Slashdot Mirror
Arctic Ice Extent Understated Because of "Sensor Drift"
dtjohnson writes "The National Snow and Ice Data
Center (NSIDC) has been at the forefront of predicting doom in the arctic as ice melts due to global warming. In May, 2008 they went so far as to predict that the North Pole would be ice-free during
the 2008 'melt season,' leading to a lively Slashdot discussion. Today, however, they say that they have been the victims of 'sensor drift' that led
to an underestimation of Arctic ice extent by as much as 500,000 square
kilometers. The problem was discovered after they received
emails from puzzled readers, asking why obviously sea-ice-covered
regions were showing up as ice-free, open ocean. It turns
out that the NSIDC relies on an older, less-reliable method of tracking
sea ice extent called SSM/I that does not agree with a newer method called AMSR-E. So why doesn't NSIDC use the newer AMSR-E data? 'We do not use AMSR-E data in our analysis because it
is not consistent with our historical data.' Turns out that the AMSR-E data only goes back to 2002, which is probably not long enough for the NSIDC to make sweeping conclusions about melting. The AMSR-E data is updated daily and is available to the public. Thus far, sea ice
extent in 2009 is tracking ahead of 2005, 2006, 2007, and 2008, so
the predictions of an ice-free north pole might be premature."
From the summary:'We do not use AMSR-E data in our analysis because it is not consistent with our historical data.'
What's the point of being consistent with a flawed methodology? I would have thought the thing to do would be to collect the new data, base newer model off that and then perform a statistically weighted correction to the older dater. Both data sets can be maintained if required.
Am not sure I see a point in consistency for consistency's sake, when you in the light of newer information you now know the original measurements are flawed.
Cheers,
Ian
Both the AMSR_E and SSM/I data are satellite derived products.
http://www.ncdc.noaa.gov/oa/satellite/ssmi/ssmiproducts.html
http://www.aqua.nasa.gov/about/instrument_amsr.php
Science isn't an exact science, people are involved and people make mistakes. Scientist need to remember that they are human too and they will make mistakes. Data can be off or altered, I remember a local weather channel use to use a point for the local temperature until they built a Dunin Donuts next to it, and heat escaping the building or cars or something (it was a long time ago) raised the temperature 5 or 6 degrees warmer then the actual weather.
Climate Scientists are trying to make very accurate predictions where they don't have the data to do so. We can probably say global warming is real, however that is a very broad statement. But to say The Polar caps will be gone in 2008 or by 2012 NYC will be flooded, is grossly misunderstanding the complexity of the earths environment.
Granted that most of the fear mongering worst case scenarios stuff isn't from the people doing the real science but from activists groups who pick and choose data to make people afraid so they do what they want. But still the Scientists don't like saying to people Hey I could be wrong, but thats OK because with the scientific process being wrong takes us the next step closer to the real answer. They want to in general portrait themselves like the Sci-Fi scientist who know what is going on and is always right.
If something is so important that you feel the need to post it on the internet... It probably isn't that important.
No, the point is that no matter which data set you look at, the trend is downwards. "Deniers" are those who completely ignore all of that data and say it's not happening at all. And trust me, they're out there.
"n May, 2008 they went so far as to predict that the North Pole would be ice-free during the 2008 'melt season,' "
No they didn't.
They said it was a remote possibility.
This was taken up by the anti global climate change, altered, and then used to "prove" that global warming wasn't happening when it didn't happen.
The fact it is presented that way by the story submitter shows which way they think, and thus how reliable the overall story is.
Compare it to a game benchmark or whatever. You keep a standard, even if it's flawed, because that's the only way you get comparable results. You can't take a raw number for MIPS or millions of polygons/second or transactions per second or whatever the metric of choice is in your field (here, one is obviously ice sheath coverage) and use numbers from wildly different methods to even try to devise a historical trend. The value observed might not correlate exactly (or even very well) with old ones, but unless the flaws in the method cause great variability within that framework, the historical trends will still be accurate, or at least more accurate compared to what would happen if you changed your methodology each year and still tried to extract longer trends.
It might not be a good choice, and suggestions to run double series over the (short) timespan where overlapping data is indeed available would of course be better, but you can't just switch to the latest and greatest if you want some kind of consistency in your data.
From TFA:
<i>"Sensor drift is a perfect but unfortunate example of the problems encountered in near-real-time analysis. We stress, however, that this error in no way changes the scientific conclusions about the long-term decline of Arctic sea ice, which is based on the the consistent, quality-controlled data archive discussed above."</i>
If the media outlets and attention seekers sensationalise the real-time output, then unreasonable conclusions might well be drawn. What's the alternative though? To not make this real-time data available? Scientific hypotheses will be tested against the corrected data, so this sensor drift doesn't affect them. These are preliminary measurements only, not full-blown experiments with scientific conclusions. The polar bears are still going to have to become better swimmers.
It's a little ironic that this data will have been used by one group with an agenda to sensationalise climate change, and now will be used by the (perhaps overly) sceptical amongst us to poo poo it. Some have an agenda to sensationalise both. All serve to cloud the real message.
While I respect your skepticism of the scientific press, I think this reasoning suffers from two flaws. First
All I'm saying is that most of the 'studies' I've seen floating around the press smell fishy to me.
Relying on the press to get your scientific information is going to be incomplete. The press reports particularly sensationalistic doom & gloom stuff, whereas most science goes out of its way to take a neutral tone. It is too much to ask a non-scientist to pay attention to the leading journals (I'm thinking of Science and Nature here), but we are also at a point in our history where science needs to inform our politics. This is obviously troublesome for democracy, and why I sympathize with your skepticism of science.
Second,
I'd rather we follow simple common sense and watch out for our planet because it's the frickin' right thing to do instead of running around like headless chicken being afraid of our children being cooked alive by the sun
This reasoning is suspect because, aside from global warming effects, green house gas emissions aren't very harmful. It is relatively easy to see the pollutant effects of particulate emissions: they make things dirty and also hard to breathe. GHG emissions, on the other hand, are fairly clean and only have a mediated effect on human health (through climate change). Your strategy would have us fix only the easy to see problems even if there are more important environmental matters that require advanced scientific techniques to understand.
There is no question that data analysis and prediction is subject to errors, sometimes quite large ones. The real question is whether these errors are due to researcher bias. Unfortunately climate data and predictions are apparently more motivated by political beliefs and biases than hard facts.
Many people have strong feelings that disaster is about to occur. Perhaps this comes from childhood recollections of maternal warnings about running with scissors or touching hot stoves. These fears can be reinforced by religious beliefs that portend the end of the world. Because this psychological factor is so prevalent we need to be especially skeptical of predictions of future disasters.
[citation needed]. Oh, wait, you just invented those doom mongers yourself, bravely defeating a horrible strawman.
It's always a very good idea to take single quotes from a summary out of context, and make sweeping statements about that. This is especially true for science. Science really isn't one of those topics that require some in-depth knowledge to understand what's going on.
Taking off the sarcasm tag for a moment, this is one of the worst "science" pieces I've seen on slashdot in perhaps the last year. Cobbling together some serious accusations of scientific incompetence from a series of links doesn't really show anything. How the hell do I know how to interpret these statements in context? The links are all taken OUT of context and put into an entirely new argument without any further analysis or explanation. I'm left with what amounts to some hand waving and ranting about "scientific bias". Without a real analysis by someone qualified to make it this "story" is best left ignored.
AccountKiller
So, to be clear, this issue has arisen over the last 4-6 weeks. The records for the last decade, clearly showing a significant trend towards less sea-ice, are unaffected.
"None are more hopelessly enslaved than those who falsely believe they are free." -- Goethe
But to say The Polar caps will be gone in 2008 or by 2012 NYC will be flooded, is grossly misunderstanding the complexity of the earths environment.
Yeah, but climatologists don't suffer from that misunderstanding. They're the ones who have to actually slog through that complexity.
Granted that most of the fear mongering worst case scenarios stuff isn't from the people doing the real science but from activists groups who pick and choose data to make people afraid so they do what they want.
An astute point, and really it was both the activists and the -- well, whatever the opposite of an activist is, someone who wants to do nothing is called -- who with the help of the media took the scientists claims of a chance for a minimum and an ice free north pole (just the pole, btw, not all arctic ice gone entirely) and run with it as if the scientists are saying it's a sure thing. The activists to cry doom and gloom, and the inactivists to pounce on as proof the whole thing is bunk if the results come out on the "wrong" side of the scientist's claimed 60:40 odds.
But still the Scientists don't like saying to people Hey I could be wrong, but thats OK because with the scientific process being wrong takes us the next step closer to the real answer. They want to in general portrait themselves like the Sci-Fi scientist who know what is going on and is always right.
They didn't just say "Hey I could be wrong", they attempted to quantify the chances of them being wrong. Then they voluntarily report on censor errors that briefly screwed up their data, while I'm sure knowing that this would be blown way out of proportion and used to "prove" that they never know what they're talking about at all. In other words, the opposite of trying to appear like they can't be wrong. So I'm not buying it at all.
Just because news headlines omit the qualifiers does not mean they do not exist.
The enemies of Democracy are
The number of similarities between global warming and the older, more traditional religions have been documented numerous times and places: The high priesthood for whom the sins don't apply, the levied guilt, prophets of doom, attack on science by a faithful flock, the purchase of indulgences (carbon credits), concerted attempts to control the secular leadership as a means to bring the general population into line, etc., etc.
The only non-similarity -- and it's a shame, really -- is that the medieval inquisition had those really cool hooded robes. The modern Global Warming Cult has no fashion sense whatsoever, as best as I can make out.
Such as the immunization and the possible link to autism, lets say it creates a 1% increase in autism how ever it saves 25% from death, the benefits out weigh the risks and the parents who avoid this are poor judges on risk assessment.
Arrgh!
Speaking of fear mongering, it has been repeatedly shown that there is absolutely no link between autism and vaccines.
Please, can't this FUD just die already? It's already caused deaths in the UK from a loss of herd immunity!
You might want to read TFA. The sensor drift only started in Jan 2009, and it was spotted within a few weeks.
And quite reasonably; it's almost exclusively utter bullshit. And not taking *real medicine* when you have a serious condition is a very fucking bad thing. Moreover, some of this 'medicine' is itself harmful.
These two 'analogies' are just plain wrong. The relationship between "climate" and "climate scientists" is "thing" and "experts on thing", and same with "medicine" and "doctors". For these two, however, the relationship is "thing" and "people affected by thing". Less nonsensical analogies would instead use "copyright experts" and "economists". Unfortunately, this, while more correct, doesn't induce nearly as much rage (and thus indirectly support for your position) in the average Slashdotter, so I suppose it's reasonable you didn't use them instead. Not that it would've mattered anyway; you don't really have any sort of solid argument, just blatant anti-intellectualism.
OK, here you go, have fun. All the data in modern climate science is freely available in massive quantities. (The GISS datasets are just one example.) It's certainly true that there's a lot of crap journalism around climate change; please don't confuse the finger pointing at the moon for the moon itself. Go read RealClimate, or Scientific American (hell, even New Scientist if you like comics) or (better yet) search out the specialist journals.
"None are more hopelessly enslaved than those who falsely believe they are free." -- Goethe
This is a prime example of the sort of rationalization that passes for denialist reasoning. When confronted with a huge mass of evidence supporting an unpalatable conclusion, they cherry-pick any error, no matter how small or irrelevant to the conclusion, and insist "if this is wrong, then maybe it is all wrong." Since in any human endeavor, there are always errors, it is always possible to rationalize away any conclusion that you prefer not to confront.
This is of course quite typical. The data in question is real-time, raw data. In most scientific enterprises, such data is kept private by the researchers until it can be cross-checked and validated. But in climate research there is a level of openness and public access that is almost unparalleled in science, with even preliminary data publicly available. Of course, the actual scientists know that such data is subject to revision and do not base important conclusions upon it. So the error has no impact on the conclusion that there is a long-term decrease in Arctic ice due to global warming. But that won't stop denialists from talking about it as though it invalidates everything.
To quote TFA:
This and no other is the root from which a tyrant springs; when first he appears as a protector - Plato (423 to 327 BC)
That's an empty assertion, apparently motivated by the conflict between the conclusions from overwhelming climate data and the writer's ideology.
Where is the sociological data to support it? All these claims about "political beliefs and biases" among climate scientists are working backwards from a desire to reject the conclusions of science to ad hominem attacks on the scientists themselves - attacks which make presumptions about the politics of scientists which are naive in the extreme. A great many - perhaps most - scientists are not political at all. They're too busy with their science to worry about politics outside of their own university departments, and anyway consider most politicians and commentators a bit too stupid to concern themselves with one way or the other.
So where's your data on "political beliefs and biases" among climate scientists? As most of them are funded by governments, can you show an example from any scientific community of a pronounced pattern of biting the hand that feeds it? Consider the scientists funded by drug companies. Do their results cut against their funders?
"with their freedom lost all virtue lose" - Milton