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Nature: Global Temperatures Are a Falling Trend
New submitter sosume writes "An article in Nature shows that temperatures in Roman times were actually higher than current temperatures. A team lead by Dr. Esper of the University of Mainz has researched tree rings and concluded that over the past 2,000 years, the forcing is up to four times as large as the 1.6W/m^2 net anthropogenic forcing since 1750 using evidence based on maximum latewood density data from northern Scandinavia, indicating that this cooling trend was stronger (0.31C per 1,000 years, ±0.03C) than previously reported, and demonstrated that this signature is missing in published tree-ring proxy records."
this should be good!
"Global Temperatures Were a Falling Trend."
The long term graphs in TFA show a long term decline, but they all still kick up sharply at the end when we get to the industrial age.
Drill baby drill - on Mars
Yeah, you can ask anybody who studied antique history. We all know that the romans grew wine in England. How do people think they managed to do that? Of course it was warmer back then than nowadays.
And then in the 1750's we had a very cold period where we can deduce from paintings that the East Sea was often frozen shut in the winter.
Is this really news to anybody?
Grats, slashdot for the misleading title. It is not like it was unknown that there has been a cooling trend on a 1000-year timescale. It may have been stronger than previously thought. This paper estimates it at -0.32 K/ka - Mann 2008 had it at -2.something K/ka. It was to be expected that the denialist would latch onto some cherry picked sentences - business as usual.
Ubi solitudinem faciunt, pacem appellant.
A team lead by dr Esper of the University of Mainz has researched tree rings and concluded that over the past 2,000 years
That's odd, according to the image from the paper the trend in question is from 138 BC–AD 1900. Of course, after reading the Guardian article, it's clear that the only papers in Nature worth this "reporter's" time are those that confirm his professional opinion on the state of global temperatures. Tell me, why exactly didn't they construct a trend from 138 BC–AD 2012? Was that 1900-2012 range more difficult to acquire for some hilarious reason? I mean, the data is in the graph right there.
You can select special time ranges, you can select windows and you can look at millions of years of data and say that temperatures right now are no big deal. But when you start to look at the rate of change (even in the paper's graph linked above) and you notice recently we're starting to approach rates that are increasingly less frequent in the historical record, I think it's okay to start to talk about what could be causing it. I mean now we're talking about the last two thousand years and yeah, that's an acceptable window but if we never swing back down below to average it out, at what point are you going to admit that the theory of C02 affecting global average temperatures has some weight to it? Trust me, if we increase by 2 degrees Celsius, you can increase this window back five millennium and say "Hey, they used to have temperatures warmer than we do now." It's entirely possible to endlessly play this game by moving the goal posts. But I don't think the Earth is going to be able to adapt as well as humans do to rapid change. I guess the only thing that can convince people is time and repercussions that actually inconvenience humans.
My work here is dung.
That wasn't the point of the paper. You interpret it as flamebait because you believe that it presents an argument against AGW. It does no such thing, but you have revealed your own bias.
So, you want to throw out data that doesn't fit your model?
Perhaps you should link up with the Creationist institute?
Do not pick and choose words or results from scientific papers. The scientists who published this paper are part of the X who agree that CO2 emissions are warming the planet.
Palm trees and 8
Another in a long list of inflammatory and inaccurate articles from secondary sources.
Like yesterday's baloney about Obama's executive order.
The first thing you should learn as a thinking adult is to read the primary source. In this case the Nature article.
Once they eliminate all of the other, non-tree-based lines of evidence, this should finally bust the myth of Northern Scandinavian Warming wide open!
sed "s/SJW.*$/... never mind. I was about to say something stupid, and also, I'm a troglodyte./Ig"
There are plenty of legitimate concerns over the increase in CO2 levels. In fact, just doing a quick search, it's easy to see that CO2 is affecting the pH of the ocean:
K. Caldeira and M. E. Wickett, "Anthropogenic carbon and ocean pH", Nature 425:365, 2003
K. Caldeira and M. E. Wickett, "Ocean model predictions of chemistry changes from carbon dioxide emissions to the atmosphere and ocean", J. Geophys. Res. 110:C09S04, 2005
J. C. Orr, et al., "Anthropogenic ocean acidification over the 21st century and its impact on calcifying organisms", Nature 437: 681-686, 2005
C. L. Sabine, et al., "The oceanic sink for anthropogenic CO2", Science 305:367-371, 2004
H. O. Portner, "Climate change affects marine fishes through the oxygen limitation of thermal tolerance", Science 315:95-97, 2007
H. O. Portner, "Climate change and temperature dependent biogeography: Oxygen limitation and thermal tolerance in animals", Naturwissenschaften 88:137-146, 2001
R. A. Feely, et al., "Impact of anthropogenic CO2 on the CaCO3 system in oceans", Science 305:362-366, 2004
which, in turn, has a number of devastating consequences for marine life, among other things:
Y. Shirayama and H. Thorton, "Effect of increased atmospheric CO2 on shallow water marine benthos", J. Geophys. Res. 110: C09S08, 2005
S. Widdicombe and H. R. Needham, "Impact of CO2-induced seawater acidification on the burrowing activity of Nereis virens and sediment nutrient flux", Mar. Ecol. Prog. Ser. 341: 111-122, 2007
H. L. Wood, et al., "Ocean acidification may increase calcification rates, but at a cost", Proc. Royal. Soc. B-Biol. Sci. 275: 1767-1773, 2008
M. D. Iglesias-Rodriguez, et al., "Phytoplankton calcification in a high-CO2 world", Science 320: 336-340, 2008
S. Collins and G. Bell, "Phenotypic consequences of 1000 generations of selection at elevated CO2 in green alga", Nature 431: 566-569, 2004
M. A. Gutowska, et al., "Growth and calcification in the cephalopod Sepia officinalis under elevated sewater pCO2", Mar. Ecol. Prog. Ser. 737: 303-309, 2008
S. Dupont, et al., "Near-future level of CO2-driven ocean acidification radically effects larval survival and development in the brittlestar Ophiothrix fragilis", Mar. Ecol. Prog. Ser. 373: 285-294, 2008.
A. J. Anderson, et al., "Life on the margin: Implications of ocean acidification on Mg-calcite, high latitude and cold-water marine calcifers", Mar. Ecol. Prog. Ser. 373: 265-273, 2008
W. M. Balch and V. J. Fabry, "Ocean acidification: Documenting its impact on calcifying phytoplankton at basin scales", Mar. Ecol. Prog. Ser. 373: 239-247, 2008
J. A. Berge, et al., "Effects of increased sea water concentrations of CO2 on growth of the bivalve Mytilus edulis", L. Chemosphere 62: 681-687
T. F. Cooper, et al., "Declining coral calcification in massive Porites in two nearshore regions of the northern Great Barrier Reef", Glob. Change Biol. 144: 529-538, 2008
F. Gazeua, et al., "Impact of elevated CO2 on shellfish calcification", Geophys. Res. Lett. 34: L07603, 2007
K. R. Hinga, "Effects of pH on coastal phytoplankton", Mar. Ecol. Prog. Ser. 283: 281-300, 2002
O. Hoegh-Guldberg, et al., "Coral reefs under rapid climate change and ocean acidification", Science 318: 1737-1742, 2007
P. L. Jokiel, et al., "Ocean acidification and calcifying reef organisms: A mesocosm investigation", Coral Reefs 27: 473-483, 2008
H. Kurihara, "Effects of CO2-driven acidification on the early development stages of invertebrates", Mar. Ecol. Prog. Ser. 373: 275-284, 2008
S. I. Siikavuopio, et al., "Effects of carbon dioxide exposure on feed intake and gonad growth in green sea urchin, Strongylocentrotus droebachiensis", J. Aquac. 266: 97-101, 2007
H. Kurihara, et al., "Effects of raised CO2 concentration on the egg production rate and early development of two marine copepods (Acartia steueri and Acartia erythraea)", Mar. Pollut. Bull. 49: 721-727, 2004
H. Kurihara, et al., "Effects of increased seawater pCO2 on early development of the oyster Crassostrea gigas", Aquat. Biol. 1: 91-98, 2007
H. Kurihara, et al., "Sub-leath effects of elevated concentration of CO2 on planktonic copepods and sea urchins", J. Oceanogr. 60: 743-750, 2004
Looking at the graph you can see at least 6 instances of abrupt temperature increases and at least 5 times temps exceeded the trend.
In that context, our recent increases are not unique. If you want to pin the recent increases on Man, then you need to explain how the past increases came to be and why the current increases are not driven by the same forces.
When Fascism comes to America, it will call itself Anti-Fascism, and tell you to give up your guns.
Real Climate has a much more interesting take on the paper:
http://www.realclimate.org/index.php/archives/2012/07/tree-rings-and-climate-some-recent-developments/
Finding the weak points in various temperature proxies and using that knowledge to improve the overall accuracy of the temperature record is a good thing, and a normal part of the scientific process. Sensationalist reporting of the type The Register engages in just serves to inflame the debate without adding anything useful to the discussion.
Since you're too lazy to google "tree ring data proxy temperature" or some variation thereof...
http://wattsupwiththat.com/2009/10/30/yamal-treering-proxy-temperature-reconstructions-dont-match-local-thermometer-records/
http://pielkeclimatesci.wordpress.com/2010/05/17/comments-on-the-tree-ring-proxy-and-thermometer-surface-temperature-trend-data/
Basically, tree ring width is sensitive to a LOT of factors, and generally, temperature doesn't affect them nearly as much as these other factors. Using tree rings as a proxy data is analogous to using a car's radiator temperature to determine its speed. It certainly affects it, but the signal is pretty low and the noise is rather high...
This retarded press release was written by someone that can't even GRASP the science, or purpose, of the published paper. Please, for the love of god, stop posting science topics on /. based on what some ingrate with a word processor posts up to some off-beat web periodical with a political agenda. The "graph" given by the press release article doesn't even appear in the paper and is missing a lot of annotations and descriptions necessary to properly evaluate the data. Important things. Like a Y-axis. And the method used to develop the data- surprise, most of it's modeled/reconstructed. Which is FINE if you grasp what they were trying to do with this publication.
And before I jump into the paper can we clearly define what journal an article is published in? Saying "Nature" is misleading. It's "Nature: Climate Change". Not similar, at all.
The paper is a methods paper. It's outlining a very interesting way to get at fine-resolution temperature fluctuations on a not-so-far-back time scale. Additionally, the moving average rise in temperature isn't suggesting it was HOTTER back then than now (as this submission and the press release indicate) but that instead our ESTIMATES of how hot it was are off.. SLIGHTLY. How far off? Here, let me copy primary literature for you. I hear that's good journalistic practice.
"...These findings together with the trends revealed in long-term CGCM runs suggest that large-scale summer temperatures were some tenths of a degree Celsius warmer during Roman times than previously thought. It has been demonstrated4 that prominent, but shorter term climatic episodes, including the Medieval Warm Period and subsequent Little Ice Age, were influenced by solar output and (grouped) volcanic activity changes, and that the extent of warmth during medieval times varies considerably in space. Regression-based calculations over only the past millennium (including the twentieth century) are thus problematic as they effectively provide estimates of these forcings that typically act on shorter timescales. Accurate estimation of orbitally forced temperature signals in high-resolution proxy records therefore requires time series that extend beyond the Medieval Warm Period and preferably reach the past 2,000 years or longer6. Further uncertainty on estimating the effect of missing orbital signatures on hemispheric reconstructions is related to the spatial patterns of JJA orbital forcing and associated CGCM temperature trends. First, the simulated temperature trends, indicating substantial weakening of insolation signals towards the tropics, can at present be assessed in only two CGCMs (refs 7, 8). More long-term runs with GCMs to validate these hemispheric patterns are required. Whereas the large-scale patterns of temperature trends seem rather similar among the CGCMs, the magnitude of orbitally forced trends varies considerably among the simulations. Additional uncertainty stems from the weight of tree-ring data and varying seasonality of reconstructed temperatures in the large-scale compilations. Although some of the reconstructions are solely composed of tree-ring data, others include a multitude of proxies (including precipitation-sensitive time series) and may even include non-summer temperature signals. Some of these issues are difficult to tackle, as the weighting of individual proxies in several large-scale reconstructions is poorly quantified. The results presented here, however, indicate that a thorough assessment of the impact of potentially omitted orbital signatures is required as most large-scale temperature reconstructions include long-term tree-ring data from high-latitude environments. Further well-replicated MXD-based reconstructions are needed to better constrain the orbital forcing of millennial scale temperature trends and estimate the consequences to the ongoing evaluation of recent warming in a long-term context."
I wish I could just copy past the whole article into peoples brains and make them understand the difference between science and sensationalism.
The fact that climate change took place centuries or even millennia ago doesn't prove that it was not caused by people. Humans have been doing things to affect the climate for a long time.
Charles C. Mann, in his excellent book 1493, discusses a theory that the "Little Ice Age" (a period of cooler than usual temperatures from roughly 1550-1800) was the result of the Columbian Exchange. Basically, the Native Americans had populated large portions of the New World, and in so doing had cleared most of the forest lands. After Columbus and his successors arrived, the Native Americans died at an insane rate from European diseases, and new forests grew across vast swathes of the Americas. This in turn resulted in far lower CO2 levels and consequently lower temperatures.
When Al Gore and other politicians start saying 'the time for discussion is over' on such a complex subject, technically-trained people know that the time for discussion and study is just starting. This article summarizes an interesting study that points to warmer temperatures in roman times. Archaeological studies also support this. For example, many of the seaports that those Romans used are now far inland thanks to a lower sea level due to cooling temperatures. AGW believers minds are firmly closed to any idea that does not include imminent peril from 'hockey-stick' warming. The reality is that the support for AGW caused by atmospheric carbon dioxide concentrations rests on very crude computer models of the global climate that will probably be the subject of horse laughs 50 years into the future.
The Micheal Mann hockeystick used in An Inconvenient Truth is substatntially located aroudn th e same lattitide, using European and Russian trees. So if you are going to call this into question, you have to also call Mann's hockey stick into question. Ironically, they will both live or die together. What this paper does is correct for orbital mechanics, so in a way, it is a refinement that tilts the hockey stick a bit.
Slashdot's rate-of-post filter: Preventing you from posting too many great ideas at once.
So let's see, there are a few holes in your argument. I don't think your environmentalist point of view is necessarily wrong, but some of the evidence you provide is flawed.
It's important you realize that the majority of photosynthesis doesn't include trees, see for example algaes: http://en.wikipedia.org/wiki/Carbon_sink
Additionally, our cars are not even a blip on the global scale for carbon output: http://www.dailymail.co.uk/sciencetech/article-1229857/How-16-ships-create-pollution-cars-world.html
Furthermore, while it isn't on a global scale, we've basically stopped having a negative impact on forest sizes here in the US for a while: http://www.wendmag.com/greenery/2011/02/the-u-s-has-more-trees-now-than-100-years-ago/
Next, many of the sources of greenhouse gases are unrelated to burning things, and just normal biological processes which are involved in food PRODUCTION: http://science.howstuffworks.com/environmental/life/zoology/mammals/methane-cow.htm
Food for thought (pun intended), but I'm not challenging your goals, just want you to be more informed in your arguments or you make yourself and any others that hold your views look bad.
What stuff? The stuff you happen to believe in?
As you can see in the graph of TFA, it has been colder and warmer than the mean line (hint: its the red dots)
As you can see in the graph of TFA, it has been colder and warmer than the mean line without us doing a lot (hint: its the red dots)
The problem is that you WANT a warmer climate and when you are proven wrong then the "cautionary principle" is called in to underline your presumptions. Data, or it wont happen.
TFA --> (hint: its the red dots)
No 2000 years is nothing, let alone 50 years of industry by men. Yes, it has been slightly longer, but it was only until the postwar economic boom since we really cranked up the CO2 and other natural gases.
quo errat demonstrator
rm -rf --no-preserve-root /
The current hockeysticks, which completely validate the original Mann paper, are based on multiproxy reconstructions that range from polar ice cores to tropical lake sediments to coral reef proxies etc. etc. But yes, as you said, if the orbital forcing is indeed as strong as they speculate from one highly regional source, the hockey stick gets perhaps a bit tilted. It's fundamental message stays the same, though.
Ubi solitudinem faciunt, pacem appellant.
An article in Scientific American back around 2003-2004 (I forget when exactly) covered work that seemed to show that indeed, we were not only overdue for another ice age, but we had begun going in back a few thousand years ago. But the advent and epansion of farming (which has a tendency to warm things, for several reasons discussed in the paper/article) increasingly mitigated the cooling trend. The variance between actual temperatures and predicted temperatures for entering into an ice age was linear with the expanding acreage of farmland. So the author argued that we have been staving off the next ice age for some 4000 years. He had citations, sorry I'm too lazy to go back and find the article.
It's easier to be a result of the past, but more fun to be a cause of the future! http://www.spacefinancegroup.com/
"Oolons
Did Lewis read the same paper?
Thanks to the link below I got to read the actual paper - the standard of reporting on this issue is atrocious. The paper looked at tree data from a small area of Scandinavia. Also pointing out that they have experienced a lot less warming in recent years than other northern areas.... Hmm do you think that may be true 1000's of years ago - it could have been warmer or cooler than the global average we don't know. So for CLIMATE in Lewis's article read WEATHER, i.e. Local effects for which it is extremely inaccurate to extrapolate to the world. Glad my knee jerk feeling that this was a daft extrapolation has been verified by the paper."
and
Anonymous Coward
Paper says:
"These findings, together with the missing orbital signature in published dendrochronological records, *suggest* that large-scale near-surface air-temperature reconstructions9, 10, 11, 12, 13 relying on tree-ring data *may* underestimate pre-instrumental temperatures including warmth during Medieval and Roman times."
Lewis says:
"CLIMATE WAS HOTTER IN ROMAN, MEDIEVAL TIMES THAN NOW: STUDY"
flame on...
The English word fart is one of the oldest words in the English vocabulary.
Either it is the long-term climatic change that the IPCC and others have been warning about, or it isn't. You say "a few years of drought" - that isn't long-term climate at all, but short-term weather patterns. Anyway, the US east of the Rockies (which I'll bet is where you are) is yammering about hot temperatures and drought being signs of global warming. Meanwhile, lots of the rest of the planet is having a cool, rainy summer. Your local weather is exactly that: local, and short term.
I am definitely a skeptic. There is no question that CO2 contributes to a greenhouse effect, however, there is no evidence (and never has been) that this triggers large positive feedback cycles. It has all been based on computer models, and most of the predictions of those models have been wrong.
Enjoy life! This is not a dress rehearsal.
We're basically entering an ice age
please provide a source when making claims. how can you tell?
I encourage every slashdotter interested in the global warming debate to take a hard look at the Vostok Ice Core Data. This is the most solid (ahem) evidence of global temperature change over any sort of significant time scale. It's hard data, not "interpreted" or "adjusted" measurements. Longer term data is here.
Obviously, we're currenty in an Ice Age - when the Earth is in a warm period there is no year-round ice anywhere, not even the poles. The Earth gets much warmer during the warm periods, though mostly it warms at the poles and becomes a more even tropical temperature, IIRC.
It's possible that we're actually exiting the long term ice age, but that's a heck of a claim to make (since it's ~50 million years old, the odds would be very low), and would require a heck of a lot of evidence.
Socialism: a lie told by totalitarians and believed by fools.
Whatever you choose to call them, it is clear that there are a group of people who like to style themselves "skeptics" who reject the overwhelming consensus of climate scientists--a consensus that has been reviewed and endorsed by the National Academy of Sciences (along with nearly every elite professional scientific society in the world). It is also clear that this "skeptic" point of view has been supported by an extremely well-funded public relations campaign backed by individuals and organizations who have a financial interest in sales of fossil fuels.
A distinguishing feature of this kind of "skeptic" is that their "skepticism" is notably one-sided.
For example, a genuine scientific skeptic will read the scientific literature on historical climate reconstruction and will reach the following conclusions: Reconstructing global temperatures prior to actual temperature recording is difficult, and relies on the use of "proxies," which are indirect methods of estimating temperature. These are subject to a variety of errors and artifacts, and global coverage is spotty. In addition, there is limited information regarding factors driving temperature, such as atmospheric CO2 and energy output of the sun. This is an active area of research and quite interesting, but does not really shed a great deal of light on modern global warming, which has unambiguously been demonstrated to be the result of increased atmospheric CO2.
On the other hand, the "skeptic" will reject the great mass of climate reconstructions (generally with ad hominem remarks about climate scientists or scientists in general), but will accept as gospel truth a just-published article that yields divergent results suggesting that temperatures in the past might have been higher than previous estimates. Similarly, the "skeptic" will enthusiastically embrace the "evidence" of third-hand accounts of medieval agricultural practices in northern europe as indicating that there was a warm period during medieval times--and conclude (in a bizarre jump of logic) that if medieval times were warm for some reason that (with our very limited information about climate drivers of the time) we don't understand, that we don't have to worry about the fact that we are currently seeing exactly the type of temperature increases that are predicted as a consequence of the CO2 that we are adding to the atmosphere.
Of course, a real scientist will have a very different reaction: We don't know if there was some unexplained process that warmed things up during medieval times--there isn't enough information to figure out for sure that that really happened, or if it did, what the cause was. But what if it did? That's even more disturbing. We know what the modern warming is due to--it's due to increased CO2. What if there is some other process that could produce a comparable warming in the absence of increased energy from the sun (because we've measured that, and we know it's not increasing)? Wow, that's really scary! What if that unknown process were to suddenly kick in on top of CO2? The projected warming from CO2 is bad enough, but add in some warming from some other unknown mechanism on top of that, and we could have a real catastrophe! This makes controlling CO2 even more important than I thought!
Here's one of my favorite sources. Examine the graphs, and you'll find that few inter-glacial periods lasted over 20 thousand years, and we've been in ours for... 20 thousand years. Add to that the trend over the last 10 million years, and it seems that these ice ages are getting colder and colder. Straight line projection for another 10 million years puts us in snow-ball Earth territory. It's entirely possible that higher life on land was (and still may be) nearly at an end.
However, if you just want to be anal, like most Fox News fans when it comes to the topic of global warming, we can just take NASA's satellite measurements of surface temperatures since 1972. The Earth is warming. There's no way an intelligent person can look at that graph and not draw the obvious best line fit conclusion. Actually, that's not quite right, because there are plenty of intelligent people who are simply incapable of seeing what they don't want to see.
Celebrate failure, and then learn from it - Nolan Bushnell
The planet has been cooling for the last 55 millions years and we are in an ice age that is getting colder in the long term. In the medium term we are in a warm interglacial and the temperature is cooling towards the next Milankovitch minimum in about 23,000 years. That is the trend you are seeing since Roman times. Without humans the planet would be cooling not warming.
Over the last century and half the climate has warmed as the the planet comes out of the Little Ice Age.
Over the last half a century you have AGW on top of the natural variations due to forcing by C02, Methane, Soot, reduction in SO4 and feedback from changes in water vapour in the atmosphere.
Over the last decade and a half the planet hasn't warmed because due to low solar radiation and less El Nino events.
No Nature doesn't care about us and will most likely freeze us to death. In the short term we may cook ourselves first though.