junk science, good for a laugh or two. It's been abandoned by the mainstream, but there are stragglers that still believe in it. It's out of the IPCC 2007.

Underlying these issues, which I agree with you are not worth debating, as they are firmly settled, is the question of how do you define a statistical aberration from the "norm" of climate. Or is that at all possible. Many who would debate these subjects quite intensely have not actually even read the published papers on the subject, which shows how weak the belief structures are.

Today, 2008, it certainly is possible to take either Mann's 1998 algorithm, and critically review it as garbage. Trees in one small part of the USA supposedly tell us "global temperature" for a broad section of the global historical base - with those "teleconnection" signals. Uh....huh...

Wahl and Ammann managed to reproduce Mann’s results even when the data and methods in question were omitted.

http://www.cgd.ucar.edu/ccr/ammann/millennium/refs/WahlAmmann_ClimaticChange_inPress.pdf

Wegman himself is backtracking, basically making excuses for his failure to investigate whether the criticisms in his politically backed report had any impact on the papers results. He is now essentially saying “Even though Mann’s results turned out to be accurate my criticisms were valid.”

We have the dozen or so similar results published since 1998 all saying essentially the same thing as Mann’s 1998 paper. There is no published work on the other side of the argument published in any reputable journal.

Oh, and one more thing. All the “analysis” has been referencing Mann et all 98 which only went back to 1400, at which point the MWP was already over and should not be expected to show up in the data.

 

[Dancing David]

Thanks Mhaze ( you could tone down the rhetoric a little still but you are doing great) and Lomiller.

I have a lot to try to understand.

I think the other stuff is worth debating, I am asking people to discuss something else. The data we have to understand the period we are in right now.

 

[Dancing David]

I find this graph really interesting as a place to start:
http://www.ncdc.noaa.gov/paleo/globalwarming/medieval.html

but it will take me a while to tease that apart,

this one is cool as well:
http://www.ncdc.noaa.gov/paleo/globalwarming/paleobefore.html

 

[drkitten]

I just feel that before I can understand the current trends in the multivariate fashion, it would help to know what has happened in the apst. I think that 65 million years is a little long for an accurate baseline, so i would settle for about 5 million. But the accuracy at those scales is going to be lacking, so the last four glacial cycles is what i will probably settle for.

I'm still not sure why you want information that far back.

There's still the problem that modern agriculture (and by extension modern civilization) depends on temperatures of the sort that have persisted over the past three hundred years, not over "the last four glacial cycles."

I mean -- despite my fundamental disagreement with mhaze, let's pretend that he's right and the currently observed warming trend is the result of natural processes (we're moving out of a warm interglacial period into a really hot interglacial period because, I dunno, God decided he wanted a sauna).

Even if this were the result of a natural process, it is STILL a practical necessity to preserve the agricultural capacity of the world to avoid mass starvation. Whether natural or anthropogenetic, large-scale climate change would be a disaster of the highest order.

So what are the actions we could take to mitigate large-scale global warming? How is our best course of action different if it's a natural cycle? Our best bet is STILL to reduce carbon emissions and such in order to reduce the Earth's heat-retention capacity.

 

[mhaze]

...despite my fundamental disagreement with mhaze, let's pretend that he's right and the currently observed warming trend is the result of natural processes .. .what are the actions we could take to mitigate large-scale global warming? How is our best course of action different if it's a natural cycle? Our best bet is STILL to reduce carbon emissions and such in order to reduce the Earth's heat-retention capacity.

Interesting perspective, essentially active planetary climate engineering.

We don't know 10% of what it would take to do that reliably over the long term, but it is certainly something that should be active research.

That would require fairly precise knowledge of coupled feedbacks and a complete understanding of the water cycle, factors currently of "Low Understanding."

Our best bet is STILL to reduce carbon emissions and such in order to reduce the Earth's heat-retention capacity

Well, that would be like taking 19th century technology and trying to land on the Moon.

 

[Dancing David]

I'm still not sure why you want information that far back.

I am the child of two geeks from a family of manygeeks and I find the subject interesting?

Part of it really is just an intrest in paleoclimate and paleobotany.

There's still the problem that modern agriculture (and by extension modern civilization) depends on temperatures of the sort that have persisted over the past three hundred years, not over "the last four glacial cycles."

Wow where did that come from, I may undersatnd more about the knife edge of agriculture, our modern technology and economy of scale than you think.

So what has got you all bent out of shape, do not judge me on questions you haven't asked please.

I did not know you were going to judge me on my own preferences, should I extend the same prejudice to you? Pardon me for having an interest in somethings just because they interest me.

I mean -- despite my fundamental disagreement with mhaze, let's pretend that he's right and the currently observed warming trend is the result of natural processes (we're moving out of a warm interglacial period into a really hot interglacial period because, I dunno, God decided he wanted a sauna).

That would suck (as in the venturi effect in a broken airplane window), but thanks for trying to derail the thread into something else. Would you please not do that? You can start your own thread if you wish.

Even if this were the result of a natural process, it is STILL a practical necessity to preserve the agricultural capacity of the world to avoid mass starvation. Whether natural or anthropogenetic, large-scale climate change would be a disaster of the highest order.

Duh, again don't judge me on questions you haven't asked.
Double and triple duh.

I remember 1988 and the corn curling and the beans dying, thank you very much.

So what are the actions we could take to mitigate large-scale global warming? How is our best course of action different if it's a natural cycle? Our best bet is STILL to reduce carbon emissions and such in order to reduce the Earth's heat-retention capacity.

Thanks for starting your own thread on this topic.

 

[Dancing David]

Interesting perspective, essentially active planetary climate engineering.

We don't know 10% of what it would take to do that reliably over the long term, but it is certainly something that should be active research.

That would require fairly precise knowledge of coupled feedbacks and a complete understanding of the water cycle, factors currently of "Low Understanding."

Our best bet is STILL to reduce carbon emissions and such in order to reduce the Earth's heat-retention capacity

Well, that would be like taking 19th century technology and trying to land on the Moon.

Please to not respond to Dr. Kitten's derail of the thread.

So what specificaly do you have against the NOAA studies, i am asking from the data stand point;
Is it the metanalysis?
Is it the configuration of the models?
is it the lack of integration of new data?


Such as this representation here, I would say it is about as useful as such things usually are:
http://www.ncdc.noaa.gov/paleo/globalwarming/medieval.html

 

[mhaze]

Please to not respond to Dr. Kitten's derail of the thread.

So what specificaly do you have against the NOAA studies, i am asking from the data stand point;
Is it the metanalysis?
Is it the configuration of the models?
is it the lack of integration of new data?


Such as this representation here, I would say it is about as useful as such things usually are:
http://www.ncdc.noaa.gov/paleo/globalwarming/medieval.html

Where are the error bounds and confidence levels?

Is it a "statistical pool" from which, say, you can average?

Are any of the studies reasonably disqualified?

Do you have the source studies or are you just looking at the pretty chart?

 

[Dancing David]

Where are the error bounds and confidence levels?

Is it a "statistical pool" from which, say, you can average?

Are any of the studies reasonably disqualified?

Do you have the source studies or are you just looking at the pretty chart?

Thanks for the response.

I was just asking.
They say it is from Capter 6 of the IPCC Working Group I Fourth Assessment Report 2007

Cites here:http://www.ncdc.noaa.gov/paleo/pubs/ipcc2007/ipcc2007.html

I wouldn't call it a pretty chart, it hasn't been made into a sculpture yet.

 

[mhaze]

Thanks for the response.

I was just asking.
They say it is from Capter 6 of the IPCC Working Group I Fourth Assessment Report 2007

Cites here:http://www.ncdc.noaa.gov/paleo/pubs/ipcc2007/ipcc2007.html

I wouldn't call it a pretty chart, it hasn't been made into a sculpture yet.

The thermometer record overlay is skewed as is freely admitted:

http://www.ncdc.noaa.gov/paleo/pubs/ipcc2007/ipcc2007.html

The HadCRUT2v instrumental temperature record is shown in black. All series have been smoothed with a Gaussian-weighted filter to remove fluctuations on time scales less than 30 years; smoothed values are obtained up to both ends of each record by extending the records with the mean of the adjacent existing values.
​

A stated conclusion in the text (Not even qualified to "NH only"):

it appears that the late 20th and early 21st centuries are likely the warmest period the Earth has seen in at least 1200 years
​

Drawn from a comparison of different meth0ds:

• Modern period - thermometers
• Past era - proxies

But are the proxies calibrated to thermometers? No. The so called "divergence problem". Where is the proxy data for the last half of the 20th century? The Briffa series continued to 2000, but the section past 1960 was truncated.

http://www.climateaudit.org/?p=1792
​

Cooling was inconvenient to the predetermined conclusion.

Here is one of many general discussions on these multiproxy studies in IPCC chapter 6.

http://www.climateaudit.org/?p=2245
​

If this aggradation of multiproxy studies and thermometer readings (and the resulting chart) was the work of students, what grade would they get?

 

[BobK]

I saw a link to a cogently written hypothesis at ICECAP today explaining why human contributions to warming are insignificant.

Here is a direct link to the hypothesis.

I found it to be plain language and easy reading.

Links to the first three parts are embedded in the article. Might want to read those first.

 

[TrueSceptic]

I saw a link to a cogently written hypothesis at ICECAP today explaining why human contributions to warming are insignificant.

Here is a direct link to the hypothesis.

I found it to be plain language and easy reading.

Links to the first three parts are embedded in the article. Might want to read those first.

Why did you post that here? This thread is about establishing a temperature baseline with which recent temperature increases can be compared and put in context.

 

[mhaze]

You've answered your own question?