Anthopogenic Global Warming Myth or Real ?

[CapelDodger]

I find it interesting that you think this. Seems to me that it would only take one significant negative feedback mechanism that we're not currently aware of. Hardly an impossibility surely?

Practically impossible. Apart from lomiller's point, planetary processes have been observed for a good while now and they're well understood by existing science (some of which was developed precisely to understand them). So I'm not expecting any sudden surprises.

I'm partly convinced now. I'm also partly sceptical. Another 7 years will probably change the ratio a little I admit.

It'll probably change it a lot, IMO. With luck we can compare notes in 2015 .

 

[lomiller]

Practically impossible. Apart from lomiller's point, planetary processes have been observed for a good while now and they're well understood by existing science (some of which was developed precisely to understand them). So I'm not expecting any sudden surprises.



It'll probably change it a lot, IMO. With luck we can compare notes in 2015 .

The big unknown for 2015 is the amount of Aerosols China will pump into the atmosphere. A new coal fired power plant will actually have a net cooling effect for the the first 10-20 years of it’s life, after which the longer lifespan of CO2 in the atmosphere will start to win out over the more powerful cooling effect of the aerosols it’s emitting.

China is building 2 new coal power plants every day, but this may be offset by continued decreases in aerosols in Europe and NA so no one is certain if aerosols are increasing or decreasing at the moment. To further complicate things they tend to be more regional then CO2.

 

[CapelDodger]

The big unknown for 2015 is the amount of Aerosols China will pump into the atmosphere. A new coal fired power plant will actually have a net cooling effect for the the first 10-20 years of it’s life, after which the longer lifespan of CO2 in the atmosphere will start to win out over the more powerful cooling effect of the aerosols it’s emitting.

Chinese and Indian poluttion is certainly an important and unpredictable factor, as is the short-term global economy. Of course these aren't feedbacks, they're different forcings which already exist. I don't expect any great surprises to arise.

China is building 2 new coal power plants every day, but this may be offset by continued decreases in aerosols in Europe and NA so no one is certain if aerosols are increasing or decreasing at the moment. To further complicate things they tend to be more regional then CO2.

I think that's every week, not day, and I don't give the claim too much credence. There's more than a whiff of "Overfulfilling The Five Year Plan" to it. Orders go down, reports come back up saying "We've done that". Whether all these plants are real and actually operate is questionable. China is still far from being a transparent society.

What we could do with is a really good Earth-Observation satellite to give us firm data on aerosols. And if wishes were horses we'd all be eating steak .

 

[DogB]

Not impossible, but by that token, neither is an unknown positive feedback. An overnight recovery in the world's economy isn't impossible, but based on all available evidence, it's probably not going to happen and we'd be daft to plan around it. The current trend in surface temperatures is not unexpected given what the ocean currents are up to right now, so what reason (beyond wishful thinking) do we have to think the earth will cool down through the next El Nino?

The intent of my question was not to suggest that there was any real likelihood of this occurring. I was more interested in CD’s interpretation.

If some new important process that we've not considered before rears its ugly head, the best we can do is attempt to understand it and incorporate it into the science and modify our predictions accordingly.

A good answer.

It's worth pointing out though that negative feedbacks only reduce something's effect, not cancel it out. If there was some unknown process that will kick in and reduce the earth's temperature back down to normal (whatever that is), it's taking its sweet time about doing it if the last century is anything to go by.

As I said above, the question was hypothetical but personally I could see a five year cooling occur without in any way invalidating the current understanding of AGW. Hell, you don’t even need to invoke some mysterious new effect – the world was pretty much constantly in El Nino from 91 to 94, a La Nina of similar length could do the job.

 

[DogB]

You would still need to be able to explain paleo-climate data with that new negative feedback in play. If there is a strong unknown negative feedback it must be one that does not prevent warming when the world comes out of an ice age. This would put some very significant constraints over what this feedback could be.

Not really.

In the past the CO2 levels have tended to follow temperature changes, now they're driving it. If we accept this we must accept that paleo-climatic behaviour is only of limited predictive use.

As everybody keeps saying - we're in a whole new ballgame here.

 

[DogB]

Practically impossible. Apart from lomiller's point, planetary processes have been observed for a good while now and they're well understood by existing science (some of which was developed precisely to understand them). So I'm not expecting any sudden surprises.

Surely the whole current situation is one big fat sudden surprise?

It'll probably change it a lot, IMO. With luck we can compare notes in 2015 .

 

[CapelDodger]

If some new important process that we've not considered before rears its ugly head, the best we can do is attempt to understand it and incorporate it into the science and modify our predictions accordingly. It's worth pointing out though that negative feedbacks only reduce something's effect, not cancel it out. If there was some unknown process that will kick in and reduce the earth's temperature back down to normal (whatever that is), it's taking its sweet time about doing it if the last century is anything to go by.

Whatever it might be, it hasn't reached it's tipping-point yet. For all we know the tipping-point could be at 4C warmer, or 40C, or may not exist at all. The chance of the tipping-point being reached in the next seven years is negligible.

"Negative feedbacks" have, to my knowledge, been speculated and occasionally postulated for at least thirty years, to no effect. Coincidentally, thirty years is the characteristic time-period for climate (distinguishing it from weather or El Ninos). One has "Fail" to its name, the other doesn't. You can guess which horse I'm backing.

 

[CapelDodger]

Surely the whole current situation is one big fat sudden surprise?

Not to me. I'm old and cynical enough not to be surprised easily. Anyone could see it all coming if they knew what to look for.

What's much more difficult to foresee is the immediate aftermath, a chaotic situation if ever there was one. My policy has been to insulate myself from it as best I can, within reason.

 

[CapelDodger]

In the past the CO2 levels have tended to follow temperature changes, now they're driving it. If we accept this we must accept that paleo-climatic behaviour is only of limited predictive use.

Not really. The system remains the same, and the forcings remain the same. It doesn't matter what the cause of the CO2 variation is (feedback or direct) it has the same physical effect. At the moment we have to tease that effect out of paleoclimatic data, but by 2100 we'll have lots of direct observations to go on.

As everybody keeps saying - we're in a whole new ballgame here.

That's true in terms of the situation we're creating, but the basic physical rules remain the same. What the implications are on-the-ground is yet to be determined.

 

[DogB]

Not really. The system remains the same, and the forcings remain the same. It doesn't matter what the cause of the CO2 variation is (feedback or direct) it has the same physical effect. At the moment we have to tease that effect out of paleoclimatic data, but by 2100 we'll have lots of direct observations to go on..

Really?

Forcings like massive deforestation and (as mentioned above) large scale aerosol formation (from coal burning) surely aren't relevant when we're discussing the paleo-climatic data because they didn't happen before.

I'm sorry if I'm being a bit contrary but it’s just we’re butting up against the part of the AGW hypothesis that I find the most difficult. In the past CO2 has always been the bit player in the game. The earth warmed in the presence of ‘normal’ CO2 levels and then later cooled in the presence of ‘high’ CO2. Other forcings, be what they may, overwhelmed the CO2 effect. Now we are hypothesising that CO2 is the 500lb gorilla in the room.

I’m not saying the idea is wrong - I’m just saying my natural sceptical side struggles with the concept.

That's true in terms of the situation we're creating, but the basic physical rules remain the same. What the implications are on-the-ground is yet to be determined.

No argument.


BTW- Shouldn’t you be asleep??

 

[mhaze]

....The earth warmed in the presence of ‘normal’ CO2 levels and then later cooled in the presence of ‘high’ CO2. Other forcings, be what they may, overwhelmed the CO2 effect. Now we are hypothesising that CO2 is the 500lb gorilla in the room.

I’m not saying the idea is wrong - I’m just saying my natural sceptical side struggles with the concept.

Warmers are pretty much CO2 freaks. It goes in line with their little dainty carbon footsyprints, schemes for social control and taxation, and unscientific, gullible beliefs. Also a strong anti industrial sentiment.

Environmentalism-The New Religion.

 

[AOK Tiger]

DogB

I'm sorry if I'm being a bit contrary but it’s just we’re butting up against the part of the AGW hypothesis that I find the most difficult. In the past CO2 has always been the bit player in the game. The earth warmed in the presence of ‘normal’ CO2 levels and then later cooled in the presence of ‘high’ CO2. Other forcings, be what they may, overwhelmed the CO2 effect. Now we are hypothesising that CO2 is the 500lb gorilla in the room.

BANG….

So nicely put.

Not being contrary.. being sensible.. almost EXACTLY how I read the situation.

The only real scientific consensus seems to be.. we cannot find natural reasons for global warming.. man is increasing CO2.. man is the reason…

All other CO2 science seems to point on so LITTLE effect on GW !

Its so “unscientific” !

 

[DogB]

Warmers are pretty much CO2 freaks. It goes in line with their little dainty carbon footsyprints, schemes for social control and taxation, and unscientific, gullible beliefs. Also a strong anti industrial sentiment.

Environmentalism-The New Religion.

DogB

BANG….

So nicely put.

Not being contrary.. being sensible.. almost EXACTLY how I read the situation.

The only real scientific consensus seems to be.. we cannot find natural reasons for global warming.. man is increasing CO2.. man is the reason…

All other CO2 science seems to point on so LITTLE effect on GW !

Its so “unscientific” !

I appreciate the support but unfortunately I have to disagree with you two also.

The problem is that I am an amateur. There’s thousands of scientists working in the field that back the CO2 mediated warming idea whole heartedly.

It’s ludicrous to assume they’re all either wrong, misguided or just riding the bandwagon.

The hugely more logical premise is that I am simply ill educated in this matter.

I’m working on becoming more educated which will, hopefully, ease my disquiet with this aspect of the hypothesis. It hasn't yet however.

 

[AOK Tiger]

DogB

I appreciate the support but unfortunately I have to disagree with you two also.

The problem is that I am an amateur. There’s thousands of scientists working in the field that back the CO2 mediated warming idea whole heartedly.

It’s ludicrous to assume they’re all either wrong, misguided or just riding the bandwagon.

The hugely more logical premise is that I am simply ill educated in this matter.

I’m working on becoming more educated which will, hopefully, ease my disquiet with this aspect of the hypothesis. It hasn't yet however.

Dog, it wasn’t really “support” as I don’t really think you are putting up a case (just general scepticism) .. I was trying to say you so succinctly said what I feel.

And you are not disagreeing with me I think .. I am totally with you on the scientists.

I haven’t once said “they are wrong”.. “there is a conspiracy” etc.. lets face it when science has a general consensus they are more often right than wrong.

But unlike Evolutionary theory (example) which keeps hitting with its predictions.. AGW theory keeps missing.. I am sure that it’s a matter of time .. scientists will have it all nailed down some time.. for now though its seems far to much is being based on far to little !

 

[DogB]

DogB

Dog, it wasn’t really “support” as I don’t really think you are putting up a case (just general scepticism) .. I was trying to say you so succinctly said what I feel.

And you are not disagreeing with me I think .. I am totally with you on the scientists.

I haven’t once said “they are wrong”.. “there is a conspiracy” etc.. lets face it when science has a general consensus they are more often right than wrong.

But unlike Evolutionary theory (example) which keeps hitting with its predictions.. AGW theory keeps missing.. I am sure that it’s a matter of time .. scientists will have it all nailed down some time.. for now though its seems far to much is being based on far to little !

It seems we're very much on the same page. It’s comforting to know I’m not the only one.

I greatly dislike the 'you're either for us or against us' type of attitude this debate often engenders and I dislike the terms 'warmer' and ‘denier’ equally.

I'd like to think it's possible to logically question some aspects of the theory without causing too much angst. After all, if the hypothesis is valid and robust it should be able to easily withstand my critical musings.

 

[lomiller]

In the past the CO2 levels have tended to follow temperature changes, now they're driving it.

You are incorrect in assuming it can't do both. We are dealing with a feedback loop, and CO2 is a feedback factor in that loop. As such it both drives and responds to any change and untimely sets the final equilibrium point when the system is disturbed by a forcing.

If we accept this we must accept that paleo-climatic behaviour is only of limited predictive use.

CO2 lagging other facings in past climate changes isn’t just explainable it’s the predicted behavior. Feedback theory is quite well understood, and the feedback factor must always lag the forcing or you violate causality.

 

[DogB]

You are incorrect in assuming it can't do both. We are dealing with a feedback loop, and CO2 is a feedback factor in that loop. As such it both drives and responds to any change and untimely sets the final equilibrium point when the system is disturbed by a forcing.

Why assign that feedback role to CO2? Why not water vapour? Why not methane? Why not factor X?

CO2 lagging other facings in past climate changes isn’t just explainable it’s the predicted behavior. Feedback theory is quite well understood, and the feedback factor must always lag the forcing or you violate causality.

Logical but this still begs the question - why assume a significant role for CO2 at all?

 

[a_unique_person]

Why assign that feedback role to CO2? Why not water vapour? Why not methane? Why not factor X?



Logical but this still begs the question - why assume a significant role for CO2 at all?

Research. No assumptions.

 

[a_unique_person]

It seems we're very much on the same page. It’s comforting to know I’m not the only one.

I greatly dislike the 'you're either for us or against us' type of attitude this debate often engenders and I dislike the terms 'warmer' and ‘denier’ equally.

I'd like to think it's possible to logically question some aspects of the theory without causing too much angst. After all, if the hypothesis is valid and robust it should be able to easily withstand my critical musings.

Critical musings are standard science. If you read the blogosphere, it's 99% not critical musings, but rabid hate.

 

[a_unique_person]

This is an excellent resource if you have questions.

Home page is http://www.aip.org/history/climate/



History of "why CO2" is here http://www.aip.org/history/climate/co2.htm