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."
We need to warm up before the mid-21st century ice age... http://www.upi.com/NewsTrack/view.php?StoryID=2006 0207-041447-2345r
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
The article doesn't say what happened in the 8th century, just that tree rings don't reliably go back any farther. They must be using only specific species of trees, though, because there there are several species of living trees that are much, much older. Do their rings not reflect temperature, too?
The article contains almost no technical data, but it does say there have been been conflicting results:
"In 2003, a team led by researchers from the Harvard-Smithsonian Center for Astrophysics announced that it believed the 20th century wasn't the warmest, nor the one with the most extreme weather of the past 1,000 years.
"But this research has been criticized for its selection of the indicators used to estimate historic temperatures, among other problems."
The article doesn't say what indicators the Harvard-Smithsonian group used, just that they think their indicators are better.
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.
I'd be willing to guess (although I won't be around long enough to find out) that we're just in some sort of cycle ... it's warm now ... but in a few hundred thousand years or so we'll be back to another ice age again!
Good guess. We're in the middle of an ice age right now (ice ages last a long time). We're in a brief worm period between long cold periods. The Vostock ice core data shows a cycle that's about 100 k years long. Based on the limited data we have (only 4 cycles), we should have begun a rapid return to normal conditions for this ice age about 10 k years ago. It's not clear why we haven't.
The thing is, no one really understands what drives that 100 k year cycle - does CO2 gradually accumulate until some threshhold is reached, which kicks of some powerful feedback mechanism? Is it all about Solar activity levels? Why didn't it start getting cold again 10 k years ago?
We understand the feedback mechanism involved in the longer (100 M year or longer) cycle between ice ages and a tropical Earth. The weathering of rock removes CO2 from the air, and the more of the land are that is covered by glaciers, the less this happens. That cycle is huge and powerful, but slow: it's pretty unlikely we happen to be alive at the end of the current ice age.
Socialism: a lie told by totalitarians and believed by fools.
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.
"That was a major gloabl [sic] climate change"
If you read the article you cited it says:
"While most believe the LIA to be a global event, some question this."
It may have been a localized event restricted to Europe, possibly a disruption of the Gulf Stream?
It is by the juice of the coffee bean that thoughts acquire speed, the teeth acquire stains. The stains become a warning
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.
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.
Sorry, burden of evidence is upon *you*. You are the person who wants to remove people's livelihoods. In order to do that, you had better get a case more convincing than: "How is this smart?"
Don't demean your opposition just because you don't understand them or their arguments. Obviously *everybody* doesn't want a global catastrophe to occur, but on the one hand, we have people who want to make incredible sacrafices based on an argument bound in the faith of 'progress is bad' and if we wait, we loose, and on the other, we have a 'wait for better data' approach.
If the threat were actually as clear as the doomsayers want it to be, it wouldn't be a contentious issue. You'd be able to get *real* groups of scientists working on the problem and providing solutions, rather than this 'environmental activists wrapped in lab coats' group called the supposed 'Union of Concerned Scientists'. (Which would be more accurately labelled Union of Partisan Activists)
The problem here, fundamentally, is too many science-types go to unending lengths using bad science and bad use of statistics to prove themselves right. This conversation constantly degenrates into two uninformed groups of people spouting completely false nonsense at each other based entirely on a misuse of statistics. Even in this slashdot thread you will see people getting modded up for citing (incorrectly) correlative evidence as causitive evidence.
The fundamental issue here is correlation. Good climatologists are at war with correlation implying causality. They are unable to produce proper control experiments, so no matter how convincing their results, it's able to be dismissed by others. No good science should look at correlative evidence (as you have stated plenty) and draw conclusions. Guess what, since 1980, Jupiter has seen a HUGE increase in the number of comet strikes of the previous decades. But we can't pin that on global warming.
The fundamental question is how much has humanity effected the global warming of this planet. Just showing that it is warming is completely and totally irrelevant. The important scientific question, and the one most difficult to answer, is how much humans have contributed. The methods whereby CO2 heats up a planet are fairly well understood, and no one with a sane state of mind can deny that humanity has made things worse. The scientific debate remains to what degree. Slashdot karma-whores can continually abuse the general lack of statistical know-how by stating "look how much warmer it is now!" and get modded up. The fact of the matter is using the metric of "difference in temperature in time" is completely and utterly meaningless in a debate about humanity's contribution to global warming.
And we don't even need to get into the ridiciously horrible statistical fallacies possible when one begins using "extremes" and "records" as a basis for drawing conclusions.
And yet mammoths froze standing up with food still in the stomache in vast, vast areas. And yet, flowers froze while still in bloom. Nope...everything that has every happened on earth, climate wise, is known to take thousands of years. Ya right...
I'm feeling pretty good when I say that that flowers don't stay in bloom for thousands of years at a time and mommonths don't take thousands of years to digest large quanities of lush vegitation. Simple fact is, there is more evidence that suggests periodically, VERY, VERY, VERY drastic climate changes can take place in spans of weeks, if not days or hours.
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?
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.
Let's tackle this one by one.
'Antartic climate cooling and terrestrial ecosystem response' Nature 415: 517-20
"Side-looking radar measurements show West Antartic ice is increasing at 26.8 gigatons/yr. Reversing the melting trend of the last 6000 years"
This is predicted by climate change models. The cause is precipitation - increase in ocean temperature puts moisture into the air, which comes down as snow at the central regions of the poles. Meanwhile, the edges of the polar ice masses melt.
"Both satellite data and ground stations show slight cooling over the last 20 years."
Is that from 1996? Post 1999, it emerged that the satellite data were making systematic errors. After correcting those errors, the measurements now support GW. As for ground, see above.
"During the last four interglacials, going back 420,000 years, the Earth was warmer than it is today."
"Less Antartic ice has melted today than occured furing the last interglacial"
But the onset of those temperatures was much, much slower than now. That's why global warming is so alarming. We're going to get the added temperature from the interglacials on top of the unrelated human caused changes,
The Sahara has shrunk since 1980
Title - plants reclaim the desert. Why? Perhaps the plants are better adapted to desert enivironments. Perhaps global warming has increased local humidity. Sahara expansion is more complicated than just a matter of global warming effects.
Note that *none* of the above have concluded that global warming is contradicted. They just sound like they contradict global warming, when what is happening is precisely what one would expect.
Global Change indeed. There's been a lot of talk about the mini ice age and people are saying that mankind didn't cause it. What happed from 1550 to 1890? There was a population explosion and a resultant massive deforestation in the northern hemisphere for ship building, housing and fuel. When America was "discovered" in 1492 the old growth forests were the most coveted resource of the crowns of Europe for wealth and war making. What do large stands of trees (forests) do for climate? They hold moisture and moisture/humid air holds heat. The removal of those forest caused the mini ice age (at least in the northern hemisphere where the measurements are mostly taken). The burning of the wood, and now oil, has reversed that by introducing CO2 and may push it beyond the pre-1550AD temps.
Paleoclimatology http://en.wikipedia.org/wiki/Paleoclimatology is a relatively new science and is just beginning to search for answers. Unfortunately it has become a tool for political activists who are just taking away from the credibility of a few honest scientists who are just searching for ways to measure climate in the pre-recorded history of the earth's climate. And yes, scientists are not immune to political activism.
400,000 years of Vostok ice cores data isn't good enough for you? What about Greenland ice cores, midatlantic cores, and other data?
We're at among the highest CO2 levels in hundreds of thousands of years, and a high school chem lab can easily demonstrate that CO2 traps heat. The rate of temperature change is among the fastest in measurable history (there have been some very fast times associated with things like major volcanic events, of course).
I'm not an extreme pessimist about global warming. Yes, it's happening. Yes, we're 95% of the cause. Yes, it's going to destroy native cultures and make a number of species endangered and completely destroy the habitats of others. The important thing to realize, however, is that most of the heating is going to be in the arctic - a region of great amounts of potentially farmable land (apart from the climate), huge mineral deposits (hard to get at because of the climate), great potential shipping lanes (again, there's the problem of the climate), etc. Barring something catastrophic like the failure of an oceanic conveyor, I expect to see the losses come with gains. It's just unfortunate for those who suffer the losses.
"/etc/rc.d/rc.sysinit is a gimp plugin and must be run by the gimp in order to be used."