Posted on 03/31/2006 8:24:12 AM PST by cogitator
Winter air temperatures over Antarctica have risen by more than 2C in the last 30 years, a new study shows.
Research published in the US journal Science says the warming is seen across the whole of the continent and much of the Southern Ocean.
The study questions the reliability of current climate models that fail to simulate the temperature rise.
In addition, the scientists from the British Antarctic Survey (BAS) say the cause of the warming is not clear.
It could be linked to increases in greenhouse gases in the atmosphere or natural variations in Antarctica's climate system.
Scientists are keen to understand the change in temperatures over the continent as the region holds enough water in its ice to raise sea levels by 60 metres.
Temperature rise
Temperature rises on parts of the surface of Antarctica have been seen for some time. The western side of the Antarctic Peninsula is known to have the largest annual warming seen anywhere in the world with increases of over 2.5C in the last 50 years.
Until now, very little was known about air temperatures above the vast continent.
The new work uses meteorological data collected from weather balloons launched in the Antarctic winters between 1971 and 2003. The scientists collected information from nine international research stations, mostly in the east of the continent.
The researchers were particularly interested in measurements taken in the middle troposphere, the layer of air at a height of about 5km (3 miles).
Their analysis shows that temperatures in the layer have risen by between 0.5 and 0.75C for each of the last three decades.
"It's the largest regional warming on Earth at this level," said Dr John Turner of BAS, one of the authors of the paper.
However a question remains over what is causing the change.
"There are arguments for and against this temperature rise being caused by greenhouse gases," Dr Turner told the BBC News website.
"The problem is trying to differentiate between what is happening naturally and what is happening because of man's activities".
Climate models
To try to resolve the conundrum, the BAS team compared the data with 20 simulations of the climate over the last century.
The models simulate rising levels of greenhouse gases and are used by the Intergovernmental Panel on Climate Change (IPCC) to replicate past climates and make predictions for the future.
The team found that in all cases, the models failed to simulate the rise.
The models do not match the data
Dr Turner believes this could mean the temperature rise is a result of a natural fluctuation in Antarctica's climate or that current models are inadequate.
Dr Jeff Ridley, a climate scientist at the Hadley Centre for Climate Prediction and Research in the UK, agrees.
He believes it is likely that current climate models are unable to sufficiently recreate conditions on the continent.
"I've looked at all these models and seen that Antarctica is not very well modelled at all," he said. "So we shouldn't put too much confidence in what they tell us is going to happen there."
For example, observations show that in Antarctica winds flow from the South Pole out to the coast in winter. As they move they lose energy, causing heating and mixing the air above.
But in the climate models, simulating these air flows and the mixing is too complex. Instead the model is simplified with a cold layer at the surface that does not mix with the rest of the atmosphere.
One reason for this is the scant data that has been collected across the continent. Another is that the climate models are still not very good at simulating relatively small-scale regional processes.
Dr Ridley is trying to work out how to overcome problems like this in climate models, and believes the new data will help understanding of processes in Antarctica.
But he says we should not lose faith in the ability of current models to predict worldwide climate change.
"On a global scale, the processes we have in the models work well. We are confident we are able to predict the past, and globally we can predict climate change."
LOL.
A new radar study shows that the ice sheet feeding the Ross Ice Streams is growing.
http://www.newscientist.com/article.ns?id=dn1806
The article doesn't support the "unexpected" part of the headline. Of course when the article is full of comments including "could be," "questions the reliability of," "not clear," etc. I don't know what headline I would have used.
Any "scientific" measurement cited by the BBC to support an argument of global warming, is by definition, suspect.
I just saw a "Nova" that explained the reasons why John Franklin's British Navy expedition through the Nortwest Passage failed in 1847.
The main reason cited was that they became stuck in the pack ice that lasted for FIVE YEARS straight, contrary to what other explorers had found there previously. Ice cores revealed that the ice normally thawed and reformed through the seasons, but there was in 1847, and have been since, periods of abnormal ice behavior where it does not thaw-- or where it never forms completely.
Just thought that was of interest.
I hope this won't shock anyone, but some of those cycles affect climate in a variety of ways.
There will always be these occurrences and they will always be over-played by the media in accordance with their agenda.
Well, it's not just the BBC, this paper is getting decent play in many media outlets.
What I find really interesting is that this is a definite global warming conundrum. ON the one hand, atmospheric warming is predicted by most models. There has a been a long-standing, now fairly well resolved issue about the mismatch between model predictions and satellite measurements of atmospheric warming, but Antarctica was left out of it because there wasn't enough data.
Now, the Antarctic atmosphere is showing a possible warming signal but the models don't reproduce Antarctica well, so it isn't a step forward in terms of understanding the global situation, and therefore the observed data do not provide additional support for global warming models. That's why the scientists, properly, leave natural variability in the mix because additional work has to be done to attribute the cause.
So, the Antartic has warmed 2.5 degrees. I note that nowhere in the whole article do they happen to mention the BASE TEMPERATURE. If it warms from -30C to -27.5C is just a bit different than if it warms from -2.5C to 0C.
I love it...the people who on one hand tell me that Man is nothing more than an insignificat blob of life that crawlled from the Primordial Soup are the same ones who are sure that Man is SO POWERFUL that in a hundred years we can alter the face of the planet. Pffffuuuph! We are seeing the effects of regular planetary alterations that have occurred since time began on a scale which we can bearly grasp.
More could could could.
There's more room for a measurable effect to happen when the range of variability is larger.
One of the strongest arguments against the models is that they fail to predict the past when historical data are used.
This is just another demonstration of that problem. And, for them now to make such an announcement concerning 50 year old data that has already been studied as climatology is simply to get another headline.
DARN IT! You beat me to it on POST #2!!!!!!!!!!
LOL...that just jumped out and hit me in the face!
If we really wanted to get a profile of greenhouse gases, we could put a CO2 detector in the instrument package that goes up with every radiosonde and just add another trace to the Skew-T.
"Another Alarmist Press Release"
I don't think there'd be much variability with altitude in a CO2 profile.
Not to jump tracks, but, this is a similar sentiment conveyed by advocates of another "scientific theory".
Based on?
This problem of warming throughout the universe has got to stop. Everyone..quick...run outside and point your water hose toward the sun. Sheeesh.
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