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
Inconvenient.. it means we can feel good about ourselves and continue polluting.
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?
Temperatures were lower than in Roman and medieval times, and falling... until the recent warming kicked in.
This is yet another hockey stick. I can't see how the Register is turning it into anti-AGW propaganda. Read the Nature article, not the Register.
thegodmovie.com - watch it
Where "crap" equals "plain old non-toxic non-polluting CO2".
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.
They in no way deny that human activity has affected the climate, they simply assert that changes in the Earth's orbit have caused more significant changes.
Palm trees and 8
"if you were standing in the forest, you could be hit by a falling tree. therefore, because we cut down this tree and killed that guy standing over there, we're not responsible, because getting killed by falling trees happens naturally"
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
That's a bold claim. It's easy to dismiss data, but you should at least have a reason beyond "I don't like it". Come on.
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
Yeah, everyone knows that God was smart enough to create the Earth with a feature to counteract the effect of a few billion people burning stuff all day long.
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...
IT was hot this summer! GLOBAL WARMING!!!!
Yes global warming is real, but most of the nimrods are running around claiming that the Heat wave was proof of it. I got so sick of trying to explain it that I started saying, "yes, and it's going to go up another 4 degrees every month, you had better start selling your Florida property before others find out! Minnesota is the new florida buy land near fargo!
Do not look at laser with remaining good eye.
He did. It's called extinction.
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.
There is a difference, in that they are different, but the article doesn't say anything about this study disproving AGW, only that it disproves the assertion that it is now hotter than it has ever been in the last X,000+ years.
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.
So you are saying that hypocrisy is ok when you do it, just not when someone who you perceive to have a different or opposing ideology does it?
Also, your ad hominem does nothing to help your credibility. It just makes you look like a rabid dog (ie foaming at the mouth).
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.
Maybe this paper has nothing to do with AGW?
What are you talking about? From the paper itself:
The forcing is substantial over the past 2,000 years, up to four times as large as the 1.6Wm2 net anthropogenic forcing since 1750 (ref. 4), but the trend varies considerably over time, space and with season5. Using numerous high-latitude proxy records, slow orbital changes have recently been shown6 to gradually force boreal summer temperature cooling over the common era.
That's the second sentence of the summary. How can it not be about AGW when it talks about this having an effect opposite of "net anthropogenic forcing since 1750"? Did you even read the paper?
Or are you saying AGW is nothing but goalseeking, and any data point that lessons the potential impact, or lessens the fear of a global apocalypse is thus unwelcome?
No, I did not say that. This paper looks legitimate and should be published and was published. It is interesting. My problem was that they seemed to have cherry picked a date range and then The Guardian took that and ran with it. In my opinion they flat out misinterpreted what the paper was saying. And here is the biggest problem I have with the article, the fact that they say "the last 2,000 years" when they really mean the period between 138 BC–AD 1900. I am attacking factual inaccuracies and bad reporting. Oh and you think I brought up AGW? How about this from the article:
Needless to say, prominent alarmist scientists and the UN's Intergovernmental Panel on Climate Change (IPCC) have not taken this view ...
And you're attacking me for bringing AGW into this? AGW isn't about goalseeking, it's about getting an accurate estimate on how much effect we are having on our environment. It isn't unwelcome if it's true and this paper is true. Whether this is pro or anti AGW doesn't make factual inaccuracies any less problematic in science reporting!
My work here is dung.
My kingdom for a modpoint today. The AGW issue is so emotional that discussion of data becomes impossible. No, it's worse: even the fact that there IS data to discuss is an implied attack on one position or the other.
My take on the entire thing is it's good for us to work on being more responsible, environmentally. We can and should find ways to be more efficient, cleaner, and self-sustaining, and make an aggregate profit while doing so. Sometimes it's the right thing to make a change to the way we do things, and the data is just the initial catalyst.
We've made these types of sweeping changes before, so it's not like a precedent hasn't been set. It really shouldn't be devastatingly hard to do it now. We've built interstates, we've waged wars, we've made amendments to our constitution, we've just recently enacted a game-changing healthcare bill (I'm not arguing the merits either way, just stating a big, hairy change). None of these things grind our economy to a halt; in fact, there is usually a TON of money to be made during times of change.
We don't need doom and gloom pronouncements in support of or economical arguments against these changes. We should do it because it's going to help our society in the long run.
Read RealClimate's coverage.
Basically, there was some growing problem (no pun intended) with tree-ring based temperature studies, and this study helps figure out how to take into account those problems, and a probably cause.
The bitter lessons of a veteran coder: http://bitterprogrammer.blogspot.com
We're basically entering an ice age
please provide a source when making claims. how can you tell? maybe some model is predicting it, but if we go by model predictions of the world, it would have ended many times already. acid rain, san andreas fault, ozone layer, massive famine, extinction of 90% of all species, some examples of the scaremongering you are willingly a part of.
We need to stop fighting "change" for the sake of fighting "change". The only thing that has been constant in the history of our planet from snowball earth to tropical conditions in the polar regions is that things "change". We need to stop fighting global warming / cooling / climate change and move away from the greatest red herring in history. Change can and will happen again, the concept of "normal" is a manufactured human concept that exists only because we are good at tracking things. Normal is a relative term.
We need to get back to basics and focus on things like pollution, living sustainably, recycling, improving technology and doing things like calling out Apple for dropping out of Epeat. You want to make a real environmental difference? Forget about carbon and focus on making a hybrid garbage truck that is affordable, have a Manhattan project for Thorium reactors, shut down coal power plants, focus on practical things like standardization of chargers for cell phones and putting teeth into standards like epeat.
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/
You interpret it as flamebait because you believe that it presents an argument against AGW.
No. He interprets the news article as flamebait probably based on these lines from it:
IPCC has got it all wrong, say boffins ...
Needless to say, prominent alarmist scientists and the UN's Intergovernmental Panel on Climate Change (IPCC) have not taken this view ...
The author of the news article calls the scientists who comes up with a study he likes 'boffins', and the other scientists (who are also doing sound science) who he disagrees with 'alarmist'.
... but you have revealed your own bias.
Indeed.
Look where all this talking got us, baby.
You ought to be more informed yourself. Re-read that "16 ships" article you linked. It says 16 ships create as much sulfur pollution as all the cars in the world because they burn "bunker fuel", an extremely dirty fuel. The article was given a poor title.
CO2 emissions from cars are much more than "not even a blip". That article says all the ships in the world emit nearly 1 billion tons of CO2 annually, and notes that the world's fleet of aircraft emits roughly the same amount. With a quick search, I dug up a figure for automobile emissions of roughly 0.6 billion tons of CO2 annually.
Intellectual Property is a monopolistic, selfish, and defective concept. It is "tyranny over the mind of man"
"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.
There are two articles linked in TFS. I think you have misinterpreted GP as referring to the first linked article (the Nature: Climate Change research letter) when it was actually referring to the second linked article (the Register piece subtitled "IPCC has got it all wrong, say boffins".)
It should have been obvious that GP was referring to the Register piece for two main reasons:
1. It referred to "the article" conveniently ignoring recent anthropogenic warming, which the Nature: Climate Change research letter mentions, for context, in its second sentence, but the Register piece doesn't mention at all.
2. As you yourself mention, it interprets "the article" as presenting an argument against AGW, which the Register piece does, but the Nature: Climate Change research letter does not.
I love reading - but you can't believe everything you read, either. A lot of articles are mere speculation, put forth by people who hope to be noticed. Farming increases average temperatures? Uh-uh, don't think so.
Staving off the next ice age? Hardly. Look back at the time lines of the ice ages. The interglacials have all been MUCH warmer than we have experienced in the last few thousand years. That little mini-ice age that we experienced was a tiny, tiny burp in the process of warming up, on the way to the interglacial.
And, THAT is what makes me so skeptical of all the "anthorpomorphic global warming" frenzy.
"Windows is like the faint smell of piss in a subway: it's there, and there's nothing you can do about it." - Charlie Br
California IS arid. LA is habitable only because they take water from everywhere else that they can, even by tunneling through the Sierra Nevada mountains to the Colorado river. Likewise, the Imperial Valley requires massive levels of irrigation from similar sources.
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.
The article in question was the result of actual research :) And it's well known that clearing land from forest raises temperatures. There are several reasons. One *minor* one is the contribution of CO2 from the burning of the cut materials. But there are other more significant reasons - none of which I can recall at the moment! :P
I am pretty sure that part of it is related to the way that forest moderates local temperatures - it's always cooler under the trees than out on the bare ground. But I can't remember the way it works. The timeframe went all the way back to the beginning of farming (4000 BC?)
I'm still rooting for Svensmark - and speculating on whether it's possible to maintain a city under a moving sheet of ice a mile thick. If it's in the right place (say, in a deep river valley like Pittsburgh so there wasn't much tendency to push on the side, such as a raised dome would suffer), could a city-covering frame be engineered carry the weight of the ice? If so, then some northern cities might actually be able to survive, given a sufficient energy source.
It's easier to be a result of the past, but more fun to be a cause of the future! http://www.spacefinancegroup.com/
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.
Just for information: Solar insolation changes are more relevant at higher latitudes and basically invisible in tropical proxies. So we are talking about a localized effect.
Ubi solitudinem faciunt, pacem appellant.
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 signal to noise ratio around here seems to be pretty low, as often happens with these global warming posts.
I just want to point out some of the actual content of the Nature Climate Change article (not the ridiculous Register article).
What was actually recorded/measured?
The proxy record in question is an estimate of summer temperature within a part of Scandinavia for the past ~2000 years. This is no small feat. But, it is important to recognize this (1) not a global temperature record, and not even a 'hemispheric' land record [which would involve aggregating far more data]. (2) it is also not an annual mean temperature record.
So right off the bat you know that saying ANYTHING AT ALL about changes in global mean, annual mean temperature (which lies at the heart of climate science) is going to involve a lot of conjecture and hand-waving. So go ahead and skip over 90% of the posts in response to this article and probably most of the internet, since they do not have much to do with this article.
Do these data provide a challenge to either prior data or model results?
With respect to data, please see the prior point. One regional, seasonal temperature series, however good, and however important, is not enough to overturn itself a suite of other data. It simply adds an interesting nuance and fills in some data gaps.
With respect to implications for modeling the future, note that the article explicitly states that this Scandinavian summer warmth is predicted by models. These are the same models we use to the predict the future. Thus this study is a vindication of coupled (ocean+atmosphere) models to accurately reproduce the regional pattern of climate change to well established (orbital variations) forcings.
One note on the magnitude of the 'forcing'. There is a bit of misleading language in the article and I see it echoed in posts here with regards to the magnitude of orbital forcing. There is NO ANNUAL MEAN/GLOBAL MEAN radiative forcing at the top of the atmosphere introduced by obliquity and precession (the orbital bands changing here). The forcing is entirely regional (i.e. at that latitude) and seasonal (more radiation in summer exactly cancelled by less in winter). It bears little resemblance to the forcing due to CO2 which does have a strong presence even in global and annual mean. The orbital forcing important for this problem is akin to holding a blowtorch to the mid-to-high latitude regions preferentially in summer. There is no surprise that it warms things. It tells us little about global temperatures or the global relationship between radiative forcing and temperature response.
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.
acid rain, ozone layer
Pollution controls drastically reduced the damage.
massive famine
Largely prevented by the green revolution.
extinction of 90% of all species
Still going on, they're just not species you care about.
san andreas fault
Still there, still going to be a problem at some point.
it would have ended many times already
None of these things would have 'ended the world', and most were prevented by human being choosing to change their behavior.
You seem to have confused doubt for skepticism.
Skepticism is what happens when you use data and logic to undermine a position, or undermine the data and logic supporting a position.
Doubt is what happens when someone says "nuh-uh" and thinks they've contributed meaningfully.
Yes. Unhinged doubt, based on a critical failure in your ability to judge the legitimacy of your own position. We're all on the edge of our seats wondering why a sixty year old man is sticking his fingers in his ears screaming "no no no no no it's not real."
The only reason your opinion matters is democratic voting.
StoneCypher is Full of BS