FirmhandKY
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quote:
ORIGINAL: deadbluebird
http://news.nationalgeographic.com/news/2007/03/070330-warming-arctic.html
Arctic Melting Linked to Human Causes, Long-Term Review Finds
The dramatic loss of Arctic sea ice in recent years is the result of human-induced greenhouse gas emissions combined with natural cycles, according to a new study.
Very definite "fact" stated here. Now, lets look at what this "fact" is based on ...
The loss of ice will likely (or will likely not - weasel words) change water temperatures and affect the circulation of ocean currents, which may (or may not - weasel word) alter climates around the world, the study suggests (weasel word).
The study reviewed previous research of Arctic sea ice, which showed that the ice has been steadily disappearing since 1979.
Not original research. The latest research on the Greenland and Antarctic ice shelves have different conclusions. Which is better in science - direct physical evidence in which the direct factors are observed and controlled, or reliance on previous studies that do not have the latest data, and in which there is not a standard measurement of data?
In September 2005 satellite images revealed that the Arctic ice was at its lowest level in some 50 years of observation.
"If we compare how much ice we had in September 2005 with a typical September, we've lost an amount of ice about twice the size of Texas," said lead author Mark Serreze, senior researcher at the National Snow and Ice Data Center at the University of Colorado, Boulder.
"So we're talking about a lot of real estate."
Interesting analogy, but what does it mean? Saying it was "about twice the size of Texas" sounds really bad ... but how much water is this,exactly, on the scale of the oceans? Reference to data without the surrounding context is useless and is simply a method of drawing attention and presenting a point of view. Scientifically, it's useless.
There have been previous periods of Arctic warmth not attributed to human causes, Serreze said, and ice cover grows each winter only to shrink in summer.
Duh. So ... question? What caused the "previous periods of Arctic warmth not attributed to human causes"?
But the current loss probably can't be ascribed to natural cycles alone, Serreze believes.
In the March 16 issue of the journal Science, Serreze and colleagues report that the evidence "strongly suggests" the ice loss is caused by human-induced global warming.
"Strongly suggests"? I could live with that. But ... it is an opinion (notice "he believes"). What is the level of mathematical confidence and certainty? If you can't quantify it, it's not science.
...
The researchers pored over decades' worth of satellite images, as well as records from airplanes and ships, to compile a historical picture of Arctic sea ice over the past half century.
Satellite images .... records from airplanes and ships ... nice example of inconsistent and largely subjective data.
...
Arctic temperatures have also varied dramatically from decade to decade and were abnormally warm from 1925 to 1945, the data show.
So ... question? Was there more, or less man-made "greenhouse gases" in the period from 1925 to 1945, than there was from 1945 to now? This sentence, by itself should bring questions to your mind.
Can anyone show any reason for a warm spell early in the century, and then, after 1945, tell you why the Arctic cooled down again? (Maybe it was all that facist and "arsenal of democracy" stuff from the two world wars?). 
I think this is a critical weakness in the overt conclusions of this entire "study". And they simply skip right over it. What does that tell you?
But the most recent reports demonstrate that Arctic temperatures have increased at almost twice the global average rate over the past century.
And how much is that, exactly? And based on what? If the study mentioned (the one by satellite, ships and airplanes, remember?) covers this, then what is the basis for their claims of a temperature change "over the past century"? How many temperature measurement stations were in the Arctic in 1907?
Natural variations "play a large role" in the Arctic's changing air temperature, Serreze said. But overall the observations are consistent with the melting that climate models have predicted would result from higher greenhouse-gas emissions.
How large a role? Quantify, please. How about the warming period in 1925 to 1945, followed by a cooling period during a period of higher industrial output after 1945?
"There has always been uncertainty about whether these observed changes are natural variability," he said.
"But we now have a consensus between observations and what the models are telling us. In my mind, it's very convincing that we're starting to the see the effects of human activity on Arctic ice cover."
Admits "uncertainty" but then claims that "in my mind it's very convincing". That's great. In his mind. How about other scientist that "in their mind, it's not very convincing"? His study doesn't even have the latest, most up-to-date data, does it?
Notice the flow of the article (this is a "convince them" piece, btw). First, a strong thesis as if it's fact beyond a doubt. Then, lots of weasel words, and "maybe's" and "could be's" (variability and uncertainty) followed by a declaration of "fact" that is actually supposition based on a "belief" that isn't strongly linked to the actual facts, and is in contradiction to the latest data on the Antarctic and Greenland.
Human-caused warming may (or may not - weasel words) change the seasonal ice system and dramatically speed the loss of ice, said Bruno Tremblay of McGill University in Montreal, Canada, who was not involved in the new study.
"The system can recover from a low ice year. But, as warming continues, a critical thickness is reached beyond which the system no longer recovers," he said.
Open water absorbs solar energy that would otherwise have been reflected by ice, he explained, which perpetuates the melting cycle.
"So ocean water warms, and the ice forms later in the fall, and you typically have an earlier melt onset," he said.
True facts, but not directly related. Given simply to cause anxiety about "global warming".
Vanishing sea ice might (or might not - weasel word) also spur the melting of Greenland's ice cap by warming the ocean waters into which the glaciers spill.
"In a place like Greenland the amount of heat that waters carry in summer is directly related to how much ice there would be," said Ian Howat, a researcher with the University of Washington's Polar Science Center who was not involved with the Science report.
"One can almost imagine (or not imagine - weasel words) sea ice acting like a buffer around the coast of Greenland. Remove that buffer, and the heat could more efficiently get at the edge of the ice sheet."
No data exists to link shrinking sea ice cover with Greenland's glaciers, Howat said, but he sees an intriguing correlation.
How much plainer can you get - NO DATA EXISTS! Damn people, if there is no data, it's simply not science. It's speculation.
"It's interesting that 2005 was the largest single loss of Arctic sea ice," he said.
"The glaciers in Greenland retreated more in 2005 than we've ever seen them retreat. One of the major points of our research is that the glaciers are much more sensitive to short-term variability than we had previously thought."
And in 2006, they stopped retreating. I made this exact point in another thread.
We are learning every day. It's good, in that sense, that we are gathering data about how the global climate system works, including glaciers. But the fact that such important things are discovered simply highlights our ignorance.
Many scientists believe that the loss of sea ice may (or may not - weasel words) have significant impacts on the world's climate.
A loss of ice will likely (or likely not - weasel words) change water temperatures and affect the circulation of ocean currents, altering regional climates, Serreze said.
"If you fundamentally change the nature of the Arctic, the rest of the system has to respond. The devil is in the details—what will those changes look like?" he asked.
He is admiting he doesn't know what will happen, based on his own study and his own data, even though the article certainly doesn't leave any doubt about the writers point of view, now does it?
Some models suggest (not prove - weasel word) reduced rainfall and increased droughts in the already arid western regions of North America.
The changes could (or could not - weasel word) also result in increased winter precipitation in western and southern Europe, as well as more intense storm tracks in the globe's mid latitudes.
But climate modeling is so complex that no one really knows, Serreze pointed out.
Again ... the author of the study again ... AGAIN, damit ... points out that the conclusion of what it all means isn't known!:
"But climate modeling is so complex that no one really knows."
Do you guys simply skip over those claims of ignorance?
"To my mind that's more worrisome," Serreze said. "What kind of surprises could we be in store for?"
Not a problem to worry about, unless you have another agenda. Do more research.
FirmKY
< Message edited by FirmhandKY -- 4/4/2007 9:22:04 AM >
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RE: "Scientists: Antarctic ice sheet thinning" - 
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