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20th Century Warmest In 1200 Years
gcranston writes "Research from the University of East Anglia in Norwich, U.K. shows that the 20th century was the warmest for the northern hemisphere since approximately 800AD. Historical climate data were calculated from weather 'proxies' such as tree rings, ice cores, and seashells from Europe, Asia, and North America, and attempted to address the shortcomings of earlier studies. The findings support the argument for global warming as a result of human interference rather than natural climate change."
It's "Global Climate Change",
The findings of this study are hopelessly flawed in that they conflict with the principle that only the scientific positions of the campaign contributors to the ruling party in the United States are in any way valid. Please take your actual science with its actual testing and actual methods of deduction elsewhere, as we've got Italian sports cars, mansions, and private jets to buy.
This sig, aah-ah, is comin' like a ghost-sig...
and all I can say is "MMMMMMMM, toasty!"
It's the Bush Administration's gift to the world -- lower heating bills and summer vacations all year round!
Not all scientists agree that the 20th century is the warmest period in recent history
Would they still think this in lieu of the following recently uncovered data?
Global Warming vs. Ice Age
Global Warming vs. Global Cooling
Global Warming is true vs. Global Warming is false
If this is the warmest in so many years, then back then it was hotter that what we have now.
I am defenseless. Use your button. Mod me down with all of your hatred.
There has been a 19.4% increase in the mean annual concentration of CO2 in the atmosphere from 1959 to 2004.
During the 1959-2002 period, the total CO2 emissions equaled ~220 gigatons; ~14% of the atmospheric CO2 in 1959.
In 2002, Humanity pumped 7 gigatons (6975 megatons) of CO2 into the atmosphere. That is almost 4 times the emissions from 50 years ago (1952: 1795 megatons), and is more than was released from 1751-1886 (136 years: 6732 megatons).
There is a close correlation between Antarctic temperature and atmospheric concentrations of CO2. The extension of the Vostok [antarctic ice core] CO2 record shows the present-day levels of CO2 are unprecedented during the past 420 thousand years.
Cites:
Atmospheric carbon dioxide record from Mauna Loa [ornl.gov]
Global CO2 Emissions [ornl.gov]
Historical carbon dioxide record from the Vostok ice core [ornl.gov]
Earth's atmosphere [wikipedia.org]
Historical climate data were calculated from weather 'proxies' such as tree rings, ice cores, and seashells from Europe, Asia, and North America, and attempted to address the shortcomings of earlier studies.
And we all know how accurate and exact historical measurements are.
Your hair look like poop, Bob! - Wanker.
Let's take a pool on exactly how many posts this story will receive from partisans claiming that because the earth has been this warm in the past (the 800s) through natural causes, the earth either is not unusually warm now, or if it is warm now it must be because of natural causes--
not realizing that (1) the thing that makes manmade global climate change distinguishable from natural global climate fluctuations is not how warm the earth has become, but how quickly and consistently the earth has warmed since the industrial revolution;
and (2) the problem with manmade global climate change is not how warm the earth is now, but how warm it will become if this consistent, quick rise continues...
What's your guess? 10? 40? 100?
Help me out here. If it was warmer in 800 AD, what 'human interferance' caused the global warming in the 9th century?
Insert Generic Sig Here:
Fact is, we're looking at a ~2000 year snapshot of an incredibly comlex system that's a few billion years old.
I'm not saying that there isn't claimte change -- of course there is. I'm also not saying that man doesn't affect it -- of course we do. But what I'm saying is that we don't know how we are affecting it. Maybe the "Little Ice-Age" ended because of man. Perhaps we saved ourselves from freezing to death by creating a cozy CO2 blanket?
My 2c...
Let me welcome you to Trondheim, Norway. In the second half of this January we had abnormally high temperatures, as high as +5C, in a period when -20 is not uncommon. It is actually a few years since the last time I was exposed to -20. It is not uncommon either that brief buffs of heat from the Gulf stream blow some + degrees around here even in January, but I never saw it lasting two weeks in a row-normally it's more like a day or two. This time all the snow in the city melted.
Victims of 9/11: <3000. Traffic in the US: >30,000/y
And, in a few years, when melting arctic and Greenland ice has disrupted the Atlantic Conveyor, northern europe, including Great Britain and Scandanavia, will be much, much colder.
Well, I know that for at least the past 35 years (and perhaps even longer) these temperature cycles you describe occur - and very rapidly.
I've noticed this pattern where a period of global warming occurs over the course of several months, culminating in a period of almost overwhelming heat. This is followed by a rapid and drastic reduction in global temperature to the point where actual ICE falls from the sky!
I assume that this "mini-ice-age" occurs as a direct result of the previous global warming.
After the earth has managed to balance out and recouperate from mankind's abuse, it begins to thaw and warm up - but almost immediately the rapid global warming begins, and the cycle starts all over!
And this happens EVERY SINGLE YEAR!
BRE
"Dude check me out. I'm like a little otter. A SEXY little otter"
No, it's not. Modeling climate change is far more complicated and difficult than a simpleminded approach like that. For one, it's difficult to predict the effects of aerosol and cloud formation, both of which reflect/scatter light and reduce the total incident solar energy. It's also necessary to model the CO2 harvesting charactersitics of oceans, and glacial movement as well.
I'm not saying global warming *doesn't* exist, or that it's anthropogenic, but real climatologists will tell you that saying CO2 + IR absorption = warming doesn't cut it.
The warming of the globe as a whole will cause some locations to actually cool down, as air and water currents re-route.
This does not change the fact that the globe as a whole is warming.
(And frankly it is irrelevent whether humans are to blame or not. It is warming, which is going to cause climate change. Are we ready for it? If not, we may want to try to stop it (or at least slow it down).
I doubt we are.)
'Sensible' is a curse word.
We're looking at a ~2000 year snapshot of an incredibly complex system that's a few billion years old and that our immediate livelihood and wellbeing depend on. And we keep pushing it like it has never been pushed before - all the while claiming that because we don't understand the system, it's ok to continue current behavior. How is that smart?
Ice core samples give a chronological record of atmospheric conditions - in particular CO2 concentrations.
To analyse them, we assume that before man, CO2 concentration changes are mostly an *effect* of natural temperature changes (we can eliminate other natural sources of CO2 by various methods. E.g. we know if volcanos had an effect by sulphur in the sample, etc.) and so would track temperature changes closely. We then use time periods where we both have ice core data and other temperature data to calibrate a scale to convert CO2 concentration readings into temperatures, and viola, a temperature history.
Bit more complicated than that, but that's the essentials.
Day After Tomorrow is a load of crap.
Earth is way overdue for a magnetic field reversal. They have an average interval of 1/4 million years and it has been 3/4 million already since the last one. Some say it is beginning with the loss of a magnetic pole in certain places in the southern hemisphere. It could be the cause of the ozone layer loss because as the field weakens it radius at the poles grows. When the field is strong the field meets at the poles in a tight radius.
Here are some cool sims from Los Alamos National Laboratory.
As we lose protection more radiation gets through and mother earth gets a temperature. I'm not saying that 100 years of intense burning hasn't contributed but this seems to be an ignored fact that may be contributing in a large manner.
I first heard of this from watching a NOVA program. Here is the NOVA site on earths magnetic fields with some animations.
Ok, now where did I put the SPF 10,000?
Gizmos Gagets For Ninjas
Didn't the Russians say just a couple of weeks ago that they're having the coldest winter on record?
We're coming out of an ice age. Of course it's the warmest its been in centuries. It's returning to normal.
I'm going insane here -- everyone is saying "how does this prove anything if it was warmer in 800AD?" THAT'S NOT WHAT THE ARTICLE SAYS! "Warmest in 1200 years" does NOT implicitly mean it was warmer 1200 years ago, people -- read the article, we CAN ONLY TEST BACK 1200 years using ice cores, trees, etc.... it was COLDER 1200 years ago, that's what the article says... and as for the folks who mentioned the Little Ice Age, etc. -- yes, they mention that too (and the Medieval Warm Period from 890 to 1170), but both eras were not CONTINUOUSLY warm or cool, but were PUNCTUATED by hot and cold SPELLS... The concern of global warming is that the CONTINUOUS temperature is changing. I will concede that without data before 800AD, the study is looking at a pretty small sample of time, and that there are so many factors in such a hugely complex weather system to take into consideration, so I have no problem at all with those arguments, just with the fact that the majority of people here seem to be good at quickly sorting through text looking for keywords (such as "since 800AD") without actually COMPREHENDING what they are reading.... /rant.
No it doesn't. Every hear of the thing that is 93,000,000 miles away called the Sun? It's causing global warming of Mars as well.
Strange women lying in ponds distributing swords is no basis for a system of government.
"7th century A.D. found to be warmer than 20th."
Reads a bit differently, doesn't it?
How many cars were belching so-called greenhouse gases across North America in 800 A.D.? Were the theories of man-caused global warming correct, then shouldn't the 20th century be BY FAR the warmest century ever, thanks to car emissions and CFC's?
Perhaps, before they were thinned out, the environment was being catastrophically altered by all the buffalo flatulence.
That's an important point. Calling the phenomenon Global Warming is perhaps misleading. Some places will get warmer, others colder. Some will be wetter, some dryer. Dumping more energy into a chaotic system like the climate means more extreme climates, not necessarily warmer ones.
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
I thought yesterday Slashdot told me there was no such thing as time. So 1200 years ago is actually now. I'm so confused.
Big ones, small ones, some as big as yer 'ead!
Give 'em a twist, a flick o' the wrist...
Here is some commentary on this article from the Junk Science people:
http://www.junkscience.com/feb06/NotCO2.htm
I find their opposing views are sometimes interesting.
When we can get a reliable weekly weather forcast I'll start putting more faith in their predictions and understanding of a few billion years of changes.
Is it possible that the climate is just snapping back from a thousand-year cold spell? Hasn't it been suggested that the dark ages were in part caused by a drastic drop in temperature, possibly due to abnormal volcanic activity?
I doubt anyone is denying the reality of global warming/global climate change these days, but stuff like this certainly gives me reason to wonder if it's mere vanity that makes us so certain that we are responsible for the events we are observing.
120 characters for a sig? That's bloody useless.
The last ice age started melting roughly 10,000 years ago. The climate has been on a warming trend since that time. The average temperature for the earth over the historical period since complex life developed is much warmer than it is now. Logically, our current mean temperatures are abnormally cold compared to the mean temperatures over the last 35 million years.
The high probability is that "global warming" is simply the globe resetting from the "global cooling" of the last 100,000 years. That may not be good for us, since we evolved to live in a cooler climate, but its normal for the planet.
At the end of the day, the argument is not how to prevent global warming since that cannot be done. The argument is how to adapt to the new conditions.
If the data they considered stops 1200 years ago then it can be correct that this was the warmest century in those 1200 years *and* it was colder before that. Similarly, if this was the hottest January on record that doesn't mean the hottest January ever.
Not necessarily:
Assume we are looking at n time intervals numbered 1, 2, ..., n. If the maximum observed temperature was in interval n, we can assert that this interval was the warmest of the last n intervals.
Now consider interval 0. If this interval is warmer than n, the strongest assertion we can make is that the recent interval is the warmest of the last n. If the recent interval is warmer than 0, we could make a stronger assertion. However, the validity of 'warmest of the last n remains.
In effect, you are assuming that the researchers made the strongest possible assertion. Another alternative is that they were only able to measure a certain number of intervals.
Clouds can also have a blanketing effect as well as a reflective effect. Also, H2O is a greenhouse gas, adding still more complexity to the problem. Add in the natural variability of solar influx, changes in the reflectivity of the surface due to deforestation, changing ice cover, urbanization, etc and it becomes even more complex. Frankly, I'd rather model supernova explosions, they're a lot simpler.
So here we are again, another long rant from two sides of an argument where those arguing are not in possesion of most of the facts.
It always amazes me that these two sides will get into bitter feuds over this subject and no one seems to want to put it in any context. For me what it comes down to is this: we can spend a lot of money, time, and research trying to find out if we are a contributing factor to global warming, only to discover it may be too late, or we can spend even more money, time, and research trying to change the way we interact with the atmosphere. And in the end if those who claim that global warming is impacted by humans are right and we listened to them then we are on our way to fixing it and have a cleaner environment for the future. If they are wrong and we listened to them we still have a cleaner environment and we might just find that all those chemicals we were pumping into the atmosphere had other effects which would then be limited. If, on the other hand we don't listen to them and they are right then we have to learn to live in a new world climate and deal with the vast ammounts of crap we have been pumping into the atmosphere for centuries.
What it comes down to, for me, is this: do we want to risk the global climate on this? Is it worth the piece of mind to know that what happens is out of our control instead of our fault?
Nuclear winter will cancel the global warming out.
On a more serious note, there are people that think global warming is good. Receding ice caps leave minerals in the ocean that encourage sea life and will help feed the world's population. Receding glaciers will open up valuable, fertile ground that hasn't been farmed for nearly a thousand years. And the increase in temperature will raise the humidity world wide, perhaps turning the Sahara desert into the rain forest it used to be, and expanding the world's rainforests to new latitudes.
I could also see a future when there is no freezing winter, it's jus a year-round summer like on the tropical islands. Maybe then we won't be losing so many homeless to the random snowstorms of today.
I often wonder what the world would be like if every year the north and south poles melted. Would the entire world turn into a humid tropical paradise?
The radical sect of Islam would either see you dead or "reverted" to Islam.
Everyone stop fighting over whether humans have caused the current climate change. Those saying "NO" aren't going to change their minds, even as incremental new evidence adds to the substantial body already accepted by climatologists - or maybe they're right. It's not worth arguing about, because it's an abstract blame game.
What is worth arguing about is how to slow, stop or reverse the change obviously now underway. The same science used to fight the blame game is much better used to learn how reducing emissions and sinking carbon can mitigate the serious risk of climate change destroying our civilization. Past civilizations, like the Anasazi in the American Southwest and whatever you want to call the civilization that desertified the Sahara across to the Gobi in China, might not have had our advantage of science and engineering. So their change happened slower, but was more inevitable. Let's harness our climate science to create new climate engineering to cope with this climate change, whether it's manmade or as natural as the arrival of Winter.
--
make install -not war
That's not true at all. Let's look at some example data, shall we?
YEAR | AVERAGE TEMPERATURE IN BRITAIN (deg. C)
0706 | 14
0806 | 14
0906 | 15
1006 | 14
1106 | 14
1206 | 15
1306 | 13
1406 | 15
1506 | 14
1606 | 13
1706 | 14
1806 | 17
1906 | 19
2006 | 21
Notice that even though 2006 is the hottest year of the past 1200, it in no way implies that any of the previous years were hotter, even going back over 1200 years. As shown in the data above, the earlier years could be far colder.
Cyric Zndovzny at your service.
I guess it all depends on what sort of time scale you live in. Coral reefs take thousands of years to grow. Similarly, I suspect it is difficult to imagine what other sorts of terrible TEMPORARY problems rapid temperature change would cause (rising coastlines from the ice caps, messed up ocean currents, etc.) In the long run, it might fix itself, but, as I believe John Maynard Keyes said, in the long run we are all dead.
So could you please refute his argument with, oh, I don't know, data?
You better watch out, there may be dogs about . .
They're saying that it was every bit as warm in 800 A.D. then? That kinda discounts their theory that modern man is causing global warming then doesn't it?.
No they didn't and no it doesn't.
1) Nothing was said about the temperature in 800 AD.
2) Nothing was said about the rate of change in temperature in 800 AD.
We didn't have the modern industrial society that is thought to be the primary cause of global warming today. They're just using the tree ring study by Esper, Cook, and Schweingruber as the end point for as far back as we can go. Check out this graph and its explanation on the Wikipedia for more data points.
Basically, the Medieval Warm Period was still an average of 0.4 C cooler than modern times. It took about 800 years for temperatures to drop 0.4 C to the minimum before the Industrial Revolution and only 200 years since then to rise 0.8 C, an 8X difference in rate of change. Global climate does change on its own naturally, but the change since the dawn of the Industrial Age is still the fastest we've ever seen, and we have solid science that shows how it happens in the form of the greenhouse effect. What more will it take for you people to quit filtering the world for the few tenuous scraps of information that back up your preconceived notions?
If it's for-profit but free, you're not the customer -- you're the product (e.g., the Slashdot Beta's "audience").
Even if the human race and all trace of our existence were to be wiped off the face of the planet, Do you really think things will return to normal now? And if you can answer that question, maybe you can explain just exactly what normal is anyway.
/. Anyway cause it's Friday and we're obviously all bored and ready to go home and fire up the "Green" computer and play WoW....
I think most people get so caught up in the argument that they don't realize how stupid they sound. You do realize that even if everyone in the world got a soft heart and green conscious, we'd still be burning fuels, we'd still be pumping out WV and Co2, We'd still need fires or some type of heat to keep us warm, still need livestock or something to eat, and still need some way to get around.
Even tree-hugging green freaks won't give up their modes of transportation or winter heat, or processed / clean foods. If they did, they'd be living the hermit life in the back woods competing with the wildlife for food. Which would be a fantastic TV show, but I digress.
What really makes me laugh are the people who are fully clothed with picket signs walking around telling industry to stop killing the world. As if the clothes on their back were completely made industry free. As if their food were industry free. Tofu is processed... Common folks... Hybrid cars contain plastics, yes they are derived from petroleum products. Most "Necessary" chemicals and vaccinations are either based on petroleum, or produced in "Industry" that uses petroleum.
Paper signs are produced in factories, guess what, they use petro to power the factory.
The world cannot be saved by us. You can preach, picket, and protest all you want, but some moron somewhere is going to burn something, releasing heat, Co2 and WV into the atmosphere and 'WHAM' we're back to square one. But we might as well argue the what if on
Right?
-Duff
Hey, making inflamatory statements without having any idea what we're talking about is all some of us have!!
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The parent does make a great point however I still see global warming as a theory. 1,200 years is nothing when compared to the climate history of our planet. A better measure regarding climate change are ice cores. A great article can be found here I think 740,000 years is a much better measure than 1,200. According to the article, during this period the Earth has experienced 8 seperate "ice ages" followed by a brief period of warming. The question we should be asking is what causes these natural warming and cooling periods. If we can link natural events or patterns to climate change, the current stiuation can be understood better. I think the most likely cause of climate change is Earth's changing orbit around the Sun.
Ad 2: Volcanos put no CFCs into the atmosphere. The only significant source of CFCs are humans.
Ad 3: Volcanos do indeed inject some chlorine into the atmosphere. However, these chlorine compunds are unstable, and the chlorine quickly reacts with water vapor to form HCl, which leaves the atmosphere via precipation. Thus, the chlorine injected into the atmosphere is again insignificant. CFCs are problematic because they are so stable.
Moreover, the connection between ozone depletion and global warming is tenous. Both are processes where human emissions change the large scale composition of the atmosphere, but they only weakly influence each other.
Stephan
What a lame criticism. I use CE/BCE because that's how I was taught throughout high school and university. You should try to deal with the fact that terminology changes. Or do you still refer to the sky as "the heavens", refer to the number 20 as "a score", and your car as an "automobile"? Do you use Roman Numerals? For that matter, AD itself is a relatively new term; people used to refer to "the 2006th year of our lord". Why not just revert to that, while you marvel at the miracle of fire and ponder the concept of using round wooden structures to accelerate travel. Seriously, grow up and try to live in the real world.
"Except for the fact that water vapor is SEVEN TIMES the green house gas that CO2 is, and it is present in the atmosphere in MUCH MUCH higher concentrations. Over all, water vapor contributes 280,000 time more to the greenhouse effect than CO2, and it's been doing it for ages, long before CO2 rose 25% to a measley 375 parts per million."
The residence time of water vapor in the atmosphere is very short, on theorder of a few weeks. Perturb the equlilibrium for water vapor, and within a very short time, the atmosphere returns to equilibrium. The residence time for CO2 is many, many, many orders of mgnitude longer. This means that CO2 increases can create long-term perturbatins in global atmospheric heat flow, but water vapor cant. The climate people refer to this with the pharase, "CO2 is a driver, water is a feedback."
"Possibly the real contributor to global warming is not the warm fuzzies of CO2 but the the heat itself that is released when Carbon based fuels are burned. A coal, oil or gas burning power plant needs to waste one unit of energy for every unit of energy it delivers to the consumer, and that is with the power plant operating at close to 100% efficiency. The worse the efficiency the worse the heat waste. Eventually, all energy generated or wasted by power plants ends up as waste heat. That waste heat raises the mean temperature of the atmosphere until the T gets high enough so that the energy radiated (proportional to T^4) back into space equals the total of the incident Solar energy and the waste heat energy."
That waste heat radiates VERY FAST. Ever notice how cold it gets at night? That is due to radiative heat loss. Add more heat at the surface, and the excess is very rapidly lost. You might also want to calculate the ratio of human heat release to heat input from solar irradiation; the results might show you that this argument is pretty weak.
"Atmospheric scientists know that the concentration of CO2 is not high enough by itself to cause global warming, so they postulate a "trigger" or "catalyst" effect, which is unproven. Neither my theory nor theirs can explain the last hot house period that occured 1,200 years ago. Then, the CO2 was lower than it is now and there were no power plants spewing heat, so the burning of fossile fuels was not the cause. That leave other possible causes: solar output or volcanos, to name a couple."
Your first sentence her is simply absurd. Our planet is not a ball of ice only becaus e of global warming due to CO2. The question is how much the ADDITIONAL CO2 humans are adding to the atmosphere is causing ADDITIONAL warming. And we know that effect is happening; the debates are over how much additinal warming we are/will going to experience with this much additional CO2. That discussion involves known feedback effects (not triggers) like waramer temps causing increased atmospheric water content, for example, leading to a magnification of the warming effect. BTW, this article does NOT say it was hotter 1200 years ago. That is simply as far back as their analysis goes. Other good studies show it was NOT as warm than as it is now.
>I still see global warming as a theory.
As opposed to seeing it on tuesday at the local Starbucks?
I see gravity as a thoery too.