Arctic Sea Ice Rallies a Bit 152
radioweather writes "Like the recent stock market rebound, Arctic sea ice is making a big rally over the record low set last year. According to the Alaskan
IARC-JAXA website, satellite data which shows sea
ice extent as of 10/14/08 was 7,064,219 square kilometers, when compared
to a year ago 10/14/08 it was 5,487,656 square kilometers. The one-day gain between 10/13/08 and 10/14/08 of 3.8% is also
quite impressive. On May 5th, The National Snow and Ice Data Center suggested
the possibility of an ice-free north pole
in 2008, but so far, this year has been a banner year for sea ice recovery."
Stock market what? (Score:3, Insightful)
Uhh....what? http://moneycentral.msn.com/detail/stock_quote?Symbol=$INDU [msn.com]
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ugh who uses the NASDAQ as the barometer for the stock market?
superior [google.com]
superior-er [yahoo.com]
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If we're not careful these evil ice sheets could continue growing indefinitely and destroy us all! It is our global duty to start driving Humvees everywhere and encouraging others to do the same.
THIS IS A SLASHDOT NEWS FLASH! (Score:2, Insightful)
Seriously, I wish people would stop getting so shocked about this. I remember reading in school about things like Ice ages and constaly changing climates, and I'm not that old. I beleive man's impact on the enviroment, while measurable, is severly overblown.
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Do you want to walk on ice that froze an hour ago? or ice that's been solidly frozen for decades?
The ice 'recovery' is a misnomer, even if it covers the entire arctic at peak winter, it won't be very thick compared with persistent perennial ice cover that has existed and built up thickness for hundreds/thousands of years.
Replacing 'steel' with 'balsa wood' doesn't mean the structure can hold up the same weight. i.e. polar bears.
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Except polar bears don't go that far north.
Neither do people.
Only Grise Fiord gets anyway near, and that has a dark story to it. Not only that but I think it's 3+ hours away from Pond Inlet, itself 6 hours from Iqaluit, itself 6 hours away from Ottawa. By plane. Yeah.
There's Alert, but I really doubt those GI Joes are out huntin' for caribou nose and polar bears.
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The age of the ice does matter, because younger Arctic sea ice tends to be thinner, and is therefore lest likely to persist from year to year. Warming slowly wears away the thick multiyear ice. When that's gone, we could have no sea ice in the Arctic during the summer. Some young thin ice could form during the winter and then melt away again the next summer.
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Replacing 'steel' with 'balsa wood' doesn't mean the structure can hold up the same weight. i.e. polar bears.
Correct! Balsa wood *is* more buoyant than steel. That is what you were trying to say right. ~
So that's why they build ships out of balsa wood.
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Prepare to be amazed! [wikipedia.org] Balsa wood craft are capable of crossing the pacific, and may have been one of the ways in which some pacific islands were populated.
The incredible leap is steel ships, not wooden. The idea that something that sinks as readily as steel would be a good marine material surely had a lot of public opinion inertia to overcome.
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An interesting article, that in my honest opinion, makes far more sense explaining the current global temperature changes.
http://www.space.com/scienceastronomy/sun_output_030320.html [space.com]
Re:THIS IS A SLASHDOT NEWS FLASH! (Score:5, Insightful)
I think it's cute how people like you think that the IPCC is either unaware of or deliberately ignoring papers like this ;)
Seriously -- read the report some time. It'll be educational for you. There's something like 50 papers referenced for just sunspots alone. If it A) has to do with global warming, even tangentially, and B) was published in a peer-reviewed journal in the past 10-20 years, odds are it's in there.
Science does not work in a manner of "this one paper says one thing about one aspect, so it must be God's honest truth!". The amount of research out there is pretty staggering. It is... let's just say "unfortunate" that the popular press has a habit of picking up one work or another and sensationalizing them.
Re:THIS IS A SLASHDOT NEWS FLASH! (Score:5, Informative)
Seriously, I wish people would stop getting so shocked about this.
Climatologists are not unaware that the climate has changed in the past. The issue is that climate is currently changing faster than it would have without human input, and that larger and faster changes are likely if we continue to increase our input to the climate system.
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You do know that we have a less then 200 years of good data on climate don't you?
Heck I am even all for cutting carbon just to be safe.
But what your so sure of you shouldn't be.
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You do know that we have a less then 200 years of good data on climate don't you?
Yes, which is what tells us that the late 20th century warming is faster than natural, because we also have data on the usual natural sources of warming and cooling such as solar activity and volcanoes.
But what your so sure of you shouldn't be.
The Earth is 4 billion years old, but we don't need 4 billion years of data to understand something about what's happening to the Earth now. Sure there is uncertainty, and more than a couple hundred years of accurate data helps. But the instrumental data we do have is enough to tell us that something anomal
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You do realize that all historical data that predates accurate measurements are just very rough estimates that are open to interpretation and completely unopen to experimental proof and disproof, right?
I take your point, but you missed my main point, which is that we don't need paleoclimate data to support the manmade influence on the climate; modern observations are sufficient, although paleo data helps. You're right that there are substantial uncertainties, which is why the projections for 2100 vary by several degrees. But we do know enough to say that less than 1-2 degrees warming is unlikely, which is enough to be worth taking out some insurance against the possibility of greater warming.
Climatology is more or less a pseudo-science, at best a scientific research project. It, by definition, is not humanly possible to prove right or wrong. There is no isolation of variables, perceived close similarities.
I hate to b
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I take your point, but you missed my main point, which is that we don't need paleoclimate data to support the manmade influence on the climate; modern observations are sufficient..
You keep saying this and its plainly wrong. If we have 200 years of data (which we only kinda have) we can't know anything about how often this type of shift happened in the past. Perhaps its all just one 400 year cycle? Without historic trends you cannot say a dam thing about current trends. Really this is science 101.
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If we have 200 years of data (which we only kinda have) we can't know anything about how often this type of shift happened in the past. Perhaps its all just one 400 year cycle? Without historic trends you cannot say a dam thing about current trends.
That's wrong, because we don't have to rely on just looking at temperature trend data. With modern instrumental capabilities, we can actually look at CAUSES of climate change. Skeptics love to suggest that it's all just a "natural cycle", but natural cycles, like anything else, have causes. Past climate cycles have been due to things like variations in solar output, volcanic activity, changes in global ocean circulation, etc. Today we can measure solar output, volcanic activity, ocean circulation patter
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I didn't use historic knowledge, meaning knowledge of the climate before the modern instrumental record. We've been watching the climate change and at the same time we've been watching the natural and human sources of climate change. My point is that we don't need knowledge of natural cycles from preceding centuries to know that the recent warming is not entirely natural. That's because attribution of the recent warming to human causes is not based simply on that warming being anomalous in a natural cont
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Yes, which is what tells us that the late 20th century warming is faster than natural, because we also have data on the usual natural sources of warming and cooling such as solar activity and volcanoes.
I'm not sure that's how it works. For instance, How did the global climate change between 1075 and 1100AD? Between 850BC and 870BC? etc We might have a fairly good idea for how climate in some areas changed over a period that INCLUDES that time period, but we have no data that is at all similar to what we have for the last maybe 100 years.
But the instrumental data we do have is enough to tell us that something anomalous is going on, when compared to the various measured factors in the climate system which are normally responsible for climate change.
This I don't understand either. It's like how downloaders can say "Download speed is currently 150kb/s, download will be done in 5 minutes." In reality that 150KB/s was a
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We might have a fairly good idea for how climate in some areas changed over a period that INCLUDES that time period, but we have no data that is at all similar to what we have for the last maybe 100 years.
I know. My point was that we can tell tell that there's something odd about the modern warming, based ONLY on the modern data. Specifically, we can measure the various sources of warming and cooling (solar irradiance, volcanism, industrial sulfate aerosols and particulates, natural and manmade greenhouse gases, etc.), and if we leave out the manmade greenhouse gases, we can't account for the atmosphere and ocean warming which we observe.
This I don't understand either. It's like how downloaders can say "Download speed is currently 150kb/s, download will be done in 5 minutes." In reality that 150KB/s was an instantaneous spike--the average is more like 80kb/s.
The difference is that we're not just measuring a transient response
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And I am saying that the level a belief in this put ways the dataset!
I am not even saying that it isn't happening, I am not saying we shouldn't cut our emissions.
I am saying that it is far from proven. I am just willing to modify my behavior based on the possible risk.
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And I am saying that the level a belief in this put ways the dataset!
I have no idea what that sentence means, but it doesn't change the fact that CO2 levels can account for the warming we've observed, and the usual natural sources do not. The uncertainty is not whether CO2 is causing significant warming, it's about how much further warming from CO2 will be realized in the future.
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In fact there are almost no climatologist that claim all the warming is man made. Its quite widely accepted that at least some is very natural warming.
I didn't claim otherwise. I'm pointing out that you can't explain the data if you think CO2 is a relatively small contributor.
The is also a general view that future warming will also be part natural and part man made.
We don't know whether future natural forcings will cause warming or cooling. We do believe that as CO2 levels continue to go up, the man made influence will continue to become relatively stronger than natural sources in either direction, barring something really extreme.
Read more than news papers please.
Why don't you? Try Tomassini et al.'s paper last year in J. Climate for a modern estimate of the relative natura
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That, frankly, is preposterous. How can you define what constitutes "odd", if you don't know what's normal first?
We know, because we can directly compare what is happening to the aspects of the climate system which control temperature.
Our attribution of global warming to humans is not based solely or even primarily on saying it's "odd" within a historical context. The enhanced greenhouse effect was predicted in the 19th century on general physical principles, before we had decent historical records. The current warming is "odd" within the context of measured natural sources warming.
To overuse a cliche, if you want t
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We know, because we can directly compare what is happening to the aspects of the climate system which control temperature.
I agree with your general statements about us being able to do this, but you are making a pretty big assumption saying that you know all of the aspects which control temperature. I'm with LWATCDR in that I think we should be cutting down our emissions just in case (though does that mean we have to stop eating beef or drinking milk to make sure there are less cows farting?), but considering we can hardly predict the weather next week, it is a little silly to think that we know exactly all the factors involve
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But the instrumental data we do have is enough to tell us that something anomalous is going on, when compared to the various measured factors in the climate system which are normally responsible for climate change.
This I don't understand either. It's like how downloaders can say "Download speed is currently 150kb/s, download will be done in 5 minutes." In reality that 150KB/s was an instantaneous spike--the average is more like 80kb/s. With the amount of data we have, it seems like we're measuring the slope but we really don't know where we are on the curve? Given at most 100 years of solid data, do we REALLY know all that?
Remember kids: this is said in an discussion about an article that insinuates an upward trend from the fact that there is a slight slump in a long downward trend.
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Yes, which is what tells us that the late 20th century warming is faster than natural.
It does not. Perhaps you should look at the data. Its warming. But the rate is faster than natural... we think, we suspect, we guess. But we don't really know.
We may not need 4 billion years of data, but more than 40 (aka satellites and ocean buoys etc) years of good data would be a start. Also ice cores have evidence of faster changes than we are experiencing. There is *nothing* unprecedented with current weather trends. The problem is how much is our influence. Read the scientific papers rather than th
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Therefore we can cope with cooler better than warmer
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It does not. Perhaps you should look at the data. Its warming. But the rate is faster than natural... we think, we suspect, we guess. But we don't really know.
The problem is that if you look at natural sources of warming alone, our measurements of the forcings along with our modeling of responses, indicates that it should have cooled instead of warmed. A difference in sign is a pretty significant anomaly.
We may not need 4 billion years of data, but more than 40 (aka satellites and ocean buoys etc) years of good data would be a start.
I certainly agree that more data helps, although the surface temperature record is usefully reliable for longer than 40 years.
Also ice cores have evidence of faster changes than we are experiencing.
The only faster changes we have clear cut evidence for in the ice cores are associated with collapses and restarts of the meridional ove
People in glass houses... (Score:2)
Good advise, but your own risk assesment that you are 'so sure about' doesn't have any probability caveates at all?
The GP did have one such caveate (ie: 'likely'), the best science available says 'very likely'. But maybe I have misunderstood, maybe you are talking about the GP's implicit assumption that humans are causing the climate to change, if that's the case then the science says 'certain'.
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you should google "ice core" sometime. you can even see the ppm of various gases over history on various websites. it's all there. look for yourself if you don't trust media/news/science research of unknown funding.
Statistics? (Score:4, Informative)
According to the study's website [uaf.edu], the extent of the ice coverage is an estimate "calculated by certain algorithm."
It would be premature to suggest this as a panacea without knowing the statistics behind this estimate. Without this, we don't know if 3.8% is even statistically significant? They don't even offer a margin of error.
Even the "Data Download" [uaf.edu] offers only the bottom line estimate at a given point in time. What is the formula that feeds into that?
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My quick Google search couldn't find the paper with the exact algorithm, but this paper [uni-bremen.de] describes a related algorithm. Skimming it, I can't tell what the error bars on 1-day deltas are. I do see from that paper that the biases between different data products can be larger than 4% (although they seem to be most likely more like 2%). I would imagine that time deltas are more accurate than absolute estimates. Anyway, bottom line is I don't know if it is significant, but you could probably dig up the algori
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Do you show the same level of skepticism when its something you already agree with?
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Do you show the same level of skepticism when its something you already agree with?
I don't agree or disagree that seawater is more or less freezing in Alaska than it was in the past. Since I'm not like...in Alaska, I can't know whether this estimate is wrong.
It is simply not clear whether the shifts that this data shows are statistically significant.
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The 3.8% was a one day change, not the total observed ice reformation. The linked article says that current coverage is back to 2005 levels.
How did they determine what the 2005 levels were?
How did they determine what today's levels are?
Without that information, we do not know whether this information is credible. I suppose the question should be: how do we know the delta between today and 2005 is statistically significant?
People are arguing whether this is caused by man or not, which political candidate is going to under-respond or over-respond, but what is the point in doing that if the data is B.S. in the first place?
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Given the interannual variability in the long term data [nsidc.org], differences between 2005 and 2008 levels are almost certainly not statistically significant. The change between the 1950s and today is a different matter.
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Let me add another question or two:
Have these statistics been adjusted for the break-up of the Markham Ice Shelf? How about for the increase in glacial calving?
These are both factors that have tremendously increased the ice surface area, but by moving freshwater ice into the Arctic Ocean, not by increasing sea ice itself.
Cold is on the way... (Score:2, Insightful)
2008 [slashdot.org]
is the coldest year of the 21st century and output from the sun is declining [slashdot.org].
Maybe Al Gore and his carbon cult followers were...wrong.
Re:Cold is on the way... (Score:5, Insightful)
Solar output and atmospheric heat retention are two completely independent variables.
The fact that one is rising, while the other is falling is merely a fortunately coincidence.
My own personal view is that there's a heck of a lot that we don't know about the mechanics of the atmosphere. Until we figure everything else out, though, it's probably a good idea to err on the side of caution.
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Solar output and atmospheric heat retention are two completely independent variables.
At least you admit that solar output is a variable which puts you way ahead of most of global warming people. As far as the 'atmospheric heat retention' I presume you mean the effect of the atmosperic carbon dioxide concentration which is allegedly increasing heat retention. The evidence that a change in atmospheric carbon dioxide concentration from 280 ppm at the end of the last ice age to 385 ppm today has any effect a
Re:Cold is on the way... (Score:5, Insightful)
Re:Cold is on the way... (Score:4, Insightful)
My own personal view is that there's a heck of a lot that we don't know about the mechanics of the atmosphere. Until we figure everything else out, though, it's probably a good idea to err on the side of caution.
And which side is caution on, exactly? Spending money (that could be used for other things) to reduce CO2 emissions "just in case", or not spending money tinkering with CO2 because if global warming turns out not to be anthropogenic, we could bring on the next (little?) ice age?
(I happen to think the effects of a minor global temperature increase are a lot less serious than the effects of another ice age, but that my just be my Canadian upbringing talking.)
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Spending money (that could be used for other things) to reduce CO2 emissions "just in case", or not spending money tinkering with CO2 because if global warming turns out not to be anthropogenic, we could bring on the next (little?) ice age?
I'm sorry, but "Global warming is not anthropogenic" is no longer a credible scientific position. The serious scientific questions are along the lines of "Is climate sensitivity to CO2 closer to 2 degrees, or 4 degrees?"
Incidentally, if you're concerned that reducing CO2 will bring on a "little ice age", then you've already conceded that CO2 levels lead to warming. And it's not hard to add more CO2 if we decide we want/need to. It's adding less that's hard.
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I'm sorry, but "Global warming is not anthropogenic" is no longer a credible scientific position.
Among political scientists perhaps, physical scientists and particularly climatologists would argue otherwise.
The fact is that CO2 is a relatively minor greenhouse gas (the effects of water vapor are several times as great), and anthropogenic contributions are a small percentage of global CO2 production (be eg geochemical processes). It may not even be the case that increased CO2 (of whatever cause) raises globa
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Among political scientists perhaps, physical scientists and particularly climatologists would argue otherwise.
You're obviously unfamiliar with the climatological literature. I follow the major journals every month. I invite you to peruse the latest issues of Nature, Nature Geoscience, Science, Journal of Geophysical Research, Geophysical Research Letters, etc., and look at how many papers dispute this point.
The fact is that CO2 is a relatively minor greenhouse gas (the effects of water vapor are several times as great),
The natural greenhouse effect is on the order of 30 degrees C, which is why the planet is not a frozen iceball. CO2 is a smaller effect, but a few additional degrees of warming is still significant.
and anthropogenic contributions are a small percentage of global CO2 production
What is re
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This whole issue has become so politicized that any dissenter is viciously attacked, personally and professionally.
You might do well to watch "Doomsday Called Off" [google.com] to see other scientists' research in beleaguered opposition.
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Ah yes. When all else false, resort to global conspiracy.
When you want to discuss some scientific evidence, let me know. (No, I'm not going to watch a video, but you can summarize it if you like.)
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The point of my last paragraph in my other response, in case it wasn't clear, was that the costs of making an error aren't symmetric. Even if you ignore the large amount of science which supports the enhanced greenhouse effect, if we cool too much it's easy to make it warmer. But if we warm too much, it's hard to make it cooler. This means we should be concerned more about potential warming than cooling.
And a potential 3-4 degrees C of warming (and larger in boreal regions like Canada) in 100 years, whic
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Most european industries know from experience that money spent to reduce CO2 emmission (meaning almost exactly reduce fuel usage) is not lost, but invested in far better conditions than the financial market can promise. ...a
You may also note that fuel usage usually not only produce CO2 but also various midly toxic chemicals that can cause a local overoccurence of some diseases. Burning fuel as if there was no consequences has so many proven bad consequences that arguing over a not totally proven one is just
Re:Cold is on the way... (Score:5, Insightful)
If I'm told to err on the side of caution, do you know what I would do? Nothing!
You're driving in complete darkness and someone tells you there might be a cliff nearby. You're told to err on the side of caution. What do you do? Speed up? I think not. You stop, or at least slow down.
Right now CO2 levels are already higher than they've been in at least a million years, and we're increasing them at an accelerating pace. Basic physics as well as our observations of present and past climate suggest that this will lead to warming, possibly by a dangerous amount.
Continuing to add CO2 at an accelerating pace may be "doing nothing different", but it is not "doing nothing". It is doing a very significant Something.
We don't know everything about the climate, but we know that reducing CO2 back to pre-industrial levels is unlikely to do anything worse than keep us at the present climate (and even then we are likely to still warm a little due to heat already stored in the ocean). By contrast, there are a lot of climate risks associated with staying on our current emissions trajectory.
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You're driving in complete darkness and someone tells you there might be a cliff nearby. You're told to err on the side of caution. What do you do? Speed up?
That depends on how believable that someone is. If he's known for being mistaken about nearby cliffs, and somebody else tells me that we're being chased by large carnivores or men with guns, then yeah, the prudent thing might be to speed up.
(Some people will turn anything into a car analogy.)
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The scientific evidence from past climate changes, present observations, and future physical predictions, is that there are "cliffs" nearby, but we're not completely sure how far away or how high they are. Basically, don't give the system an unprecedented kick unless you know what it's going to do.
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Some people think that the scientific evidence from past climate changes, present observations, and future physical predictions, is that there are "cliffs" nearby,
There, fixed that for you.
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As much as some people would like to portray this as a "he said, she said" debate where all claims are equally valid, this is not really a matter of opinion.
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As much as some people would like to portray this as decided fact, this really is only a matter of opinion since we lack the ability to perform meaningful (as in, all factors are controlled or accounted for) experiment.
Crazy car analogy take 2? (Score:2)
You're driving in complete darkness and someone tells you there might be a cliff nearby. You're told to err on the side of caution. What do you do?
Turn on the headlights. For fuck's sake do you WANT to get eaten by a grue?!
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That's a good point: we want to learn about what's near us. But in this analogy, it's foggy, the headlights don't go very far, and if we want to see what's ahead we have to keep driving. So do we slow down while hoping our headlights will warn us in time, or do we keep going at full speed?
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Looks like the economy took care of damaging itself even though nothing has been done. For some reason, it seems making a pyramid scheme out of housing is worse for the economy than investing in innovative technologies. Who would have thought?
Re:Cold is on the way... (Score:5, Informative)
Once again, this is why people who don't know anything about a topic shouldn't comment on it.
Earth's oceans, especially the Pacific, are truly massive heat reservoirs, and changing how they interact with the atmosphere can strongly affect the atmosphere's temperature in the *short term*. In the long term, the planet is still dominated by its radiation balance, of course.
The linked article was describing, quite accurately, how the early part of this year was in La Nina conditions. El Nino is caused by the weakening or reversal of the Walker circulation (an atmospheric flow around the Equator). The Walker circulation helps encourage the upwelling of cold waters in the eastern Pacific, so El Nino conditions prevent more of this cool water from reaching the surface. As a net change, the equatorial Pacific ends up much warmer on the surface, raising atmospheric temperatures. In La Nina conditions, the situation is reversed; a stronger Walker circulation encourages more upwelling, and thus colder surface (and hence atmospheric) temperatures.
This has *absolutely nothing* to do with the planet's long-term temperature, which even a six year old looking at a graph could recognize through the year-to-year noise.
Now, if you *really* want a breakdown of how it ranked (records since 1880), here you go (remember that the first half of this year was in strong La Nina conditions!):
January [noaa.gov]: 31st warmest
February [noaa.gov]: 15th warmest
March [noaa.gov]: Warmest for land on record, 13th warmest for ocean
April [noaa.gov]: 13th warmest
May [noaa.gov]: 8th warmest
June [noaa.gov]: 8th warmest
July [noaa.gov]: Tied for 5th warmest
August [noaa.gov]: 10th warmest
September [noaa.gov]: Tied for 9th warmest
Spring [noaa.gov]: 7th warmest
Summer [noaa.gov]: 9th warmest
January to July [noaa.gov]: 9th warmest
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Well, sure, it's not THAT cold...yet. The general idea of global warming, though, is that the carbon dioxide in the atmosphere is trapping heat that would otherwise be radiated into space, and the effect is increasing. Most importantly, the amount of the increased heat being retained should generally be increasing as the carbon dioxide concentration increa and it should be impossible for there to be less heat retained, if the theory is correct. If global temperatures in the sea and air decrease, however,
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There is, of course, variation and 'noise' in the air and water surface measurements as well as the effects of mixing and circulation but the general idea should one of steadily increasing temperatures. Your list should have 2nd warmest, warmest, 2nd warmest, warmest, etc. rather than 9th warmest, 10 warmest, 8 warmest, etc.
No. There is quite a lot of interannual weather variation, which you can see in any of the instrumental temperature data sets. The greenhouse effect doesn't predict that every year will break or nearly break the previous year's record in a monotonic increase, and you don't see that in the climate model predictions either. You do see an overall upward trend, but on timescales of a decade or so, there can be considerable short term fluctuation above and below the main trend.
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The greenhouse effect doesn't predict that every year will break or nearly break the previous year's record in a monotonic increase, and you don't see that in the climate model predictions either. You do see an overall upward trend, but on timescales of a decade or so,
From a global energy balance point of view, the amount of heat retained by Earth must increase every year if the theory about atmospheric carbon dioxide significantly reducing heat radiation into space is correct and that retained heat must m
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Some places colder, some warmer but overall temperatures must increase...every year...all other things being equal.
All else is not equal. For one, there is substantial variability from year to year in cloud cover, which prevents heat from reaching the Earth's surface (reflected into space). Over the long run, the greenhouse effect wins out, but only over the long run. In addition, there is a lot of variation in how much heat ends up in the ocean vs. stays near the surface; in some years, the ocean takes more and the surface gets less, and vice versa. Finally, heat can move from the deep ocean to the surface and vice
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All else is not equal. For one, there is substantial variability from year to year in cloud cover, which prevents heat from reaching the Earth's surface (reflected into space).
You are conceding, then, that the reflectivity of the cloud cover can vary from year to year. That puts you ahead of many global warming advocates. Isn't it also possible that warmer surface temperatures (which you must admit would be expected with global warming) would lead to increased evaporation, increased atmospheric moisture,
Re:Cold is on the way... (Score:4, Insightful)
You are conceding, then, that the reflectivity of the cloud cover can vary from year to year. That puts you ahead of many global warming advocates.
No, it's a well known fact.
Isn't it also possible that warmer surface temperatures (which you must admit would be expected with global warming) would lead to increased evaporation, increased atmospheric moisture, and increased cloud cover, thereby increasing reflectivity and providing a global temperature feedback control mechanism?
Yes. There are two major cloud feedbacks, one for cloud albedo cooling as you describe, and one for cloud greenhouse warming.
Yet, current models either don't account for that or simply assume that reflectivity is constant.
That's wrong; dynamic cloud feedbacks are in all modern GCMs.
Nevertheless, the CO2 theory of global warming must result in more heat present in the oceans every year.
No, it doesn't, for reasons I just stated.
Of course, that's not what is observed, which completely undermines the entire simplistic theory of co2-based global warming,
As I just said, (1) cloud modulation alters your claim of "monotonic heat increase", and (2) ocean heat observations are not very accurate.
but its adherents wave that away as a minor point,
That's because there isn't anything yet statistically inconsistent with model predictions.
just as they ignore variations in heat originating in the planetary core
They're ignored because they've been measured and are utterly negligible, on the order of a hundredth of a degree.
and variations in solar output.
Those aren't ignored either; there is a large literature of it, and is in fact one of the pieces of evidence supporting CO2-induced warming. Solar output trends are inconsistent with the warming which has been observed.
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You might say that variations in reflectance are a "well known fact" but the fact is that studies of the effect of reflectance on global warming are relatively recent
Study of stochastic fluctuations in forcing on global warming go back until at least the 1970s; in fact, it was an early competing hypothesis to the greenhouse effect. Hasselmann's 1976 paper is seminal here, although I'm not sure which paper was the first to look at clouds specifically.
and are not properly accounted for in current models.
It's true that clouds are the least properly modeled aspect of the climate. For prediction that's important; for historical attribution, it's less important, because we've measured it. It's not true that you can replace t
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Study of stochastic fluctuations in forcing on global warming go back until at least the 1970s; in fact, it was an early competing hypothesis to the greenhouse effect. Hasselmann's 1976 paper is seminal here, although I'm not sure which paper was the first to look at clouds specifically.
Did you read the link I provided? "Precision earthshine observations to determine global reflectivity have been under way at BBSO since 1994, with regular observations commencing in late 1997...The low albedo during 1997-2
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Minor correction: Lord Kelvin actually calculated that the age of the earth was 25 million years old rather than 4,000.
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Did you read the link I provided?
Yes. As I said, stochastic fluctuations in clouds as related to climate have been studied since the 1970s. Radiometric studies of Earth albedo go back to the 1960s, The Earthshine data is more recent.
If you read the paper associated with your link, you find that they don't use the cloud albedo changes to explain long term trends in global warming. Rather, they speculate whether the warming has caused, and will cause, future cloud albedo changes. You might want to read Evan et al.'s followup GRL piece.
The historical record shows that global temperatures have swung to great extremes over just the last few thousand years.
No
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I agree that cloud parameterizations are uncertain; they are very likely the largest uncertainty in GCM feedbacks. If we find out that climate sensitivity is lower than we thought, it will likely be because cloud feedbacks are weaker than we thought.
I do contend, though, that we know the cloud feedbacks aren't so negative as to make the enhanced greenhouse effect a minority contribution to modern global warming, as many skeptics contend. There is a pretty large literature on the error bars of this feedbac
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Once again, this is why people who don't know anything about a topic shouldn't comment on it.
Wow, welcome to slashdot, get used to it!
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Do you truly believe his mission was more than to do some damage to foreign economies? Flying his personal jet to encourage other people not to fly. Encouraging governments worldwide to pay more to reduce CO2 levels, he, ex-vice-president of USA who has done nothing to reduce those levels in his own country while he was in power (Kyoto protocol, anyone?). You call environmentalist, i call hypocrisy.
Last "Little Ice Age" has ended merely 200 Years ago. It wasn't human-related. Sun-related, most likely. What
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Last "Little Ice Age" has ended merely 200 Years ago. It wasn't human-related. Sun-related, most likely.
Sun and volcano related.
What if the temperature pendulum went that high because of this?
For one, because solar output has increased very little over the last 50 years, when we saw the most warming. See, for instance, the review in Science by Foukal et al. in 2006.
We have seen increased sun activity during last decades, now that the sun is calm we see a decrease in global temperatures.
If you think that the climate responds that quickly and largely to a relatively small change in trend, you're going to have an even harder time explaining the previous 40 years of warming than I mentioned above.
Sounds pretty logical for me as I still don't think that human influence would be that significant on the global scale.
Have you calculated the magnitude of the effect? I didn't think so.
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"2008 is the coldest year of the 21st century and output from the sun is declining.
Maybe Al Gore and his carbon cult followers were...wrong. "
erm, do you understand that the sun's output isn't declining, but rather is in part of a 11 year cycle? oh yeah, 11 years is an estimate, they vary from 9 year to 14 year variation. no, you don't understand that the number of sun spots is a cycle that can change like the weather, and sun spotless (nearly) years are a common (roughly every 11 years since recorded meas
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IIRC, some cycles were skipped during Little Ice Age. We might see similar behavior where the increase is insignificant followed by another period of calm sun.
slow start of next sunspot cycle too (Score:4, Insightful)
Just wait until the election (Score:3, Funny)
I'm sure President Palin will fight back the ice fantastically efficiently, for the good of the economy. You betcha! [today.com]
This is not a measure of total ice (Score:4, Informative)
It's important to keep in mind that this isn't a measure of how much ice there is in the arctic.
The figures they are reporting are sea ice coverage estimates, and typically work as follows: the arctic is broken up into a grid, and for each area of the grid which does not fall on land they ask the question "is >15% of the surface covered with ice?"
If the answer is yes, it's counted as "ice;" if not, not.
There are several ways this can give results you wouldn't expect:
--MarkusQ
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That's true, but it should also be noted that sea ice extent is still a climatically interesting quantity. Non-submerged ice area is closely related to surface albedo, i.e. how much shortwave solar radiation is reflected from the Earth, which obviously relates to how much the Arctic warms (polar amplification). Both sea and land ice contribute, but sea ice is of particular interest because it is more vulnerable to melting than are land ice sheets in the Arctic. This is due to it being situated on relativ
Yes, but... (Score:2)
Correct, but bear in mind that this isn't a measure of sea ice coverage either; it's a doubly aggregated value that must be taken with a dram of salt water. While it is true that the percentage of sea surface covered with ice is strongly correlated with local albedo, the percentage of sea surface parcels which are covered with more than a certain threshold percentage of ice is much less strongly correlated, especially when that percentage is far from the median. IIRC correctly, using the median value as t
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Yes, I agree. I hadn't heard of the median/mode weighting that you mention as giving the best fit. Do you know a reference? Thanks.
Correction (Score:2)
No, it was a heuristic I picked up from a statistician I worked with years ago, and I'm not even certain I've stated it correctly.
The basic idea is a generalization of the rounding rule. If you have a bunch of values evenly distributed between 0.0 and 1.0 you can approximate their sum by counting how many are >= 5.0 and multiplying by 10. So I see already that I got it w
Arctic volcanos (Score:2)
So the volcanos on the Lomonosov and Gakkel ridges shut down. Less steam heating of the bottom of the Arctic Ocean, less ice melts at the top of the ocean.
And this boggles peoples minds because....?
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The volcanoes are mostly not under the sea ice, their heating doesn't measurably reach above depths of 1500 meters, and the total heat is nothing compared to what it takes to melt siginificant quantities of sea ice. It's rather ridiculous to claim that they have anything to do with sea ice melting.
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Earth heats up: Global Warming
Earth cools down: Global Warming getting worse.
Re:Wait... (Score:5, Informative)
No, and they're being *deliberately* misleading. Arctic sea ice this year hit the second lowest level in recorded history [nsidc.org]. Last year was the lowest.
Arctic sea ice extent during the 2008 melt season dropped to the second-lowest level since satellite measurements began in 1979, reaching the lowest point in its annual cycle of melt and growth on September 14, 2008. Average sea ice extent over the month of September, a standard measure in the scientific study of Arctic sea ice, was 4.67 million square kilometers (1.80 million square miles) (Figure 1). The record monthly low, set in 2007, was 4.28 million square kilometers (1.65 million square miles); the now-third-lowest monthly value, set in 2005, was 5.57 million square kilometers (2.15 million square miles)./I.
To report values now, from *October*, during the refreeze is just bloody ridiculous. Yes, different years melt and refreeze at different times; there's a lot of spring and fall fluctuation. What matters are the maximum and minimum extents.
FYI, arctic sea ice normally low in years after El Nino winters and high in years after La Nina winters. Winter of 2006-2007 was in El Nino conditions, leading to the record 2007 melt. But winter of 2007-2008 was in a strong La Nina. The fact that we got the second lowest ice extends on record despite this is incredibly disturbing.
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It's not misleading; summer minimum ice extent and annual ice extent are two different quantities, both of which are interesting and climatically relevant.
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I mistyped the closing tag. That wasn't intentional.
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I hear soybeans and arctic ice are really hot right now.
Didn't you read the summary? Ice is getting cold again!
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No, this report only discusses extent. There are other people who report ice volume, which is more difficult to estimate. I don't know what the current volume estimate is.
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Long live? I would rather compare them to rabbits - 5000 in 1950, 20000 - 25000 now. But the little polar bear who is apparently in danger looks sooo cute on a poster... Environmentalists are all about donations after all. And saving polar bears is so easy -- you can always show results.
Long live my carma...
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Michel Jarraud, who is a big fan of global warming, of the World Meteorological Organization reluctantly admitted that global temperatures have not risen since 1998, according to a BBC article.
That's a pretty misleading representation of what he said [bbc.co.uk].
Global snowfall is at record levels
I haven't looked at snowfall records, but global precipitation is expected to increase in a warming world.
and there are fewer, not more, hurricanes.
AFAIK, there are more hurricanes. Some research suggests that there will be yet more in the future, some research suggests there will be fewer; some suggests they will get stronger even if fewer. Hurricanes are a legitimate area of deep uncertainty in climate science; it's not clear how their behavior should change.