Slashdot Mirror
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.
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"
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.
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.
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 /
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!
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.