Validity of Marcott et al. contention that “Global temperatures are warmer than at any time in at least 4,000 years” and “Global temperature….. has risen from near the coldest to the warmest levels of the Holocene within the past century.” A heat spike like this has never happened before, at least not in the last 11,300 years” ”
Guest post by Dr. Don J. Easterbrook
Part I of this series looked at the validity of conclusions for the 11,300 time span covered in Marcott et al. “A Reconstruction of Regional and Global Temperature for the Past 11,300 Years.” This segment (Part II) analyzes conclusions in the Marcott et al. paper in which they contend that “Global temperatures are warmer than at any time in at least 4,000 years” and “Global temperature….. has risen from near the coldest to the warmest levels of the Holocene within the past century.” A heat spike like this has never happened before, at least not in the last 11,300 years”
As in Part I, this segment analyzes the Marcott et al. conclusions using the scientific method of Feynman in which conclusions are checked against well-established data from other sources,. As Feynman points out, if a hypothesis (conclusion) disagrees with observations and data, it is wrong. It doesn’t make any difference how beautiful the hypothesis (conclusion) is, how smart the author is, or what the author’s name is, if it disagrees with data or observations, it is wrong.
So let’s check the Marcott et al. conclusions against several of the best data sets available.
For this exercise, we’ll use (1) the GISP2 oxygen isotope data of Stuiver and Grottes (1997), (2) the GISP2 paleotemperature data of Cuffy and Clow (1997) and Alley (2000), and (3) temperature reconstructions from Chinese tree rings. Among the many data sets that could be used, the GISP2 ice core data have been selected because (1) the ice core data is based on thousands of isotope measurements that quantitatively reflect paleo-temperatures, (2) the chronology is accurate to within about 1-3 years, (3) even small fluctuations of ice core paleo-temperatues can be clearly and unequivocally correlated with advance and retreat of glaciers globally, confirming that the ice core data mimic global temperatures, and (4) Greenland temperatures measured over the past century match global temperature trends almost exactly, confirming that Greenland temperatures march in lock step with global temperatures. Thus, the GISP2 ice core data provides an excellent check against conclusions about global climate—it is quantitative, chronologically accurate, and representative of global climate. Keep in mind, however, that the magnitude of temperature fluctuations generally increases with latitude, i.e., the higher the latitude the greater the temperature fluctuations are likely to be, so Greenland temperature variations are likely to be greater than global averages. It also means that we are more likely to see details of temperature changes in the Greenland data than in global averages.
Figure 1 shows a comparison of the Marcott et al. temperature curve for the past 4,000 years (1A), the Greenland GISP2 temperature curve of Alley (2000), based on the data from Cuffy and Clow (1997) (1B), the Greenland GISP2 and Δ18O (the ratio of oxygen 18 to oxygen 16 relative to a standard) from isotope data measured by Stuiver and Grootes (1997)(1C), and a temperature reconstruction based on Chinese tree rings (1D) (included as an example of the good correlation of the GISP2 data to places far away from Greenland).
Several things are worth noting about the Greenland data. There are two kinds of temperature data: (1) figure 1B, which shows temperatures from borehole measurements, and (2) figure 1C, which shows variation in oxygen isotope ratios. The significance of this is that temperature variations in both curves are essentially the same, confirming one another. The Little Ice, Medieval Warm Period, Dark Ages Cool Period, Roman Warm Period, and other temperature peaks show up equally well in both types of curve.
Figure 1. Comparison of the Marcott et al. temperature curve (A); the Greenland GISP2 temperature curve of Alley (2000) based on data from Cuffy and Clow (1997) (B); Greenland GISP2 oxygen isotope ratios (delta 18O) from ice core data measured by Stuiver and Grootes (1997)(C); and temperature reconstruction from Chinese tree rings (D) (Liu et al., 2011).
The Marcott et al. curve shows a nearly vertical line for recent warming, which they claim puts present temperatures above any in the past 4,000years. This nearly vertical part of their curve apparently comes not from their proxy data, but is pasted on from elsewhere and plays a central role in their contention that present temperatures and the rate of warming are ‘unprecedented in the past 4,000 years.’ Let’s test both of these assertions against ice-core and global glacial data.
Both the Greenland GISP2 temperature curve (Figure 1B) and the oxygen isotope curve (Figure 1C) clearly show that except for the Little Ice Age and Dark Ages Cool Period, temperatures for all of the past 4,000 years have been warmer than the end of the ice core (1950 AD). The Medieval Warm Period was 1.1° C warmer than the top of the core (1950) and at least four other warm periods of equal magnitude occurred in the past 4,000 years; four other warm periods were ~1.3°C warmer; two other warm period were 1.8-2.0°C warmer; and one warm period was 2.8°C warmer. At least a dozen periods more than 1°C warmer than 1950 occurred, clearly contradicting the Marcott et al. conclusions.
Figure 2. Peak temperatures warmer than 1950 in the past 4,000 years.
The top of the GISP2 ice core is 1950 AD, so we need to look at more recent temperatures in Greenland in order to get to the ‘present temperature’, i.e., has the temperature in Greenland risen since 1950? Figure 2 shows 1880 to 2004 temperatures in Greenland (Chylek et al., 2004, 2006). Temperatures in 2004 were slightly lower than in 1950, so temperatures at the top of the Greenland ice core are not significantly different than those ‘at present.’
Figure 3. 1880 to 2004 temperatures in Greenland (Chylek et al., 2004, 2006).
The Marcott et al. conclusion that “Global temperatures are warmer than at any time in at least 4,000 years” is clearly contrary to measured real-time data and thus fails the Feynman test, i.e., it is are wrong.
Marcott et al. contend that “Global temperature….. has risen from near the coldest to the warmest levels of the Holocene within the past century.” A heat spike like this has never happened before, at least not in the last 11,300 years. “If any period in time had a sustained temperature change similar to what we have today we would have certainly seen that in our record.” Let us test this conclusion against real-time data. First, their statement that “Global temperature….. has risen from near the coldest to the warmest levels of the Holocene within the past century” is not true. The coldest part of the Little Ice Age occurred about 400 years ago, during the Maunder Minimum, so right off the bat, their conclusion is flawed. They appear to be unaware of the cyclic nature of temperature change and use the low point of the 1880-1915 cool period as their starting point for assessing the rate of warming over the ‘past century,’ rather than 1913-2013. Comparing the depth of cooling in a cool period with a warm period peak is comparing apples and oranges. It distorts the real rate, which should be measured from cool peak to cool peak or warm peak to warm peak. The 1880-1915 cool period was followed by the 1915-1945 warm period, the 1945-1977 cool period, and the 1978-1998 warm period (Figure 4). The rate of warming from 1913 to 2013 is about 0.7°C per century (which is about the same as the warming rate over the past 400 years as we have been thawing out of the Little Ice, long before atmospheric CO2 began to rise significantly).
Figure 4. Global temperature during the past century.
So let’s compare this rate (0.7°C per century) to rates of temperature increase in the past 11,300 years. Figure 5 shows rates of temperature change in the Greenland GSP2 ice core from the end of the last Ice Age through the Holocene (Figure 4A). Figure 4B shows some of the higher rates of temperature change in Figure 4A. The highest rates occurred at the transition from the Ice Age to Holocene when warming rates in Greenland were 20 to 24°F per century and the huge continental ice sheets that covered large areas of North America and Eur-Asia melted dramatically. As shown in Figure 4B, the rate for the past century (0.7°C) is puny indeed compared to late Ice Age/early Holocene rates.
Figure 4. A. Temperature changes in the Greenland GISP2 ice core from the end of the last Ice Age through the Holocene. (Easterbrook, 2011 modified from Cuffy and Clow, 1997). B. Rates of temperature change. (Easterbrook, 2011)
Holocene rates of warming and cooling were not as profound as those at the end of the last Ice Age, but were nonetheless greater than or equal to recent warming rates. Marcott et al. contend that “If any period in time had a sustained temperature change similar to what we have today we would have certainly seen that in our record” As shown in Figure 4A, we do indeed have a record of warming rates far in excess of those in the past century.
The Marcott et al. conclusion that “Global temperature….. has risen from near the coldest to the warmest levels of the Holocene within the past century.” A heat spike like this has never happened before, at least not in the last 11,300 years” is clearly contrary to measured real-time data and thus fails the Feynman test, i.e., their conclusion is wrong.
Next, in Part III, we’ll analyze the Marcott et al. conclusions that “Over the coming decades we are likely to surpass levels not seen on the planet since before the last ice age.” “Surface temperature reconstructions of the past 1500 years suggest that recent warming is unprecedented in that time.” Our global temperature reconstruction for the past 1500 years is indistinguishable within uncertainty from the Mann et al. reconstruction”
I was pretty astonished by Mosher’s suggestion:
“And it’s rarely done unless one has a replacement theory that is as good as the theory it replaces.”
Really? We should embrace hypotheses which are not in concert with observations until some
theorist devises a new theory which is better? Just because we do not know a theory which is right, we should endorse one we know to be wrong? That may be the craziest thing I have ever heard.
Can someone explain for a n00b like me why we’re comparing greenland to global. Shortterm anomalies to longterm anomalies?
Steven Mosher says: March 13, 2013 at 1:58 pm
. . . For instance, in the time of Galileo, optical theory could not account for phenomena that were observed by means of telescopes. So, astronomers who used telescopic observation had to use ad hoc rules until they could justify their assumptions by means of optical theory.
What telescopic phenomena are we talking about here?
In Galileo’s time they didn’t have the accuracy needed to detect stellar aberration, and though they were looking for parallax, its absence only proved Galileo was wrong about the earth moving. Brahe showed that claims of spotting stellar parallax were due to poor accuracy. It wasn’t until the next century that Bradley detected aberration, and he, too, was looking for parallax.
I can’t think of any optical phenomena they could see back then that contradicted their current optical theories. Heck, Newton’s optical theories held up pretty well until Michelson/Morley in the late 19th Century.
Tom Jones says:
March 14, 2013 at 6:34 am
Very well said. The idea that no one can criticize a theorist until they have a replacement theory is nothing but a ploy to save a failed theory.
Oflo says:
March 14, 2013 at 8:18 am
“Can someone explain for a n00b like me why we’re comparing greenland to global. Shortterm anomalies to longterm anomalies?”
Forgive because this will be a bit short hand for it.
In basic the global warming hypothesis argues that the earth warms… however the biggest warming takes place at the poles and the least amount at the equator. It also claims that current warming is solely or almost solely due to man. It also claims CO2 is the almost sole cause of the current warming. If we warm 3 degrees “we’re all going to die”. Thus we need to stop the warming. AKA we must kill all humans because they are the cause of the warming.
When we look at the greenland ice cores we see a few things.
1. It has been far far warmer in the past.
This means that humans may not be to blame for current warming. This also means the world will not end.
2. When matching the warmer periods to CO2 level can we see any evidence of CO2 causing warming? Too which we can fairly safely say not much evidence of this.
This means even if we assume that the current raise in CO2 is purely man made. That CO2 doesn’t have anywhere near the effects claimed and thus the world will not end.
In basic greenland ice cores should contain among best evidence to support man cause warming. Yet they contain little to no evidence to support much of the arguments put forth by the hypothesis of global warming.
An argument put forth to counter this is that these past warming period only happened in the north hemisphere. This argument put forth by Mann(the hockey stick guy) to explain away nature.
The problem is that the southern hemisphere has refused to warm… in fact the south pole appears to be cooling and is gainning ice. Since the south pole is gaining ice and the north losing ice, ironicly Mann maybe correct in saying that the past warming period were purely in the northern hemisphere… evidence would suggest the current warming only happening in the northern hemispehre is natural as well.
Since global warming hypothesis has changed millions of times and the goal posts moving millions of times past argument by pro-global warming hypothesis are now wrapping around to hunt them.
Mike McMillan says:
March 14, 2013 at 8:49 am
“Steven Mosher says: March 13, 2013 at 1:58 pm
. . . For instance, in the time of Galileo, optical theory could not account for phenomena that were observed by means of telescopes. So, astronomers who used telescopic observation had to use ad hoc rules until they could justify their assumptions by means of optical theory.”
Nonsense. The merchants and rulers of Galileo’s time embraced the telescope immediately because he took them to a tower over the harbor and showed them ships in the distance that would not arrive in the harbor for hours. They invested in telescopes immediately. Those who called the telescope an instrument of the Devil did so because what it showed conflicted with their theoretical preconceptions. In this context, the Devil is an ad hoc hypothesis.
Once again, Mosher is grasping for excuses for failed theories.
YouAreWrong Again says:
March 13, 2013 at 9:47 pm
“Clever misuse of quotes”…
“The paper by Marcott et al is behind a paywall for now, but, thankfully, I have access so I can see your quote placement in your opening paragraph dutifully misleads your readers to believe that Marcott et al state “A heat spike like this has never happened before, at least not in the last 11,300 years”. That sentence, and conclusion, is NOT part of the paper. The paper doesn’t even use the word ‘spike’.”
If you cannot or will not produce your quotation here then it is a non-player.
“Then you go through a painfully wrong comparison (apples to oranges my friend) to show just how misguided the Marcott authors are.”
If you are not going to present the comparisons and explain your objections then you have another non-player.
“Please Dr. Easterbrook. Attempt to get your comparison published. Would be great to have the reviewers response posted here.”
It would be great to have the reviewers here to ask them why they passed on Marcott’s little essay in non-science. You are aware that when McIntyre asked Marcott about the twentieth century Marcott said only that those results are not robust. What??? Then why publish the paper? The twentieth century is what interests us.
If you are in training to be a troll then you are doing well. If you want to be taken seriously by readers and commenters at WUWT then you will have to offer substantial comments on the topic at hand. You have offered no substantial comments and, as explained above, have asked no substantial questions.
Kobashi et al. (2011).published GISP2 location temperatures until 1950 using nitrogen and argon isotopic ratios (δ15N and δ40Ar) from the GISP ice core. They also derived current temperatures with a “forward model”.
http://www.co2science.org/data/mwp/studies/l1_gisp2summit.php
Even in their reduced 1000 year range, neither the increase nor the absolute value of current temperatures are uncommon.
The main increase from the little ice age was before 1940. CO2 and other green house gases cannot be the reason for that (CO2 had only increased from 280 ppm in 1750 to about 310 ppm in 1945). Perhaps black carbon may have been a contributor. Other than that, the increase was certainly mainly natural.
Hey! I already defended Mosher once this thread; isn’t once a year/decade enough?
I’m doubt optical theory is the correct science at question here, but optical use had certainly affected his work.
Galileo was working with the knowledge of the era and made incredibly accurate measurements. Until more physics was involved, his measurements stood even if he wasn’t able to discuss them. Galileo was See only a step away from being a guest of the Inquisition so he had to avoid supporting the Copernican theory publicly for years.
Retrograde movement of the planets, actively used in astrology, was better observed with telescopes by Galileo. During his hunt for parallax he observed and subsequently identified the moons of Jupiter and at the same time observed the true motion of Jupiter which he had expected to be in retrograde movement at the time. Galileo used stops (light blocks with smaller holes in the center) to improve the image of Jupiter.
On the surface, Galileo was reducing glare and he was, but he introduced physical light obstacles into the telescope that blocked transient/tangential light from reaching the eye. Again ray wave optics were involved if in a different form.
A Telescope’s objective lens collects light and focuses it down the telescope tube. The larger the objective, the more light and theoretically the more magnification.
A large (to Galileo approximately 3″) telescope objective refracts (bends all light hitting it and send much of it down the telescope tube. When you are trying to observe a distant apparently miniscule object, all you really want to see is the light coming from that object. Instead you have all of the universe’s light bouncing around the telescope tube; so Galileo’s introducing baffles into the telescope with holes blocked out much of this transient light. The baffles (stops really) stop most of the light, except the light the telescope is aiming directly at. Galileo’s addition of stops, clarified his picture of Jupiter so well that he observed small stars with Jupiter and over time they stayed with Jupiter.
A closing statement from See “GALILEO’s SCIENTIFIC RESULTS”
So is Galileo included with Feynman and wrong too?
I should’ve included that my last line/question is aimed at Mosher.
Dr. Easterbrook, Nick Stokes is correct. The top of the ice core data is not 1950, nor is it 1905 as indicated by your graphic. It’s 1855. It therefore captures none of the 20th century warming. It can’t even capture the climate of the late 19th century. It certainly can’t provide a reliable indicator of the global climate period over any of that timeframe.
Furthermore, this has been pointed out more than once over the last few years and all of it directly confirmed by Dr. Richard Alley, whose data you are citing. Please correct your error and reassess your arguments in light of it.
Some will enjoy this . .
Read this and you will see that Progressive LBJ spent all the money a long time ago . . DC is broke and broken . . they are all in denial . . no we do not have a spending issue if we could only raise taxes to the same as Europe with a C02 tax and a VALUE ADDED SALES TAX .. but that is still a lie . . the money is spent for decades and decades read about it here. http://articlevprojecttorestoreliberty.com/the-great-society-etc.html
Read more and see graphs on spending cuts . . in GRANT MONEY . .
http://www.scientificamerican.com/article.cfm?id=sequestered-science-federal-funding-research-timeline&WT.mc_id=SA_CAT_BS_20130315&posted=1#comments
Hard to believe any of this is simply error. It reads like deception.
Edit: “i.e., it is are wrong.”
wheelsoc says:March 14, 2013 at 7:37 pm
Dr. Easterbrook, Nick Stokes is correct. The top of the ice core data is not 1950, nor is it 1905 as indicated by your graphic. It’s 1855. It therefore captures none of the 20th century warming. It can’t even capture the climate of the late 19th century. It certainly can’t provide a reliable indicator of the global climate period over any of that timeframe.
Furthermore, this has been pointed out more than once over the last few years and all of it directly confirmed by Dr. Richard Alley, whose data you are citing. Please correct your error and reassess your arguments in light of it.
Your post is pointless. Even if you add the whopping .7-.8°C we have warmed since 1850 to GISP2, we are still a good 2°C below the warmest times in the Holocene, according to Alley’s work.
http://i49.tinypic.com/oji4b7.jpg
A) Being glaringly and demonstrably wrong on the very subject he’s trying to broach is not a pointless concern. Refusing to fix a problem that has been pointed out before is not a minor issue. This isn’t a matter of opinions or tastes, this isn’t a quibble over statistical methods or data quality. this is a matter of bare and simple facts. Dr. Easterbrook is OBJECTIVELY wrong, has been notified of his mistakes in the past, and persists in being wrong regardless.
If he can’t get simple facts straight despite everyone’s best effort to give him correct information, why should anybody care what he has to say? Why should Anthony Watts knowingly give him a platform from which to spread misinformation? Dr. Easterbrook’s showing himself to be untrustworthy and unreliable as a source of accurate information and it doesn’t reflect well on this site. I’m sorry, but there is no nicer way to say this. Is credibility a pointless matter?
B) You seem to have ignored the other point I made that data from a single spot is not a GLOBAL climate record. Perhaps you think otherwise? Then surely an even better source for comparison would be the very paper this demonstrably untrustworthy blog post is supposedly addressing, Marcott et al. 2013. You know, the one that uses 73 climate proxies spread out over the globe instead of a single proxy from a single spot. They checked their distribution of proxies against a similar distribution of instrumental records and the full instrumental record to make sure that it didn’t give them too small a picture (like using data from a single point on the globe almost certainly would). That’s where you should be drawing your data from.
The study points out that while there have been times in the Holocene with a GLOBAL climate warmer than today’s, they are not many; despite a previous downward trend below the average of the Holocene, we are now in an unusually warm state. We are already among “the warmest times in the Holocene,” and we are on track to exceed all the past records handily by the end of this century under any plausible GHG emissions scenario. To make it more clear: we went from being in one of the colder periods to being in one of the very warmest, all in the last century. The natural background forcings that had been working to depress global temperatures for the last 5,000 years would have continued to producing cooling into the future, a trend which was evident up until the early 20th century. Using our understanding of the forcings that drive glacial-interglacial periods, we would have been looking at the onset of a new “ice age” in about 1,500 years. There is no indication of any mechanism to depress temperatures again and make sure that the hot-house conditions will be as short-lived as they were in the past.
We’ve already contributed our GHGs to the forcings that erased the downward trend in a single century due in no small part to our enhancing of the atmosphere’s Greenhouse Effect. Not only have the full effects of our Greenhouse Effect enhancements not yet caught up to us, we haven’t even slowed that enhancement. The only way to go is up, past the previous highwater marks of the Holocene at a rapid pace, past the climate conditions that existed since the dawn of civilization itself, and into territory our species has never experienced.
It’s not just the average temperature that’ll be unprecedented for us, either. We’ve already jacked up atmospheric CO2 concentrations to levels not seen in the last 15 million years, and done so at a speed that exceeds the phenomenal rate seen during the Permian-Triassic “Great Dying” by at least an order of magnitude. Both the magnitude and rate of increase have serious implications not only for the direct, physics-governed Greenhouse Effect but also for the chemistry of the oceans, on which we depend for much of our food and oxygen. Something else to ponder, unless you’d care to dismiss it as “pointless” too.
wheelsoc says:
“The study points out that while there have been times in the Holocene with a GLOBAL climate warmer than today’s, they are not many…”
Therefore, the Null Hypothesis has never been falsified, and you are spreading a false alarm.
“While there have been times…” means that the current global temperature is not unprecedented. Further, global warming has been stalled for many years now. Wild-eyed arm waving at this point is emotion based fright.
The current rising trend has been repeated for more than 150 years. Temperatures have risen at the same rate, even when CO2 was much lower. That indicates that CO2 has no measurable effect. The planet is simply recovering from the LIA — one of the coldest episodes of the entire Holocene. CO2 has little or nothing to do with it.
Despite your emotional outburst, we are not at or near the warmest Holocene temperature.
As a matter of scientific fact, CO2 levels have been much higher in the past, and at times when the planet descended into a major Ice Age. CO2 has also been very high when the biosphere teemed with life and diversity. Even with the current rise in harmless, beneficial CO2, the atmosphere is starved of CO2. And we are still in a cooler part of the Holocene.
There is no long-term correlation between CO2 and temperature. But with better granularity, we see that changes in CO2 are the result of changes in global temperature, not the cause. There are no empirical measurements showing that ∆CO2 causes ∆T.
Your emotion-based rant is the result of the constant, 24/7/365 hammering of alarmist propaganda — eventually, the public begins to repeat their anti-science nonsense.
Try to think for yourself; be skeptical of their assertions. They want to control you, and they will if you let them.
wheelsoc says:
March 15, 2013 at 11:42 am
A) Being glaringly and demonstrably wrong on the very subject he’s trying to broach is not a pointless concern. Refusing to fix a problem that has been pointed out before is not a minor issue. This isn’t a matter of opinions or tastes, this isn’t a quibble over statistical methods or data quality. this is a matter of bare and simple facts. Dr. Easterbrook is OBJECTIVELY wrong, has been notified of his mistakes in the past, and persists in being wrong regardless.
If he can’t get simple facts straight despite everyone’s best effort to give him correct information, why should anybody care what he has to say? Why should Anthony Watts knowingly give him a platform from which to spread misinformation? Dr. Easterbrook’s showing himself to be untrustworthy and unreliable as a source of accurate information and it doesn’t reflect well on this site. I’m sorry, but there is no nicer way to say this. Is credibility a pointless matter?
dje response: Before hurling meaningless insults, YOU need to get your facts straight! If you had bothered to check:
1. The Alley curve, labeled by Alley himself is “Years before present (2000 AD)” (taken directly from his curve).
2. Alley’s own dataset says:
“Temperature in central Greenland
Column 1: Age (thousand years before present)” i.e. 2000 AD
This is exactly what is in my WUWT post.
I think you owe me an apology for your ugly and totally false accusation.
“Therefore, the Null Hypothesis has never been falsified, and you are spreading a false alarm.”
What “null hypothesis” are you talking about? As for spreading “false alarm,” what about spreading false, easily correctable information about the GISP2 data? Perhaps you can bend Anthony Watts’ ear a bit about this significant error in the guest post.
“…means that the current global temperature is not unprecedented.”
I didn’t think that was in dispute. Did you? Perhaps I was unclear.
“Further, global warming has been stalled for many years now.”
Noise really adds up when you only look at a decade of data, especially since climate is generally understood over periods three times longer than your sample.
Things don’t just happen for no reason. The factors that have masked the underlying warming trend are due to physical processes; solar forcings, volcanic eruptions, and the ENSO cycle (a cycle which is almost exactly as long as the period of time you chose to graph). Take those factors into account and remove their quantified influences. Then you see that not only do the different datasets more closely agree with each other (as they are sensitive to different aspects of the climate system), but they also show an unabated warming trend that is statistically significant on shorter timescales than the data without those factors taken into account.
In other words, you need to consider WHY the climate can seem to stall or accelerate even in the face of an underlying, long-term trend. Climate doesn’t just happen. But while this level of analysis would at least show that you care about the physics underlying the climate system instead of just the dumbest, most context-free numbers, even that much data processing will still not let you easily make a statistically significant conclusion from only ten or so years of temperature data. Because there is still short-term noise.
“Despite your emotional outburst, we are not at or near the warmest Holocene temperature. … And we are still in a cooler part of the Holocene.”
Yes, we are near it. Today’s temperatures are warmer than about 82% of the Holocene, despite your graphic (which, YET AGAIN, is not a global record and doesn’t cover the late 20th century in any case; as clearly indicated by the citation on it). That’s coming off a long-term cooling trend which saw temperatures gradually declining to a low that was well below the Holocene average. It wasn’t all The Little Ice Age, unless you can posit a mechanism of “recovery” that explains how the short-term LIA is supposed to still be affecting us today. We had already come out of the LIA a hundred years ago.
What has been driving the temperature up since, and where does it stop? Why do you and others here rely on data from a single spot on the globe and insist on using it as a global proxy?
” Even with the current rise in harmless, beneficial CO2…”
Tell that to the seas. Ocean acidification is already happening faster than natural variability can explain, and it’s already affecting important sea life from ,a href=”http://www.oregonlive.com/pacific-northwest-news/index.ssf/2012/04/oregon_state_research_traces_o.html”>commercially important oysters in the US to carbonate-dependent organisms near the base of the food chain in certain regions where carbonates are relatively low.
Even if you somehow discount the entire Greenhouse Effect to imagine that the future won’t be warmer, how do you plan to cope with a rapidly dropping ocean pH that is a direct result of our CO2 emissions? How does that figure into “harmless” and “beneficial?”
wheelsoc says:
“What ‘null hypothesis’ are you talking about?”
Which indicates that wheelsoc is not up to speed on the subject of the Null Hypothesis. I recommend reading the WUWT archives for a few months before expressing ignorance of a central concept in climatology.
Next, the GISP2 data that I posted is an empirical observation, supported by numerous peer reviewed papers. I note that you have only your assertions. Such assertions are typical of those who are uncomfortable with verified real world observations.
And your nonsense about ocean “acidification” has been so thoroughly refuted here that I won’t bother to go over it again. You can do an archive search yourself, and get up to speed on the numerous articles and comments debunking the belief in ‘acidification’. But linking to the ARS Technica blog is foolish in itself, since that site has been repeatedly hacked, and readers’ personal information compromised; you could look it up. Me, I won’t click on a blog that allows my information to get hacked. YMMV.
WUWT is the internet’s “Best Science” site. You can learn all the facts necessary here, including the meaning of the climate Null Hypothesis — a corollary of the Scientific Method. [Or, you can scramble around searching out all you can about the Null, so you can try to appear knowledgeable in your next comment.]
The fact is that there is no measurable evidence showing that CO2 is harmful in any way, at current or projected levels. More is better. The “carbon” scare is designed to transfer money from the poorest to the richest in society, and it is unfortunately working. You might like your skyrocketing energy bills, and wildly inefficient birdchoppers, and ever rising food costs, but the rest of us don’t.
Also, I note that you have posted no measurable evidence showing that a rise in CO2 causes a rise in temperature. I showed conclusively that the opposite correlation is a scientific fact.
Your comments are just simple assertions, which are not supported by empirical evidence. Changes in temperature cause changes in CO2. I challenge you to produce a similar chart, showing that ∆CO2 is the measurable cause of ∆T. The fact is that CO2=CAGW is only a conjecture; a belief; an opinion. It forms the basis of climate change theology. But there is no measurable, empirical, testable evidence proving AGW. None.
Finally, a stand-up guy would apologize to Dr Easterbrook for that erroneous attack. So we will see what you are — or aren’t.
Don J. Easterbrook says: March 15, 2013 at 1:22 pm
“1. The Alley curve, labeled by Alley himself is “Years before present (2000 AD)” (taken directly from his curve).
2. Alley’s own dataset says:
“Temperature in central Greenland
Column 1: Age (thousand years before present)” i.e. 2000 AD”
On item 1, do you have a link to show that that label is from Alley himself? I am doubtful.
Here is Alley’s diagram on GISP2 from Quaternary Scoence, 2000. And Here is his diagram from PNAS 2000. Both clearly label the axis as thousand years before 1950.
On item 2, it is your interpretation that before present means before 2000. But standard usage is before 1950. And it’s clear Alley uses that.
I’m not up to the task of repeating the whole of climate science in a few comments, so let’s at least start by establishing that “95 years before present” does indeed refer to 1950 minus 95 years; my original issue. I don’t think I’m making a false accusation, and here’s why:
I’ve found a copy of the Alley (2000) paper that was cited, hosted online by a university in the Dominican Republic. The paper only defines “before present” as before 1950. It also refers to the same Cuffey and Clow (1997) data as Dr. Easterbrook, which again defines BP as before 1950. In fact, the NCDC maintains the data and makes it available as a CD-ROM, the notes of which explain what dating convention is used in no uncertain terms . Before Present = Before 1950.
As an unofficial source, here’s someone confirming it from an email exchange with Dr. Alley, unless you’d care to call him a liar in which case we still have the NCDC pages and the published literature on GISP2.
The fact is that “before present” in these data sets and papers means “before 1950,” due to the way radiocarbon dating became established and standardized. It’s a standard convention in the geosciences and paleoclimatology. To use the term otherwise would be inviting confusion and so would need to be specified in the publication. Alley (2000) only ever defines “before present” as years before 1950, and does so consistently. Nowhere else in the paper, or in the referenced data and other publications associated with GISP2, is any different definition used. The dating convention is spelled out by the NCDC. There is no inconsistency to engender ambiguity. There is no allowance for the “years before 2000” interpretation favored by Dr. Easterbrook.
The ball’s in the other court. What Dr. Easterbrook has offered seems to be ably handled by Nick Stokes; it seems to be a clear case of misinterpretation, and is apparently contradicted by Alley (2000). I’ll need some hard evidence to believe that 95bp refers to some non-standard “years before this paper was published” date to refute all the documentation I’ve provided and based my interpretation on, and I maintain that Dr. Easterbrook is wrong. What reason do you have for going against the word of the very same man whose data is being misrepresented in this guest post? Insistence that 95ybp does NOT mean 1855 seems to blatantly fly in the face of the man whose data you’re citing, and all the associated data and publications. I have given plenty of evidence for my case, and explained why I’m not taking the representation here at face value. Of course I’ll apologize if I turn out to be wrong, but it must be shown that I am despite all this evidence.
This could, of course, easily be cleared if up someone were to ask Dr. Alley (again). I should note that this apparent “controversy” has flared up more than once on this blog, since his GISP2 data has been repeatedly cited in posts here as evidence for this or that and usually with the same apparent mistake about dating conventions. Seems like a liability to me. Has any effort on the part of anybody, guest poster or blog operator, been made to do so after these issues have repeatedly been raised? You don’t have to take some other blogger’s word for it, you can take Dr. Alley’s. Confirmation that can be posted and referred to in the future would settle whatever issue there is, and keep these comment threads from being derailed.
Nick Stokes says:
Here is Alley’s diagram on GISP2 from Quaternary Scoence, 2000. And Here is his diagram from PNAS 2000. Both clearly label the axis as thousand years before 1950.
On item 2, it is your interpretation that before present means before 2000. But standard usage is before 1950. And it’s clear Alley uses that.
dje response—You really do need to learn how to read! You also need to learn the difference between delta 18O and temperature. This is NOT the Alley temp curve–these are the delta 180 curves. Look at the axes! They are delta 18O from the Stuiver-Grootes data, and yes, the top of the core is 1950 for the oxygen isotope curves. But Alley’s curve is a temp plot, not delta 18O, and he himself labels the horizontal axis “Years before present (2000)”.
A wise man once said, better to be thought a fool than to speak and remove all doubt.
DJE,
Well, where’s your evidence that Alley labelled that axis Years before present (2000). I don’t believe it.
“You really do need to learn how to read! You also need to learn the difference between delta 18O and temperature. This is NOT the Alley temp curve–these are the delta 180 curves.”
My reading is fine. Look at the PNAS link, curve (b) – in purple. Clearly marked as temperature. From the caption: ” Temperature converted from ice-isotopic ratios (41) using the glacial-interglacial calibration of ref. 12, shown in °C.”.
And the QS diag – see the second word on the y-axis from the right? Temp!
Nick Stokes says:
My reading is fine. Look at the PNAS link, curve (b) – in purple. Clearly marked as temperature. From the caption: ” Temperature converted from ice-isotopic ratios (41) using the glacial-interglacial calibration of ref. 12, shown in °C.”.
And the QS diag – see the second word on the y-axis from the right? Temp!
dje response
No, your reading is NOT fine. (1) Look at the axis label–this is a Byrd core, NOT GISP2, and (2) in case you hadn’t noticed, this is NOT the Alley curve I used.
I give up–you’re hopeless!
Don Easterbrook says: March 16, 2013 at 12:33 am
” (1) Look at the axis label–this is a Byrd core, NOT GISP2″
Nope. A bit more from the caption re curve (b):
“(b–e) GISP2 data mostly from ref. 8, with the accumulation and temperature originally from ref. 40. (b) Temperature converted from ice-isotopic ratios (41) using the glacial-interglacial calibration of ref. 12, shown in °C”
<i."(2) in case you hadn’t noticed, this is NOT the Alley curve I used"
No, it isn’t. That exact curve is not in either of the papers Alley wrote in 2000. But that was your claimed source. Someone constructed it from the data that came with the QR paper. That makes it even less likely that Alley wrote the axis label that you claim.
I contacted Dr. Alley directly and asked if he could help clarify the issue. He replied in two emails that he does NOT recall ever publishing a plot where “before present” meant starting backwards from the year 2000 for GISP2 data.
Specifically he pointed me to the Age Scales page from the NCDC GISP2 site, and said of Easterbrook’s graphs that he’s “…fairly confident that what they are plotting is still on the standard GISP2 timescale, with the 0 set to the year 1950. You’ll notice if you look at the raw data that they do run into negative time for the youngest ones.”
He clarified again regarding the plot posted here, that “… 0=1950 AD/CE is my understanding of what they are citing, and they can go look at the original data used by Cuffey.”
The data he refers to are from the Cuffey and Clow data at the NCDC page I linked to previously, with 0 being 1950 and -37.5 meaning a calendar date around 1993-1992. Back to Alley’s data, this would put 0.0951409 thousand years before present (the top datum in the column) at 1855, as virtually everybody else had already concluded years ago.
This would be consistent with all the data and the relevant pages from the NCDC about the GISP2 project that I’ve provided, the standard dating convention for this area of research, and with his own use of “before present” in Alley (2000). Nor can I find anything where “before present” means “before the year 2000 AD.” The latter would be inconsistent anyway.
Seems pretty open-and-shut to me, unless some new evidence can be produced to back up Dr. Easterbrook’s assertions regarding the dating convention. Where is the original source for the graphic with the x axis labelled up to the year 2000, supposedly labelled as such by Alley?