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.
Careful, there, Peru me boy, you’ll frighten yourself to death. Your arguments are the usual warmist Argumentum ad Ignorantium: “If I can’t think of any other reason than CO2 to blame, then the cause must be CO2!” You’re simply ignorant of the many other possible causes of fluctuating temperatures.
There is not one event that can conclusively be blamed on the rise in CO2. It is entirely speculation, based on your Argumentum ad Ignorantium. When you return to the echo chamber you came from, you will feel comfortable, because they don’t believe in the scientific method. Here, you will get set straight.
See, we’re talking about global warming on this “Best Science” site. By disregarding the numerous charts from various sources that I posted, you can’t understand that I was showing various global locations that all show the same thing: the planet was warmer many times in the past.
All available evidence [as opposed to models, which are not evidence] shows that during the Holocene there were numerous times when global temperatures were significantly higher than they are today. Since that fact destroys the CAGW argument, you simply ignore the evidence, and fall back on your ridiculous assertions that this is as warm as it has ever been in the Holocene. Cognitive dissonance at work.
The alarmist contingent still refuses to avbide by the scientific method, but relies instead on a mythical “consensus” to support their true belief. Thirteen years after MBH98, serial liar Michael Mann still refuses to disclose his data, methodologies and metadata that he based his Hokey Stick chart on. Mann’s chart has been repeatedly debunked, and only his credulous followers still believe in it. Mann’s chart attempted to erase the MWP and LIA, against mountains of evidence to the contrary.
You are doing the same thing, by preposterously claiming that the Minoan Optimum was no warmer than today. CO2=CAGW is your conjecture. You own it, and you have the onus of proving it. Yet you cannot demonstrate any harm that CO2 has caused the planet.
You complain about regional examples – then you use the Arctic region as global evidence. Global ice cover is about average because the Antarctic holds almost 90% of the world’s ice — and Antarctic ice is expanding. Global CO2 affects temperature everywhere. But you cherry-pick one lame example: the Arctic region. Is that the best you can do?
Keep in mind that scientific skeptics have nothing to prove. The onus is entirely on the alarmist crowd to convincingly show that their conjecture explains reality better than the null hypothesis – which has never been falsified – while the alternate CAGW hypothesis has been repeatedly falsified. That is why it has been downgraded to the level of conjecture.
Trying to claim that today’s mild temperature is as warm as the Roman, Minoan and Holocene Optimum makes you sound like a raving lunatic. It is a ridiculous and erroneous statement with no basis in fact. Best to stop digging before you reach China, and have to turn around.
@Henry,
You may have misunderstood my comment. Milankovitch cycles clearly a decline in Northern Hemisphere summer solar irradiance over the past 10 millennia, which is consistent with the decline in Greenland temperatures. The LIA is only the end of that decline, where it may be noted that probably the Mounder Minimum contributed (some -0.2 C) to the already low NH temperaratures.
So it is no surpise that temperatures in Greenland declined over the past 10 millennia, and during the LIA as well.
So the 20th Century warming (of +0.8 C globally) is the real ‘unusual’ period during the Holocene, and especially the current rate of increase (some +0.2 C/decade global, and +0.3 C/decade in the NH) is completely inconsistent with the Milankovitch cycles and solar activity alike.
Smokey says:
January 2, 2011 at 9:52 pm
“All available evidence [as opposed to models, which are not evidence] shows that during the Holocene there were numerous times when global temperatures were significantly higher than they are today. Since that fact destroys the CAGW argument, you simply ignore the evidence, and fall back on your ridiculous assertions that this is as warm as it has ever been in the Holocene.”
No, the fact the globe was possibly, or even likely warmer during certain periods compared to now during the Holocene does not in any way refute the CO2 induced global warming theory. The globe has warmed and cooled for various reasons in the past, but the current warming is most likely caused by increases of GHG, especially CO2. Your assertion that the current rise in CO2 concentrations was caused by the MWP is preposterous! You linked to a graph of temperature and CO2 variations derived form Antarctic ice cores. It shows that in the last 400,000 years CO2 levels did not rise above 300 ppm in the midst of big temperature swings, and you think a little bit of warming a few hundred years ago caused the recent 100 ppm spike! We are upsetting the equilibrium of the carbon cycle by pulling carbon that has been sitting in the earth for millions of years and pumping it into the atmosphere. WE are causing the spike in atmospheric CO2 concentration! We need to reign in this massive global experiment by reducing our output of GHG.
Thankfully Peru already noted many of false notions that you entertain. I am sorry for sounding a little harsh, Smokey. Unfortunately I don’t have time to continue this conversation. But I hope that you will spend a little more time reading actual scientific literature about climate change, rather than putting your faith in blog science.
Henry@bgood2creation
You say: The globe has warmed and cooled for various reasons in the past, but the current warming is most likely caused by increases of GHG, especially CO2.
this is allegation is simply wrong
For example,
if you study the pattern of the warming, for example,
like here, we have some average temperature data since 1946,
http://img502.imageshack.us/img502/8705/navacerrada.gif
This is in Spain, which I think is pretty much average as average goes for a place to stay on earth! The station has been very accurate in its recordings and only one day’s recordings are missing. Note that the average minimum temps. since 1980 have stayed constant. If green house gasses were to blame for the warming (the trapping of heat), you would think that it should have been minimum temps that would show the increase (of modern warming). But that line is completely straight…..So it cannot be greenhouse gases that caused modern warming. It must be something else that is causing warming…..obviously.
Similarly, another weather station that showed no significant increase in minimum temperatures during the past 200 years is that of Armagh in Northern Ireland. http://www.arm.ac.uk/preprints/445.pdf
http://www.letterdash.com/HenryP/more-carbon-dioxide-is-ok-ok
Henry@Rob
I have not studied the M-cycles yet. Do you have actual data showing the change in W/m2 caused by these cycles? Also where we are in each of the 3 different cycles?
The article is simply not scholarly by any stretch. Don manages to contradict his own research web page above. Above he notes that “1999 to 2010 global cooling. No global warming has occurred above the 1998 level and temperatures have declined slightly.” However, on his glacier fluctuations research web page he notes instead “For example, the present warm period (1977–2007) is slightly
warmer than the 1920–1950 warm period, and the 1947–1977 cool cycle” Try to fit those two statements. That material from others is not accurately represented or credited is apparent at this same research website. His figure 14C and 15C are pictures I took. The terminus lines are ones I denoted on the images. The dates for the lines are not correct- for 15Cm it is 1985, see Boulder Glacier third image discussed here Blog post on Boulder Glacier
For 14C the date stamp from my picture is still evident and the date is 1985 as well. Easton Glacier.
bgood2creation says: [random talking points follow]
First off, you need to understand the proper usage of scientific terms. There is no global warming “theory.”
There is the null hypothesis of natural climate variability, which has never been falsified, and there is the alternate CO2=CAGW conjecture, which has been repeatedly falsified — not least by the planet itself.
You must first understand the basic differences between a conjecture, a hypothesis and a theory. Theories can make accurate predictions. But no model has been accurate in predicting the future climate: the table shows one correct model prediction, vs 27 wrong predictions. Therefore, model guesses are at the level of conjecture; they are an opinion, based on the programmer’s bias; GIGO: garbage in, globaloney out. Further, models are not scientific evidence. They are a tool, nothing more — and not very good tools at that.
You look at a chart and come away with exactly the opposite conclusion that any rational person would arrive at: you say that “in the last 400,000 years CO2 levels did not rise above 300 ppm in the midst of big temperature swings…”
That shows beyond any doubt that CO2 is not the driver of the climate. While CO2 remained flat, the global temperature varied widely. But with CO2 ≈40% higher over the past century and a half, temperatures are still well within their normal and natural parameters, and there is no testable, empirical evidence proving that CO2 has caused any harm to the planet. None. CO2 makes no discernable difference. As a matter of fact, current temperatures are unusually mild.
CO2 has no measurable, testable, quantifiable effect on temperature, no matter how much you wish it were so. The fact that the climate sensitivity number is still debated is a direct consequence of not being able to measure or quantify a unit of temperature change resulting from a unit of CO2 emitted. If something cannot be measured, it fails the scientific method. It’s that simple. Without the scientific method, it is only pseudo-science.
It’s embarassing to read someone parroting alarmist talking points here without understanding the basics. To get up to speed on the actual science, I recommend you do an archive search for “CO2”. Read all the articles and comments. There are a lot of them. The CO2/temperature conflation has been extensively discussed, and the only reliable correlation is that CO2 follows temperature. It will take a couple of days to catch up, but you will start to get an understanding of the situation. As of right now, you are simply repeating incorrect information based on alarmist talking points, without having a basic understanding of the issue.
Henry@mspelto
I’m not sure if I catch your drift. Different writers came to the same conclusions (from the same data, especially referring to the Holocene), e.g. see here:
http://wattsupwiththat.com/2009/12/09/hockey-stick-observed-in-noaa-ice-core-data/
After studying these particualr graphs, I became skeptical of global warming as such being a problem. I know mine is still a minority view. But to change my mind, you willl first have to show me that warming in the past has caused catastrophes and huge problems. Until then, I’m not going to believe that warming in the future will cause catastrophes and huge problems, especially warming that we can barely measure. Now the opposite, global cooling, that really is something to worry about….
Note that if you look at the fourth graph, it is clear that our current temperature, even though on the incline, is still far below the average of the last 10000 years, when, by some co-incidence(?), most of humanity and civilization developed. In fact, temps. are still declining from about 4000 years ago. This is something often overlooked by those believing global warming is bad for us, and mostly willfully ignored by those whose livelyhoods depend on it.
In this respect it was the LIA that was unusual and modern warming simply looks like a return to the mean. Lucky for us!!
Ice ages are not something to look forward to….
In any case: all nothing to do with the CO2. More CO2 is good for us. It simply brings better crops and more food on the table.
http://www.letterdash.com/HenryP/more-carbon-dioxide-is-ok-ok
HenryP,
Here is one problem that was linked to global warming in the past.
http://en.wikipedia.org/wiki/Anoxic_event
Henry said: “To change my mind, you will first have to show me that warming in the past has caused catastrophes and huge problems. Until then, I’m not going to believe that warming in the future will cause catastrophes and huge problems”
Here’s a list of animals that went extinct in North America during the warming period at the end of the Pleistocene: “Giant sloths; short faced bears; giant polar bears; California tapirs; peccaries; the American lion; giant condors; Miracinonyx (“American cheetahs”, not true cheetahs); saber-toothed cats like Xenosmilus, Smilodon and the scimitar cat; Homotherium;[3] dire wolves; saiga; camelids such as two species of now extinct llamas and Camelops;[4] at least two species of bison; stag-moose; the shrub-ox and Harlan’s muskox; horses; mammoths and mastodons; and giant beavers as well as birds like teratorns. In contrast today the largest North American land animal is the American bison.”*
Here’s a list of animals that went extinct in South America during the warming period at the end of the Pleistocene: Giant ground sloth, Megatherium, the camel-like litoptern Macrauchenia, Cuvieronius, Stegomastodon, Doedicurus, Glyptodon, Hippidion and Toxodon, and the Smilodon.*
Here’s a list of animals that went extinct in Australia during the warming period at the end of the Pleistocene: “Short-faced kangaroo (Procoptodon goliah), Diprotodon (a giant wombat), the Marsupial Lion (Thylacoleo carnifex), the flightless birds Genyornis and Dromornis, the 5-meter snake Wonambi and the giant lizard, the megalania”.*
Here’s a list of animals that went extinct in Asia during the warming period at the end of the Pleistocene: “Woolly mammoth, straight-tusked elephant, aurochs, cave lion, cave bear, Cave hyena, Irish elk, woolly rhinoceros, Merck´s rhinoceros, narrow-nosed rhinoceros, and Elasmotherium”.*
And Henry, those are just the large animals, that leave dramatic fossil evidence of their extinction (*see the Wikipedia page on Pleistocene megafauna). The number of smaller animal species and of plant species both large and small that went extinct in the warming period at the end of of the Pleistocene is larger still.
I would think that these continent-wide extinctions of tens of species following an earlier period global warming would meet any reasonable person’s definition of a “catastrophe” or “huge problem”.
I think that this evidence of catastrophes resulting from global warming in the past might cause to a reasonable person to wonder whether warming in the future might cause catastrophes, as well.
But I suspect that is still not enough for you.
“Here’s a list of large animals that went extinct in North America during the warming period at the end of the Pleistocene: “Giant sloths; short faced bears; giant polar bears; California tapirs; peccaries; the American lion; giant condors; Miracinonyx (“American cheetahs”, not true cheetahs); saber-toothed cats like Xenosmilus, Smilodon and the scimitar cat; Homotherium;[3] dire wolves; saiga; camelids such as two species of now extinct llamas and Camelops;[4] at least two species of bison; stag-moose; the shrub-ox and Harlan’s muskox; horses; mammoths and mastodons; and giant beavers as well as birds like teratorns. In contrast today the largest North American land animal is the American bison.”*
Here’s a list of large animals that went extinct in South America during the warming period at the end of the Pleistocene: Giant ground sloth, Megatherium, the camel-like litoptern Macrauchenia, Cuvieronius, Stegomastodon, Doedicurus, Glyptodon, Hippidion and Toxodon, and the Smilodon.*
Here’s a list of large animals that went extinct in Australia during the warming period at the end of the Pleistocene: “Short-faced kangaroo (Procoptodon goliah), Diprotodon (a giant wombat), the Marsupial Lion (Thylacoleo carnifex), the flightless birds Genyornis and Dromornis, the 5-meter snake Wonambi and the giant lizard, the megalania”.*
Here’s a list of large animals that went extinct in Asia during the warming period at the end of the Pleistocene: “Woolly mammoth, straight-tusked elephant, aurochs, cave lion, cave bear, Cave hyena, Irish elk, woolly rhinoceros, Merck´s rhinoceros, narrow-nosed rhinoceros, and Elasmotherium”.*
—…—…
And here is the list of relationships between the increase in temperature (of some 2 degrees) and the disappearance of that list of large animals…. Zero. The increase in temperature would INCREASE the survivability and food and living area available to those large mammals.
Here is the reason they all died so rapidly: HUMANS moved in to their formerly isolated habitats killed them. Why did these humans kill them, and not smaller creatures? First and foremost, your ancestors ate them for food – or killed them as rivals for food – or killed them as rivals for life. In NO case can you establish any link between temperature and their death. In EVERY case we can immediately relate new human populations with the large animal deaths.
Small animals? Simple. On continental-sized areas, no one, even now, can kill enough of small critters to destroy them. Small critters are not a threat to survival either (disease not being known at the time and so even diseases or fleas and malaria or yellow fever was not a reason to kill even rats, mice, or vermin or insects.)
On islands? Easy. But on continent-sized areas? It has NOT happened even today.
I noticed something interesting in the 10,000 years Greenland ice core temperatures chart. The three sharp drop in climate temperatures (circa 8400 BC; circa 4700 BC; and circa 1300 to 1100 BC) and a bit dip in between 850 and 750 BC in the beginning period of the Little Ice Age. Also something about a time period within the Minoan warming.
The 8400 BC drop seem to correlate to a major volcanic eruption elsewhere in the world in that time frame? Or an asteroid or comet crashing on Earth?
The 4700 BC drop seem to correlate to the supposed origin story of Genesis in the Bible? The sinking of Atlantis before 4700 BC?
The 1300-1100 BC drop seem to correlate to the Exodus (Moses leading the Jews out of Egypt and into the promised land)?
The 850-750 BC dip seem to correlate to the sack of Troy and the founding of Rome?
The Minoan Warming period seems very interesting – it might be a period of time when there was the biblical flood occurred as told in the Bible? (Between 3500 to 3200 BC – melting of the remaining ice glacier shelves led to the great flooding?)
Just an interesting observation. Climate changes have proven to directly or indirectly influenced key religious and political events throughout human history.
Henry@JCL
Don’t trust Wikipidia too much.
I found complete changes made to the definition of the GHG effect
after referrring to it on some AGW sites.
Henry@RACookPE1978
Thanks! I thought I smelled a rat. God bless you!
Henry@Observant
Could be true
but again..
all has nothing to do with the CO2!!!
racookpe1978,
Oregon Perspective once again falls into the fallacy of the Argumentum ad Ignorantium: “Since I can’t think of another cause of these extinctions, then they must be due to global warming.” It is literally an argument from ignorance, and your response easily debunked it.
Extinctions happen all the time, constantly — otherwise, we would have pre-historic, pre-human and pre-SUV acheropterix still flying around witth their rudimentary feathers.
What’s really scary is that that is the best argument the alarmist contingent can produce.
Henry and Smokey-
Science conclusions are based on peer-reviewed evidence and reason, not on mere opinions. You have many opinions, but little evidence.
For example, Henry, where is your evidence that climate change was not a major factor in megafaunal extinction with global warming. You cite none.
The scientific community does agree on the reality of those extinctions, but does not agree on their cause. For example, see Haynes G, 2009. American Megafaunal Extinctions at the End of the Pleistocene.
The scientific community does agree “that global climate change, which is anthropogenic in origin, is progressing at a speed that is unprecedented at least during the last 22,000 years.” And that will effect the ability of individual species of plants and animals in the natural world to survive.
For my evidence for that opinion, based on ice cores see:
Rates of change in natural and anthropogenic radiative forcing over the past 20,000 years. Fortunat Joos and Renato Spahni. PNAS, February 5, 2008, vol. 105, no. 5, 1425–1430 (at http://assets0.pubget.com/pdf/18252830.pdf)
Here’s the summary:
“The rate of change of climate codetermines the global warming
impacts on natural and socioeconomic systems and their capabilities
to adapt. Establishing past rates of climate change from
temperature proxy data remains difficult given their limited spatio-temporal
resolution. In contrast, past greenhouse gas radiative
forcing, causing climate to change, is well known from ice cores.
We compare rates of change of anthropogenic forcing with rates
of natural greenhouse gas forcing since the Last Glacial Maximum
and of solar and volcanic forcing of the last millennium. The
smoothing of atmospheric variations by the enclosure process of
air into ice is computed with a firn diffusion and enclosure model.
The 20th century increase in CO2 and its radiative forcing occurred
more than an order of magnitude faster than any sustained change
during the past 22,000 years. The average rate of increase in the
radiative forcing not just from CO2 but from the combination of
CO2, CH4, and N2O is larger during the Industrial Era than during
any comparable period of at least the past 16,000 years. In addition,
the decadal-to-century scale rate of change in anthropogenic
forcing is unusually high in the context of the natural forcing
variations (solar and volcanoes) of the past millennium. Our analysis
implies that global climate change, which is anthropogenic in
origin, is progressing at a speed that is unprecedented at least
during the last 22,000 years.”
Where are your citations of peer-reviewed evidence for your many opinions?
Henry-
You’ve asked for experimental data showing the effect of changes in CO2 on global temperatures. Many research papers have addressed that question, which is why the scientific community is in consensus, and in disagreement with you, on CO2’s effect.
A comparison of past global atmosphere’s from ice cores with corresponding global temperatures is one way scientists have thoroughly addressed this question. A very detailed, 36-page analysis from NASA in 2008 is an excellent example of that kind of work: http://pubs.giss.nasa.gov/docs/2008/2008_Hansen_etal.pdf.
Can you cite anything comparable to defend your point of view?
To quote from the above:
“Decreasing CO2 was the main cause of a cooling trend that began 50 million years ago, the planet being nearly ice-free until CO2 fell to 450 ± 100 ppm. Barring prompt policy changes, that critical level will be passed, in the opposite direction, within decades. If humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted, paleoclimate evidence and ongoing climate change suggest that CO2 will need to be reduced from its current 385 ppm to at most 350 ppm, but likely less than that. If the present overshoot of this target CO2 is not brief, there is a possibility of seeding irreversible catastrophic effects.”
Can you cite a comparable study of the dynamic relationship between past global atmospheres and and associated global temperatures?
This paper also answers your earlier question about why observed temperature changes have not been greater:
“How long does it take to reach equilibrium temperature
with a specified GHG change? Response is slowed by ocean
thermal inertia and the time needed for ice sheets to disintegrate.
Ocean-caused delay is estimated in Fig. (S7) using a
coupled atmosphere-ocean model. One-third of the response
occurs in the first few years, in part because of rapid response
over land, one-half in ~25 years, three-quarters in 250
years, and nearly full response in a millennium.”
What is your citation for the expected response time to changes in GHG?
Smokey says:
January 2, 2011 at 9:52 pm
“Careful, there, Peru me boy, you’ll frighten yourself to death. Your arguments are the usual warmist Argumentum ad Ignorantium: “If I can’t think of any other reason than CO2 to blame, then the cause must be CO2!” You’re simply ignorant of the many other possible causes of fluctuating temperatures.”
Please explain what are those ” many other possible causes” that have caused Global Warming as well as a regional warming in Greenland unprecedented in the last 3300 years.
“All available evidence [as opposed to models, which are not evidence]…”
I have been talking about DATA , both instrumental and paleoclimatological. The so-called “skeptics” love to accuse the climate scientists of relying only on models, but that is quite false. They use DATA, as well as models (that are tested against the data. If the data contradict them, the models are rejected)
“… shows that during the Holocene there were numerous times when global temperatures were significantly higher than they are today.”
There is significal regional variability in past temperatures. The Medieval Warm Period, for example, was warmer than today in the North Atlantic, but cooler in the Tropical Pacific.
See here:
“Global Signatures and Dynamical Origins of the Little Ice Age and Medieval Climate Anomaly”
http://www.meteo.psu.edu/~mann/shared/articles/MannetalScience09.pdf
In South America, where I live, there was a MWP, but not as warm as today. See here:
“Ammonium concentration in ice cores: A new proxy for regional temperature reconstruction?”
http://www.leif.org/EOS/2009JD012603.pdf
Millenia earlier there was the warmest period in the Holocene, the Holocene Maximum. This too presented strong regional variability:
“Holocene thermal maximum in the western Arctic (0–180W)”
http://esp.cr.usgs.gov/research/alaska/PDF/KaufmanAger2004QSR.pdf
“Since that fact destroys the CAGW argument”
This is quite false. The holocene thermal maximum (HTM) was warmer than the 20th century average , as the Kaufman paper concludes: “At the 16 terrestrial
sites where quantitative estimates have been reported, temperatures (mainly summer estimates) were 1.6 +/- 0.8ºC higher during the HTM than present (approximately the average 20th century)”.
This in no way contradicts climate science. Higher temperatures in the past occurred in respose to past climate forcing, mainly changes in insolation, either from Milancktovich cycles for the Holocene Thermal Maximum or Solar Activity for the Medieval Warm Period and the Little Ice Age. This past warming and cooling events permit to determine the climate sensitivity to forcing changes. If, as the “skeptics” consistently affirm, the temperature reconstructions are wrong and the HTM and the MWP were indeed warmer than the reconstructions indicate, this means that the climate sensitivity is bigger than the climate scientists estimate (that is, a lot more than 3ºC per doubling of CO2), so future warming will be greater than the climate models, (that use a 3ºC per doubling of CO2 climate sensitivity) indicate.
“you simply ignore the evidence”
As the sample of the literature that I have shown indicate, this is not true. This sentence describe you, that ignore the last 105 years of warming in Greenland.
“and fall back on your ridiculous assertions that this is as warm as it has ever been in the Holocene.Trying to claim that today’s mild temperature is as warm as the Roman, Minoan and Holocene Optimum makes you sound like a raving lunatic. It is a ridiculous and erroneous statement with no basis in fact. ”
Your personal attacks against me are a perfect decription of yourself. The DATA shows that in Greenland the last 100 years have warmed between 2º
(continuation)
Your personal attacks against me are a perfect decription of yourself. The DATA shows that in Greenland the last 100 years have warmed between 2º C and 4ºC , no matter if you don’t like it. Your chart end in 1905. For the decade 2000-2010 the anomaly with respect to 1900-1910 is:
http://data.giss.nasa.gov/cgi-bin/gistemp/do_nmap.py?year_last=2010&month_last=11&sat=4&sst=1&type=anoms&mean_gen=1212&year1=2000&year2=2010&base1=1900&base2=1910&radius=250&pol=reg
Based on this station data:
http://data.giss.nasa.gov/cgi-bin/gistemp/findstation.py?datatype=gistemp&data_set=1&name=&world_map.x=291&world_map.y=42
You may ignore the evidence, but the Greenland Ice sheet not. It is in a process of accellerating melting, as GRACE data shows:
“Increasing rates of ice mass loss from the Greenland and Antarctic ice sheets revealed by GRACE”
http://thingsbreak.files.wordpress.com/2009/10/increasing-rates-of-ice-mass-loss-from-the-greenland-and-antarctic-ice-sheets-revealed-by-grace.pdf
And before you accuse me of focusing just on the Arctic (that is where Dr. Don J. Easterbrook obtained the data, because the GISP2 isotope data is from GREENLAND) the same article shows ACCELERATING ICE SHEET MELTDOWN IN ANTARTICA from GRACE data.
But you can ignore the evidence if you like. The millions of people that live in low elevation coasts not, they will have to move to higher elevations, with incalculable socio-economic costs.
Smokey says:
January 3, 2011 at 11:13 am
Oregon Perspective once again falls into the fallacy of the Argumentum ad Ignorantium: “Since I can’t think of another cause of these extinctions, then they must be due to global warming.”
Smokey, I have to agree with Peru on this one:
From Peru says:
January 3, 2011 at 1:19 pm
“Your personal attacks against me are a perfect description of yourself. ”
Peru and I have cited many papers, filled with data and analysis, in answer to your questions and to support our views. You and Henry offer little more than personal opinion in response.
Where are your citations from peer-reviewed journals that challenge what we have presented above?
Alternately, where is your own refutation of the data and analysis that we have referenced?
Two generations of scientists have worked diligently to provide answers on these topics.
“Arguing from ignorance” by ignoring the existing science which we cite is indefensible given the potential importance of these issues to human welfare.
Look at my last two citations or Peru’s last three citations, all of which were quite substantial, and please respond.
Smokey says:
January 3, 2011 at 6:55 am
“You look at a chart and come away with exactly the opposite conclusion that any rational person would arrive at: you say that ‘in the last 400,000 years CO2 levels did not rise above 300 ppm in the midst of big temperature swings…’
That shows beyond any doubt that CO2 is not the driver of the climate.”
No, it shows that CO2 is not the only driver of climate. Milankovitch cycles initiated the warming, and CO2 increases amplified it. Here are a few statements from Caillon et al 2003:
“This confirms that CO2 is not the forcing that initially drives the climatic system during a deglaciation. Rather, deglaciation is probably initiated by some insolation
forcing (1, 31, 32), which influences first the temperature change in Antarctica (and possibly in part of the Southern Hemisphere) and then the CO2. This sequence of events is still in full agreement with the idea that CO2 plays, through its greenhouse effect, a key role in amplifying the initial orbital forcing. First, the 800-year time lag is short in comparison with the total duration of the temperature and CO2 increases (5000 years). Second, the CO2 increase clearly precedes the Northern Hemisphere
deglaciation (Fig. 3).”
and
“Finally, the situation at Termination III differs from the recent anthropogenic CO2 increase. As recently noted by Kump (38), we should distinguish between internal influences (such as the deglacial CO2 increase) and external influences (such as the anthropogenic CO2 increase) on the climate system. Although the recent CO2 increase has clearly been imposed first, as a result of anthropogenic activities, it
naturally takes, at Termination III, some time for CO2 to outgas from the ocean once it starts to react to a climate change that is first felt in the atmosphere. The sequence of events during this Termination is fully consistent with CO2 participating
in the latter 4200 years of the warming. The radiative forcing due to CO2 may serve
as an amplifier of initial orbital forcing, which is then further amplified by fast atmospheric feedbacks (39) that are also at work for the presentday and future climate.”
Here is a url for the paper:
http://icebubbles.ucsd.edu/Publications/CaillonTermIII.pdf
I hope this clears up your confusion a little.
You can learn more with John Cook, with links to actual peer-reviewed scientific literature at:
http://www.skepticalscience.com/co2-lags-temperature.htm
Here is an excellent presentation by Richard Alley. At 33:50 he deals specifically with your issue:
http://www.agu.org/meetings/fm09/lectures/lecture_videos/A23A.shtml
Even Richard Lindzen says that a doubling of CO2 will result in 1 degree C increase (minus any feedbacks). This is just basic physics.
Smokey, if you can produce any peer reviewed paper that demonstrates the MWP caused any of the recent rise in atmospheric CO2 concentrations, I would love to see it. I am not going to waste time in a WUWT re-education program. I prefer to learn science from qualified scientists.
Clearly WUWT is becoming ever more desperate, promoting this spin to save the “global warming has stopped” meme in the face of, er…more global warming. How else to explain the publishing of a post of such laughable ineptness?
The Goddard stuff was silly, but this tops it.
And that’s with the adjustments.
Sounds like we need to send the data back for another round of government grant adjustments, to get the right answer.
Oregon cites a model-based conclusion that “is computed with a firn diffusion and enclosure model.” Enough with the lame grant-sucking links, OK? Models are not evidence, they are opinion. Try to think for yourself. I can provide a thousand links debunking climate alarmism, but I prefer to do my own debating. [But for those interested in numerous links debunking the CO2=CAGW conjecture, here’s a starting point.]
With about $7.5 billion per year being shoveled into “climate studies”, there is ample motive to use always-inaccurate models to get to the feeding trough. Read The Hockey Stick Illusion, available on the right sidebar, and you will clearly understand how the climate scam operates, who runs it, and who benefits.
And Phil Jones himself falsified the claim that the current rate of temperature rise is anything unusual. But it’s impossible to reason with members of the CO2 Doomsday Cult, any more than we can reason with Mrs Keech’s flying saucer cult, or the Jehovah’s Witnesses; they are all doomsday cults just like yours, with exactly the same kind of true believer acolytes.
The numerous charts and cites I have provided throughout this thread show conclusively that current temperatures are well within Holocene parameters. In fact, we are in the “sweet spot”. Not too hot, not too cold, but ju-u-u-u-st right. Sorry you’re unhappy about the lack of any catastrophe.
The null hypothesis of natural variability has never been falsified. And anyone who believes mass extinctions occur as a result of a 0.7°C rise over a century certainly has a screw loose. True believers can’t see just how silly that sounds to rational folks.
Finally, bgood2creation, you could not possibly have done a fraction of your reading assignment. It is obvious that your mind is closed to any possibility except climate catastrophe — for which there is still no credible evidence. You say you aren’t going to waste your time here. I don’t believe you, but if you’re telling the truth, good luck to you back in your usual echo chamber, which I assume is your cartoonist’s blog. He is your “qualified scientist”?? Please. He’s no more credible than Al Gore. [Notice that scientific skeptics don’t need a “How To” guide to do our thinking for us.]
FYI, this article was written by a well qualified scientist who has forgotten more about the climate than the three of you, plus your cartoonist pal, will ever learn. But you would rather nitpick objections that are only due to your lack of reading comprehension. This article wasn’t written for a journal, it was intended to help regular folks understand that there is nothing unusual happening. Only true believers are frightened of our normal weather.
Smokey:
You could do nothing else than repeat that “models are not evidence” instead than respond to the abundant DATA and EVIDENCE (paleotemperatures, instrumental record, measurements of sea level rise, data from GRACE, etc) that show that you are deadly wrong?
You only show in response incomplete timeseries (such as Greenland temperatures without the last 105 years that warmed a whole 2-4ºC there, temperatures unprecedented in at least 3300 years).
With your personal attacks and complete lack of peer-reviewed references you are showing yourself as a complete willful ignorant individual.
(Willful ignorant: someone that chooses to ignore the evidence for personal convenience)
Smokey says:
January 3, 2011 at 5:05 pm
“Oregon cites a model-based conclusion that “is computed with a firn diffusion and enclosure model.” Enough with the lame grant-sucking links, OK?”
I think you’ve confirmed the conclusion of nearly every commenter above, except for yourself and Henry.
You refuse to respond to data and analysis on climate research produced by hundreds of scientists from around the globe: a Swiss lab in the case you are mocking above.
Or you misrepresent the science to discredit it: Bubble enclosures in polar ice cores represent the only direct record of the paleoatmosphere. A diffusion and enclosure “model” of how gas is trapped in firn ice is used by ice core scientists to determine atmosphere gas concentrations at single time points and to allow comparison of ice core records across different sites.
I suspect if you only accept results from unpaid “scientists” who use no complex “research methods”, you and Henry never need worry about encountering “credible evidence” that might change your mind.
You only need reply, if you will actually read and review the publications I’ve cited above. They are just a few of the hundreds of examples of “credible evidence” of climate change – past, present, and future.