I repeat, his point about the value of scientific 'consensus' is valid.  Not to mention the point about media magnification of that consensus into dire predictions.  You can't pretend it didn't happen and 30 years barely qualifies as a partial blink in geologic time.

*turns the light on*

first i apologize if i do too much retreading of what others have argued. i had to stop reading this post at about page 6...only so much time in the day.

First, the UN is one of the most corrupt organizations even devised by mankind. anything put out by this organization should be considered at least suspect if not an outright fabrication.

Second, scientists have a tendency toward various degrees of zealotry. there is a correlation between how vocal they are and their level of zealotry with the few exceptions. scientists are also paid by governments, corporations, educational institutions, etc, which make them all prone to manipulation and pressure. believe it or not some are paid political operatives pushing agendas with their theories and credentials. at one time i'm sure you could have found 2500 scientists that believed the earth was flat...actually you still might if you offered them tenure and a nice salary

so how are laypeople to figure out this whole global warming thing, free of politics and financial motivations? well, it takes alot or research, a spoonful of logic and firm grasp of human nature and motivations. i'll state my opinions and let you folks argue the merits.

as a lobbyist for the trillions of trees and plants out there i must tell you that, in fact, CO2 is not a pollutant...and should the aforementioned trees advocate that oxygen is a pollutant i would tell them where to stuff it...Now that we have de-villified carbon dioxide perhaps we can look at it in a more objective manner.

Let me propose to you that CO2 is a result of rising temperatures, not a driver of them, meaning, temp goes up, so does CO2 and vice versa. this means you can detect a rising of temperatues (possibly) from increasing ppm of CO2 but you cannot predict or forcast temperature based on these levels. I offer to you that if CO2 was a driver of temperature we would have seen a larger temp increase based on observations would we not? Skewing these numbers is the introduction of a very modest amount of CO2 from our activities. Isnt that something on the order of 3% to 14% depending on who you ask? Let us also take into consideration that CO2 is not a particulary good greenhouse gas. Isn't it water vapor that wins the crown as the 800lb gorilla of the greenhouse effect? Funny, i don't see anyone complaining about the water/vapor dripping/spewing from the tailpipes of all our vehicles...For a personal demonstration of the role of water vapor, feel free to spend a night in the wilds of Florida then transport yourself to the wilds of Arizona. i think you will find that the absence of water vapor provides for a much chillier night, take a blanky

so, if we are to believe my ramblings, CO2 is not the handlebar moustached villain tying us to the railroad that we once thought. so then what is causing the temperature rise? hmmm, this is like figuring out why your car won't start. do we start with the fuel system? the electrical system? *flips a coin*

first off i'd like to know if the temperature record is even accurate. That's kinda important. I belive the current popular belief is that we are between 1 and 2 degrees warmer than at the time of the industrial rev. Lets just assume that this is correct. the first question to ask is 'What is the margin of error of the equipment used?'  well to the best of my searching ability the going rate for modern devices used to measure temperature its between about 1 and 3 degrees, with some as high as 5 degrees. also bear in mind that it is almost a certainty that by and large our modern devices are more accurate than onces used 50, 100 and 150 years ago. so here now we are stuck with results that are within the margin of error   that kinda puts a fly in our ointment. further clouding our efforts is that we also have to consider the 'margin of error' of the reporting device, aka, the human being. human beings are notoriously lazy, have the ability to lie, be manipulated, make stuff up, fudge things and even eat ketchup sandwiches...so unfortunately even if we had (and always did) perfect devices, our lowly monitors would quickly swallow up our findings with their margin of error. so what are we to do? well, for a while now we've had sattellites that can measure temps, but how accurate are those? most people agree, pretty accurate so long as similar analysis methods are compared. there have even been fairly accurate devices used in the near past but we still have that problem of the human being...but lets forget that and move on, many things have been decided on much larger assumptions than this one, at least it appears we have a warming trend, which is enough to go on for now.

ok, so back to what is causing this. well the first most logical place to look is the sun, considering it accounts for about 99.99999999% of our global warming on a daily basis. there are reports of the other planets in the solar system heating up which is mildly alarming in itself, but apparently this is not convincing to many. each instance has some other possible explanation so it's mostly dismissed. the link between sun spots and temperature on earth seems to get a little more traction, but is still dismissed by the global warming folks. so, given the choice of culprits..the sun which accounts for pretty much all of our ambient temperature on earth or carbon dioxide which accounts for 0.038% of our atmosphere....you obviously pick the CO2 right?   but choices aside, lets say the sun's commitment of warming love to us has remained constant. apparently our protective electormagnetic field has weakened about 10% over the last 150 years. could this have a bearing on the increase in temps? could the increase in radiation penetrating deeper through the atmosphere cause a 1 to 2 degree rise in temp? that's a darn good question we might want to ask ourselves.

so at this point it seems unlikely that we can attribute the warming to CO2. we are inconclusive about the sun so we'll just go ahead and scrap that one too. that leaves us to come up with some new ideas. how bout these?

many of our temperature measuring locations are in or near major metropolitan areas. over the last 150 years or so we've gotten a nice 'paving over effect' going. we fill up vast areas with concrete, asphalt, glass and other heat absorbing, reflecting and magnifying materials. though our overall saturation of efforts is not very great at the moment (there are still large open areas in many parts of the world mostly free of such things) could then not have an effect? it could certainly skew temperature records that include mostly the cities we live in. this would affect nighttime temps to a greater degree being that many of these types of materials relese heat slowly after peak temperature, not to mention the temperature pressures from the inside of a structure could influence the materials as well. now lets add to this hypothesis by including more rural areas that have had alot of tree clearing, either for farm land or development. the lack of shade and cover can also affect ground temperatures over time. perhaps this is enough to account for 1 to 2 degrees?

adding further to the above hypothesis, lets include that human beings have a thing for fire. we like to control it and keep it in check. what would happen if we weren't there to put out the thousands and thousands of forest fires and the like? well they would likely burn cuz i don't think the chimps or the dolphins are gonna do anything about it...burning of materials puts soot and particulate matter into the atmosphere. this blocks out some of the solar radiation coming in. there was a volcano in 1995 i belive it was that spewed nasty into the atmosphere and lowered the gobal temp by 1 degree for an entire year! might unchecked forest fires over millions of acres annually put a similar amount of crud into the air? maybe...and if that stopped happening? hmm. i suppose we could pick up the mantle and spew our own crud into the air to make up the loss but thats kinda dirty and we'd probably make an effort to stop doing so..kinda like we started to do in the 70s (and before). they actually had lead in the gasoline back then can you belive that...hrmph.

ok so lets just say we don't have any clue why it seems to be warming and just think about the consequences. looking at the nicely produced documentaries out there you'd think it was armageddon and that global warming is worse than a direct hit by a gamma burst. first, to believe the media, global warming is the cause of everything. if its too cold, too rainy, too dry, too windy, too hot, you're sad, you're happy, your cat is sad, your cat is happy...etc etc. it's the all magical phenomena that can do anything to everything. this takes me back to the beginning where i said scientists tended toward zealotry...well it's true, so one should expect a bit of hyperbole in slickly produced tv programs. let us consider what happens on the planet if it gets warmer. for those of you who don't know, our planet is about 3/4 water. warming a planet that is 3/4 water will result in an overall increase in the water vapor present in the air. warmer air can hold more water. so, though some deserts may form where once they were not, overall you can expect an increase in rainfall worldwide. those that claim to know state that the colder and polar regions will experience a larger portion of the warming than equitorial places. it makes logical sense that this is the case. that means that there will be a smaller temperature disparity worldwide. disparate temperatures promote violent weather, just take a look at the weather map when a cold front comes through your area. less disparate temps means less violent weather on land. warmer sea temps facilitate the formation of hurricanes and increases their longevity. on the plus side here, as the global winds calm due to a greater normaliztion of temperature, they will be easier to track and forcast. small plus but worth mention. greater rainfall and higher temps, especially in the colder climes, allows a greater production of food and accumulation of groundwater. the calmer weather on the interiors will also promote better weather forcasting, further enhancing food production and safety. the oceans will rise, though doubtfully as much as the doomsayers would have you believe (they always puff things up a bit). many coastal cities will become inundated with water, causing all manner of problems, but its not the end of the world..Venice anyone? it won't happen overnight so those small islands set to disappear will have their citizens relocated in plenty of time. and if you are worried about those poor poor 3rd world country people, well they don't have much to start with so it doesn't take much to pack up and follow the waterline back...its those rich developed peoples that have the headaches of disappearing beachfront, flooding cities, etc...it's much harder to pack up a skyscraper or a $2m beachhome    luckily some can afford seawalls, structural reinforcements and the like and since it'll be a long time coming, there's time to spread out the pain. hey, it'll even create lots of well paying jobs...tropical diseases, hmm, it seems some of the worst tropical disease outbreaks happened in the most untropical of places, i chalk this up to the equivelence of the killer bee issue, last i checked not everyone in texas has been eaten (yes, hyperbole   ) by bees...theoretically possible, but likely to be a much much smaller issue. for the most part, the world could enjoy less drastic temperatures, lower highs and higher lows..a general evening out. now for certain some poor bastards *cough*england*cough* could see dramatic shifts in their climates, these are mostly areas that depend on modern ocean flows for their warmth/cooling. sorry old chap, perhaps a spot of hot tea?   there is no reason to believe the weather would be more drastic than now, just different for some. the chicken littles would have you belive you'd summarrily catch fire, get flooded out then buried in a land slide while dying of typhoid...c'mon..really? lets not forget change sparks increasing bio-diversity, we might get a few new frogs out of the deal

all this said, there is no reason we shouldn't move on to lower emission vehicles, alternative power, blah blah blah. why? cuz we need the technology to move forward. we need ways of generating large amounts of power under high efficiency with low waste. why? cuz we have to infest the cosmos with our human-ness   and these are steps to that end. not to mention the current energy system is unstable economically and geographically. its also satisfyingly unnerving to slam on the accelerator and hit 60 in 4 seconds without the roar of an engine (i'm predicting engineered sound will be all the rage in 2020, it'll be like ring tones, your 'engine note' could be anything...starfighter, '70 hemi cuda, 'yellow submarine' ever increasing in volume and pitch as you approach 100...)

suggestions:

ethanol but only from sources at least as efficient as sugar cane.

wind power, but only in rural areas to save money on costly infrastructure building and maintenance (lines, poles, stations, etc)

solar power, everywhere! why not? it's about to be terribly cheap and efficient. a perfect addition to your stuffs!

fuel cells, not for your car...for your home! houses tend to have more room for large things like fuel cells and fuel storage. high tech things called 'trucks' could bring the necessary fuel round to your house   much like propane and butane today. then plug your car into your house, but you'll still want some liquid fuel for distance *see ethanol* we can call it a 'hybrid'....*cough*   you then plug your house into the urban grid and share/borrow from neighbors all across the world as needed, each house it's own little power plant. we can call it a distributed grid and this will also up the effectiveness of your solar as its spread across a wider area. solar shingles anyone?

nuclear? tough one, fusion, definitely. also see hydrino, zero-point energy. some cool prospects there negating the need for fission, fusion may still be needed for those first star cruisers

but anyway, this post is getting too long. my main point is to make you all think, to hop outside your political and idealogical boxes and think about things from a fresh perspective. find out what YOU think, not what you believe of what you've been told. with that i leave you with a few snippets to think about...

you ever notice how the temperature can be freezing outside yet the snow is still disappearing?

why do penguins have black backs and white fronts? it's almost like they suffered under higher UV radiation in the past...maybe they had a hole in the ozone, oh but thats the other pole right? the magnetic one...

you think if all the ice on antarctica melted we'd find some really cool sh*t?

why are amphibians dying at alarming rate? what's up with the bees? the migratory species?

why is our magnetic field weakening?

what does that mean as we approach solar maximum in a few years, expected to be the strongest in modern times?

what happens if a solar flare knocks out our satellites and power grids across the world?

why do people loot, riot and pillage when their sports team wins? what would these people do with no power for 6 months...a year?

why did those pesky mayans end their calendar on december 21, 2012? personally i think its because..."it's the dawning of the age of aquarius, the age of aquariiiiuuusss..."

but hey, now you have something to worry about instead of global warming, variety is the spice of life you know

Prima facia, indeed, you can ask the question: if climate models still aren't pefect, why won't scientists change their mind again? That question is valid, but can be adequately answered if you look at the full picture.

Well... Wikipedia.  There ya have it.  Just another example of 1970's media hyperventilation based on... nothing, I guess.

I doubt any AGW advocates had anything to do with that wiki entry, either.  You bore me.

The burden of proof is on those inisisting on drastic change.  They've failed to meet it.

@dmantione -

Your criticism of Will is interesting for what it ignores:

Don't know about you, but I was also an adult in the 1970's.

when it comes to areas like medicine and food the burden of proof is on the side of the agent who wants to add something to the existing foods / medicines. Before you can add something new you have first to proof that it is harmless; now with CO2 is it for some wicked reason the opposite? Staying on Status Quo - that is keeping the CO2 levels in the same range as they were in the past few hundred thousand years which was a very successful time for mankind - should not need any proof at all actually, its just bonus. If you change the atmosphere it has potential effects, now why should you not need to first proof that those effects are not harmful as it would be for food or medicine.

Is it because the potential effects are more impersonal and indirect than getting ill from food or dying from medicine?

increased CO2 levels also change the pH of the oceans. I am not denying that this might have happened before (standard response from you guys) but the point is that we as a civilization which is successful under the current state of the biosphere we should try to keep the current state as every deviation is a risk.

This is the principal conceipt - that we can somehow 'arrest' the environment & maintain it in some arbitrarily defined condition.  Every argument for 'doing something' is premised on this unprovable, not to mention futile, assumption.

I agree with you alllllmost entirely. That's why we should attempt to confirm whether this is indeed anthropogenic; if we didn't cause global warming, then why would we be arrogant enough to think we could stop it? However, if we are the cause (or even a contributor), then something should be done (and/or we could tone down destructive efforts enough to let nature right itself). If the former is true, then we probably exist in an unstoppable process, and if the latter is true, then it is far more likely that the "status quo" is a stable equilibrium - it is almost perfectly self-sustaining, barring outside influences. The question is whether or not we are that outside influence, or even one among many. I think that it is arrogant to assume we could come close to changing the climate at all in the first place, but probable arrogance certainly doesn't equate to a proof or disproof.

On the other hand, finding evidence of human causes does not implicate only us. For example, as Lomborg points out, there are different ways by which CO2 affects the atmosphere and questions about the quantifiability with which we can predict consequences of CO2 rises. He cites one study that estimated surface solar irradiation due to solar activity to account for about 40% of observed global warming, while another, made in the same year, found changes in solar irradiation to be too small to produce a noticeable effect - i.e. there is some debate. There is another theory that links temperature variations to sunspot cycles - recent research has put forward a possible reason for the link, one that involves clouds, which are acknowledged to be problematic in climatological predictions. However, as you can imagine, there are a number of unanswered questions.

In short, we really don't know enough to make a real decision about anthropogeny. Let's not be too hasty in condemning ourselves. On the other hand, we can't dismiss the possibility of it quite yet (which I think is the point I wanted to make to Daiwa).

Well said, sir!

That is exactly why I did not immedeately wanted to judge about this part of Mr. Will's argument, I was born in 1977, so I cannot judge from my own memory of the matter. Prima facia his argument was correct. However, now that I have read up he was just bringing up the point of a scientific minority. Perhaps a significant minority, but still a minority and more people were afraid of global warming than global cooling. Comparing the opinion of a scientific minority with a scientific concensus today is simply not a valid reasoning to state that scientists change their mind according to the latest trend.

Well what most people don't know is that 10% CO2 concentration is FATAL to Humans.  Your lungs cannot function because they cannot get the CO2 out of your blood, and your blood begins to acidify.  So you either sufficate even in optimal O2 atmosphere, or die of acidosis.

This is idiotic reasoning . Even though 2008 was cooler it was still actually abnormally hot if you compare it to data ever since recording began.

The erath can easily produce more then enough food for people, however it is the distribution of Earth's resources that is the problem.