global warming: salvaging fact from heaps of BS

[swansont]

To swansont

 

We seem to have crossed paths. I wrote my last post without seeing yours. We must have been putting them in together.

 

First : reliability of my references. If I post a reference from New Scientist, it is reliable in terms of fact. Interpretation, of course, is always debatable. My references are, like anyone else's, reliable if taken on those terms. I also have to say that I am always suspicious of debaters who fail to address points, but attack people or references instead. Sometimes that is a sign of a weak argument. If I post something from a biased political source, of course you can challenge it. However, my references have not been from that source.

 

Even a scientifically-oriented magazine such as New Scientist adds a layer of interpretation, and sometimes that layer is very thick. It's a summary of a journal article, and it glosses over details. These are not necessarily scientists writing the articles — the veracity cannot simply be assumed.

 

 

Second : ," "All models are wrong, but some are useful." "

I could not agree more. However, accuracy also varies. Some astronomical models, for example, which are based on equations known to be accurate to umpteen decimal places, and have as inputs, facts that are likewise enormously accurate, may produce outcomes that are incredibly accurate. Global Climate Models do not fit this category.

 

Your comments about unknowns are right on the button. But it goes beyond volcanoes and solar output. As I have shown recently, it extends to oceanic currents that behave in unexpected ways, and to wind patterns that have unexpected effects (Antarctica), and to uncertainties in the formation of clouds. There are sure to be other unknowns that currently live up to their name, and which will show themselves in due course. The time may come when all significant unknowns are accounted for, and models perform close to flawlessly, but that is not today. I suspect that if you are honest with yourself, you will admit that you know this already.

 

But again, you seem to be concluding that arbitrary precision is necessary before the models are useful. Energy is conserved, so if the model accounts for e.g. 95% of it. It underpredicts in one geographical region, then it means some other area will warm more than the prediction. Model critics jump on the two discrepancies, but in the meantime, the overall heating was there, even with 5% of it still unknown. The model is "wrong" but is still useful. You have not shown otherwise.

[Edtharan]

Energy is conserved, so if the model accounts for e.g. 95% of it.

True. We can map where the unknowns are and take a guess at what they are using this fact. Energy is conserved. This too is what is underpinning the whole Global Warming Debate.

 

Energy is conserved. So if we have a constant (or nearly constant) rate of energy incoming, and we are effecting the rate that this enrgy can escape, then what is going to happen to the energy?

 

That energy will go somewhere in the climate systems, it just can't vanish from the universe. This energy will cause an imbalance (ie more energy in one location than another), and it will try to even out. As it does this it will do "work" and that work will be on the climate systems.

 

Thus, if there is extra energy within the climate systems, and it is not evenly distributed (as it won't be), then it will cause changes to those climate systems as the energy tries to even out.

 

This is what is meant by global warming and global climate change. It is a consequence of the laws of thermo dynamics: Energy must be conserved.

 

To deny climate change is to deny the laws of conservation of energy. It is simple as that. The rest of the stuff (models, etc) are just our attempts to work out how this extra energy will effect the climate systems as it evens out.

 

Sure the models might not be perfect, but the fact of the matter is that greenhouse gasses prevent heat (energy) from escaping the Earth's climate systems. The sun has not significantly changed its output in the last 100 years (and even so this would just exacerbate the problems), but the amount of greenhouse gasses that are being pumped into the atmosphere buy us humans has increased.

 

Even the question of whether or not we are exceeding prior natural greenhouse gas events is moot. The Earth is warming (whether naturally or by human intervention) and we have a means that would allow us to control that to some degree.

 

Warming is bad for us as it would disrupt many ecosystems that we rely on.

 

We have the tools to stop this happening, so if we think that it is a good idea to prevent making life harder for our children, don't you think that it is a good idea to do so?

 

This is what I don't get about GW deniers. Either they have to disregard basic physics (conservation of energy) or not care about their children's future.

 

It is an inescapable consequence of thermo dynamics that there will be more energy in Earth's climatic systems and this extra energy will effect them. These effects will be disruptive (we will adapt and survive, we just might not have the same quality of life as we have now). If we can do something to prevent it, should we not do so?

 

That's true, but still ignores many unknown factors. That's why they are called unknowns.

Yes, there are unknowns, but 2 facts are all that is needed:

1) Greenhouse Gasses trap heat energy in the Earth's climate systems

2) Energy can't be created or destroyed so it will have to go somewhere and it will cause things to change.

 

Just these 2 facts alone dictate that Climate change will occur. You are just arguing against specific effects of this climate change and because the climate systems are complex and non-linear, they will be inherently hard to predict (and almost certainly we will never be 100% accurate). But, just because it is hard to predict and we will never be completely accurate does not mean that we should give up any attempt to do so, and it does not mean that that Global Warming is not occuring.

 

When the first models were set up, their accuracy was much less, since many factors were not well understood - there were more unknowns. Since then, models have improved, but recent reports still show serious errors due to other unknowns that keep appearing. The Arctic ice melt was a major one.

What you seem to have conveniently forgotten is that although these models seem to be under predicting the problems (or that the problems are occuring in a different place), they are still predicting that there will be problems and that GW is real.

 

If I post a reference from New Scientist, it is reliable in terms of fact. Interpretation, of course, is always debatable. My references are, like anyone else's, reliable if taken on those terms.

I kind of agree (sort of). Yes, NS is a basic reference, but it is not as reliable as a peer reviewed journal. NS is accountable for its content (mostly at their own initiative), but they are journalists (although familiar with science and how it operates).

 

I would accept that an article in NS is a valid reference, but that an article in a peer reviewed journal trumps whatever is taken from NS.

 

It is a bit like Wikipedia. Sure you can reference it, but it is not a completely reliable reference for all things.

 

I think its best use is to clarify a position or the concept being debated rather than a technical reference.

 

I also have to say that I am always suspicious of debaters who fail to address points, but attack people or references instead.

A agree that attacking the person is not a valid argument (ad hominem logical fallacy).

 

However, if it can be shown that the data that you based your argument on is wrong, then your conclusions form that data is also likely to be wrong. So when disputing the accuracy and validity of data, attacking a reference is perfectly valid (but the counter arguer has to show that the data of that reference is wrong).

 

However, my references have not been from that source.

But the data might be incorrect, or the data in the reference might be an interpretation from data in another source (this is usually the way it is in NS, so it is valid to challenge the NS references).

 

There are sure to be other unknowns that currently live up to their name, and which will show themselves in due course. The time may come when all significant unknowns are accounted for, and models perform close to flawlessly, but that is not today. I suspect that if you are honest with yourself, you will admit that you know this already.

The unknowns only influence the specific effects of GW, not the fact that GW is happening and that there will be effects caused by it.

 

Models of the Earth's climate system are pretty accurate over short term (days) for a specific location. They are also fairly accurate over long terms (>50 years - but of course if something dramatic occurs within that 50 years it can throw out the model until the modellers take that change into consideration), but in between these scales the models are not as accurate.

 

Your arguments are that because we have inaccuracies in the middle scale, then the long term scale must also be wrong. This is a complete logical fallacy (Composition).

 

Actually this whole argument against the models falls under the Perfect Solution logical fallacy.

[SkepticLance]

To swansont

I have said that models are not reliable and not accurate. I do not believe I have said they cannot be useful. Models serve many functions, and prediction is only one. My gripe is against those who believe they can be used for valid predictions. If you claim other uses for them, then fine.

 

Edtharan said :

 

"Thus, if there is extra energy within the climate systems, and it is not evenly distributed (as it won't be), then it will cause changes to those climate systems as the energy tries to even out."

 

But as I have pointed out many times, in a warming world, the distribution of temperature is more even. Tropical and temperate regions warm much less than polar regions, and thus temperature differentials are less, not more.

 

Also, I think Edtharan's ideas are a bit simplistic. Energy input verus energy output on a global scale is only the beginning of the picture, and the details are of vital importance. For example : much greater amounts of heat energy can enter the ocean and create a much smaller rise in temperature compared to energy entering the atmosphere. Thus the transfer of energy air/water is of vital importance. Since the oceans can store and transfer massive energy around, oceanic currents become of vital importance, and these are still not as well understood as we would like.

 

Edtharan said :

 

"We have the tools to stop this happening, so if we think that it is a good idea to prevent making life harder for our children, don't you think that it is a good idea to do so?"

 

I am not sure if this coment was directed at me or was more general. Anyway, here is my answer. Yes, of course, we need to act in a proper manner in relation to global climate change. However, as I have said before, we need to make sure our actions are considered, well researched, and carefully planned. There are just too damn many idiots out there screaming for precipitous action.

 

For example : many European countries are importing palm oil as the basis for biofuel. The countries that produce palm oil cut down tropical rain forest to plant oil palms. Result : things are made worse. Panicky, rushed action of this ilk is just stupid. There are things that can be done, which do not carry penalties and we should be doing them. We should not be acting stupidly.

 

A comment about journals such as New Scientist versus peer reviewed ones. NS is written by journalists - but science trained writers. They consult with professional scientists, but word the articles themselves. The result is something we can actually read and understand! The basic facts are normally very accurate, according to the scientific knowledge base of the time. Where interpretation is applied, read with a pinch of salt. But this is true for all articles, including peer reviewed ones.

 

If you look at peer reviewed journals such as Nature or Science, then you get items that are painstakingly accurate. However, you need to read them as though reading a foreign language, with dictionary in hand, unless the article falls within your own specialty. I have had to study a number of such articles for professional reasons, and I have, on occasion, re-written the entire damn thing in plain English before really getting to grips with the content, to the degree required. I suspect that most people simply do not get past the abstract, which makes the value of the article much less.

[swansont]

To swansont

I have said that models are not reliable and not accurate. I do not believe I have said they cannot be useful. Models serve many functions, and prediction is only one. My gripe is against those who believe they can be used for valid predictions. If you claim other uses for them, then fine.

 

I equate this with being useful, and that seems to be the use by almost everyone else, AFAICT. "Not accurate" an incredibly blunt instrument of criticism, since it's not quantified. What constitutes sufficient accuracy?

[SkepticLance]

Swansont

 

You may recall Prof. James Hansen using models to predict a 5 metre rise in sea level by the year 2100. This is the sort of thing I have a problem with. Models simply are not reliable or accurate enough to do this. It is total irresponsibility.

[Cap'n Refsmmat]

What sort of margin of error did he put on his claim?

 

The media might report it as "the sea will rise by 5 metres! We're all going to die" but he may have stated it as "the sea will rise by five metres, plus or minus two."

 

Margin of error is key when using predicted numbers like that.

[SkepticLance]

To the Cap'n

 

Either way, it is an extraordinary claim. Bearing in mind that current sea level rise is 3 mm per year, as global average, to suggest even 3 metres by 2100 is incredible. It is also a statement designed to stimulate alarm, even panic. As I have said before, we need a considered, carefully planned, researched and managed approach to remedial action. These kinds of claims are not going to achieve that. Instead, they could result in stupid over-reactions that lead to disaster.

 

It is vital that rational people keep things in perspective. Stupid predictions will not help.

[swansont]

Swansont

 

You may recall Prof. James Hansen using models to predict a 5 metre rise in sea level by the year 2100. This is the sort of thing I have a problem with. Models simply are not reliable or accurate enough to do this. It is total irresponsibility.

 

I'll need a citation for this. Where did he make this claim, and under what context?

 

What I've seen is from The Threat to the Planet - The New York Review of Books July 13, 2006

 

http://www.nybooks.com/articles/19131

 

"The Earth's history reveals cases in which sea level, once ice sheets began to collapse, rose one meter (1.1 yards) every twenty years for centuries. That would be a calamity for hundreds of cities around the world, most of them far larger than New Orleans."

 

Which is not a prediction that this would actually happen in the next century, nor is it based on models.

[Cap'n Refsmmat]

Bearing in mind that current sea level rise is 3 mm per year, as global average, to suggest even 3 metres by 2100 is incredible.

Of course, his estimate probably took into account far more important details than your back-of-the-envelope calculation.

[SkepticLance]

To swansont

 

The reference to Hansen and five metre sea level rise was a paper edition of New Scientist. However, a less specific version can be read on :

 

http://environment.newscientist.com/article/mg19526141.600

 

I quote from Hansen's words in the web article:

 

"I find it almost inconceivable that "business as usual" climate change will not result in a rise in sea level measured in metres within a century. Am I the only scientist who thinks so?"

 

And a second quote :

 

"As an example, let us say that ice sheet melting adds 1 centimetre to sea level for the decade 2005 to 2015, and that this doubles each decade until the West Antarctic ice sheet is largely depleted. This would yield a rise in sea level of more than 5 metres by 2095.

 

Of course, I cannot prove that my choice of a 10-year doubling time is accurate but I'd bet $1000 to a doughnut that it provides a far better estimate of the ice sheet's contribution to sea level rise than a linear response. In my opinion, if the world warms by 2 °C to 3 °C, such massive sea level rise is inevitable, and a substantial fraction of the rise would occur within a century. Business-as-usual global warming would almost surely send the planet beyond a tipping point, guaranteeing a disastrous degree of sea level rise."

 

Hansen admits that there is no 'proof'. I would say there is no strong evidence either. I would also say that statements such as Hansen's are irresponsible and dangerous, and lead to panicky action that should be avoided.

 

 

 

To the capn.

 

You need to re-read my post. I have made no calculation. The IPCC reports that sea level rise is 3 mm per year. That is not exactly a 'back of the envelope' calculation. It is simple empirical observation carried out by experts. So please take care not to say something that leads people to misunderstand my actual message.

Edited July 13, 2008 by SkepticLance

[Cap'n Refsmmat]

You need to re-read my post. I have made no calculation. The IPCC reports that sea level rise is 3 mm per year. That is not exactly a 'back of the envelope' calculation. It is simple empirical observation carried out by experts. So please take care not to say something that leads people to misunderstand my actual message.

 

And you assumed that his number is "incredible" given that sea levels are rising slowly right now, even though his account likely takes into account numerous other factors that would change the rate of rise. In other words, I find your incredulousity not credible.

[SkepticLance]

Yes Hansen's number is incredible. Current sea level rise is 3 mm per year. For Hansen's figure to be correct, that rate has to accelerate exponentially. I could accept that there may be an increase, but from 3 mm per year to not much less than a metre per year, based on his suggested doubling each decade????? That is not credible.

[swansont]

In my opinion, if[/b'] the world warms by 2 °C to 3 °C, such massive sea level rise is inevitable, and a substantial fraction of the rise would occur within a century. Business-as-usual global warming would almost surely send the planet beyond a tipping point, guaranteeing a disastrous degree of sea level rise."

(emphasis added)

 

Note the conditional. This is not a prediction of what will happen, it's what could happen if certain conditions are met. The fact that it has happened before means such conditions have existed and are thus achievable. I agree with the Cap'n. Your incredulity is not credible. Further, your use of this as an argument against warming models is incorrect.

[SkepticLance]

Swansont

 

It is more than a conditional suggestion. It is an opinion. Hansen has absolutely no scientific basis for his suggestion, and your willingness to accept his opinion suggests you need to sharpen your own scepticism.

[iNow]

Swansont

 

It is more than a conditional suggestion. It is an opinion. Hansen has absolutely no scientific basis for his suggestion, and your willingness to accept his opinion suggests you need to sharpen your own scepticism.

 

If I'm not mistaken, swansont was showing you how the Hansen quote you referenced as anecdotal support for your claims of model inaccuracies was, in fact, a conditional statement premised on an "if" operator and had nothing whatsoever to do with the models. Now, instead of addressing the questions put to you, you're trying to turn this around and suggest that swansont has simply agreed with the conclusions of that statement due to some faith in it's originator, and you're furthering admonishing him for this act which never even took place?

 

I'm not sure if you've missed the point on purpose or by mistake, but the fact remains that the point was missed and you continue to misrepresent the events of this thread.

[Cap'n Refsmmat]

Swansont

 

It is more than a conditional suggestion. It is an opinion. Hansen has absolutely no scientific basis for his suggestion, and your willingness to accept his opinion suggests you need to sharpen your own scepticism.

 

Did you even read the entire article?

[scalbers]

One point that isn't always mentioned in public discourse is that we have to be cautious and "play it safe" in the face of some of this uncertainty. This is because it takes a long time for CO2 in the atmosphere and ocean to disappear, even if we stop all emissions. So we wouldn't have the option of waiting to see how the models play out, then decide we were wrong and then try and reverse course. Once the genie is out of the bottle it will be very difficult to put it back in.

[swansont]

Swansont

 

It is more than a conditional suggestion. It is an opinion. Hansen has absolutely no scientific basis for his suggestion, and your willingness to accept his opinion suggests you need to sharpen your own scepticism.

 

It's not an opinion, it was a statement based on historical record, but you previously claimed it was the result of models. Were you mistaken then, are you mistaken now, or is it both?

[Edtharan]

But as I have pointed out many times, in a warming world, the distribution of temperature is more even.

Yes, as more energy is put into changing the way energy moves around the climate systems.

 

Energy input verus energy output on a global scale is only the beginning of the picture, and the details are of vital importance. For example : much greater amounts of heat energy can enter the ocean and create a much smaller rise in temperature compared to energy entering the atmosphere.

And here is your problem. You keep insisting that energy input only equals temperatures. It does not! (how many times must this be said before you understand ).

 

Yes, temperatures might be more even. Yes, the ocean can absorb a lot of heat. But is it not the heat, or temperatures that are the only problems. The problems are with energy.

 

The energy might not show up as heat or temperature changes, but instead as changes to how that heat or temperature is moved around. One of which is to move more of it to the poles. This would greatly increase the rate ice cap melting and provide faster sea level rises (much faster than 3mm a year).

 

Which brings me to:

Either way, it is an extraordinary claim. Bearing in mind that current sea level rise is 3 mm per year, as global average, to suggest even 3 metres by 2100 is incredible.

As you said: "in a warming world, the distribution of temperature is more even". This means that the poles are going to heat up. This means that melting is going to increase. But you have a problem with the fact that melting will increase.

 

The average temperature of the Earth (currently) is around 16 degrees C. So if the Earth's temperature differences were to become more even, this is the temperature that they will converge to.

 

However, with the poles they are a system in a dynamic stability. that is the amount of ice that is accumulating is roughly equal to the amount of ice that is being lost (melting). It is not a static stability because the two effects (accumulation and loss) are not directly linked (that is because ice is lost from the poles, it does not automatically mean that it will be immediately added).

 

This means that if there is an increased rate of melting or a reduction in accumulation, then there will be a net loss of ice.

 

When ice is lost from the south pole or the Greenland ice sheets, this loss will lead to an increase in sea levels (where as if it is from the Arctic then this will not lead to an increase in sea levels).

 

However, there is a link between ice coverage (including the Arctic) and warming (this is direct warming unlike the general increase in energy due to the greenhouse gasses). This is because Ice and Snow are good reflectors of sunlight (high albedo) and that rock and sea are bad reflectors and good absorbers of sunlight. This warming produces not only a global increase, but it is also a local increase (which means the area around these experiences the warming (again, unlike what the greenhouse gasses do).

 

So, with a small increase in temperature that increases the rate of melting, it will reveal more sea and land. These in turn will amplify the warming and hence increase the melting, which revelas more land and ocean...

 

...and so on.

 

This feedback effect of the warming/melting/warming cycle is a positive feedback loop. This create an exponential amplification of the initial warming and any results from it.

 

So, looking at the underlying effects of what actually happens when the melting starts in these places leads to an exponential increase in melting. And, as sea level is a (nearly) linear effect of this melting (basically the land area covered be the rising water will disturb it from a perfect linear increase), then if the melting is exponential, we can expect that the increase in sea level will follow that same (exponential) curve closely.

 

Actually the fact that we are getting any sea level rise must mean that the ice caps are melting as there is a finite amount of water on Earth and there are no other massive stores of water that are being drained fast enough to account for that level of sea level increase.

 

It can't be from rivers as the water that is coming down the rivers was initially taken from the oceans (so the net amount of water there is 0 - or close enough to it to not be a significant factor).

 

So the very fact that there is a sea level rise means that the ice caps are melting. And when the ice caps melt and expose more land or ocean (although with the ocean we would not get a sea level rise), then this produces both a local and global increase in temperature and both a global and local increase in melting in a positive feedback loop (which causes an exponential increase in this cycle).

 

What this means is your disbelief of an exponential increase in sea level rise is completely unfounded and is in fact a logical fallacy (argument from ignorance).

 

ALso your argument that tghe sea level rise is only 3mm per year so is nothing to worry about is also another logical fallacy (Appeal to tradition).

 

Just because it has been 3mm per year in the past does not mean that it is still going to only be 3mm per year in the future. In fact, the sea level rise in the past has actually been negative, so this argument "in the past it has only been X" should mean that there is no water in the oceans. This is why the "appeal to tradition" is a logical fallacy.

 

a far better estimate of the ice sheet's contribution to sea level rise than a linear response.

What he was talking about here is that he thinks there is a positive feedback loop that will cause the sea level rise to be non-linear (exponential) rather than linear. As I have showed, there is a direct link that provides a positive feedback loop (hence exponential) between melting and ice cover.

 

As ice melts it increases the amount of land exposed to sunlight. The more land (rather than ice) exposed to sunlight, the more local and global warming that will occur. The more warming that occurs, the more ice that melts.

It is that loop that is important. And it is that loop that shows that there will be a non-linear rate of melting (and hence sea level rise).

 

I would also say that statements such as Hansen's are irresponsible and dangerous, and lead to panicky action that should be avoided.

He says that he can't prove that his 10 year doubling time is accurate, but he is not saying that he can't prove that there will an exponential increase in sea level rise. He also says that it is an estimate (in other words not a prediction).

 

As he is a scientist involved in climate research, measuring and modelling, I would guess his estimates are actually an educated guess.

 

Lets assume that he got it quite wrong and it is only half what he expects: Doubling every 20 years.

 

2000 - 2020: 3mm/year (average) = 3mm/years * 20 years = 60mm

2020 - 2040: 6mm/year (average) = 60mm + (6mm/year * 20 years) = 180mm

2040 - 2060: 12mm/year (average) = 180mm + (12mm/year * 20 years) = 420mm

2060 - 2080: 24mm/year (average) = 420mm + (24mm/year * 20 years) = 900mm

2080 - 2100: 48mm/year (average) = 900mm + (48mm/year * 20 years) = 1860mm

 

1.86 meters. And that is only if half the increase is achieved and only if the rate is a doubling (it could be greater but it also could be less).

 

One of the things you have to udnerstand about an exponential increase is that near the beginning it will look like a linear increase. This is why you can't just go off a chart, but look at the underlying system for the reason you will have an increase. So at this stage of the game, you might not see it in a diagram, but if you understand the reason that we will get an increase in sea level (the melting/warming/melting cycle I explained above) then you can see it will have to be exponential.

[SkepticLance]

Edtharan

 

 

First, I do fully understand the distinction between heat and temperature. However, the discussion related to storms, and non-hurricane storms are drive by temperature differentials.

 

Re melting.

Current sea level rise has very little to do with ice melting at or near the poles. It is partly to do with thermal expansion of the oceans, and partly to do with melting of ice and glaciers in mountainous areas away from the poles - such as the Himalayas, Andes etc. The melting of polar sea ice has no effect on sea levels, and very little land bound ice near the poles has yet melted.

 

As the Earth warms further, sea level will rise further. However, to suggest that the rate of sea level rise will double each decade is quite unjustified.

 

You mention positive feed-back mechanisms. Did it occur to you that there are negative feed-back mechanisms also? I will not go into detail since that has already been discussed.

 

I am not arguing against action to slow or reverse global climate change. I am arguing against alarmist rhetoric that leads to stupid panic reactions. Every year, there are further idiot suggestions for ways to engineer climate globally that are more likely to lead to massive global environmental disaster. Let's cool the alarmist statements and work through the changes in a sane manner.

[swansont]

I will reiterate: you've made two conflicting claims. Which one is wrong, or were both of them wrong?

[SkepticLance]

Swansont

 

I accept that I made an error ascribing Hansen's ridiculous claim to GCMs. However, that only makes it worse. When a scientist with Hansen's influence makes such claims and has them taken seriously on the basis of what seems to be a genuine 'back of the envelope' calculation, we are in real trouble!

 

The real point is that shabby predictions lead to alarmist outcries, and panicky calls for action. As I said before, that is exactly what the world does not need. We need carefully researched, managed, monitored, and rational action.

[iNow]

When a scientist with Hansen's influence makes such claims and has them taken seriously on the basis of what seems to be a genuine 'back of the envelope' calculation, we are in real trouble!

 

The real point is that shabby predictions lead to alarmist outcries, and panicky calls for action. As I said before, that is exactly what the world does not need. We need carefully researched, managed, monitored, and rational action.

 

So not only have you misrepresented Hansen's comments, but now you are misrepresenting the response to them. Please share your sources which support the contention that ANYBODY engaged in "alarmist outcries, and panicky calls for action" as a result of Hansen's work.

 

If your response does not cite specific responses to Hansen's specific comments then you have AGAIN argued against something which never even happened in the first place.

[Edtharan]

First, I do fully understand the distinction between heat and temperature.

Actually you did misunderstand. It is not the distinction between Heat and Temperature, but Heat/Temperature and Energy.

 

The misnamed Global Warming (by the media) is all about the retention of Energy within the global climate systems. Heat and Energy are just one way that this Energy can manifest.

 

Current sea level rise has very little to do with ice melting at or near the poles.

Yes, as I said the melting of the Arctic will not change sea levels. However, the Antarctic ice cap lies on land (yes there is also sea ice there too and melting this sea ice will not cause a rise in sea levels). and it is this melting that will cause a rise in sea levels. Not only from the amount of melt water, but also from the fact that the ice weighs a lot and has been pushing down the crust and once it starts to go the crust will spring back up (although this will take longer than the 100 year time frame we have been discussing).

 

I also specifically mentioned that this applied to the Ice Caps of Greenland and Antarctica.

 

It is partly to do with thermal expansion of the oceans

The only way the oceans could be expanding thermally is if they are warming up. Hang on... Climate systems warming up... That is Global Warming. So why are you "sceptical" of global warming?

 

and partly to do with melting of ice and glaciers in mountainous areas away from the poles - such as the Himalayas, Andes etc.

This indicates that the atmosphere is also warming up. So you have agreed that the Oceans are warming up and that the Atmosphere is warming up.

 

Warmer oceans and atmospheres should cause less ice at the poles (and a loss of ice will mean that the water has to go somewhere - which is the oceans). Ice caps over land (Antarctic and Greenland) will cause an increase in sea levels.

 

The amount of water locked up in glaciers (excluding the ice caps of Antarctica and Greenland) are not enough to significantly raise the sea levels. If enough water was being lost from glaciers to raise global sea levels by 3mm / year, then we would have to see a much greater reduction of them than we already are.

 

Glaciers are at most a few hundred metres thick. The Ice caps on Greenland and Antarctica are kilometres thick. It is an order of magnitude of difference and that Mountain Glaciers just can't provide enough water to account for the rise in sea levels.

 

You mention positive feed-back mechanisms. Did it occur to you that there are negative feed-back mechanisms also?

Yes. And I do know that they have been discussed before (I think I even mentioned a couple my self).

 

However, in the Warming -> Melting -> Warming cycle there is not direct negative feedback loop. There are some that are indirectly tied to it, but that one is a direct positive feedback loop without any negative ones directly involved. And that is the danger as once that one starts it will be almost impossible for us to stop. The only way to stop it is for us to amplify the effects of the indirect negative feedback loops (without amplifying any harmful positive ones tied to them) in an effort to overwhelm the (accelerating) effects of the positive one. If there was a direct negative feedback loop in that system, then we could easily control it with that negative loop, but as one doesn't exist it has the potential to get away form us and exceed our ability to prevent it.

 

I am arguing against alarmist rhetoric that leads to stupid panic reactions.

I too am against panic reactions. But I am also against the "business as usual" as sticking your head in the sand until it is too late leads to panic reactions.

 

Science has known about global warming (or at least the potential for it) for decades, and yet it was all "business as usual". We are getting very close to certain tipping points (and maybe even past some of them). This is why there are panic reactions. Once these tipping points are past, then positive feedback loop dominate (the tipping points are when the effects of the Positive feedback loops exceed the effects of the Negative ones) and we loose control.

 

The difficulty is to separate the alarmist reactions from the alarming realities.

[SkepticLance]

To Edtharan

 

I think you misunderstand my position. I am not a global warming denier. I accept that the world is warming, and that human actions, via greenhouse gases, are the primary cause. I also accept that action is needed to reduce or reverse this. However, I am sceptical of certain parts of the global climate change picture. Mostly I am sceptical of those who think they can predict the future.

 

My statement about current sea level rise having little to do with the melting of land bound ice at or near the poles remains correct. Sea ice is vulnerable to melting when the sea warms. In the Arctic, there has been considerable sea ice melting, and recent studies have suggested a northerly oceanic current is a major cause, bringing in warmer water.

 

Ice on land in these areas, though, does not appear to be contributing to any significant degree to sea level rise. Precipitation is close to equal to melting. The main body of Antarctica is actually cooling, albeit to a minor degree.

 

However, ice in warmer climes, such as the Himalayas, is melting. This, plus thermal expansion, appears to be the bulk of the 3 mm per year sea level rise.

 

I should say something about the hypothetical 'tipping points'. These are purely theoretical. There is no empirical evidence to 'prove' they exist, or are a threat. The world has warmed many times in the past. In the last interglacial period, 120,000 years ago, the world warmed to about 2 Celsius more than it is today, and no 'tipping point' caused runaway warming.

 

On the other hand, despite ten interglacial warmings, each warming period has come to an end and reversed. Looks like there is a good chance that negative feed-back systems took over.

 

It is also interesting to note that the long term trend over the ten interglacial warmings, is for each successive warming to get a little warmer than the one before. If this trend was typical for the current interglacial, the world would have to warm a further 3 Celsius or thereabouts to fit the graph. And this warming would be entirely 'natural'.

 

OK, the warming of the past 30 years is not natural - but driven by AGWs. However, I hope you see the point. The time for panic is not here.