global warming: salvaging fact from heaps of BS

[iNow]

The time for panic is not here.

Per my presentation two posts ago, you have yet to cite specific instances of "panic."

You have yet to be specific about who or what you are arguing against, and continue with this abstract and unfounded notion of "emotive responses" to the issue.

[Edtharan]

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.

They are only "theoretical" because they haven't happened in this period (yet).

 

Anyone who understand the basics of how non linear systems work, will know that in any non linear system there are "tipping" points. These are where the various positive feedback loops locally exceed other local negative feedback loops. These can be temporary or permanent.

 

Yes, they can be temporary. One thing about non linear systems is that they can have lag in them. When one factor goes up, it can be some time before a dependent factor responds to this. A simple one is with rabbits. More food means more rabbits can survive. But there is a gestation period before the baby rabbits are born. This introduces a lag into the system and can delay the response of other factors depend on the lagged factor. This lag will create oscillations in the values of various attributes. It is almost a signature of non linear systems.

 

Have a look at the situation we are in now. Recently (in geological time) we have bee experiencing dramatic swings in global temperatures. From ice ages to warmer than today. The climate systems are oscillating.

 

Another thing is that some systems have natural limits, or can be limited by other negative feedback loops. These create a metastable state which can trap a system in one of several states that are "locally" (local as in the system state, not as in spatial position) stable.

 

So in a complex system you will expect that there are factors that will stay relatively stable despite changes, but when a certain threshold is reached, fast and dramatic changes will occur to that factor.

 

But does this apply to the climate systems?

 

Well, if you look at what I was saying about melting.

 

In this model, imagine that you have a large black sheet divided into grid cells. However, on top of that sheet you have crushed ice (so it reflects the sunlight). The ice, however, is not evenly distributed. In some places it is quite thick and in other places it is thinner.

 

Now for a while you can slowly raise the amount of heat directed at the sheet and what you will find is that the ice will only melt a little bit. But once one section if the ice is completely melted and exposing the back sheet underneath, the surrounding ice will melt faster.

 

This exposes more black sheet and so more heat is absorbed which melts the surrounding areas faster (and you have more area that is next to th4e black areas).

 

This is a tipping point. Once you have that black sheet exposed, it greatly accelerates the melting of nearby sections which exposes more black plastic.

 

Now, I am not talking about just the land. I am also talking about the ocean.

 

In the poles there is sea ice, and this will reflect sunlight without turning it into heat. But once this sea ice starts to melt, it will absorb the sunlight turning it into heat. This then speeds up the melting of sea ice.

 

But, the problem with a warmer ocean at the poles is that it also warms the atmosphere. But this warming will have a lag. What you might expect is that as the sea ice melts it will provide some form of cooling (why do you put ice cubes into a drink? as the ice melts it takes the heat needed to melt from its environment). What you would probably expect is a slight cooling for some time before the warming lag catches up with the land.

 

And that is just what you said is happening. The sea is warming up around the poles and the land at the poles is getting slightly cooler

 

Not only is this showing that that is occuring, it is also indicative of a non linear system that is prone to tipping points.

 

You are showing a distinct lack of understanding about the nature of non linear systems as opposed to linear systems.

 

You seem to be rejecting tipping points because they haven't occurred .

 

The thing is there is plenty of evidence that they have occurred in the past (the whole glacial/interglacial swings is one really big give away). Also the fact that the Earth has an average temperature of around 16 degrees C, and that certain events have pushed it away from that average and held it there for a period before something pushes it away again. These are all fingerprints of non linear systems subject to tipping points.

 

In linear systems the factors would be proportional to whatever changes are occuring, so if the sun gets a little warmer, then you would expect the Earth to get proportionally warmer as well.

 

In non linear system without tipping points, you would expect to see constant fluctuations with changes to the inputs to the system. What you would not expect to see are stable periods.

 

In non linear system with tipping points would would expect to see stable periods punctuated by periods of fluctuations (ie: The last ice age then these interglacial periods, or the warmer periods in the times of the dinosaurs).

 

In non linear systems (in general, not just the ones with tipping points), you would also expect to see some forms of self similarity. That is on small scales you will also get these kinds of behaviours. So on the scales of centuries, or even as small as decades, you would expect to see in a non linear system with tipping points, periods of stability coupled with other periods of instability. The El Nino/La Nina is actually one such event that I can explicitly point to that does exist within our climate systems.

[SkepticLance]

To Edtharan

 

I do actually understand the basics, and oversimplified examples using black grills are seriously unnecessary. You seem to have ignored my point. That is, the world has been significantly warmer than today and did NOT suffer from a 'tipping point' leading to runaway warming. Until we have something better to go on, you are discussing theory that remains dubious.

[Cap'n Refsmmat]

The world may have once been warmer, but that doesn't mean that the present warning isn't going to screw us over.

 

 

That's my problem with the "it's happened before" argument: it might have happened millions of years ago, but it's still bad.

[Edtharan]

That is, the world has been significantly warmer than today and did NOT suffer from a 'tipping point' leading to runaway warming. Until we have something better to go on, you are discussing theory that remains dubious.

Ok, if the world was warmer in the past, what made it so warm then and now is colder? Answer: A tipping point.

 

The Earth has been warmer and it has been colder. The amount of energy emitted from the sun has not varied enough to account for the differences in temperatures alone. However, non linear systems with tipping points do account for it. Even non linear systems alone (with the tipping points) can not account for the behaviours of the climate systems. The fact that the warm and cold periods were stable means that there are tipping points and that these were in effect.

 

It is not "dubious" at all. You are ignoring the data (that the Earth has have variations in it's climate systems and it has had stable periods despite those variations) which proves that the Earth's climate systems are non linear and have tipping points.

 

This is why I thought that you didn't understand the basics of non linear systems. The two factors: variations not directly proportional to the inputs and periods of stability despite variations in the inputs, are direct evidence that a system is non linear (output not directly proportional to the input) and has tipping points (a non linear system that has periods of stability despite variations in the input).

 

As the climate systems show both of these properties, I can't seem to understand why you can't make the link between a system that displays these factors as having the consequences of those factors.

[SkepticLance]

Edtharan

 

I am trying to point out the difference between that which is known to be true, and that which is merely theorised. Sure, the global climate system is non linear. This is part of something I have been saying for years - that the climate is governed by numerous variables, some of which are not at all predictable. These variables lead to a non linear system. And due to the unpredictable nature of some of these variables, the future of Earth's climate is not predictable.

 

120,000 years ago, the world warmed to 2 C more than today, and after that cooled into another glacial period. Whether that was a kind of 'tipping point' or merely a periodic change in an important climate variable, we cannot judge for sure. As I understand it, it is normally ascribed to cyclic variables such as orbital.

 

If it was a 'tipping point', then it was a negative feed-back rather than the positive feed-back systems you are so fond of.

[swansont]

The world may have once been warmer, but that doesn't mean that the present warning isn't going to screw us over.

 

 

That's my problem with the "it's happened before" argument: it might have happened millions of years ago, but it's still bad.

 

It's actually worse in this case, in my view, because the "it's happened before" argument is being dismissed in one instance (with regard to the rapid sea-level rise) as being a "ridiculous claim," while the other argument (temperatures historically stabilize, eventually and then go down) is being invoked, even though the the circumstances are different (namely, a whole bunch of CO2 that we've dumped into the atmosphere and ocean).

[SkepticLance]

Swansont

If your comments in your last post were directed at what I have been saying, then you are misquoting.

 

I used the pre-historical data to point out that a positive feed-back, runaway warming, tipping point did not happen last time - at least to the point of 2 C warmer than now. Not to try to say that temperatures must stop increasing and fall again. I fully recognise the difference between now and 120,000 years ago.

 

However, I am saying that there is no reason to believe in that kind of tipping point until after we get warmer than last time. It may be true, but at this point in time it is only someone's pet theory - not a demonstrated reality.

[iNow]

However, I am saying that there is no reason to believe in that kind of tipping point until after we get warmer than last time. It may be true, but at this point in time it is only someone's pet theory - not a demonstrated reality.

 

Nonsense. A very significant percentage of the other 257 posts in this thread and others argue strongly against your suggestion that there exists no reason to accept these facts as valid or that they are someones "pet theory."

 

I don't mind if you offer legitimate arguments against the science, but thus far you've been failing miserably, and your failure is consistent.

[Edtharan]

Sure, the global climate system is non linear. This is part of something I have been saying for years - that the climate is governed by numerous variables, some of which are not at all predictable.

Yes, not predictable at all if you use think that it is a linear system. However, non linear maths can make the predictions.

 

These variables lead to a non linear system.

The variables don't "lead" to a non linear system, the describe the non linear system.

 

And due to the unpredictable nature of some of these variables, the future of Earth's climate is not predictable.

Actually it is not the "unpredictable" nature of the variables at all. We are not trying to predict the values of the input variables to the system in any way.

 

What leads the system to unpredictability (of any degree) is that we don't know precisely the input values.

 

Although we can't know the input values precisely, we can run the models many, many times with slightly different input values and see what common behaviours the models have under these conditions.

 

Certain things seem to come out: When temperatures exceed certain level in certain locations, sudden, dramatic and very difficult to prevent changes occur to the Earth's climate systems.

 

Now, depending on certain other values of input variables that we might not know about (you unpredictability) do have some minor effect. Essentially by choosing values for them (rather than getting them from measurements), we can see what would happen.

 

Now this technique does not require us to actually have these measurements because we run the models again and again with different values of these unknowns. So even if we don't know the values, we have tested what would occur. In this case, measurement of these "Unknown" factors just narrows down the which result (that we already have) are the ones it is actually going to be.

 

So, yes, there are unknowns, but they have already been accounted for and we don't actually need to know them (it will help, but not really necessary).

 

Actually this is the most fundamental thing about modelling in non linear system (and even linear system too). The fact that you keep demonstrating that you don't understand the very basics of this topic indicates to me that you don't actually know what you are talking about.

 

It is even just common sense. If you don't know the value of something, then work out what the result would be for all values of that unknown. That way you can know what would occur regardless of what value that unknown actually is.

[SkepticLance]

Edtharan

 

I don't know if you realise this, but a good part of your last post is just paraphrasing things I have said. We are arguing semantics, not science.

[swansont]

Swansont

If your comments in your last post were directed at what I have been saying, then you are misquoting.

 

I used the pre-historical data to point out that a positive feed-back, runaway warming, tipping point did not happen last time - at least to the point of 2 C warmer than now. Not to try to say that temperatures must stop increasing and fall again. I fully recognise the difference between now and 120,000 years ago.

 

However, I am saying that there is no reason to believe in that kind of tipping point until after we get warmer than last time. It may be true, but at this point in time it is only someone's pet theory - not a demonstrated reality.

 

Then I don't understand why you keep bringing it up. I also think you are interpreting "tipping point" and "runaway" in ways that are contrary to how others have used it.

 

Runaway warming does not mean a temperature increase that never stops — that violates thermodynamics. It means a temperature increase, to some new equilibrium, that can't be averted even if we stopped dumping massive amounts of CO2 into the atmosphere; the feedback would be too large of a contribution. The tipping point would be where that happens. It is the recognition that changing the CO2 contributions would happen on a decade-scale time that is the call for action now, rather than waiting until it's too late.

 

To assume because temperature hit an equilibrium in the past that no tipping point was reached is, by itself, invalid.

[SkepticLance]

Swansont

 

In a debate like this, it is really difficult to avoid misunderstandings. I am not so much trying to tell a story as to point out the weakness in other people's ideas. The basic point I am trying to get across is that the twin concepts of 'tipping points' and 'runaway positive feed-back' are theories, and are not demonstrated to be correct.

 

I have seen enough descriptions of theoretical negative feed-back mechanisms, to believe that they are equally likely as positive. Both are theory, and we simply cannot predict with any degree of surety. However, these theories are taken by those with political agendas to generate alarm.

 

I am against alarmism, as I have repeatedly said, because it leads to wrong remedial actions. I have described how some of these 'remedial' actions have actually made matters worse (palm oil for biodiesel leads to rainforest destruction etc.).

 

It is vital that we avoid alarmism, and carry out remedial action correctly. They may mean slowly - which is a damn sight better than panic led action that causes more harm.

[iNow]

• I am against alarmism, as I have repeatedly said, because it leads to wrong remedial actions.
   
  
• I have described how some of these 'remedial' actions have actually made matters worse (palm oil for biodiesel leads to rainforest destruction etc.).
   
  
• It is vital that we avoid alarmism, and carry out remedial action correctly.
   
  
• They may mean slowly - which is a damn sight better than panic led action that causes more harm.
  

 

Can you please provide a few specific examples of this alarmism which you've repeatedly referenced?

[scalbers]

I would point out once again that in our menu of "tipping points" we should consider the time it takes to reverse the CO2 increases in the atmosphere/oceans, in addition to any temperature amplification phenomena.

 

There are multiple time scales of the returns to equlibrium, though several thousand years after we stop emissions the atmospheric CO2 could still be elevated by roughly 10-20% and the oceanic levels more than that so that the acidification issue may be one of the longest lasting legacies of our pollution.

 

Half the increased CO2 could still be in the atmosphere 50-100 years after we stop. This is tricky to assess though since part of the reason there is a net flux of CO2 from the atmosphere to the ocean is because of the increasing atmospheric concentrations over time in relation to the emissions. If emissions were to stop, this flux to the ocean might also slow down, then the estimated recovery time to get the CO2 out of the atmosphere becomes longer.

Edited July 20, 2008 by scalbers

[SkepticLance]

Possible not pertinent to the current thread, but I was interested to see the following reference.

 

http://www.sciencedaily.com:80/releases/2008/07/080717224333.htm

 

This item states that, even though recent warming is due to human activity, the main driver of climate change over the past few hundred years is variations in solar activity, and especially solar magnetic effects.

[iNow]

Possible not pertinent to the current thread, but I was interested to see the following reference.

 

http://www.sciencedaily.com:80/releases/2008/07/080717224333.htm

 

This item states that, even though recent warming is due to human activity, the main driver of climate change over the past few hundred years is variations in solar activity, and especially solar magnetic effects.

 

 

If you read the article, you'll see it did not refer to past few hundred years, but past few thousand.

 

 

Also, one should be quick to notice that this wasn't a study with conclusions, but a paper with speculations (BIG difference):

 

During his conference at the El Escorial summer courses, the researcher pointed out that the possibility of a relationship existing between the sun and climate on Earth is quite “plausible”, since it is the main source of energy of everything that occurs within the Earth's atmosphere, “but empirical tests need to be found that show that such a correlation exists, and over what timescale.” Trying to find a connection over billions of years, where changes in the sun's interior have an effect, is not the same thing as looking for variations over just a few thousand years, “where we think only fluctuations in the magnetic energy of stars can play any type of role” the researcher commented.

 

 

Vázquez pointed out that over the last 40 years solar activity has not increased, and has in fact remained constant or even diminished, which is why it is difficult to attribute a significant global warming effect to it

 

 

 

Still waiting on specifics, btw.

Edited July 20, 2008 by iNow
Added 2nd quote

[swansont]

Possible not pertinent to the current thread, but I was interested to see the following reference.

 

http://www.sciencedaily.com:80/releases/2008/07/080717224333.htm

 

This item states that, even though recent warming is due to human activity, the main driver of climate change over the past few hundred years is variations in solar activity, and especially solar magnetic effects.

 

What it actually states is that there is a correlation, and that they are still looking for a mechanism.

[SkepticLance]

To swansont

 

If you remember our earlier arguments, you will remember I have argued for correlation, and admitted that the mechanism was still not known.

[JohnB]

To assume because temperature hit an equilibrium in the past that no tipping point was reached is, by itself, invalid.

The fact that the warm and cold periods were stable means that there are tipping points and that these were in effect.

"Equilibrium?" "Stable?"

The evidence suggests that historically the climate system has never been stable or reached equilibrium.

 

I would add that equilibrium is impossible as the system changes in response to various inputs and there is a lag in response. By the time the climate changes to accomodate the changed inputs, the inputs have changed and a different responses is needed. I would also add that in many references I've read, the Holocene is referred to as "unusually stable" compared to previous interglacials.

 

There are problems with using the historical record. As a first instance the movement of the plates will change the ocean currents and the distribution of heat by those currents. For this reason (except for generalities) I think it inadvisable to use any time period before circa 3 million BP as a comparison.

 

However it is reasonable to view predictions of disaster due to say 500 ppb of CO2 a bit sceptically when the record shows that 5,000 ppb did not lead to the end of the world.

 

One must also consider historical facts when discussing sea level rise. Is there any evidence of disaster in the US or anywhere else due to the rise of around 400 mm since 1776? The rise has been at least 3.6 metres since the Roman Empire (working on 1.8mm/year for 2,000 years), a good 7 metres since the Pyramids were built. Things should be kept in perspective.

[scalbers]

I agree the solar activity has been fairly constant the past few decades and thus would not explain the current warming. As for sea level, an accelerated rise (well beyond the historical 1.8mm/year) would be a big deal for modern civilization with all the coastline development. Overall, perhaps the warming is most harmful in its ecological effects in shifting the ranges (or existence) of many forms of life, particularly when habitat is fragmented by human development. Ocean acidification poses threats to the entire marine food chain, if overfishing weren't enough already.

[iNow]

Diseases transmitted by mosquitoes (like malaria) are moving northward and also into higher altitudes since the air is warmer and the bugs no longer die like they used to.

[swansont]

"Equilibrium?" "Stable?"

The evidence suggests that historically the climate system has never been stable or reached equilibrium.

 

Equilibrium was a poor choice on my part. Quasi-steady-state would perhaps be a better description: a range, over some period of time, where the fluctuations are small compared to the larger changes that had happened. If you look at the last half-million years of temperature data, there are some changes of several degrees, but the fluctuations on thousand-year times outside of this are of are much smaller.

 

 

However it is reasonable to view predictions of disaster due to say 500 ppb of CO2 a bit sceptically when the record shows that 5,000 ppb did not lead to the end of the world.

 

Considering that the recent change in CO2 is of order 50,000 ppb I have to think you meant ppm, but then, when in the last half-million years has the CO2 been 5,000 ppm? Something does not jibe here.

 

And who is saying that the world is going to end?

 

One must also consider historical facts when discussing sea level rise. Is there any evidence of disaster in the US or anywhere else due to the rise of around 400 mm since 1776? The rise has been at least 3.6 metres since the Roman Empire (working on 1.8mm/year for 2,000 years), a good 7 metres since the Pyramids were built. Things should be kept in perspective.

 

As scalbers has said, it's the degree to which coastal development has taken place.

 

It hasn't been 1.8 mm/year over all time of course. Extrapolating the curve from last 100 years — in either direction — isn't valid.

 

http://www.friendsofscience.org/assets/documents/FOS%20Essay/Climate_Change_Science.html shows it hitting a minimum in ~ 1860

 

http://en.wikipedia.org/wiki/Image:Post-Glacial_Sea_Level.png is hard to read for the time in question, but it looks like the rise in the last ~8000 years (the big inflection point) is about 5 meters. If you blow it up, there looks to be a more subtle inflection point a ~4500 years bp, with the rate of increase being smaller after that point.

Edited July 21, 2008 by swansont

[SkepticLance]

I have to make a comment about another myth - that of malaria returning with global warming.

 

Malaria was rife throughout Europe and North America (along with other 'tropical' diseases like yellow fever) during the Little Ice Age. William Shakespeare lived and wrote in the middle of this cold time, and he mentions malaria no less than 9 times in his plays (under the medieval name - ague).

 

http://www.cdc.gov/Ncidod/eid/vol6no1/reiter.htm

 

"Such mention of agues did not disappear when the coldest years of the Little Ice Age began. In 16th century England, many marshlands were notorious for their ague-stricken populations and remained so well into the 19th century. William Shakespeare (1564–1616), who was born in the autumn of Bruegel's first fierce winter, mentioned ague in eight of his plays. For example, in The Tempest (Act II, Scene II), the slave Caliban curses Prosper, his master: "All the infections that the sun sucks up/ From bogs, fens, flats, on Prosper fall and make him / By inch-meal a disease!" Later, Caliban is terrified by the appearance of Stephano, who, mistaking his trembling and apparent delirium for an attack of malaria, tries to cure the symptoms with alcohol: ". . . (he) hath got, as I take it, an ague . . . he's in his fit now and does not talk after the wisest. He shall taste of my bottle: if he have never drunk wine afore it will go near to remove his fit . . . Open your mouth: this will shake your shaking . . . if all the wine in my bottle will recover him, I will help his ague." "

 

This 'ague' was eliminated by action to attack the various species of malaria carrying mosquitoes. In England, the biggest action was the draining of the fens near London, where those mosquitos bred.

 

The final coup de gras to malaria was early 20th century, with the use of DDT to kill mosquitos. In fact, if you took the period from 1750 (coldest part of the LIA) to, say, 1950, then the incidence of malaria in the west inversely correlates with temperature.

 

Malaria is more a disease of poverty than tropical climate. It is fully capable of thriving in a range of temperatures. However, it is eliminated by eliminating the vector. Today, we have a range of techniques for eliminating the vector, and the reason it still is prevalent in Africa etc is simply a lack of resources (poverty) to do what is needed.

[iNow]

So? Mosquitos carry with them other health ailments besides just malaria. Why the long diatribe against but one example? The fact remains that the warmer ecosystems which can support the bugs are moving northward and into higher altitudes, whereas in the past, before the warming climate, the action of moving northward or to higher elevations restricted the flow of these ailments.