UK and North west Europe - Climate change

[jethro]

Trouble is though, each and every deviation from average weather is held up as an example of AGW in progress. Lately we've been treated to the add on of "weather isn't climate" which it isn't, on an individual event basis; the statements then continue with "but climate change means we expect more and more of these extreme weather events".

For what it's worth (which probably isn't much) IMO no one really knows what to expect from climate change. There's speculation and prophecy aplenty which gets dressed up as projection and prediction but in all honesty, I think a crystal ball would yield as many accurate results as models and super computers.

I am however rather puzzled, until last year we had been led to believe (from most, if not all professional bodies) that we in the NH would have warm winters, snowy cold ones were increasingly unlikely to happen. At no point do I remember cold and snowy being in the projections for our winters as a result of AGW, the expected results of AGW were in one direction only - warm. Now we've had a snowy winter last year, to date a colder, snowier one this year, suddenly AGW is also capable of producing this.

Goal posts are continually being moved in this debate, it helps no one, either here or in the world at large. Personally, I'd have far more respect for professionals and amateurs alike if they held up their collective arms, shrugged their shoulders and said "actually, we don't really know". Because having looked at so much peer reviewed stuff, from both sides, that's the current reality.

No one knows.

[jethro]

I'm not a METO basher but as a demonstration of my point above here's a report from them discussing the El Nino in 2007. Largely it's an ok report, it says due to El Nino we can expect a warmer 2007, it reports in brief how and why. All fine and dandy.

Until that is, you get to the ' Katie Hopkins from Met Office Consulting said: "This new information represents another warning that climate change is happening around the world.' What has climate change got to do with El Nino?

This week, due to the recent spell of weather we've had this: http://news.bbc.co.uk/1/hi/sci/tech/8451756.stm

I'd suggest there's a distinct lack of communication between various departments at the METO

Is it any wonder the general public are confused and getting more and more disgruntled?

[sunny starry skies]

It 's a probem in the distiction between global climate and regional weather patterns that are the result of the global climate interacting with the land, ice and oceans. Until present the smart money was on warmer winters and summers due to a more northward-tracking jetstream, but recent summers and winters have bucked this trend. This could be a result of the SOI/solar minimum patterns at present, which appear to be offsetting GHG-induced warming, and so you'd then expect the pattern to revert to a more northerly-tracking jetstream when the SOI pattern changes. However my money is actually on something that Gray Wolf has highlighted - that the Arctic warming is disturbing the usual stability of the weather patterns up there (such as the polar vortex), and resulting in a greater likelihood of colder air filtering a little further south and giving us weather headaches. Meanwhile the Arctic is even warmer as a result of displacing it's colder air south.

Forecasting global climate change is not the problem - you have to invent some new physics and whole new drivers to the system to explain why the world has warmed, why it isn't GHGs when physics says it should be, and then what other new mechanism explains the current warming. So far the only plausible explanation (with supporting evidence) is anthropogenic GHGs as the driver for the upward trend. I imagine (quite seriously) a Nobel prize will follow for the person who can find, and prove with physics, otherwise!

But regional climate is how the total heat is distributed around the globe, and that is a much harder problem, and one that most of the supercomputer time is spent on I think. There are so many more variables to manage that it's clearly not as straightforward to solve the problem. It's consequently a much les settled branch of the science. What was said was that it was likely that our winters would be milder/wetter and our summers would be hotter, but if the recent British weather is not just SOI-induced, then maybe that is something that has not been got right in the GCMs. You seem to have an unhealthy skepticism for inexact science too, though this is something clearly prevalent in many media/lay person's views: that the science has to be right in all areas or else it's all wrong. Regional climate is likely one of those areas where it's not 100% right, and the North Atlantic is one region in which climate has done unusual things in the past. Namely it doesn't always do what the rest of the globe does - for example with having the MWP and LIA, both regional events, by far strongest in the North Atlantic and limited or absent in the rest of the world. The take-home message is that a modelled future regional climate that is not capturing all features of our weather perfectly crucially doesn't change the basic science of AGW, though!

sss

I'm not a METO basher but as a demonstration of my point above here's a report from them discussing the El Nino in 2007. Largely it's an ok report, it says due to El Nino we can expect a warmer 2007, it reports in brief how and why. All fine and dandy.

Until that is, you get to the ' Katie Hopkins from Met Office Consulting said: "This new information represents another warning that climate change is happening around the world.' What has climate change got to do with El Nino?

This week, due to the recent spell of weather we've had this: http://news.bbc.co.u...ech/8451756.stm

I'd suggest there's a distinct lack of communication between various departments at the METO

Is it any wonder the general public are confused and getting more and more disgruntled?

Great post Jethro - definitely something that climate scientists need to get on board with. Though one of their problems is this:

[from the bbc link, Richard Betts from the Met Office:]

"It's easy to blame the media and I don't intend to make generalisations here, but I have quite literally had journalists phone me up during an unusually warm spell of weather and ask "is this a result of global warming?"

When I say "no, not really, it is just weather", they've thanked me very much and then phoned somebody else, and kept trying until they got someone to say yes it was.

Talking up of the problem then gives easy ammunition to those who wish to discredit the science."

[end quote]

So all it takes is for the media to find one reasonably credible person to talk it up. And you've highlighted a beauty there - another person within the Met Office, and someone who should know better. The result - a knock to the public's interpretation of the science, even though the science hasn't changed.

sss

[noggin]

Until that is, you get to the ' Katie Hopkins from Met Office Consulting said: "This new information represents another warning that climate change is happening around the world.' What has climate change got to do with El Nino?

Good grief. Is Katie Hopkins not that vile woman who was on The Apprentice a few years ago? I'm sure it was her. She was later ejected from the MetO due to her publicity-seeking behaviour, which included a set-up naked frolic in a field, for the delectation of the media, and the proud claim, whilst being interviewed by one of Sir Alan's colleagues, that she had indeed caused the break-up of many marriages by having affairs with married men.

.....and we are expected to take what people like her tell us, seriously?

[noggin]

http://news.bbc.co.uk/1/hi/entertainment/6747051.stm

Here it all is, in all it's glory.

It could make you question the integrity of some parts of the MetO.

[sunny starry skies]

Good grief. Is Katie Hopkins not that vile woman who was on The Apprentice a few years ago? I'm sure it was her. She was later ejected from the MetO due to her publicity-seeking behaviour, which included a set-up naked frolic in a field, for the delectation of the media, and the proud claim, whilst being interviewed by one of Sir Alan's colleagues, that she had indeed caused the break-up of many marriages by having affairs with married men.

.....and we are expected to take what people like her tell us, seriously?

No, it would seem that you shouldn't take her seriously. Seems there's little reason for her to know anything about climate change at all, and perhaps not surprising she was fired from the Met Office if she was serving up howlers like the one Jethro highlighted, quite apart from her dodgy personal life. But she is not representative of the climate science community, thank goodness - I wouldn't take the word of someone as shallow and blatantly publicity-seeking as her! I would hope that such lessons have been learned by the Met Office in the years since that incident, particularly in the light of that (far more recent) interview by Darren Betts.

sss

[Thundery wintry showers]

For me, that Darren Betts article is a breath of fresh air. It does not downplay the case for AGW but, quite correctly, points out how the scientific message to the public gets corrupted with time, and in particular the tendency to blame individual weather events on AGW.

However I have to say I often get an impression of many of those politically involved with AGW trying to make out that the science is more certain than it really is to avoid creating doubt in the minds of the general public, and I don't think it helps, because when people see through it, they feel they are being lied to. When I talk of certainty, I'm not talking about whether or not AGW exists (the scientific evidence overwhelmingly highlights this as a given) but rather how strong its contribution to the recent warming was, and how significant, given atmospheric feedback processes, it will prove to be over the coming century.

[pyrotech]

For me, that Darren Betts article is a breath of fresh air. It does not downplay the case for AGW but, quite correctly, points out how the scientific message to the public gets corrupted with time, and in particular the tendency to blame individual weather events on AGW.

However I have to say I often get an impression of many of those politically involved with AGW trying to make out that the science is more certain than it really is to avoid creating doubt in the minds of the general public, and I don't think it helps, because when people see through it, they feel they are being lied to. When I talk of certainty, I'm not talking about whether or not AGW exists (the scientific evidence overwhelmingly highlights this as a given) but rather how strong its contribution to the recent warming was, and how significant, given atmospheric feedback processes, it will prove to be over the coming century.

what can i say?

fantastic posts about climate change and the hype and misrepresentation by some of the media.

What is really needed now is a full unbiased evaluation of the situation looking at CO2, Sunspot cycle and weather patterns.

Its 100% fact that solar cycle effects climate over periods of time. Its also fact Co2 can intensify it. Fact also that weather patterns can disrupt over short periods of time the normal expected patterns. We all know the other terrestrial phonomenens.

I see sunspot cycle a main driver, excessive max cycles for previous decades since 60s. How can anyone in the public believe when obviously there is other drivers other than CO2. Lets say for arguments sake ( not what my data says) that sunspot cycle has effected climate change by 30% only. 60% is then by CO2 and 10% by natural seismic activity ( Volcanoes etc). Now that would be more understandable than CO2 co2 and co2. It would atleast take in account historical data from over centuries about the other effects.

Would it really be a bad thing for these groups to say that in order to romain proactive and prudent that a continuous evaluation will be made, taking in all possible effects.

What if next winter is again simillar to an 80s winter? What if sea ice again starts to reform further south again.

Will we still put our heads in the sand and say must be a one off as CO2 is to blame because we previously decided that was the cause.

There is nothing wrong with being incorrect and making a judgement on facts you can see and being wrong with the outcome.

What is wrong is to judge that your first decision is the right one with out dynamically re evaluing new and old data and looking for other possibilities.

I am not a CO2 theory hate campaigner, i just think there is more to the picture. The sunspot cycle has been mentioned by NOAA this year as possibly causing a colder winter over in the USA. This was in their forecast. so even they see a connection with low solar min, high solar max obviously has oposite effect.

I normally find sceptics of the effect by solar weather are by those who have little information on the solar cycle. Please look at data for cycles 19 - 23. Then look at how low and long its taken for cycle 24 to start.

some seem to want to blame the cold ovr Northern hemisphere on anything other than Solar cycle ( local weather conditions, El nino)

One thing for sure its not due to less CO2! there is more now than ever

Its like looking in the stable, seeing it empty but denying the horse has escaped till they see it in the field.

I know some would say that my 80s winter was lucky, nothing more. But i can asure you it was based purely on this data.

Summers will return to 80s summers too, infact back to our normal four seasons with normal anomalies. As long a the sun remains in a low or normal cycle rather than the active period it went through for over 40 years.

Anyway some interesting posts over last 24hrs and can i thank you all for your posts.

[Devonian]

what can i say?

fantastic posts about climate change and the hype and misrepresentation by some of the media.

What is really needed now is a full unbiased evaluation of the situation looking at CO2, Sunspot cycle and weather patterns.

...

PT, let me just question this.

Asking for a full evaluation of the science is one thing but preconditioning such a evaluation with the assumption that it, the science, is biased (as you do I think?) means it, the evaluation, is well, biased. Surely any evaluation needs to find out if there is bias not assume it? Indeed if you can assume there is bias you don't need an evaluation!

The Suns role in climate. It's simple, show it to be greater that science has so far discovered and a Nobel prise awaits you

Edited January 15, 2010 by Devonian

[sunny starry skies]

PT, basically what Dev says. You seem to base your belief that sunspots play a great role on just that - a 'belief'. Attribution studies show that the Sun does play a role, the only thing is that it's a relatively minor one. Similarly "natural variations" as dominantly expressed by the Southern Oscillation Index also play a role. The two (both in a 'negative' phase at the moment) appear to be cancelling out anthropogenic GHGs, something well-understood in the climate science community. But you can't explain the warming of the past 40 years without anthropogenic GHGs. It's nice to talk of the Sun playing a big role, but where's the mechanism? Such a mechanism requires the Earth to be particularly sensitive to very small variations in the Sun, in a way not yet physically described, and yet be insensitive to something that it is well-understood, changing substantially, and does have a simple, clear physical basis for warming the planet.

You talk of asking for an unbiased evaluation, and for other drivers to be taken into account. They already have been, if you read the relevant detection and attribution literature. You assume the scientific community is biased - why would it be so? Actually the best way to continue funding for a research topic is to propose that the science is not settled. Very few people have proposed a change to the basic mechanism of warming, and invariably flaws have been found in their proposed mechanisms. The only way you can discount the relevant research is if you think there is some global scientific conspiracy, which there simply is not (it wouldn't be possible for there to be one even if they wanted to do it, given the size of the community). You do realise there's now a 10-year long publically accessible database that conclusively proves there is no global climate conspiracy...... the "climategate" emails! The best the thieves could do was take a very few words out of context.

Actually, you can play around with the drivers all you like, say with something as simple as a multiple regression to explain the last 100 years of temperature, and you can't explain it without anthropogenic GHGs. As Dev said, Nobel prize for the person that finds a mechanism that can explain the warming world without GHGs, and explain why GHGs are not warming the world (as physics says they should). Such an explanation has so far eluded all the finest minds of the world in the 100 years since Svante Arrhenius... pyrotech, you up to the challenge??

sss

[Gray-Wolf]

With the beginning of solar cycle 24 apparently well underway now and a large El-Nino underway (and the negative AO loosing it's intensity) I think we'll find the 'Sun's role' loosing it's appeal over the summer months and other 'natural factors' being put into the frame for the warming. The increase in methane release will be my guess (a third more now being released in the Arctic since 02' giving a 7% overall increase in atmospheric methane since it's 'stall' in the 90's)

Eventually there will be no argument but ,by that time, not only will we have caused it but also procrastinated away the opportunity of mitigating it....way to go Skeptics

[VillagePlank]

It's nice to talk of the Sun playing a big role, but where's the mechanism? Such a mechanism requires the Earth to be particularly sensitive to very small variations in the Sun ...

Well, It doesn't have to be particularly sensitive to cause a change of 0.25C/10 years. The sun coming up in the morning, causes a much bigger change than that. If extra heat was trapped somewhere (oceanographers look out) and then released at a slower rate rather than the assumption that the sun's activity influence is 'instant' then the record breaking solar activity of the last 50 years might go some way to explain some of the modern warming. Indeed even on a diurnal basis, sun heat is 'trapped' here on the Earth's surface, otherwise, the temperature on Earth would fall like a stone the minute the sun went in.

Not to say that this explains climate, but the mechanisms for trapping solar energy and emitting it at a slower rate than acquired are demonstrable, and are a part of scientific knowledge, today - so no Nobel Prizes, are required ...

Actually, you can play around with the drivers all you like, say with something as simple as a multiple regression to explain the last 100 years of temperature, and you can't explain it without anthropogenic GHGs. As Dev said, Nobel prize for the person that finds a mechanism that can explain the warming world without GHGs, and explain why GHGs are not warming the world (as physics says they should). Such an explanation has so far eluded all the finest minds of the world in the 100 years since Svante Arrhenius.

Arrhenius' paper has mistakes in it, and I can't find one source or publication pointing out the mistakes. The biggest one is that the temperature increase measured, empirically, is based on the mean temperature of the moon, and is extrapolated, by least linear squares, to produce a logarithmic relationship. The mean temperature of the moon stated in the paper is wrong, and, as I'm sure you are aware, logarithmic relationships, particularly those that have been derived from LLS, tend to be very sensitive about such things. Of course, this might turn out not to be material, and complete nonsense - I haven't done the maths to confirm, or deny it - but the fact of the matter is, a critical variable on determining such a relationship, relies on an assumptive error.

Back to Nobel Prizes ... let's make one assumption, and play with it: I neither can say that this is right, indeed, it might probably be wrong. Let's assume both solar energy and the GhG effect are constant. What does the climate look like, then? Following that, let's make GhG variable, and solar constant (this is the modern consensus), and then, let's make GhG constant, and solar variable. What does the climate look like in all of these cases?

Has anyone done the work? With a logarithmic effect with the wrong assumption, it could well be that we are already on the flattening top part of the curve, where more doesn't really affect things that much. If that turned out to be true, then climate models would require some other variable to account for warming.

IF that is the case, my bet would be on the sun. However, a quick peruse of this post shows an awful lot of 'if', 'but' and 'however'. It should be taken with a view that the expression of idea is free, whether or not it is idiotic.

Eventually there will be no argument but ,by that time, not only will we have caused it but also procrastinated away the opportunity of mitigating it....way to go Skeptics

The "New-Year-Love-In" is over, I take it. All guns blazing, et al?

[Solar Cycles]

PT, basically what Dev says. You seem to base your belief that sunspots play a great role on just that - a 'belief'. Attribution studies show that the Sun does play a role, the only thing is that it's a relatively minor one. Similarly "natural variations" as dominantly expressed by the Southern Oscillation Index also play a role. The two (both in a 'negative' phase at the moment) appear to be cancelling out anthropogenic GHGs, something well-understood in the climate science community. But you can't explain the warming of the past 40 years without anthropogenic GHGs. It's nice to talk of the Sun playing a big role, but where's the mechanism? Such a mechanism requires the Earth to be particularly sensitive to very small variations in the Sun, in a way not yet physically described, and yet be insensitive to something that it is well-understood, changing substantially, and does have a simple, clear physical basis for warming the planet.

You talk of asking for an unbiased evaluation, and for other drivers to be taken into account. They already have been, if you read the relevant detection and attribution literature. You assume the scientific community is biased - why would it be so? Actually the best way to continue funding for a research topic is to propose that the science is not settled. Very few people have proposed a change to the basic mechanism of warming, and invariably flaws have been found in their proposed mechanisms. The only way you can discount the relevant research is if you think there is some global scientific conspiracy, which there simply is not (it wouldn't be possible for there to be one even if they wanted to do it, given the size of the community). You do realise there's now a 10-year long publicly accessible database that conclusively proves there is no global climate conspiracy...... the "climategate" emails! The best the thieves could do was take a very few words out of context.

Actually, you can play around with the drivers all you like, say with something as simple as a multiple regression to explain the last 100 years of temperature, and you can't explain it without anthropogenic GHGs. As Dev said, Nobel prize for the person that finds a mechanism that can explain the warming world without GHGs, and explain why GHGs are not warming the world (as physics says they should). Such an explanation has so far eluded all the finest minds of the world in the 100 years since Svante Arrhenius... pyrotech, you up to the challenge??

sss

Aye, but you can't prove AGW is the culprit either. Show me 100% proof, and a nobel prize awaits you also!

See this is the problem, all of us can only guess as to which is greater, natural, or AGW!

[Solar Cycles]

For me, that Darren Betts article is a breath of fresh air. It does not downplay the case for AGW but, quite correctly, points out how the scientific message to the public gets corrupted with time, and in particular the tendency to blame individual weather events on AGW.

However I have to say I often get an impression of many of those politically involved with AGW trying to make out that the science is more certain than it really is to avoid creating doubt in the minds of the general public, and I don't think it helps, because when people see through it, they feel they are being lied to. When I talk of certainty, I'm not talking about whether or not AGW exists (the scientific evidence overwhelmingly highlights this as a given) but rather how strong its contribution to the recent warming was, and how significant, given atmospheric feedback processes, it will prove to be over the coming century.

A bit late in responding, been under the weather ( pardon the pun ).

An interesting article it as to be said. How refreshing to see an employee from the MetO, speaking openly about AGW, without the OTT comments. They obviously have a serious problem, regarding press management. Time to restructure that part of the organization surely!

[7andY]

Isn't it just the tiny bit curious that pro-AGW people are quite happy that a small change in overall CO2 can cause big climate changes, but a small change in solar output doesn't?? Hmmmm....

7&Y

[Devonian]

Isn't it just the tiny bit curious that pro-AGW people are quite happy that a small change in overall CO2 can cause big climate changes, but a small change in solar output doesn't?? Hmmmm....

7&Y

Atmospheric CO2 has increased by more than a third. If the Sun became that much more radiant we would fry.

[jethro]

Doesn't that then infer that a tiny increase of Solar activity would be important?

It's the logarithmic nature of CO2 which doesn't add up in this debate IMO. The greatest increase in temperatures should have been seen at the beginning of the industrial age, not in recent decades.

[Thundery wintry showers]

Aye, but you can't prove AGW is the culprit either. Show me 100% proof, and a nobel prize awaits you also!

See this is the problem, all of us can only guess as to which is greater, natural, or AGW!

Well, while that's true in itself, it only tells part of the picture, because forecasting in science is all about probabilities. A forecast is, by definition, guesswork, but it can be highly educated guesswork and be subject to estimated confidence levels of 90% or 95% say. However the "we can only guess" is often taken to imply "we don't have a clue", used to downplay the notion that something that is forecast is probable, as opposed to just possible.

If we don't warm significantly over the next two decades and natural forcings don't exert a significant cooling influence then there will be serious doubts on whether AGW has exerted a greater forcing than natural forcings. But on the other hand, if we get a substantial warming over the next two decades, and no contribution or even a cooling influence from natural forcings, there won't be...

[sunny starry skies]

Aye, but you can't prove AGW is the culprit either. Show me 100% proof, and a nobel prize awaits you also!

See this is the problem, all of us can only guess as to which is greater, natural, or AGW!

Hi SC, you're slightly obfuscating. In science, 100% proof is not possible. We can be very confident in that we can reconstruct 20th century climate using the relevant drivers, and you just can't replicate the change without AGW. AGW is resoundingly now a solid academic "theory" rather than an academic "hypothesis", in that the predictions made by the theory in a wealth of areas have been verified. Now you can falsify that "theory", but just as with relativity, quantum mechanics, cell theory, atomic theory or any other you care to mention, you can never 100% prove them. By definition.

Similarly, it is now incumbent on the "skeptics" to disprove the theory, something they have failed to do so far.

IPCC AR4 goes for: "The observed widespread warming of the atmosphere and ocean, together with ice mass loss, support the conclusion that it is extremely unlikely (<5%) that global climate change of the past 50 years can be explained without external forcing, and very likely (>90%) that it is not due to known natural causes alone."

The wealth of experimental, modelling and observation data supports a stronger conclusion than that, but whatever the confidence, you can never be 100%.

So you can fudge it with "we can only guess", but as has been mentioned, these are very good "guesses", given the successful attribution studies, the basic underpinning physics, and the observational data. They are not, in fact, "guesses", as they are estimations with errors. So far, observations are entirely within the estimations of error, such as for this decade, as I've just posted in the general discussion.

sss

[sunny starry skies]

Doesn't that then infer that a tiny increase of Solar activity would be important?

It's the logarithmic nature of CO2 which doesn't add up in this debate IMO. The greatest increase in temperatures should have been seen at the beginning of the industrial age, not in recent decades.

You're not trying to say solar activity is increasing are you? :lol: But the general answer to your point is of course no - and it's demonstrable by the fact that tiny increases and decreases in solar activity over the 20th century (the only time when we have sufficient data) do not have spectacular consequences for the temperature record.

These guys seem to understand the logarithmic relationship between CO2 and temperature (realised that I don't know if everyone can read the link as I'm on a University computer):

http://www.nature.co...ature05699.html

Royer et al (2007). Climate sensitivity constrained by CO₂ concentrations over the past 420 million years. Nature 446, 530-532 (29 March 2007)

For the uninitiated, the suggestion was that as CO2 sensitivity will decline with increasing concentration, the world will not warm as much in the future (at higher CO2 concentrations) than in the past (at lower CO2 concentrations). So this Nature paper tackles that problem by looking for analogues of higher temperatures/CO2 concentrations than present (as the two are undeniably inextricably linked :lol:) throughout the Phanerozoic, and conclude that the sensitivity of CO2 to a doubling from present concentration is unlikely to be less that 1.5C, in line with the IPCCs estimate of between 1.5 and 6.2 °C (5–95 per cent likelihood range). This means that increased CO2 = significantly increased temperature, now as at the dawn of the Industrial Revolution, in fact as at any time in the last 420 million years.

sss

Edit: VP, I wasn't trying to say Arrhenius got it exactly right first time, the theory has been steadily improved since then by many people, but the basic premise that increased CO2 = warmer world hasn't changed. As far as your thoughts on variable/constant drivers - you'll be aware of the best models of drivers to explain 20th Century climate, that solar is NOT constant, but vaies, just not by that much, and my above comments tackle possible logarithmic effects. Seeing as the first decade of the 21st Century still fits, within 2 sigma error, a linear warming trend since 1975 (see my link in the general climate change discussion), why do we need to try and evoke a logarithmic trend when it's not there?

2nd edit: as this discussion is now very similar to that on the general change page (much of that my fault), and not NW europe-specific, any further posts on general climate should be over there?

sss

Edited January 17, 2010 by sunny starry skies

[Solar Cycles]

Hi SC, you're slightly obfuscating. In science, 100% proof is not possible. We can be very confident in that we can reconstruct 20th century climate using the relevant drivers, and you just can't replicate the change without AGW. AGW is resoundingly now a solid academic "theory" rather than an academic "hypothesis", in that the predictions made by the theory in a wealth of areas have been verified. Now you can falsify that "theory", but just as with relativity, quantum mechanics, cell theory, atomic theory or any other you care to mention, you can never 100% prove them. By definition.

Similarly, it is now incumbent on the "skeptics" to disprove the theory, something they have failed to do so far.

IPCC AR4 goes for: "The observed widespread warming of the atmosphere and ocean, together with ice mass loss, support the conclusion that it is extremely unlikely (<5%) that global climate change of the past 50 years can be explained without external forcing, and very likely (>90%) that it is not due to known natural causes alone."

The wealth of experimental, modelling and observation data supports a stronger conclusion than that, but whatever the confidence, you can never be 100%.

So you can fudge it with "we can only guess", but as has been mentioned, these are very good "guesses", given the successful attribution studies, the basic underpinning physics, and the observational data. They are not, in fact, "guesses", as they are estimations with errors. So far, observations are entirely within the estimations of error, such as for this decade, as I've just posted in the general discussion.

sss

Your right, 100% proof in science is not required. As for disproving the theory, no need, I accept it, as countless other skeptics do. So the emphasis is not on skeptics disproving the theory, but on you and others, proving the theory is robust enough to stand up to criticism. And that criticism being, AGW is being over estimated, as the last 11 years have proved!

[sunny starry skies]

Your right, 100% proof in science is not required. As for disproving the theory, no need, I accept it, as countless other skeptics do. So the emphasis is not on skeptics disproving the theory, but on you and others, proving the theory is robust enough to stand up to criticism. And that criticism being, AGW is being over estimated, as the last 11 years have proved!

1. 11 years is not a climate record. At short timescales other factors can temporarily dominate, such as ENSO, which is what has happened. Funny that 11 years takes us back to 1998, an El Nino-induced record spike in temperature. What about going to 1997? or 1999? Too inconvenient a truth for you?

2. The last 10 (or 11 or whatever) years still fit nicely in the increasing trend as predicted by AGW. The end of 2009 is on the mean trend. See:

http://tamino.wordpr...this/#more-2108

Given the wiggles about the mean trend, driven by weather patterns such as ENSO, as you can see from the previous decades, why is this decade so different?

3. Looks like there's nothing in the last 11 years to trouble AGW theory...

4. 100% proof is not "not required" but "not possible". By definition.

5. If you accept the theory, then to falsify it you need to find data that defeats the theory's fundamental pillars.

sss

Edited January 17, 2010 by sunny starry skies

[Solar Cycles]

1. 11 years is not a climate record. At short timescales other factors can temporarily dominate, such as ENSO, which is what has happened. Funny that 11 years takes us back to 1998, an El Nino-induced record spike in temperature. What about going to 1997? or 1999? Too inconvenient a truth for you?

2. The last 10 (or 11 or whatever) years still fit nicely in the increasing trend as predicted by AGW. The end of 2009 is on the mean trend. See:

http://tamino.wordpr...this/#more-2108

Given the wiggles about the mean trend, driven by weather patterns such as ENSO, as you can see from the previous decades, why is this decade so different?

3. Looks like there's nothing in the last 11 years to trouble AGW theory...

4. 100% proof is not "not required" but "not possible". By definition.

5. If you accept the theory, then to falsify it you need to find data that defeats the theory's fundamental pillars.

sss

Your right 11 years is a short time span, but 30 years is but a blip also. I think the next 10 years will show us which as the greatest effect, natural cycles or manmade ones. Until then all aboard the merry go round!

[Thundery wintry showers]

SC,

As well as Sunny Starry Skies's points above, I think there's also a bit of inconsistency there in your argument- AGW cannot be "proved", but on the other hand it has been "proved" over the last 10 years that AGW is being overestimated? You cannot "prove" either way when we're talking any kind of long-range forecast.

The only way we can prove that AGW is being overestimated is in 50-100 years' time, if global temperatures end up at the lower end of the IPCC's range or outside of the lower bound altogether (I say this because unfortunately I don't see a Low Emissions scenario arising given the inertia among politicians, industries and the public alike). Conversely if temperatures end up warming by 3-5C it will imply that AGW isn't being overestimated.

[Solar Cycles]

SC,

As well as Sunny Starry Skies's points above, I think there's also a bit of inconsistency there in your argument- AGW cannot be "proved", but on the other hand it has been "proved" over the last 10 years that AGW is being overestimated? You cannot "prove" either way when we're talking any kind of long-range forecast.

The only way we can prove that AGW is being overestimated is in 50-100 years' time, if global temperatures end up at the lower end of the IPCC's range or outside of the lower bound altogether (I say this because unfortunately I don't see a Low Emissions scenario arising given the inertia among politicians, industries and the public alike). Conversely if temperatures end up warming by 3-5C it will imply that AGW isn't being overestimated.

Fair point TWS, although I feel 50-100 years wouldn't be required. More like 20 years, would be a solid enough platform, to gauge which we we are heading!