[Winstonm]

Daniel1960, on 2013-May-06, 19:39, said:

If you read the site to which I linked, you find Marcott's response to the following question: Is the rate of global temperature rise over the last 100 years faster than at any time during the past 11,300 years?

A: Our study did not directly address this question because the paleotemperature records used in our study have a temporal resolution of ~120 years on average, which precludes us from examining variations in rates of change occurring within a century. Other factors also contribute to smoothing the proxy temperature signals contained in many of the records we used, such as organisms burrowing through deep-sea mud, and chronological uncertainties in the proxy records that tend to smooth the signals when compositing them into a globally averaged reconstruction. We showed that no temperature variability is preserved in our reconstruction at cycles shorter than 300 years, 50% is preserved at 1000-year time scales, and nearly all is preserved at 2000-year periods and longer. Our Monte-Carlo analysis accounts for these sources of uncertainty to yield a robust (albeit smoothed) global record. Any small “upticks” or “downticks” in temperature that last less than several hundred years in our compilation of paleoclimate data are probably not robust, as stated in the paper.

What exactly is your point? The Marcott study looks at 11300 years of global temperatures by use of proxies. The methodology does not allow for measurements of small variables in small increments by geological timeframes. Fortunately, we have had thermometers for the past 100 years so there is no need to look at fossil proxies to know what has occurred recently.

By comparing the Marcott study showing cooling against the known temperatures of the past 100 years the result shows a temperature spike that is unprecedented and is paralleled by the advent of the industrial revolution and increased greenhouse gas emissions caused by man.

Marcott states his study cannot determine what has happened in the last 100 years. By pointing that out, you appear to be observing that a Chicago roller coaster won't take you to the New York Central train station. O.K. I buy that. And your point is?

[Al_U_Card]

Daniel1960, on 2013-May-06, 19:39, said:

Any small “upticks” or “downticks” in temperature that last less than several hundred years in our compilation of paleoclimate data are probably not robust, as stated in the paper.

Previously discussed up-thread but reading skills being what they are...

Just more hype and "climate"-science by press release. The alarmist crowd spend more time looking for hockey-sticks and "worse than we thought" stuff than they spend on analyzing and checking their data and conclusions. Lucky for them that the true believers never look too closely.

[Daniel1960]

Winstonm, on 2013-May-06, 21:47, said:

What exactly is your point? The Marcott study looks at 11300 years of global temperatures by use of proxies. The methodology does not allow for measurements of small variables in small increments by geological timeframes. Fortunately, we have had thermometers for the past 100 years so there is no need to look at fossil proxies to know what has occurred recently.

By comparing the Marcott study showing cooling against the known temperatures of the past 100 years the result shows a temperature spike that is unprecedented and is paralleled by the advent of the industrial revolution and increased greenhouse gas emissions caused by man.

Marcott states his study cannot determine what has happened in the last 100 years. By pointing that out, you appear to be observing that a Chicago roller coaster won't take you to the New York Central train station. O.K. I buy that. And your point is?

Incorrect. If we average the past 120 years, like in the Marcott study, we would not see the recent temperature spike either. We have no idea if a similar spike could have occurred in the study, because of the methodology. Hence, the recent temperature data cannot be compared directly to the proxy data. This is the same problem that Mann had when he tried to splice the thermometer data with his proxies. My point is that this study cannot be used to determine if the recent temperature rise is unprecedented - in either rate or absolute terms.

Other proxy data does show that sharp temperature spikes have occurred in the past - and larger than those of the past century:

http://www.nature.co...st-ice-24288097

My original point was that some people will choose that which best supports their own viewpoint. As an example, take the following article which emphasizes that the Marcott paper shows that recent temperatures are lower than 5000 years ago.

http://reason.com/bl...e-lower-than-it

Remember my original post on this? Depending on where one starts calculating the temperature trend, one could get a rise of 1.6C/century or a drop of -0.1C/century.

[Winstonm]

Daniel1960, on 2013-May-07, 05:23, said:

Incorrect. If we average the past 120 years, like in the Marcott study, we would not see the recent temperature spike either. We have no idea if a similar spike could have occurred in the study, because of the methodology. Hence, the recent temperature data cannot be compared directly to the proxy data. This is the same problem that Mann had when he tried to splice the thermometer data with his proxies. My point is that this study cannot be used to determine if the recent temperature rise is unprecedented - in either rate or absolute terms.

Other proxy data does show that sharp temperature spikes have occurred in the past - and larger than those of the past century:

http://www.nature.co...st-ice-24288097

My original point was that some people will choose that which best supports their own viewpoint. As an example, take the following article which emphasizes that the Marcott paper shows that recent temperatures are lower than 5000 years ago.

http://reason.com/bl...e-lower-than-it

Remember my original post on this? Depending on where one starts calculating the temperature trend, one could get a rise of 1.6C/century or a drop of -0.1C/century.

Moving averages smooth data. Of course a moving average would not show as great of temperature spike. The critical aspect of the Marcott study shows that the cooling trend lasted 5000 years. Our current data (non-Marcott) reflects that the entire 5000 years of cooling has been wiped out in just 100 years - and that is unprecedented.

The Marcott study confirms that the current heating cycle is unprecedented for the past 11300 years.

Good luck trying to spin it into a silk purse.

[Daniel1960]

Winstonm, on 2013-May-07, 14:29, said:

Moving averages smooth data. Of course a moving average would not show as great of temperature spike. The critical aspect of the Marcott study shows that the cooling trend lasted 5000 years. Our current data (non-Marcott) reflects that the entire 5000 years of cooling has been wiped out in just 100 years - and that is unprecedented.

The Marcott study confirms that the current heating cycle is unprecedented for the past 11300 years.

Good luck trying to spin it into a silk purse.

You can spin it however you like, but even Marcott says that the study does not confirm that the heating cycle is unprecendented. What more proof do you need?

[Winstonm]

I guess it depends on your source of information. I prefer the National Science Foundation. Speaking about the Marcott results:

Quote

The last century stands out as the anomaly in this record of global temperature since the end of the last ice age," says Candace Major, program director in the National Science Foundation's (NSF) Division of Ocean Sciences. The research was funded by the Paleoclimate Program in NSF’s Division of Atmospheric and Geospace Sciences.

"This research shows that we've experienced almost the same range of temperature change since the beginning of the industrial revolution," says Major, "as over the previous 11,000 years of Earth history--but this change happened a lot more quickly."

I am confident that Candace Major is not one of the thousands of worldwide scientific co-conspirators who would have had to band together to fake the global warming evidence.

[Winstonm]

Daniel1960, on 2013-May-07, 15:55, said:

You can spin it however you like, but even Marcott says that the study does not confirm that the heating cycle is unprecendented. What more proof do you need?

Speaking of what Marcott actually said:

Quote

"The Earth's climate is complex and responds to multiple forcings, including CO2 and solar insolation," Marcott said. "Both of those changed very slowly over the past 11,000 years. But in the last 100 years, the increase in CO2 through increased emissions from human activities has been significant. It is the only variable that can best explain the rapid increase in global temperatures."

Sorry that Marcott does not agree with your assessment of his data.

[Daniel1960]

Winstonm, on 2013-May-08, 06:56, said:

Speaking of what Marcott actually said:


Sorry that Marcott does not agree with your assessment of his data.

Funny that Marcott's quote does not agree with your assessment of his report:

"Thus, the 20th century portion of our paleotemperature stack is not statistically robust, cannot be considered representative of global temperature changes, and therefore is not the basis of any of our conclusions."

... and his answer to the following question:

Q: Is the rate of global temperature rise over the last 100 years faster than at any time during the past 11,300 years?

A: Our study did not directly address this question because the paleotemperature records used in our study have a temporal resolution of ~120 years on average, which precludes us from examining variations in rates of change occurring within a century.

Cannot get more direct than that. Feel free to average the last 120 years of thermometer data and compare that to the Marcott study. I did this with both the GISS data and CRU data, and got anomalies of +0.01 and -0.01C, which is nothing special. I also find it humorous that you stated that the study smoothed the data, which would remove the type of temperature spike witnessed recent, and then claim that no such spike has occurred over the past 11,000 years. Since the methodology would remove such a spike, how would you know if one occurred?

[Winstonm]

Daniel1960, on 2013-May-08, 08:33, said:

Funny that Marcott's quote does not agree with your assessment of his report:

"Thus, the 20th century portion of our paleotemperature stack is not statistically robust, cannot be considered representative of global temperature changes, and therefore is not the basis of any of our conclusions."

... and his answer to the following question:

Q: Is the rate of global temperature rise over the last 100 years faster than at any time during the past 11,300 years?

A: Our study did not directly address this question because the paleotemperature records used in our study have a temporal resolution of ~120 years on average, which precludes us from examining variations in rates of change occurring within a century.

Cannot get more direct than that. Feel free to average the last 120 years of thermometer data and compare that to the Marcott study. I did this with both the GISS data and CRU data, and got anomalies of +0.01 and -0.01C, which is nothing special. I also find it humorous that you stated that the study smoothed the data, which would remove the type of temperature spike witnessed recent, and then claim that no such spike has occurred over the past 11,000 years. Since the methodology would remove such a spike, how would you know if one occurred?

1) No, the methodology would not remove such spikes but it would smooth such spikes. Spikes of this magnitude would still be evident. 2) The question asked and answered is irrelevant. It is like asking a major league pitcher how he shoots his jump shot, him saying, sorry, I don't play basketball, then you claiming his denial of basketball proves that basketball rules have never changed. 3) I am sorry you do not want to accept data that conflicts with your beliefs, but surely you understand that what you want to be reality has no effect on actual reality.

John Maynard Keynes said it best: "When the facts change, I change my mind. What do you do, sir?"

[Daniel1960]

Winstonm, on 2013-May-08, 08:46, said:

1) No, the methodology would not remove such spikes but it would smooth such spikes. Spikes of this magnitude would still be evident. 2) The question asked and answered is irrelevant. It is like asking a major league pitcher how he shoots his jump shot, him saying, sorry, I don't play basketball, then you claiming his denial of basketball proves that basketball rules have never changed. 3) I am sorry you do not want to accept data that conflicts with your beliefs, but surely you understand that what you want to be reality has no effect on actual reality.

John Maynard Keynes said it best: "When the facts change, I change my mind. What do you do, sir?"

Whether the spikes are removed or smoothed is a matter of semantics, as the effect is the same. As I showed you earlier, smoothing the last 120 years of thermometer data effectively smoothes out the recent temperature spike. The temperature could oscillate at twice the rate experienced last century, but if it did so at intervals less than the smoothing interval, they would not be evident. The question is not irrelevant, but pertinent to this discussion. Your analogy is completely absurd, as is dismissing the question, because it does not correspond to your version of reality is rather foolish, don't you think?

I accept the data, as it does not conflict with my beliefs at all. I do not understand why you continue to make such claims, even after the authors have refuted them. This is simliar to those who claimed that the Himalayas would still melt in 2035, even after it was shown that there was no valid source for this statement.

I agree with Keynes. Marcott changed the facts (actually clarified them), and I changed my mind. Why haven't you?

[Winstonm]

Daniel1960, on 2013-May-08, 10:05, said:

Whether the spikes are removed or smoothed is a matter of semantics, as the effect is the same. As I showed you earlier, smoothing the last 120 years of thermometer data effectively smoothes out the recent temperature spike. The temperature could oscillate at twice the rate experienced last century, but if it did so at intervals less than the smoothing interval, they would not be evident. The question is not irrelevant, but pertinent to this discussion. Your analogy is completely absurd, as is dismissing the question, because it does not correspond to your version of reality is rather foolish, don't you think?

I accept the data, as it does not conflict with my beliefs at all. I do not understand why you continue to make such claims, even after the authors have refuted them. This is simliar to those who claimed that the Himalayas would still melt in 2035, even after it was shown that there was no valid source for this statement.

I agree with Keynes. Marcott changed the facts (actually clarified them), and I changed my mind. Why haven't you?

Perhaps you have not seen this:

Quote

The belief of many is that this process of “smearing” ages would so smooth out any spike which may have occurred in the past, that it wouldn’t show in the Marcott reconstruction. This means, so they say, that warmings like we saw in the 20th century could have happened multiple times in the past, and the Marcott work doesn’t provide any evidence against that.

Let’s find out, shall we?

From the same:

Quote

The spikes are a lot smaller than with no age perturbations, which themselves are smaller than the physical signal. But they’re still there. Plain as day. All three of ‘em.

My opinion: the Marcott et al. reconstruction is powerful evidence that the warming we’ve witnessed in the last 100 years is unlike anything that happened in the previous 11,300 years.

Opinion? Yes. But opinion backed by data, not data ignored because it does not fit opinion.

[Al_U_Card]

Using "Tamino" as a reference is equivalent to considering the SkepticalScience blog as factual.

The upshot is that hyperbole and prevarication are the stock and trade of alarmists. Cold (couldn't resist... ) hard facts refute the CAGW meme every time it appears. From every weather event under the sun to warmcold and wetdry, the eventual, scientific analysis has, thusfar, ALWAYS shown that doomsday will have to wait for an asteroid strike or some other disaster. CO2 is just not doing it for now...

[Daniel1960]

Winstonm, on 2013-May-08, 12:27, said:

Perhaps you have not seen this:



From the same:

Opinion? Yes. But opinion backed by data, not data ignored because it does not fit opinion.

Please do not haul into an argument with Grant. We do not see eye to eye. Never have. His opinion means very little to me.

[Winstonm]

Daniel1960, on 2013-May-07, 05:23, said:

Incorrect. If we average the past 120 years, like in the Marcott study, we would not see the recent temperature spike either. We have no idea if a similar spike could have occurred in the study, because of the methodology. Hence, the recent temperature data cannot be compared directly to the proxy data. This is the same problem that Mann had when he tried to splice the thermometer data with his proxies. My point is that this study cannot be used to determine if the recent temperature rise is unprecedented - in either rate or absolute terms.

O.K., given that Marcott does not determine if the recent rise is unprecedented, that in no way refutes the recent rise. We can see by Marcott that global temperatures fell by 0.9 degrees over the past 5000 years. From other temperature data we can see that the entire 5000 year cooling has been wiped out in the past 100.

From those two observations, we can draw our own conclusion about the cause. The only variable that has changed is manmade CO2.

[Al_U_Card]

If the recent rise is similar to those that occurred before [CO2] had changed then they were the result of something else. (Natural variation, perhaps?)

Argument from ignorance ("I don't know what else it might be so it must be that!") never leads to quality conclusions.

The fact that the Marcott study, like so many other highly-hyped climate-science projects, has major flaws in its data collation and analysis is another issue.

[Daniel1960]

Winstonm, on 2013-May-09, 07:11, said:

O.K., given that Marcott does not determine if the recent rise is unprecedented, that in no way refutes the recent rise. We can see by Marcott that global temperatures fell by 0.9 degrees over the past 5000 years. From other temperature data we can see that the entire 5000 year cooling has been wiped out in the past 100.

From those two observations, we can draw our own conclusion about the cause. The only variable that has changed is manmade CO2.

I think we can finally find some common ground. I agree that the Marcott paper does not refute the recent rise - very few people actually do. Also, the recent thermometer temperature data is approximately equal to the smoothed proxy data of 5000 years ago. Jos Haelaars shows a comparison of the Marcott study with other proxies. Other proxies show a similar temperature decline as the Marcott study, but with much wider swings. Remember, the sharp 20th c uptick is thermometer data, not proxy (which ended around 1950). The Marcott study shows a much smoother transition than an average of the other proxies, all of which show an absolute maximum prior to 4000 years B.P., and a local maximum around 1000 years ago.

http://ourchangingcl...ons_marcott.png

The only other data matching the same timescale comes from Richard Alley's paper which analyzes the Greenland ice core data. The graph has much wider swings due to a single proxy and the expected greater response in Greenland to climatic changes.

http://www.sott.net/...P-ice-core-data

While CO2 has certainty changed, we cannot conclude that it is the only variable that has changed. The Marcott study, while informative, neither proves nor disproves that the recent warming is unprecended or that it has been cause by an increase in atmospheric CO2. The largest criticism should not be of the study itself, but those media outlets that proclaim that recent temperatures are "close to 11,000 year peak" (Nature) or "significantly cooler than the 4000-yr average" (Forbes). Neither of these statements are supported by the Marcott data. This goes back to my original post about selectively choosing the data to support ones own views.

[Winstonm]

Daniel1960, on 2013-May-09, 08:27, said:

I think we can finally find some common ground. I agree that the Marcott paper does not refute the recent rise - very few people actually do. Also, the recent thermometer temperature data is approximately equal to the smoothed proxy data of 5000 years ago. Jos Haelaars shows a comparison of the Marcott study with other proxies. Other proxies show a similar temperature decline as the Marcott study, but with much wider swings. Remember, the sharp 20th c uptick is thermometer data, not proxy (which ended around 1950). The Marcott study shows a much smoother transition than an average of the other proxies, all of which show an absolute maximum prior to 4000 years B.P., and a local maximum around 1000 years ago.

http://ourchangingcl...ons_marcott.png

The only other data matching the same timescale comes from Richard Alley's paper which analyzes the Greenland ice core data. The graph has much wider swings due to a single proxy and the expected greater response in Greenland to climatic changes.

http://www.sott.net/...P-ice-core-data

While CO2 has certainty changed, we cannot conclude that it is the only variable that has changed. The Marcott study, while informative, neither proves nor disproves that the recent warming is unprecended or that it has been cause by an increase in atmospheric CO2. The largest criticism should not be of the study itself, but those media outlets that proclaim that recent temperatures are "close to 11,000 year peak" (Nature) or "significantly cooler than the 4000-yr average" (Forbes). Neither of these statements are supported by the Marcott data. This goes back to my original post about selectively choosing the data to support ones own views.

You sound like most of the religious right I have sparred with whose basic defense is: if you cannot prove to my satisfaction your position, then I will continue to believe what I want, irrespective of how irrational that position may be.

There will never be a 100% causal connection proven between CO2 increases and climate change. It is like being one of those who wish to believe that the entire LA police department engaged in a gigantic criminal conspiracy to frame OJ for murder and because of that belief set him free, regardless of the evidence. Evidence and proofs are part of law and subjectivity. There can never be a 100% proof because proof must be accepted.

The Marcott study adds to our knowledge. The most reasonable answer as to what is causing the warming is human CO2 production. There is some kind of chance that it may not be the cause - just as there is some kind of chance that the LA police department conspired to frame OJ.

But I happen to think the jury got it wrong.

[Daniel1960]

Winstonm, on 2013-May-09, 11:24, said:

You sound like most of the religious right I have sparred with whose basic defense is: if you cannot prove to my satisfaction your position, then I will continue to believe what I want, irrespective of how irrational that position may be.

There will never be a 100% causal connection proven between CO2 increases and climate change. It is like being one of those who wish to believe that the entire LA police department engaged in a gigantic criminal conspiracy to frame OJ for murder and because of that belief set him free, regardless of the evidence. Evidence and proofs are part of law and subjectivity. There can never be a 100% proof because proof must be accepted.

The Marcott study adds to our knowledge. The most reasonable answer as to what is causing the warming is human CO2 production. There is some kind of chance that it may not be the cause - just as there is some kind of chance that the LA police department conspired to frame OJ.

But I happen to think the jury got it wrong.

No, I am not part of the religious right, and no, I am believing what I want based on irrationality.

As a scientist, I do not require 100% in anything, it simply not possible. While CO2 increases are certainly a plausible explanation, is it the most reasonable? The vast majority of scientists accept the results that a doubling of CO2 in a closed system leads to ~1C temperature increase. However, how that transcends to an open and chaotic climate system is not generally accepted. Most acknowledge that there are atmospheric feedbacks that affect the overall response, but differ as to the direction and magnitude. Hence, a wide range of values have been calculated (generally from 0.5 to 5), based on certain measured criteria. Much of the difficulty arises in separately the natural component from the manmade. This is where the proxy data are important. Namely, how can we determine the natural effects. To say the most reasonable answer to the warming lies in human CO2 production shows bias, based on Western perception. Why is it more reasonable than solar or oceanic circulation? Most Russian scientists have come to the conclusion that the sun has played the largest role, and some are maintaining that we are above to enter a new Little Ice Age:

http://principia-sci...tov-Feb2012.JPG

It is certainly plausible, but is it reasonable?

I also agree that the jury got it wrong.

[PassedOut]

Daniel1960, on 2013-May-09, 12:22, said:

No, I am not part of the religious right, and no, I am believing what I want based on irrationality.

But of course Winston did not suggest that you are part of the religious right.

[Winstonm]

PassedOut, on 2013-May-09, 13:18, said:

But of course Winston did not suggest that you are part of the religious right.

Exactly, and if this was not clear I apologize. The religious right does not hold a monopoly on cognitive bias - we all share that attribute. And there are many groups - many non-religious - whose belief systems are not supported by objective data.