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Why the Sun seems to be 'dimming'

Posted by: Sigurd - Thu Jan 13, 2005 5:48 pm
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Why the Sun seems to be 'dimming' 
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Post Why the Sun seems to be 'dimming'   Posted on: Thu Jan 13, 2005 5:48 pm
This is not really a "very" space related topic, but I think it's a MUST to read article:

http://news.bbc.co.uk/2/hi/science/nature/4171591.stm

A small part of it:

Quote:
Even the most pessimistic forecasts of global warming may now have to be drastically revised upwards.

That means a temperature rise of 10 degrees Celsius by 2100 could be on the cards, giving the UK a climate like that of North Africa, and rendering many parts of the world uninhabitable.

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Post    Posted on: Fri Jan 14, 2005 12:24 am
Don't know if I buy it.

One of the other recently stated things I recall hearing about was that the rise in temperatures and subsequent melting of polar ice risked shutting down the thermohaline circulation, which includes the Gulf Stream, by dumping massive amounts of fresh water into the system. The Gulf Stream is supposedly the major reason Great Britain does not have the same climate as other locations at its latitude. If anything, global warming's effects were supposed to turn the Brits into popsicles. Now this comes along.. and they're claiming a location at or above 50 degrees north (we're talking same general latitude as Newfoundland here) is going to be similar to present-day North Africa. Sorry, I just don't believe them.

Am I denying global warming? Not by a long shot. I do believe it's happening, and I'm very concerned about it.. especially considering I live 12 feet/4 meters above present sea level. I get the feeling like they're whipping up new possible scenarios daily and just throwing them out there for an attention-deficit population. I think these scenario-of-the-day reports are potentially harmful, because the average person still doubts the whole global warming thing to begin with. The average person does not understand how it's possible that the effects of global warming *can* actually make some locations colder. Explain that to them, and then turn around and tell them to throw that explanation out the next day, and then tell them it's valid again the day after that, and all you end up with is someone who doesn't want to hear about it at all. Hell, I have an interest in the subject and even I have difficulty keeping up with it sometimes.

Do I have an alternative? A better answer on how to keep it in the public eye? No. I wish I did. I think some effort needs to be put into rethinking the presentation of this stuff, though.. otherwise more and more people are going to dismiss it entirely as "tree-hugging hippie crap" and such, no matter what evidence you show them.

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Post    Posted on: Fri Jan 14, 2005 12:51 am
I've also read the article about the gulf stream.

I think both articles are true, except the temperature written in the latest one.
(the older article, for peopel who didn't read it: http://news.bbc.co.uk/2/hi/science/nature/3266833.stm)

With looking at even older articles:
http://news.bbc.co.uk/2/hi/science/nature/1401082.stm
"One estimate suggests that without the Gulf Stream winter temperatures in the UK could fall by an average of 11 degrees C"

With other words, we will have "the same temperature" as now in 2100 if we combine both theories.
Of course this doesn't count for OTHER parts of the world.

And after 2100, also western europ will get hotter and hotter if we don't act.

Anyhow, I think we agree, we don't have to wait UNTIL it's a lot hotter... Cause it's not a single event at a time, similar as a Tsunami...
Researchers should give a lot clearer message to the public.

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Post    Posted on: Fri Jan 14, 2005 2:47 am
Sometimes I think that the mainstream media is more interested in trying to scare us out of our wits than anything else. I think they need to get away from the doomsday-scenario-of-the-week stuff and spend a little more time talking about how to fix things. But, sensationalism sells papers.. gets viewers.. generates web traffic.

Although I plan on taking a mental break from it to watch the coverage of Huygens tomorrow, I've been putting a decent amount of thought into how to start dealing with part of the problem. Won't get into it now, but all I can say is that I hope better and more educated minds than mine are working on the same and not just working out new ways to scare us.

Re-reading that article just now made me cringe. Looking it over as I'd guess an average person would skim through it leaves me with 1) less sunlight, 2) +10 C. across the planet, 3) scare tactic of equating England with the Sahara. Doesn't add up when you skim it, which I can see a LOT of people doing. Yes, I see the bit about particulates vs. CO2 levels. I understand that. But do you think the average reader will read all that and digest it all? Furthermore, how many people are going to dismiss it just because it's something that they won't see in their lifetimes?

The whole system is more complex than just CO2 vs. particulates and light levels. What about the change in albedo from having less ice and more water? What about the capacity of the larger bodies of water to store heat? (and CO2, for that matter.. something I recently saw suggested quite a bit of it was going into the oceans) What about the changes in ocean currents from the disruption of thermohaline circulation? Will the atmosphere compensate in ways most people might not think of, like generating more and stronger huricanes/typhoons/cyclones to shed some of the built-up heat? (I've seen it said before that they may even pump excess heat out into space.. although I'd like to read more about that before accepting it as fact) How will the planet react to the redistribution of weight from the shrinking of the polar ice? Just saw again recently that the Antarctic ice cap is large and massive enough to deform the Earth. What happens when you remove a huge chunk of that weight? Could the changes alter tectonic activity all around the planet? The last bit has no connection I can think of to the rest of the questions, but I threw it in to help demonstrate just how big the big picture can get.

Of course, the above questions are largely rhetorical for this thread, unless you feel there's something to gain by answering and stimulating discussion.. and I am rather sleep deprived tonight, so please forgive me if I've rambled too much or made an idiot of myself. I'm sure I could've done a lot better.. but all those years of killing brain cells has taken its toll. :shock:

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Post    Posted on: Fri Jan 14, 2005 4:57 am
Strategery71, I think you have done a great job, with answering in a very logical and rational way.

I agree 100% with you, it's very complex and rising sea (more water reflection = less heat), etc... ice melting..changing the location of water mass... deforming earth... creating earthquakes....
Of course those are assumptions.. but very very possible ones.
As example, ice drifting on water, will not change the sea level neither create anymore mass (the ice itself, even above the water, is larger cause of air etc in the ice, but it has the same mass as it would be water itself, creating no diffrence, in water mass)
But a lot lot lot of ice is on land... and that's anough to rise the sea several "meters".

We know it can be so "huge".. threathening all of our lifes... but while we know so much... we also know so very little...
And most people.. ignore it... and that's a real shame.

I guess most people don't realize this isn't a thing we can do with trail and error.

And almost all researches see "terrible" changes, causing huge concerns.
It's not that several people report bugs they find in my application... that I say.. it's possible their computer that isn't working right... that I ignore it... caus it doesn't crash every time...
Our planet gets hotter and hotter.. it's not because we're not 100% sure about all the reasons or what elements alter the effect , that we have to ignore it.. until we see a full scale environment crash with our own eyes.

As you described... it could create a lot more hurricanes (as we also have seen this year)... and a lot more freak wheather... as europ is getting year by year now.. (as the UK is hit right now...)
http://news.bbc.co.uk/2/hi/uk_news/4168589.stm
http://news.bbc.co.uk/2/hi/in_depth/pho ... 168659.stm

Some people think people will succeed.. people will fix.. we're stronger as our planet and environment... I think people's foolishness about it.. may proof fatal at some point...
As in the phantom of the opera (a show and movie ), the sentence "The Point of No Return".

But to get most people intrested and to accept it... we will end in a discussion of evolution or creatinism (created by a god).... some people think god wouldn't do it.. or it's his wish... it's a punishment... only others will get hit...
People will have to get a lot more developed.. and accept facts to take their responsibility, instead of projecting and pushing them away to some religion or leader, before "all" of them or atleast most of them will respond.

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Post    Posted on: Fri Jan 14, 2005 1:03 pm
Unfortunately, Strategery71 (Down with the Cylons!) has made a point that many of us (at least Stateside) have been thinking for a long time: the whole global warming thing seems to just be so much bunk on the face of it -- and even if it's not, it's nearly impossible to try and sort out the sensible pieces from the popularized pseudoscience. As an aerospace engineering major, who has had (somewhat regretfully) very little training in macroecologies and the like, I can say firsthand that a fairly well-educated, highly opinionated, concerned-for-the-fate-of-humanity person like myself can easily be convinced to give up on understanding the global warming issue. It's now gaining the same connotations in many areas as UFOs, astrology, and palm readers.

Of course, there is the fact that of the above list, global warming is the only one that could forseeably kill people.

And yes, I'm going to blame the media again for this one.

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Post    Posted on: Fri Jan 14, 2005 2:18 pm
There is a problem here. I watched the episode of Horizon last night and I do find their programmes very good. The actual phenomenon of global dimming cannot be disputed in any way. The trouble starts in the conclusions made about the effects of global dimming and global warming. Nobody is stupid enough to deny that the planet has been getting warmer, indeed, it is well acknowledged that we are at the peak of an interglacial. But here we realise why geography is an arts subject and not a science. What is the "normal" temperature that earth should be at and how do you quantify it? The average temperature in the UK was higher in medievel times than it is now. That exposes the proponents of global warming as an effect of CO2 emmisions as flawed. The Knights Templar did not travel by V8 Jaguars up and down Watling Street.

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Post    Posted on: Fri Jan 14, 2005 3:33 pm
I thought the issue was that global dimming (brought about by increased particulates in the atmosphere due to pollution) was off-setting global warming (brought about by specific chemistries being poured into the atmosphere). Sort of, but not quite, canceling each other out. Because it didn't quite cancel out we still have had a (relatively) brief period of relatively sudden (but measurable) warming, particularly across the 20th century.

So if we addressed one of these, global dimming (by reducing our particulate pollutive output), then global warming (which appears more difficult to deal with) would be able to really take hold and hence the prediction of a +10 C rise in temps by 2100.

Perhaps I missed something?

DKH

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luke.r wrote:
What is the "normal" temperature that earth should be at and how do you quantify it? The average temperature in the UK was higher in medievel times than it is now. That exposes the proponents of global warming as an effect of CO2 emmisions as flawed.

There is no normal temperature for the earth, but we have been able to measure rates of temperature change. If the rates of change are slow enough, then life has a chance to adapt, even to the point of surviving periodic ice-ages. But if temperature changes too fast (as many researchers believe might be happening now, as the current rate of change is abnormally high), then life has a harder time adapting. There is no need to refer to a "normal" temperature, so there is no flaw from that perspective.

Of course, there may be unseen flaws elsewhere. But that's a different story.

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Post    Posted on: Fri Jan 14, 2005 3:59 pm
Dr_Keith_H wrote:
I thought the issue was that global dimming (brought about by increased particulates in the atmosphere due to pollution) was off-setting global warming (brought about by specific chemistries being poured into the atmosphere). Sort of, but not quite, canceling each other out. Because it didn't quite cancel out we still have had a (relatively) brief period of relatively sudden (but measurable) warming, particularly across the 20th century.

So if we addressed one of these, global dimming (by reducing our particulate pollutive output), then global warming (which appears more difficult to deal with) would be able to really take hold and hence the prediction of a +10 C rise in temps by 2100.

Perhaps I missed something?


You're right, and if the dimming polution gets lower.. warming will go up a lot...
But as also written above, because of the gulfstream, wich will get less active(as some predict) when it gets hotter in the world, Europ will have about an exra 100 years of same(or a little colder first) temperature (but still also more freak wheater).

@luke.r, I think it's science, not art.
Relativity, changes in temperature per time unit, shows us that there is a problem, proven by science.

>>"The average temperature in the UK was higher in medievel times"
The problem is, the current ammounth of CO2, would create a lot higher temperature, compared to natural changes in history.
But now they see and think it's blocked by the other polution particles (dimming), but this polution is already halted a lot by treaties in the past, while greenhousegas polution is going to rise a lot with current industrial changes.

>>"That exposes the proponents of global warming as an effect of CO2 emmisions as flawed"
I think it isn't flawed, but that many other elements also play a vital role.. as example the dimming is creating the CO2 a problem for a lot more years in the future, instead of right now.

@spacecowboy, I'm following global warming already many years...
With reading all those research project and combine it.
Then we see that they say "could" happen, as example with the GulfStream "could" stop, they are not 100% sure of everything, but they DO think for 99% or more that it will happen at some point.
That's why I think we should take a lot info as possible fact.

Planet is getting hotter (fact), Gulf Stream is weakening (fact), Gulf Stream may come to a halt in 100 years (Large chance), CO2 makes the plannet hotter (Large Chance, on small scale tests it's a fact), Other polution is dimming sunlight creating a cooling effect (Large chance), Sea level is rising (fact), Will rise a lot more (Large chance)...

Of course we all have to combine it... and I think it isn't difficult to understand.
Of course there're also other elements, but I think those are the most important.

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Post    Posted on: Mon Jan 17, 2005 12:14 pm
From my own experiences and observations I'm suspecting that political parties and pressure groups are abusing science, the fears of the people and the psychics of the people for their own political and sometimes obscure goals.

If we remove this abuse and go down to all the reasons that might cause warming or dimming we will be faced to a very complex situation. Since man learned to make use of fire he is polluting the atmosphere. In the ancient times this seems not to have had any effect - but over the milleniums, centuries and decades it has been adding up. Second the number of humans at Earth has been growing exponentially during all these eons - and they all needed fire until electricity has been invented.

The use of fire since invention of electricity is due to purposes electricity cannot be used for efficiently. Before the first civil use of nuclear energy the generation of electricity required fire.

Additionaly scientists have become aware of the solar impact on temperatures recently and time by time find other small sources of impacts too. all this has to be combined together but the way isn't known yet for sure - and it seems to be changing permanently beacuse the relations between the existing number of each source is changing.

Two points not under human control are eruptions of vulcanoes and the natural burning of carbon in China - very huge subsurface fires destroying valuable carbon mines.

All models I've read of seem to have a significant problem - to macro-scaled. Significant micro-scaling is needed from my point of view.

But to get rid of the problem there should be research and development, engineering on technologies to remove and to avoid dimming particles as well as warming gases.

Wouldn't that be a good topic for the WTN XPRIZE? It would have a relation to private space vehicle teams too to a certain degree and get them additional sources of money.



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Post    Posted on: Mon Jan 17, 2005 2:05 pm
Geography cannot be classed as a science as there is only one Earth. Therefore, they have no means of comparing data on what and how things are effecting it. As regards to guessing how high temperatures will/can go and how quickly, they are simply that, guesses. The programme itself was peddling the global dimming data merely as a precursor to their favourite topic of global warming (and in quite a sensationalist manner). Knowing how the global temperature has changed in the past as rapidly as it is now without known human interference, you cannot take human activity as the cause for global warming as a given. However, I am not foolish enough to believe that the lack of proof thus far prooves the other either.
P.S. You can argue the point for emmisions regulation without the environmental lobby. Its called efficiency and saves a hell of a lot of money. That line might even persuade the Americans :)

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Post    Posted on: Mon Jan 17, 2005 3:30 pm
luke.r wrote:
Geography cannot be classed as a science as there is only one Earth. Therefore, they have no means of comparing data on what and how things are effecting it. As regards to guessing how high temperatures will/can go and how quickly, they are simply that, guesses. The programme itself was peddling the global dimming data merely as a precursor to their favourite topic of global warming (and in quite a sensationalist manner). Knowing how the global temperature has changed in the past as rapidly as it is now without known human interference, you cannot take human activity as the cause for global warming as a given. However, I am not foolish enough to believe that the lack of proof thus far prooves the other either.

Wow. I'm gonna try and be polite about this ... although the discomfort is severe in the extreme, it is moderated by the thought that you are merely trolling for a response ... were you not the luke.r who has contributed very well in the past then I would of course let rip with wild abandon.

Now before I lose track ... let's see, where should I begin.

Geography is a science and not an art. Despite what you think. Go and look up the word "geography" and, if you have reasonable comprehension skills, you will find out why. While you are there check out the words for "art" and "geology" too, it might save some confusion in the future. Although if your comprehensions skills are so poor as to not distinguish the critical differences then perhaps I'm wasting my time already. I will thus merely consider this an excercise for myself.

Every single data point obtained by human beings on every single thing can be eventually deconstructed to "guesses", this is because the mind has to rely on sensory apparatus (and the tools to enhance this apparatus, e.g. a compass) and has to make the giant assumption that the apparatus is telling it the truth. Watch John Carpenter's "Dark Star" for a good, and funny, example of this sort of thinking.

So yeah, they are guesses.

But, luke-baby, there are flat out wild stabs in the dark (which is what I'd like to inflict on you for no more reason than I aspire to be a murdering bastard) and then there are guesses based on carefully researched information (often prefixed by the qualifier "educated"), I'll leave it up to you to guess which one current predictions of global warming fall into.

You don't seem to understand that global dimming is currently a GOOD thing as it is currently moderating the effects of global warming. I understand that global warming has had a lot of press and has had it for a long time, but just because you can still go to Venice for holidays doesn't mean global warming has been a load of horse-hockey dreamed up by meteorologists wanting some way of boosting their funding level. The key point is that the severe effects are to be felt in the relatively near future.

The point is that the current rate of temperature change exceeds that known before is strongly correllated with industrialisation. The boys and girls doing the correlation have a fairly easy job of this because they take their measurements over geological timescales. So if human activity has nothing to do with global warming it is one hell of a coincidence.

Give me a link to support the following quote.

PFYA wrote:
Knowing how the global temperature has changed in the past as rapidly as it is now without known human interference


Looking forward to reading it.

DKH

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Post    Posted on: Mon Jan 17, 2005 4:22 pm
Luke,

Geography IS a science...

(PS!, Dr_Keith_H I would also love to use some other words for Luke right now ;))

And Luke, there're "more" planets, earth is the only earth, but you're also the only user on this forum called "luke.r".
This science is also based on the science that water on sea level boils at 100 °C.
This science is also using same "techniques" used to detect changes of temperature every year.

Other techniques of detecting Gas, Smoke.. are used to detect "what" and how much of everything is in our air.

If all those "changes" is not a science... maybe I'm not a human ?
And it's true, we don't know "all" about it.. but don't worry.. if you're sick.. and we don't know all about it.. we'll call in an artist ;)

Your comment: "no means of comparing data", I think you're living in the past.. or did you drop out of school when you where 12 ?

Math and science can work with "unknown" elements, cause we know they are "unknown". And in most cases we don't have to know the limitations... and I guess we don't wanne know them on earth!
Changing temperatures "now" and thousands of years ago.. that's "comparing data".. and earth layers have all the info, also the Ice on the north and south pole.

I think we should call your post a moment of weakness and foolishness ;) (PS!, Keith, I didn't attacked him personal, I gave him a chance to explain his "foolish" moment :P )

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Last edited by Sigurd on Mon Jan 17, 2005 4:28 pm, edited 1 time in total.



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Post    Posted on: Mon Jan 17, 2005 4:27 pm
Sigurd wrote:
(PS!, Dr_Keith_H I would also love to use some other words for Luke right now ;))


Well he's a moderator here, so you have to be careful.

DKH

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Post    Posted on: Mon Jan 17, 2005 4:43 pm
Cheers for being restrained in your reply but if I make a tit of myself, I should get it as good as anyone else does :)
In the UK, if you study Geography for a degree, you will receive a BA Hons, and not a Bsc. Although I am happy to credit Geography as science, my friends who did "real" science degrees (like engineering) were having none of it. Still, you are right, I am not.
I do understand that global dimming was shown to be a restraining influence on global warming, however I question wether it is a good thing in itself. It would seem to be one cock-up accidently shielding us from another, not a good reason to keep doing it.
Just to clear things up a little, I am not denying the current climate change we are going through or even that industrialisation is a contributary factor. I just disagree with the way that the environmental lobby cherry picks its data with the world seeming to only come into existance in either the 1860's or even better the 1950's.
I hope this link will do...
http://www.koshland-science-museum.org/ ... ical02.jsp
Quote:
Younger Dryas – Abrupt Climate Change

Climate can exhibit abrupt shifts over large regions of the world. As the last glacial period was giving way to the current warm interglacial period, average temperatures in Greenland returned to glacial levels for more than 1,000 years. This unusual period, which is called the Younger Dryas, ended abruptly about 12,000 years ago. Evidence from an ice core drilled in Greenland indicates that temperatures there rose approximately 15°F (8°C) in less than a decade.


Quote taken from the National Academy of Sciences, found on the above internet link.

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