Guest post by Dr. Don J. Easterbrook
1934 has long been considered the warmest year of the past century. A decade ago, the closest challenger appeared to be 1998, a super-el nino year, but it trailed 1934 by 0.54°C (0.97°F). Since then, NASA GISS has “adjusted” the U.S. data for 1934 downward and 1998 upward (see December 25, 2010 post by Ira Glickstein) in an attempt to make 1998 warmer than 1934 and seemingly erased the original rather large lead of 1934 over 1998. The last phases of the strong 2009-2010 el nino in early 2010 made this year another possible contender for the warmest year of the century. However, December 2010 has been one of the coldest Decembers in a century in many parts of the world, so 2010 probably won’t be warmer than 1998. But does it really matter? Regardless of which year wins the temperature adjustment battle, how significant will that be? To answer that question, we need to look at a much longer time frame‒centuries and millennia.
One of the best ways to look at long-term temperatures is with isotope data from the GISP2 Greenland ice core, from which temperatures for thousands of years can be determined. The ice core isotope data were obtained by Minze Stuiver and Peter Grootes from nuclear accelerator measurements of thousands of oxygen isotope ratios (16O/18O), which are a measure of paleo-temperatures at the time snow fell that was later converted to glacial ice. The age of such temperatures can be accurately measured from annual layers of accumulation of rock debris marking each summer’s melting of ice and concentration of rock debris on the glacier.
The past century
Two episodes of global warming and two episodes of global cooling occurred during the past century:
1880 to 1915 cool period. Atmospheric temperature measurements, glacier fluctuations, and oxygen isotope data from Greenland ice cores all record a cool period from about 1880 to about 1915. Many cold temperature records in North America were set during this period. Glaciers advanced, some nearly to terminal positions reached during the Little Ice Age about 400 years ago. During this period, global temperatures were about 0.9 ° C (1.6 ° F) cooler than at present. From 1880 to 1890, temperatures dropped 0.35 ° C (0.6° F) in only 10 years. The 1880 –1915 cool period shows up well in the oxygen isotope curve of the Greenland Ice Sheet.
1915 to 1945 warm period. Global temperatures rose steadily in the 1920s, 1930s, and early 1940s. By the mid-1940s, global temperatures were about 0.5 °C (0.9° F) warmer than they had been at the turn of the century. More high temperature records for the century were recorded in the 1930s than in any other decade of the 20th century. Glaciers during this warm period retreated, temperatures in the 1930s in Greenland were warmer than at present, and rates of warming were higher (warming 4°C (7° F) in two decades). All of this occurred before CO2 emissions began to soar after 1945, so at least half of the warming of the past century cannot have been caused by manmade CO2.
1945 to 1977 cool period. Global temperatures began to cool in the mid–1940’s at the point when CO2 emissions began to soar. Global temperatures in the Northern Hemisphere dropped about 0.5° C (0.9° F) from the mid-1940s until 1977 and temperatures globally cooled about 0.2° C (0.4° F). Many of the world’s glaciers advanced during this time and recovered a good deal of the ice lost during the 1915–1945 warm period. Many examples of glacial recession cited in the news media show contrasting terminal positions beginning with the maximum extent at the end of the 1880-1915 year cool period and ending with the minimum extent of the recent 20 year warm period (1977-1998). A much better gauge of the effect of climate on glaciers would be to compare glacier terminal positions between the ends of successive cool periods or the ends of successive warm periods.
1977 to 1998 global warming The global cooling that prevailed from ~1945 to 1977 ended abruptly in 1977 when the Pacific Ocean shifted from its cool mode to its warm mode in a single year and global temperatures began to rise, initiating two decades of global warming. This sudden reversal of climate in 1977 has been called the “Great Pacific Climate Shift” because it happened so abruptly. During this warm period, alpine glaciers retreated, Arctic sea ice diminished, melting of the Greenland Ice Sheet occur.
The abruptness of the shift in Pacific sea surface temperatures and corresponding change from global cooling to global warming in 1977 is highly significant and strongly suggests a cause-and-effect relationship. The rise of atmospheric CO2, which accelerated after 1945 shows no sudden change that could account for the “Great Pacific Climate Shift”.
1999 to 2010 global cooling. No global warming has occurred above the 1998 level and temperatures have declined slightly.
The past 500 years
Temperature oscillations recorded in Greenland ice cores over the past 500 years (Fig. 2) are truly remarkable. At least 40 periods of warming and cooling have occurred since 1480 AD, all well before CO2 emissions could have been a factor.
The past 5,000 years
Figure 3 shows oxygen isotope ratios from the GISP2 Greenland ice core for the past 5,000 years. Note that temperatures were significantly warmer than present from 1500 to 5000 years ago.
The past 10,000 years
Most of the past 10,000 have been warmer than the present. Figure 4 shows temperatures from the GISP2 Greenland ice core. With the exception of a brief cool period about 8,200 years ago, the entire period from 1,500 to 10,500 years ago was significantly warmer than present.
Another graph of temperatures from the Greenland ice core for the past 10,000 years is shown in Figure 5. It shows essentially the same temperatures as Cuffy and Clow (1997) but with somewhat greater detail. What both of these temperature curves show is that virtually all of the past 10,000 years has been warmer than the present.
So where do the 1934/1998/2010 warm years rank in the long-term list of warm years? Of the past 10,500 years, 9,100 were warmer than 1934/1998/2010. Thus, regardless of which year ( 1934, 1998, or 2010) turns out to be the warmest of the past century, that year will rank number 9,099 in the long-term list.
The climate has been warming slowly since the Little Ice Age (Fig. 5), but it has quite a ways to go yet before reaching the temperature levels that persisted for nearly all of the past 10,500 years.
It’s really much to do about nothing.
Your link is to a graph that uses “Mike’s Nature Trick” of grafting the modern instrumental temperature to the Greenland oxygen isotope proxy.
While this “trick” might be acceptable in climate alarmist circles, it is typically considered fraud in most science, economic and other fields.
Shamelss? Yes, but its not Dr. Easterbrook who is guilty – its you and the site that you link.
I think MVP especially and some others have made some very good points that need to be addressed and addressed by the author.
I assume the author reads at least some of these comments and will/is in the process of answering them in due course.
I think everybody can agree that temps the last ten years globally have been flat. However, the cooling is just beginning. Check out UAH ch 4 (surface) which has just fallen off a cliff. It is now .8 degrees F below the same day last year.
http://discover.itsc.uah.edu/amsutemps/execute.csh?amsutemps
The Greenland ice sheet data points used in Figures 3, 4 and 5 both end in roughly 1900. (95 years before the year 2000) Therefore it doesn’t reflect any of the warming in the past 100 years. How does that data support the author’s statement that “most of the past 10,000 have been warmer than the present”?
There seem to be a lot of issues in these graphs that people are taking seriously. The CO2 increase versus decrease is possibly something that should be addressed, as should the dates in the proxies. but those are more or less labeling issues which do not detract from the message of the article. It might be fair to remember that in peer review, people are allowed to change their articles based on fair criticism.
And this is not really a peer-review article, its simply put, an article. I think there needs to be more labeling and corrections put into it.
The only real issue I see is the question of splicing should be cleared up. As someone who has seen first-hand how under-handed data splicing can be used to manipulate people, this is a dangerous thing to use in the first place. It needs to be labeled well so that we all know where its done.
From the Little Ice Age Thermometer : Iceland:
http://climatereason.com/LittleIceAgeThermometers/Stykkisholmur_Iceland.html
This appears to be the closest long term record to greenland. It shows the 1930’s as warmer than 1998.
@ur momisugly JohnWho December 29, 2010 at 5:37 am
Dang.
I can’t edit my previous post to correct the “bold” tags.
🙁
John Who
——————–
Please do something, John! The entire thread after that post has been affected by your mistake! (It makes for weird reading). Or – Mods, WUWT?
[It wasn’t John’s mistake, it was a WordPress error that I’m familiar with. Fixed now. ~dbs]
I like this post!
I like Ed Murphy’s idea (he is the actor??!)
To summarise what I just said on another post:
Just to be clear on this:
If someone claims that global warming is caused by an increase in carbon dioxide it is up to that person to provide me with the evidence. In this respect I would need to see clear results in the relevant concentration range and it must show how much cooling and how much warming is caused by the CO2. This would have to include the radiative cooling caused by CO2 and the cooling by CO2 caused by taking part in the process of photo synthesis.
Just because someone or some entity makes a claim it is not up to me to”prove” that it is not so. A good lesson from the bible it is that you should never follow the crowd if you are not sure they are doing the right thing(s).
So if someone makes the claim (to me) that carbon dioxide is the cause of global warming, it is up to that person to provide me with that evidence. (Al Gore! Why does no one ask him?)
For that, I would expect to be shown me exact test results and the method and instruments used to get those results.
People I corresponded with like Weart and Alley, all claim that those results
do actually exist. Well, I could not find them.
IPPC and them used a system whereby the increase of CO2 and other GHG’s were measured from 1750 to 2005 and then a value of forcing was attributed to each of them according to the warming observed. This would make sense if we knew for sure that GHG’s are the cause of modern warming.
But, surely, that is looking at a problem from the wrong end? That is assuming you know what is causing warming and then working your way back. It is the worst mistake any scientist can make.
To be completely truthful, I did make a similar mistake myself in the past. It happens when you get carried away too much with what you think is right or what you think ought to be.
So, I think I know what went wrong and why the CO2 being branded as bad…
I now think the opposite of what I thought when I started my investigations….
http://www.letterdash.com/HenryP/more-carbon-dioxide-is-ok-ok
“ABSTRACT:
Greenland ice-core records provide an exceptionally clear picture of
many aspects of abrupt climate changes, and particularly of those
associated with the Younger Dryas event, as reviewed here.
Well-preserved annual layers can be counted confidently, with only 1%
errors for the age of the end of the Younger Dryas 11,500 years before
present.”
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/isotopes/gisp2_temp_accum_alley2000.txt
So the alleged error bars are within 1% for the GISP2 data set.
NOAA paper inadvertently confirms the findings of Dr. Don J. Easterbrook (http://wattsupwiththat.com/2010/12/28/2010%E2%80%94where-does-it-fit-in-the-warmest-year-list) by showing that 9,100 of the the past 10,500 years were warmer than any of the last 100 years!!! Of course the NOAA paper fails to mention that fact… It also shows MWP and the Little Ice Age… so just why are people freaking out over a little welcomed warmth when even warmer seems to be the planetary norm over the last 10,500 years?
It would be good for someone to do a detailed comparison with other Ice Core Data Sets from around the globe. Let’s see ALL the Ice Core Data in ONE graph (or set of graphs) please. Dr. Easterbrook, are you up for that? Thanks.
The comment http://wattsupwiththat.com/2010/12/28/2010%e2%80%94where-does-it-fit-in-the-warmest-year-list/#comment-561508 forgot to turn bold highlighting off. Please fix if possible.
The NOAA paper abstract goes on about the error confidence and global climate synchronized with the Greenland Ice-Core data within 30 years. Interesting for it’s asserting that this data set has global relevance.
“ABSTRACT: Greenland ice-core records provide an exceptionally clear picture of many aspects of abrupt climate changes, and particularly of those associated with the Younger Dryas event, as reviewed here. Well-preserved annual layers can be counted confidently, with only 1% errors for the age of the end of the Younger Dryas 11,500 years before present. Ice-flow corrections allow reconstruction of snow accumulation rates over tens of thousands of years with little additional uncertainty. Glaciochemical and particulate data record atmospheric-loading changes with little uncertainty introduced by changes in snow accumulation. Confident paleothermometry is provided by site-specific calibrations using ice-isotopic ratios, borehole temperatures, and gas-isotopic ratios. Near-simultaneous changes in ice-core paleoclimatic indicators of local, regional, and more-widespread climate conditions demonstrate that much of the Earth experienced abrupt climate changes synchronous with Greenland within thirty years or less. Post-Younger Dryas changes have not duplicated the size, extent and rapidity of these paleoclimatic changes. ”
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/isotopes/gisp2_temp_accum_alley2000.txt
By the way, thank you Dr. Don J. Easterbrook for your excellent analysis. Keep up the great work. As mentioned earlier I’d love to see additional Ice Core Data Sets graphed and analyzed as you’ve done with the Greenland Ice Core Data Set.
This site has temperature histories for many Greenland sites:
http://www.rimfrost.no/
All the long term series make the 1930’s warmer than today.
Dr. Don J. Easterbrook speaking on the Greenland Ice-Core data set.
http://www.youtube.com/watch?v=vXUTYPZd_84
Dr. Don J. Easterbrook speaking on the Greenland Ice-Core data set.
Ed Murphy says:
December 29, 2010 at 9:59 am
“I wonder if all the climateheads could agree to an experiment. An idea about building three or more identical greenhouses, side by side, but far enough apart not to affect each other in any way.”
You wouldn’t be able to measure the difference. ‘Green Houses’ have almost nothing in common with ‘Greenhouse Gas Theory’. The roof of a greenhouse stops convection and the amount of heat trapped by the roof would far exceed any heat trapped by any additional CO2. Of course if you want to grow larger tomato’s then pumping CO2 into a greenhouse is a good idea. 🙂
@Doug in Seattle
Make your mind up.
Either you cannot meaningfully compare the instrumental record and the proxy record, in which case Easterbrook is wrong to say anything at all about temperatures in 2010 relative to reconstructions.
Or you *can* compare them, in which case Easterbrook is wrong to completely ignore the modern temperature record while claiming 2010 is cooler than the vast majority of the last 10k years. How you or anyone else thinks it is valid to not look at data past 1905 when making that claim is beyond me.
Either way, the article is misleading hogwash, irrespective of all the other issues raised in this thread, and your empty attempt at misdirection rather than an honest engagement with genuine criticism is duly noted.
Quick!
Someone archive the GISP2 Temperature data, before Dr. James “Thumbs On The Temperature Scale” Hansen ‘homogenizes’ the data and 2010 becomes the warmest year ever.
richcar 1225 says:
December 29, 2010 at 10:31 am
I think everybody can agree that temps the last ten years globally have been flat. However, the cooling is just beginning. Check out UAH ch 4 (surface) which has just fallen off a cliff. It is now .8 degrees F below the same day last year.
http://discover.itsc.uah.edu/amsutemps/execute.csh?amsutemps
Yeow! We’re down to the level of 1998, and everyone knows how cold that was! The Ice Age is coming…
Steven Mosher says:
December 28, 2010 at 9:21 pm
The operative question is not “has it been this warm before” the operative questions are.
1. What’s our best estimate of the temp over the next 100 years.
2. Can we do anything about it
3. should we, if we can.
1. What’s our best estimate of the temp over the next 100 years.
The best we have is none too good. There are at least a half a dozen hypotheses currently in play, which are at least arguable, regarding what is driving global climate and, by extension, global temperatures. Unless you’re an epistemological mattress back, none of them can be classified at a level higher than suggestive.
2. Can we do anything about it
Since we don’t really have a grip on what’s happening, probably not. But even if we stipulate to the AGW paradigm as “settled science” the almost complete failure of several decades of present attempts and the unimaginative nature of proposals for future action suggest that, even if the alarmists are mostly successful in implementing their plans, it will require a couple of order of magnitude improvement in our ability to measure global average temperature to detect any improvements that might occur.
3. should we, if we can.
Even rudimentary economic analysis of cost/benefit ratios and opportunity costs suggests that virtually everything currently being touted as potential solutions are horrendously bad usages of the planet’s finite wealth and resources. There are many actions humanity could be taking to protect and expand its well being and that of the planet as a whole. Trying to limit the amount of CO2 in the atmosphere in the vague hope that it will produce a state of global climate that might possibly be more benevolent is probably the least efficient and least likely to succeed use of our efforts and resources that could be imagined. Given that the people driving the climate agenda are the direct philosophical descendants of those who have been inflicting almost immeasurable misery, death, and repression on their fellow man for well over a century, in an effort to enforce their top down directed utopian delusions on the world, it is hardly surprising that this is the case.
Should we then do nothing? If the only alternative is to accept the proscriptions of the IPCC and its now vast bureaucratic machine, doing nothing would probably be the best choice. But human history has provided clear and almost incontrovertible evidence of a wiser path. Human well being has been on a real hockey stick like path of improvement over recent times. The two elements most responsible for that slope are cheap, reliable, and abundant energy and increasing individual freedom. Delivering as much of these two things to as many of the people of the world as possible should be our primary focus. Bringing most of the world to middle class levels of discretionary income would put short term stress on the Earth’s resources, but over the long term would alleviate environmental issues, which are mainly a middle class concern, population growth, which is driven by the portion of the human community living in the worst poverty, and increase our adaptability to whatever disasters do befall us in our uncertain future, because freer, wealthier societies have always shown themselves to almost infinitely more responsive and adaptable than poorer, more totalitarian, cultures.
BillD says:
“…this posting by Easterbrook completely lacks credibility and transparency. The main characteristic of a skeptical scientist is that he or she considers the data carefully, whether the conclusions agree or disagree with his or her world view.”
That last is surely projection. It is the alarmist crowd’s mind that is already made up. Skeptics still have questions. And there is voluminous evidence showing that the climate peer review process is thoroughly corrupt. See:
http://bishophill.squarespace.com/blog/2008/8/11/caspar-and-the-jesus-paper.html
Prof Easterbrook has written an article of general interest. It is not intended as a peer reviewed, refereed article, in which every nit is picked. It has helped educate readers about natural climate cycles, myself included.
There is plenty of peer reviewed, physical evidence showing that the planet has naturally warmed and cooled to a much greater extent than currently; the null hypothesis remains un-falsified:
click1 [deueterium isotope records, from 740K ybp]
click2 [Vostok, 420K ybp]
click3 [another Vostok view]
click4 [Vostok, 140K ybp. Warm is good. Cold is bad]
click5 [it has been much warmer than now many times during the Holocene]
click6 [We are currently in a warm interglacial]
click7 [Younger Dryas, per Alley]
click8 [the climate has rarely beeen as beneficial as it is now]
click9 [Greenland, based on Alley’s data]
click10 [Holocene, major warming/cooling periods]
Global harm as a result of rising CO2 has never been observed. The more we look at the past temperature record, the less influence CO2 has. The only definitive result of the recent rise in CO2 is beneficial: increased agricultural productivity.
The GISP2 graph shows only a 1.5 degree drop from the MWP to the Little ice age yet the temperature record for Upernavkik (1873-2010) shows a decrease of 6 degrees from a high in 1943 to a low in 1963. Clearly the ice cores is either not properly calibrated or is not high frequency enough to show rapid changes that have been observed in the instrument record.
http://www.rimfrost.no/
Clearly current temperatures are about average for the last 10k years, even if they have warmed in the last 150 years. Debate over.
There is no need to say any more. This article itself beats around the bush for too long, sidetracked, distracted by by warmist whoppers.
The entire warmist argument is that temperatures are high and skyrocketing higher, relatively speaking. Relative to what? The history of the past 10k years, and 100k, and 1 million show that temperatures are well within historic trends. We must switch the whole debate to examining temperature history, and thus soothing alarm.
@ur momisugly Ben D. (December 29, 2010 at 10:51 am)
I’d say that bad and incomplete labeling DOES detract from the message of the article. But “…the question of splicing should be cleared up. ”
Yes, absolutely. That appears to be the main obstacle here.
If I were to cut Easterbrook A LOT of slack, though, and pretend that wherever he was comparing ‘the past’ in a graph to ‘the present’ that he wasn’t actually referring to ‘the present’ in (Fig 2, 3, 4 or 5.) graph, but always to ‘the present’ in Fig 1 (the end values of Fig 1. do resemble those of the past decade, including 2010), then I think the following clarifications would greatly improve the article:
-clearly indicate what exactly is meant for “the present”, and in what year shown data end if it’s not the same; ideally have every graph end in the same present (even if you have to leave a period blank for lack of comparable data)
– wait a week for the year you’re discussing to be actually over, so at least the rough data is in.
– put BOTH isotope and derived corresponding temperature values on the Y-axis
– Presentation-wise (visually): use the same vertical graph-plotting, so spikes are visually comparable (to a lay person) without having to double-check the Y-axis for every graph
-have the horizontal line (for a present or base period to see positive and negative anomalies) at the same value in every graph; and either have all graphs anomaly graphs (with deviation from a base period), or all actual values, just for consistency.
– Clearly list location, data sources used, statistical smoothing used and a word about uncertainties for each graph. (a brief disclaimer paragraph for each graph, basically)
– And perhaps make it so that both X-axix and Y-axis on the graphs can be put next to each other both vertically as well as horizontally.
THEN we may still technically be looking at what amounts to little more than ‘anecdotal evidence’ (which I do think can hold validity when presented honestly), at least it wouldn’t be deceptive.
It’s good to see others (Buzz Belleville, Rhys Jaggar, John Finn, Juraj V., Christopher Hanley, BillD, Dave Springer, John Finn, Jantar, Steven Mosher, Dave H, and others) apparently also prefering (or insisting on, as I do) decent scientific standards being upheld here, blog or not.
[You may be violating blog policy. The IP address comes from Utah, to an NGO, while the email address, “smeltendeijstijd@ur momisugly…” which looks like gobbledygook, points to the UK – please provide a valid email address. A valid email address is required to comment on this blog. -moderator]
typo in previous post:
-have the vertical line…
I meant horizontal.
Hope you can fix that. tx!
[Fixed. ~dbs, mod.]