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A New Ice Age?
barakn writes "Scientists have savaged the new movie The Day After Tomorrow, which depicts global warming causing a new ice age and freezing New York solid. The movie follows on the heels of a report to the Department of Defense in February, written by two guys who are not climatologists, about the implications of global warming triggering the growth of ice sheets in the northern hemisphere. There is a plausible theory which suggests that melting ice may release enough fresh water to halt circulation of warm water from the Gulf Stream, thus significantly cooling Europe and the east coast of North America. Note that this theory depends on melting ice, not growing ice, which may be one reason scientists find the ice age scenario so hard to swallow. New satellite evidence suggests a part of this circulation may already be slowing down. Those on the North American west coast will not have to worry about ice sheets, but changes in Arctic ice could mean the western drought will be permanent. For those of you who would rather do something before it's too late, iron seems to work, but the long-term ecological implications are still unknown."
Wait... so you're telling me that a movie writer is being loose with the truth?
What is the world coming to!?
That every global warming prediction scientists have made in the last 30 years has fallen flat on its face.
According to them, we should be all dead by now.
Personally, I'm not sweating anything. There is plenty of evidence that our toxic output is not the largets or the deadliest on this planet, and thankfully things pretty much clean themselves.
I refuse to forget how many times popular science has been wrong.
clifgriffin > blog
I personally believe that all this supposed changes may eventually occur, but they are a normal cycle of the earth and be very gradual. If the human race mangaes to survive long enough, we will slowly change how we do things to meet these problems.
Regardless though, what is gonna happen will happen, and there is nothing we can do to change it. Worrying about such things seems pointless to me. The whole planet is going to be destroyed by the sun dying in about 5 billion years, why don't we worry about that as well?
i might be wrong, but arnt people saying were in the middle of an ice age right now and the only thing keeping it check is the amount of CO2 being produced. anyone?
Jack the sound barrier. Bring the noise.
A major part of climate change is the amount of CO2 in the air (CO2, carbon dioxide, is the major greenhouse gas) In figuring out how CO2 levels will change, a major term is the exchange between gas and water over the oceans; this is a key parameter in all the super complicated computer models from places like NOAA a few years ago, in SCIENCE magazine, turns out this term was wrong by an order of magnitude CONCLUSION: the models are crap why ? u r an administrator, testifying before congress on why u need 200 large. YOu could say, well we made major progress in FFT algorythmns usefull in modeling, and our understanding of image recognition to model cloud patterns...(congress falling asleep) OR u cd say GLOBAL WARMING !!! NYC underwater !!!! it is not that it is bad science, it is just that the quality of the models is not that high - noone has the lsightest idea of how our climate will change in response to any significant perturbation - sort a like MS stuff, no ?
There will be no need for the upcoming 2Kg heatsinks.
Did they touch God or did they touch the Sun?
Next you'll be telling me that Jurrasic Park, Armageddon, etc. are based on junk science!
So climate's changing. So what? It has always changed. The big news would be if it wasn't changing. - Dr. Philip Stone
Today, it's like 59 degreees F.
If that recollection is true, then we're still in an "Ice Age" and should expect the world to be getting warmer if the "Ice Age" is in fact coming to an end.
Sorry if this doesn't fit into the "human == BAD, all_natural == GOOD" paradigm, but getting struck by lightning or eaten by a lion does fall into the "all_natural" category too...
Although accurate software models of the earth's climate and weather conditions don't exist. There is certainly the hardware to run it. The worlds most powerful supercomputer the Earth Simulator is designed to be able to accurately model the earth. Hopefully advances in software modelling will enable us to actually make good use of all that raw processing power.
Why is it that people here* are so dismissive of climate change on Earth, but if it's terraforming on Mars, nary a criticism (of the scientific theory) is heard...
* a generalisation, yes, but just look at some of the comments so far!
I was hoping for global warming! I already had ordered a few 100.000s tonnes of pearly white sand to make some lovely beaches in soon-to-be-sunny Greenland... Damn it!
Hate me!
There is a plausible theory which suggests that melting ice may release enough fresh water to halt circulation of warm water from the Gulf Stream, thus significantly cooling Europe and the east coast of North America.
okay, I couldn't begin to tell you where I heard this (let alone provide a URL) but I recall hearing/reading the "global warming=new ice age" theory kinda like this:
So the earth's temperatures rise a certain level, really only a few degrees, maybe half a dozen. This means the atmosphere can hold more moisture and precipitation increases.
But - with the earth's overall temps slightly higher the temperatures over the poles would still be hella cold (just not as hella cold as before) and the moisture-laden air passing over the cold regions would dump a lot of snow, sleet and ice, which would mean expanding polar ice caps, glaciers, etc., etc., albeit this would be a cumulative effect taking place over many thousands of years.
So, like, I ain't no climatol... clima... uh, scientist or nuthin' - that's just what I read in some fancy magazine somewhere.
RTFM; please, I beg you.
Sure global warming may be happening... BUT and this is probably why the slashdot people are laisse faire, maybe it is part of the overall scheme of things by none other than mother nature.
When that little warming period and ice age hit, which was not caused by humanity, would the arguments not be the same? EG would the green people would be saying to stop burning all of those fires to heat homes?
Frankly I think the only real way of stopping global warming is to kill off about 2/3 of our planet. There are just too many of us.
Let me give you an example. Germany, which is trying to be green installed a huge number of wind powered generators in the North Sea. They have just found out that because of all those generators the coast is getting 10% more sunshine and 10% less rain. I then ask the question, are we not dammed if we do and dammed if we do not?
So unless you are ready to volenteer your life in the name of "humanity" nothing much is going to change.
BTW I do not agree with your quote as planet Earth has withstood worse things than humans and continued. What might not survive are the humans!
"You can't make a race horse of a pig"
"No," said Samuel, "but you can make very fast pig"
Could the warnings of global warming armageddon be true? Yeah, but so could the warnings of global cooling armageddon from the 1970s.
And even if either guess is true, there's no way to be sure that the problem was caused by man.
Now, all that doesn't mean we shouldn't be reasonable about reducing pollution and greenhouse gas generation. (Well, except if the older "global cooling" predictions were really true, then we should be cranking out the greenhouse gases, right?)
It would seem that the Earth's climate is normal, and we're not going to suffer a slow broil (so put away the onions, and get that apple out of your mouth).
As for the ice age theory, one of the last ice ages was caused by a lot of fresh water pouring into the North Atlantic. The difference in salinity caused the warm Gulf Stream waters to submerge, reducing the overall temperature in Europe and North America enough to cause an Ice Age. The effect took only 70 years.
It would indeed be ironic, though, if the only way to save civilization as we know is would be to increase greenhouse gasses, not reduce them.
"My country, right or wrong; if right, to be kept right; and if wrong, to be set right." --Senator Carl Schurz (1872)
Note that this theory depends on melting ice, not growing ice, which may be one reason scientists find the ice age scenario so hard to swallow.
Because our climate is probably not bound by a purely linear occurrence of events. It is full of rebounds, snap-backs, and whatever else you want to call it... like oscillations.
Just because the melting of the caps is the result of global warming doesn't mean that doing so will not trigger a rebound, causing more of the northern hemisphere to freeze. Just like freezing the caps and lowering the sea level will (theoretically) uncover methane deposits in the soil, releasing greenhouse gasses and thus warming the planet again. So stopping the nice current bring warm water up to northern Europe will cool it down, allowing more ice caps to form. Sure, one they're formed the currents might start up again and warm up Europe, but like I said, it works in oscillations.
What really surprises me is why so many people have a hard time swallowing this. Even looking back at the history of Earth's climate shows numerous ice ages and warm periods. CO2 levels have done the same as well.
Some people just need to think a little bit longer down the line. Or maybe they disregard the claims so they don't loose grant money? Not flaming, just a warranted curiosity...
Could the person who modded parent informative please translate it into English? (Spanish or French will do, I'm not too fussy).
Here's another.
Or you could just Google for paleotemperature among other things.
Or perhaps our probes are polluting the Martian atmosphere? ;-)
Are you implying that these scientists' predictions of doom are wrong? That would mean that they're just "stretching the truth" to get more grant money and don't care about being credible!... oh, wait.
Nature probably thinks we are spyware or something, and figures the only way to fix the problem is to do a "cold boot"...
Cold, salty water from the North Atlantic sinks far below and runs south. Far enough south that it brings back warmer waters north. This flow includes the Gulf Stream.
Climate research has shown that climate shifts have occurred over history in as little as a few years.
If enough ice melts and flows into the North Atlantic, it disrupts the cold saline flow, which disrupts the concomittent return warm flow. Which makes the Northern Hemisphere colder. Which brings on the Ice.
That's as simple as it gets and the ice record in Greenland bears this out.
The real problem these movies point out is the shocking rise in bad acting. Apparently something in the future (possibly estrogen-like toxins?) is destroying humanity's ability to emote properly. This is what scientists should be studying. At the rate it is occurring, bad acting could sweep the planet in just a few decades. This could have a profound impact on Broadway, Shakespeare festivals, and even school plays.
Generally, in any case by no means every theory/prediction made about climate has been wrong. Case in point James Lovelock (who happens to be one of the two founders of what's generally known as the Gaia hypothesis) and co-researchers *accurately* predicted the medium-long term results of CFC release on the ozone layer.
Science is inherently wrong, because it's the art of better explaining what we don't know. Another related case in point. Up until a dozen years ago physical oceanography uniformly concluded (based on theoretical models and very limited data sets) an understanding that the deep ocean flow was uniform and slow.
A friend of mine at WHOI put some cameras on the floor of the northern Atlantic, one day they were thinking their hardware had flaked 'cause they couldn't see anything. What was happening was silt was being stirred up by a high velocity current. What they discovered was that oceans have 'weather patterns' which operate much as atmospheric weather, fronts, low&high pressure areas etc.
This completely blew away established theories of physical oceanogrpahy (and happens to be directly related research to the abrupt climate change and ocean conveyor research article referenced in this post).
I'm glad you feel safe, however concluding that you're safe because prior research has been wrong is not a great recipe for the long term. The CFC / ozone problem is one of the first instances of scientific results materially impacting environmental policy at the global/international level. If rapid-onset ice-age is a possiblity (this has been pretty well established). And if a 'lens' of low-density fresh water over the northern oceans can trigger this abrupt change we would be foolish to conclude there's no risk worth further understanding.
Linux is Linux, if One need clarify their dist: <Dist>/GNU Linux
bsds are of course just BSD
I'm not sure how bunk the notion of Global Warming causing an ice age is (esp. since the article seems to be slashdotted so I can't read it) nor have I watched the movie. I remember when we were studying planetary science, one of the chief questions was what caused ice ages, esp. connections with the Earth's orbit and rotation. Mind you this was some years back, but if I recall correctly, one of the things we focused heavily on was the fact that the geological evidence shows that just before Ice Ages, the Artic regions have record peaks in their temperatures. It seemed that no-one was too sure about why this was the case but what seemed to be popular was how very high Artic temperatures affected the percentage of the ocean covered by ice and the different amounts of heat that land and water absorb (and also how the Southern Hemisphere was different because of its different ratio of land to water). This seemed to be pretty established physics at the time and no-one mentioned anything about global warming. Though the question of just exactly how this all worked was still up in the air. It just seems that people are applying what is known about past Ice Ages and theorising that if record high temperatures in the Artic Circle which preceded previous Ice Ages played a direct role in the Ice Ages (and you have to admit, it's pretty reasonable to assume this), global warming may eventually result in an Ice Age as well due to the same conditions that caused previous Ice Ages.
It can't be "accurate science" or "proper science" or "real science" because there is no control, nor is there any way to run any experiments to actually measure any cause-and-effect relationships.
Wrong. While it is not possible to run experiments as such, it certainly is possible to make certain predictions based on the underlying physics and look how the predictions turn out based on empirical data. Then the theory is either validated or not - in which case you modify the theory trying to account for the difference. Or, in briefer terms, you apply the basic scientific process.
And of course it is still absolutely possible to run many experiments on a smaller-than-global scale - the outcome of which help the understanding of the global climate and help predict it's future development.
And even if either guess is true, there's no way to be sure that the problem was caused by man.
That's true. There's no way to be sure of anything per se. There are ways to be reasonably sure of it based on a given set of information, though.
Well, except if the older "global cooling" predictions were really true, then we should be cranking out the greenhouse gases, right?
No. I haven't been around to read about the older predictions, so I might be wrong. However, I imagine a global warming can well induce a severe global cooling, and the other way round. And furthermore, it might well be that the previous claims were just wrong - and the underlying assumptions corrected since then in the process I described above. Of course, now you're saying "Well, what if they're wrong again?!" - that's just the problem with any scientific claim, it can always be wrong. Unless you've got some indications that the current theories are failing, though, it'd be probably be wise to assume they are correct. If on the other hand you do have such indications, you probably should do some research into the matter and find out if either you're wrong, or they are.
And as for the original poster saying: "I refuse to forget how many times popular science has been wrong."
I'm not sure what exactly "popular science" is supposed to refer to, but science is one of the few fields were being wrong is not that bad. Newton's laws on gravity have also been proven wrong, but they were still an incredibly important discovery. And while you refuse to forget how often science was wrong, you do seem to forget how often it has learned from those errors and corrected them, and how often science is right. Also: Try reading a book some day.
Switch back to Slashdot's D1 system.
For those of you who would rather do something before it's too late, iron seems to work, but the long-term ecological implications are still unknown.
Yeah, there's a good idea. I read that article and while on the surface it seems like a grand idea, it's the second part of your statement that concerns me. We don't know the long-term ecological implications and frankly, I think we'd be more likely to do long-term damage than long-term good. I just don't trust our knowledge of global warming and cooling
I think for now we're much better off sticking with reduction of greenhouse gas creation until we better understand our environment.
Here's the problem. Scientists say, "we've got global warming," and hey, maybe we do, but the Earth also goes through cycles of warming and cooling that are natural, and we don't entirely understand these yet. So now scientists aren't sure if we've got global warming or if we're simply in a natural warming stage. Yes, we do have manmade greenhouse gases. There's no question, but how much this is actually affecting global warming is up for debate.
There are many unknowns. And as we like to quote from the White House, some of those unknowns are known. Some of them are unknown. Until we really understand how global climate operates (maybe in 50 years, maybe longer), I don't think we should do anything to cause any intentional major changes because the damage we could wreak may be well beyond our ability to control, before it's too late.
But that's just my opinion.
But _The Day After Tomorrow_ is by the director of Independence Day -- how could it be anything but a quality picture?
I object to that article, and to the next reply.
Because, for example, the eruption of Mount St Helens put 1 Million tonnes of sulfur aerosols into the stratosphere - these are the things that have the most effect on the worldwide climate, the ash from volcanos is local effect only.
Now, a million tonnes sounds absolutely huge. But it is still only just over five times what, say, the State of Louisiana emits as sulfur dioxide every year.
So in other words - the US easily produces as much sulfur dioxide, and more, every year than the explosion of Mount St Helens.
Or put it this way - you get sulfur dioxide from burning fossil fuels. We mine, worldwide, billions of tonnes of coal every year (the US alone produces just under a billion). How much sulfur dioxide do you think all that lot produces? The answer is that a typical small coal-fired power station (100 MW) may produce from 20 000 up to 30 000 tons of sulphur dioxide a year. In other words, Mt St Helens is worth a measly 40 small coal-fired power stations. How many of them are there in the US alone?
This is a pretty strong argument that the higher lattitudes are temperate because of the regulating effects of the currents. Siberia is a frozen waste because it benefits from no nearby warm current, and the Sahara bakes while the Amazon is merely tropical because of the proximity to a regulating surface current. If the deep ocean current were disrupted, there is reasonable and significant doubt that a different suitable global ocean current system would develop to prevent the low lattitudes from turning into a planet-wide desert while the high lattitudes make Siberia look like a warm vacation spot.
Then it demonstrates in a fish tank how cold water currents cannot descend in fresh water as well as in salt water. This is exactly what happens near Iceland, where the warm Atlantic surface current hits Arctic waters and drops to the ocean floor to fuel the deep ocean current. Already they have scientific measurements to suggest that the deep ocean current is being fueled less now than it was 30 years ago, before which nobody understood the importance of salinity in the oceans and the deep ocean currents. This correlates to the alarming increase in icebergs which have broken away from the polar ice caps over the last few decades (something like a 500% increase, by the way.)
And the documentary takes only 60 minutes, including commercials.
I think this is similar with this stuff some scientist have been saying. The theory is something like when the earth starts to reflect less sunlight. (lesser global warming effect) it will make things colder. thereby increase the amount of icy regions. In effect, increasing the amount of light reflected. You can read the details here: http://en.wikipedia.org/wiki/Snowball_Earth very interesting :)
Regardless of whether the film is completely accurate regarding the growth of ice sheets, it will be the first time that its possible that melting ice will shot down the thermo-haline circulation belt. Most of Europe would be a frozen wasteland without it operating.
There's ice-core evidence showing that the circulation belt does shut down periodically - and that it correlates with cold temperatures in Europe.
What I'm wondering is whether or not this film will freak the public out, and make them demand action on climate change. I've seen reports that after Deep Impact and Armageddon public perception of the risk of an asteroid strike went through the roof.
We all know that its hard to convey uncertain and complex scientific issues to the general public. Maybe it will take a Hollywood blockbuster to do what 1000 UN reports never could.
TripInvite.com: Group Travel Made Simple Evit
We could reduce our population by undertaking a massive space program and colonizing the galaxy. It's about time people started to go to other stars.
A good start would be building space stations and bases on the moon and on Mars. Even a program of robot explorers would start the momentum.
One great bottleneck of robots is control - we still have very primitive self-driving cars. In outer space we would need a large array of robots to be able to operate for a long time. The Mars rovers work by themselves, but this limits their lifespan. However if they worked in groups they could maintain each other for a longer time. Periodically we can send supplies and more robots to boost the abilities of the robot farm.
Know your pads. One time pad: good for cryptography. Two timing pad: where to take your mistress.
All iron seeding studies as of 2003, confirmed the consumption of CO2 but
Fast forward to 2004.
There is an article in nature, published on March 17 2004, whose abstract says iron is not a panacea
Audio interview, (8:36 ogg, 3.3Mb) with one of the authors. Source story.Apparently the study linked to in the original post has two studies who's results will be published in April 2004
So what do we know for sure? Adding iron does cause a bloom, and does drawdown CO2 but other nutrients are used up and the CO2's ultimate fate is debatable.
The conflicting results could be regional variation in ocean conditions, but IANAO.
Either way global warming is real, and the film may bring to light the severity of future changes.
When I first got into this business in the early 90s I spent a lot of time discussing these topics on sci.environment.
It may be worth pointing out that climate change over the past decade has panned out pretty much as was expected ten years ago. It's interesting that this hasn't affected the cerdibility of the field very much.
I've dabbled a bit in sci.environment again in the last few months, but it's been a lot less satisfying. Ten years ago I had the privilege of getting into flame wars with no less than John McCarthy, as well as many other less famous but comparably intelligent, very well-informed conservatively inclined people.
To be sure, there were also many throughly propagandized folks, mostly aligned in two opposing camps, but it was possible to have a serious debate and even, once in a while, score a point.
The conversation on Slashdot is only marginally better than the decaying thrashings on sci.environment. It's better because most people here are grinding different axes, and so their ill-informed commentary is less shrill and confrontational.
There's a hell of a lot of misinformation going around here, though. It's pretty discouraging to see what gets moderated to 5, insightful or informative.
Even the hacker community, chastened though it should be by the ways in which writing code makes you face your mistakes, is sadly overconfident about its opinions. People make broad and confident statements on matters where, (obviously to those few of us here who are serious students of the matter) they know very little. Moderators sharing the politics of the poster mod these up to "insightful" ore even worse "informative".
Let me review the settled science. There's a lot that's unsettled, but when I see these points debated I despair for democracy:
mt
The Gulf of Mexico is a large tropical sea with very warm water. A major ocean current, called the Gulf Stream, carries warm water from the Gulf up the east coast of the United States, starts to curve to the east as it passes Virginia, makes a sharper turn east near Cape Cod, heads straight for Ireland and Britain, turns south and heads down the French coast to Spain. The heat from the Gulf Stream warms northwestern Europe, and is the reason why London is as far north as Quebec and Moscow, but doesn't get 4 meters of snow every winter.
The mechanism that causes the Gulf Stream to flow is that cold water is denser than warm water. The arctic water up near Greenland and Iceland sinks and the warmer, less dense water from the Gulf of Mexico flows up to take its place.
However, salinity also affects water density. If enough fresh water from the ice cap melts and flows into the area around Newfoundland-Greenland-Iceland-Scotland, the water won't be dense enough to sink. Therefore the warm water will stop flowing north from the Gulf of Mexico.
Now London gets 4 meters of snow. Scandanavians laugh at them.
Of course, this will also cause the ice cap to stop melting in this area, but it will take quite a long time to "prime the pump", perhaps several thousand years. In the meantime, the northeastern United States and Northwestern Europe experience an "Ice Age" where their climate more closely resembles the climate of Russia at similar lattitudes.
There's an unfortunate side effect of fertilizing the ocean with iron: the increased microbial activity will cause more N2O (nitrous oxide) to be released from the oceans. N2O is a much more effective greenhouse gas than CO2, and it stays in the atmosphere for centuries.
What this prediction does is to make Global Warming completely unfalsifiable. If things get a little warmer, it proves that Global Warming is imminent. If things get a little colder, it's because Global Warming is imminent. If things stay the same (which they generally never do) then that just proves that we are at an unstable tipping point. Goodbye science, hello politics.
...their servers froze
Table-ized A.I.
I have a question about the nature of climate. You say:
What about 1/f noise? Are we studying a stationary random process? Is it even legitimate from a mathematical-modeling viewpoint to talk about long-term average behavior? The prediction you make about 2304 is reasonable, but hardly long-term by geological standards.
Is it even legitimate from a mathematical-modeling viewpoint to talk about long-term average behavior?
Indeed, in a formal sense it is not easy to make a distinction between climate and weather. The casual statement "climate is the statistics of weather" becomes formally unsatisfactory when one starts to talk about climate change .
Nevertheless, I hope you will admit that I am saying something both meaningful and true when I say that the climate of Kansas City Missouri is more variable than that of Portland Oregon. How to cast this into a formal mathematical statement is not obvious, but probably not relevant for the current discussion. Whether it ought to be a practical issue for the field is something I've wondered about, but I don't think it's a current topic.
Interestingly, "climate" is conceptually better defined in our complex models than in the real world, because our models have finite sets of forcings and of free variables, and thus a clearer distinction between intrinsic and extrinsic variability than the real world does.
The prediction you make about 2304 is reasonable, but hardly long-term by geological standards.
Actually, the prediction is robust for any location at 40 degrees north latitude, at any date, on physical grounds, as long as the atmosphere is not almost totally opaque to incoming shortwave radiation (a.k.a. "sunshine") as on Venus.
I simply use it to illustrate that the predictability horizon of weather (defined as preturbations about the climatological mean) does not amount to a predictability constraint on the climate itself. I will make the same assertion for 30,000 years in the future, if you assure me that "Chicago" will be meaningful that far into the future (which I very much hope will be the case!)
I understand this doesn't go directly to your question, which is mathematical rather than physical. Climate is definitely not stationary, and quite possibly not even ergodic.
Climate is easy to define formally in our models though, much more so than in the real world. Our models can do multiple realizations of a particular year, based on specific boundary conditions and forcings. We capture enough of the variability in these models that the realizations differ. We treat the variations among these realizations as stochastic weather and the commonalities as deterministic climate.
In the real world, as opposed to in models, there is only one realization, and in fact, no clear distinction between intrinsic and extrinsic processes. So our meta-model, our model of the model, is difficult to justify formally.
In practice we don't dwell on this much. We just treat the real world as a superposition of chaotic dynamic variability (an unpredictable part) and deterministic climate change which sets up the statistical properties of the chaos.
In the simple chaotic dynamics view, weather is the state of the system (the wandering dot), and climate is the shape of the set of permissible trajectories (the whole phase diagram). Things aren't necessarily that simple in fact, but we don't have a better way of addressing the issue. Ultimately, we aren't trying to prove theorems, we're trying to elucidate complex physics, and this view appears to be both necessary and sufficient for most of our purposes.
mt
Possibilities are not probabilities are not certainties.
Not 18,185,947,580,800 kWh. From your own numbers it should be 18,185,947,580,800,000 kWh available from solar (you were off by a factor of 1000).
Completely moving to solar electric would be very expensive with current technology, and use a lot of land, but it probably could be done.
a,e,i,o,u and sometimes w and y (at be if of up cwm by)
say the polar ice melts and now there is more water to evaporate so there are more clouds in the sky, more rain, less sunshine hits the surface thus cooling the earth, rain turns into snow, ice age, ..., profit? i don't know about these things but it seems like a it could happen.
lose != loose
We should be trying to maintain global warming.
temps for last 150,000 yrs (you need flash and ie)
This temperature record for the last 160,000 years is very informative. What most "environmentalists" do not realize is that the earth is normally cold as hell. It is only throught "unnatural" affects caused by life (a.k.a man etc.) that the earth is not a frozen hell. It is true that it is possible that through industrialization we could throw the world back into an "ice age", but it is equally possible that we could delay the inevitable descent into the next ice age through these processes. I believe the latter is more likely. I work for an environmental company. If man-made things are not natural, exacly what are they? Supernatural? ughhh!! you guys hit my pet peeve today...The global mean temperature did increase over the last 100 years, most prominently over the last 30 years or so. The reasons are not totally clear.
Watching local weather reports regularly for less than two decades or so may not indicate this, since there is indeed a superimposed cyclic temperature change (related to solar activity). Moreover, there are regions where a systematic *decrease* of mean temperatures was observed over the last decades.
CO2 does not cause holes in the ozone layer
Antarctica is not a volcano
I think it will be many years before anything worthwhile comes from the IPCC and their models. I you check out chapter 7 you will find they advise why they have not included water vapour in the atmosphere in their modeles.
The issue is that water vapour is by FAR the most important greenhouse gas. CO2 is about 365 ppm these days - or 0.0356% while water vapour is in the range of 2-4% and this makes water vapour 100 TIMES more important.
Next, we need to consider irrigation. The CIA factbook does have land under irrigation on a country by country basis. It is clear these irrigation projects collectively are very significant and they have the effect of turning vast areas of arid land into moist land. All that water ends up transpired or evaporated into the atmosphere.
If we consider fossil fuels we find another large source of water vapour.
If we add it all together, which the IPCC has not done, what we find is that there has been a change in the amount of water vaopur released into the atmosphere from mankind's activites and then we must note that the UNCERTANTY in the measuremens of the water vapour are much greater than the total amount of trace gases.
Water vapour is 2 orders of magnitude more significant in concentration and it is a stronger absorber of Ultraviolet light in ALL wavelengths.
---------------
That being said, our climatologist look at an extremely short time frame. The earth has been around for about 4.5 billion years. By 570 million years ago, it had warmed and then it stayed warm for close to 90% of the time since then. There really only were 4 cold snaps and we have been in one for the last two million years. And during this last 2 million years it appears we have enjoyed about 20 ice ages, the last of which ended only 18,000 years ago.
To contrast the duration of time, suppose we were to stack up the volumes of the encyclopeadia Brittanica. If we count the number of pages we might find the thickness of each page would correspond to say about 100,000 years of the earths history.
This means that our climate modelers basically collect there data from usually less than 1/1000th of the thickness of the last page and meanwhile they ignore everything else.
IMHO this does not bode very well for their ability to make valid predictions.
I remember reading a National Geographic article nothing that CO2 concentrations have been their highest in 400,000 years thanks to ice core samples in the arctic. This was through several ice ages and the most recent dramatic spike being the start of our industrial age. Whether or not this causes global warming or climate change or it's outcome no one is really sure of. However considering earth is our life support, can you risk messing around with it? I think it's something to be concerned about rather than completely ignoring. The solution however is a difficult one. Knowing how we do things thou, we'll likely do something when it's too late sadly.