Slashdot Mirror
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."
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]
"The findings support the argument for global warming as a result of human interference rather than natural climate change."
This is like taking a one gallon sample of the stagnant pond and concluding that the only life on Earth is single celled organisms. The Earth is how old? What is the percentage of time of information available. And, how much of the surface was tested? Less than half.
I have had about all of the junk science I can stand. We need some real sceintist making real conclusions.
Athiesm is a religion like not collecting stamps is a hobby.
Would they still think this in lieu of the following recently uncovered data?
I think you mean in light of the following...
"In lieu" means instead of.
eMelody Web Directory add your site today!
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.
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.
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.
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.
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.
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?
From TFA Reliable records from trees and other sources go back only about 1,200 years. So no, they're NOT saying that it was as warm in 800 AD. They are saying that this is the warmest year since 800 AD and that they don't have have any reliable records before that! This is a big difference.
I know that this is Slashdot but you really should try reading the article before making inflamatory statements like "Another crackpot theory bites the dust."
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").
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
If by "alarming rate" you mean "alarmingly slowly", yeah. There have been times in the earth's history where we can see what looks to be a 7.0C change only a few years! In the last 100 years, our "global warming" has been on the order of 0.6C. Total. Over 100 years.
While these mechanisms are different, to call a 0.6C change over 100 years "rapid" is kind of silly. We really don't know shit about global climate patterns yet. I'm all for cutting back on pollution, and managing how we use our resources a lot better - I just get fired up about "global warming", when:
A) We don't know shit about "global warming", or climate change in general.
B) What we're currently measuring is nothing compared to other changes that we can see historically.
C) Politics, the media, and related funding has more to do with "global warming" than science does.
We need to do a better job protecting our environment, and reducing our footprint, as a WORLD. I just don't think blathering on like idiots about "global warming" is helping us do that. It'd be like blathering on about how spring means that all our snow will melt away - it does, on a regular basis. Like global climate change does to the ice caps and glaciers.
Velociraptor = Distiraptor / Timeraptor
"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 don't think Australia signed either. They must hate the Earth, too. Things haven't been right down there since they dropped ".oz"
You're right about Kyoto, though. The biggest problem with it is the nations that didn't jump on: China and India. Save the "developing nation" crap. Yes, they're dirt poor. They're also huge polluters because they can't afford proper scrubbing on their stacks. There's also a zillion of them, and CO2 isn't the only way to measure pollution. Think particulate matter. I hear lots of environmentalists saying that 300,000,000 Americans make more pollution than 3,000,000,000 Chinese and Indians. Then how come the skies of our cities aren't choked dark orange in midday like in China? (Yes, I've been there, I know.)
Oh, and for the record: Germany is the only European country actually reducing pollution to meet its Kyoto obligations. CO2 output is up 7% in France, 11% in Italy, and 29% in Spain (numbers from 2003 - the most recent available). They're supposed to reduce their emissions 8% by 2012. Looks like arrogant Europe is going the wrong way and should get its own house in order before jumping ugly with the U.S.
Good thing I've got Excellent karma. I'm going to need it after this one.
-- I'm old enough to have lived through six different meanings of the word "hacker."