global warming: salvaging fact from heaps of BS

[SkepticLance]

To Edtharan

 

Actually I agree with you that my wording of 10 million wind turbines was lousy, and misleading. Sorry about that. My recollection of my thinking at the time was related to those people who think that vast quantities of wind turbines is the total solution to global warming, but I did not make that clear. Of course, using wind to generate power is part of the solution, but only part. And probably a small part.

 

Your points 1 to 4. I tend to agree with points 1 to 3. Of course the world is warming, and the main cause is human activity. This has been the situation for the past 30 odd years. Before that, the warming is probably better explained as a return to 'normal' conditions after the Little Ice Age.

 

I have to dispute your item 4, at least on the 30 year time scale, because over that time the temperature increase, with minor fluctuations smoothed out, has been approximately linear.

 

If warming is to accelerate, then carbon emissions have to accelerate at an even greater rate. This may happen, or it may not. Predictions are dangerous.

 

Your description of the effects of melting permafrost is hardly new. It has been discussed on this and other similar threads over a long period, and I do, in fact, understand it. It is a classic example of a proposed positive feed-back mechanism. You may recall that I accept that such mechanisms do exist. You may also remember that I pointed out that negative feed-back mechanisms also exist.

 

For example : the warming of the world will lead to more rapid plant growth. Thus more CO2 absorbed. Try reading :

http://www.impactlab.com/2008/06/09/scientists-surprised-to-find-earths-biosphere-booming/

 

This is one of many possible negative feed-back mechanisms. We do not know if positive or negative feed-backs will dominate in the future, and the idea that positives will be the main effect is common among global climate change pessimists. They may be right, but we do not know.

Edited September 5, 2008 by SkepticLance

[swansont]

If warming is to accelerate, then carbon emissions have to accelerate at an even greater rate.

 

That assumes some kind of linear response in forcings other than carbon dioxide. What of the nonlinear responses, such as changes in albedo when ice coverage decreases? And the other positive feedback mechanisms that you already acknowledged?

 

Carbon emissions do not have to accelerate faster in order to have warming accelerate.

[SkepticLance]

Swansont

That may be correct. Operative word - 'may'.

 

We simply do not know what the future holds. Lots of ideas exist, but only time will tell. Will positive feed-back mechanisms be more potent than negative? I do not know. You do not know. We can only guess, and the expressed guess is usually a reflection of a person's political viewpoint, rather than a reflection of good science.

[iNow]

Please do not equivocate a "guess" with a "well informed and realistic conjecture."

[Edtharan]

For example : the warming of the world will lead to more rapid plant growth. Thus more CO2 absorbed. Try reading :

I have heard arguments both for and against increased plant growth. However, even if we do get increased plant growth, this will not stop carbon from entering the atmosphere, and it could be even worse.

 

When plants grow the do absorb CO2. However, when they die and rot, the release Methane which is 20 times worse than CO2.

 

This means that for a plant to be Carbon Neutral, they have to lock up 20 times the amount of CO2 than the methane that they release on decay.

 

It has been shown that Old Growth Forests are not Carbon Absorbers. It is only new, growing forests that absorb carbon.

 

So at best and if there is an increase in plant growth, then all it will do is delay the inevitable by a few years to a couple of decades (depending on the types of plants that grow).

 

This is not a solution at all, but a delaying tactic we could use to give us a few more years to solve the problem (and I do mean a few years, not a long time).

 

I have to dispute your item 4, at least on the 30 year time scale, because over that time the temperature increase, with minor fluctuations smoothed out, has been approximately linear.

As I have explained before, in small intervals a graph of an exponential curve will approximate a linear curve (the size of the interval depends of the rate of growth). 30 years is too short a period to determine if there is exponential growth at the rate of growth we are seeing.

 

I have explained this about your 30 year time scales and yet you still keep using it. I have been using the longer time-scales as that gives us a better set of data to determine the behaviour of the system.

 

You are making the Hasty Generalisation Logical fallacy.

 

If warming is to accelerate, then carbon emissions have to accelerate at an even greater rate.

no, only feedback loops have to exist for it to be possible. And as CO2 is only part of the situation (the albedo of the polar regions and the permafrost regions all make a contribution). Also, as permafrost melts it injects carbon into the atmosphere that does not require us to increase our output which can give us an increase in CO2 emissions without (and even despite) us changing the amount we emit.

 

You may also remember that I pointed out that negative feed-back mechanisms also exist.

And as I have (repeatedly) tried to explain that despite these negative feedback effects, we are getting a net warming effect. This means that even with the negative feedback effects that do exist, they are not enough to reign in the warming.

 

All these arguments that you keep using have been disproved. Why do you keep repeating yourself, and with disproved arguments at that?

[scalbers]

Regarding the doubling of ice melting and such, recall the present sea level rise is dominated by the thermal expansion of the oceans and is a linear effect of temperature (roughly). There is a smaller component that is caused by glacier/icecap melting. However this is the component that may well be exponentially increasing, so even if the present overall sea level rise is steady, it could accelerate drastically as the icecap component starts to dominate. I do think the rate of sea level rise has been increasing in the past couple of decades, from about 2mm/yr to 3mm/yr. So Jim Hansen's numbers that were mentioned earlier would remain as plausible.

[iNow]

An interesting post yesterday over at Stoat:

 

 

http://scienceblogs.com/stoat/2008/09/sea_level_rise_pfeffer_et_al.php

The story so far... IPCC sez sea-level rise (SLR) by 2100 (0.18 to 0.6 m), but this excluded dynamic effects on the grounds that present understanding of the relevant processes is... <more at the

link

>

 

 

 

And another good one today:

 

http://scienceblogs.com/stoat/2008/09/sea_level_rise_from_ipcc_90.php

This starts from Pielke Jr commenteing at RC that the 1990 IPCC grossly overestimated sea level rise to date, and pointing to his post here as proof. It's nonsense, of course.

 

Pielke does the familiar rub-out-all-the-uncertainty estimates stuff... <more at the

link

>

[SkepticLance]

Edtharan

 

A few points from your last post.

 

CO2 versus methane. Forests, whether climax or growing, do not produce methane as a net emission. There were some earlier reports to that effect, but further research has shown no net production. In fact, over the past few decades, methane in the Earth's atmosphere has been falling, albeit by a very small amount.

 

Methane is a relatively short term contaminant in the atmosphere. It has a half life of 12 months. This means that, of all methane released today, 75% is gone in 2 years. It oxidises to CO2 and water vapour.

 

CO2 absorption by old forests. Sadly, your earlier statement was incorrect. I used to believe, as you do, that old forests do not sequester carbon. Now I realise I was wrong. Old forests are continuously adding to carbon in soils, and discharging carbon down waterways. All this from plant fragments that fall to the ground. Some become humus, and sequesters carbon in the soil. Some washes to the sea, and a small fraction ends up as deep sea sediment, which is a long term carbon storage. Some gets buried downriver.

 

Carbon in soils is one of the most important forms of carbon storage. It has been calculated, that if the 50% of the Earth's land area that is fully arable gained 2 mm thickness per decade from extra humus, that would take up all the CO2 released by all human activities. Clearly this is not happening, but it indicates the importance of this means of removing carbon.

 

And forests, old and new, are sequestering carbon into soils. With the world growing more verdant, more carbon gets sequestered. Obviously this is not enough to stop CO2 increase, or to stop warming, and I have never suggested it was. But it may be one reason why warming remains linear, even though CO2 emissions continue to increase.

 

I have never argued that negative feed-back mechanisms act to stop warming, at this point in time. My arguments are simply pointed to the uncertainty of future predictions. Since no-one knows what will happen in the future with respect to the balance between positive and negative feed-back mechanisms, how can anyone try for a prediction?

 

Re your comment about warming being non linear.

I have explained before why I stick to the past 30 years as the example of warming. It is simply because that is the only time period in which temperature change is utterly dominated by human carbon emissions. The 35 year period before that (1941 to 1976) was one of net cooling. The 31 year period before that (1910 to 1941) was one of warming - but very substantial warming when the CO2 increase was totally insufficient to be the main cause of that warming.

 

If we are to talk about warming caused by human activities, the picture is clear for the period of 1976 to the present, but utterly muddied before that, to the extent that deriving conclusions about anthropogenic greenhouse gas effect is totally unjustified.

[foodchain]

Edtharan

 

 

If we are to talk about warming caused by human activities, the picture is clear for the period of 1976 to the present, but utterly muddied before that, to the extent that deriving conclusions about anthropogenic greenhouse gas effect is totally unjustified.

 

Tell that to Venus.

 

CO2 traps heat or energy from the sun. Increasing the amount in terms of ppm in the atmosphere is going to do just that. It might not be as bad now, but lack of change will only increase CO2 concentration, what will be the impact of 1000+ ppm of CO2 in the atmosphere, do you desire this, how do we move away from that?

 

Land is being destroyed that supports currently natural ecosystems such as the rain forest at a constant and growing pace, this is same for most the world, so I don’t think planting trees is going to equal loss, unless we hope that corn fields will do the trick. Plus I dont want a corn field carbon cycle, that just sounds scary.

 

Bottom line is natural ecosystems support life on earth, that also includes us. We don’t have the ability nor the resources to replace this and I doubt we ever will.

[scalbers]

Couple of quick notes. I think the methane half-life is somewhere in the 5-10 year range instead of 1 year. It has leveled off this decade though it increased noticeably in the past year or so.

 

It's true that soil is an important carbon repository. One global warming solution involves the use of pyrolysis to make biochar that can possibly create agriculture and energy production that is carbon negative. This is one of the few reasonable ways I can think of to try and reverse global warming. If you look up 'terra preta' one can read the fascinating story about how the ancient Amazonians apparently used such a farming practice.

 

And I agree in general that we can increase investment to a few percent of our economies to tackle global warming without a significant loss in standard of living. It's true that business as usual would bring the 1000ppm values mentioned eventually and would have a quite significant effect on climate. Clearly investments should be increased since emissions have been on an increasing trend, and the emissions have to be cut around 70% globally (90% in industrialized nations if we assume parity between all countries) just to stabilize the current CO2 concentration. The longer we wait means the sharper the needed cuts become even beyond what I'm mentioning. That means it would be cheaper to act now instead of later.

 

As a footnote I can say it's interesting how non-linear and dynamic the CO2 ocean processes are. Around 10-20% of the CO2 will remain in the atmosphere for many thousands of years before the ocean can take it in. And remember what I mentioned previously about ocean acidification so eventually all CO2 emissions would have to be prevented to deal with this, and to prevent that 10-20% figure I mentioned from piling up.

Edited September 6, 2008 by scalbers

[iNow]

I'll see your GISSTemp and raise you a Hadley Centre.

John - I'm only half paying attention right now, but IIRC the link you shared can be countered by this:

 

http://scienceblogs.com/illconsidered/2008/09/temperatures-plummeted-in-2008.php

 

This argument represents a fundamental misunderstanding of the difference between weather and climate. Climate is generally defined as the weather conditions averaged over a long period, usually around 30 years. One can not discern a trend in climate change by looking at small numbers of years, much less a single one. On top of that, this fallacious objection is using global temperatures in a single month, not even an entire year! An even cursory look at the graph above reveals the very noisy nature of monthly temperatures, even when averaged over the entire globe. The particular Jan07 to Jan08 drop used for this argument is indeed large, but it is by no means the only .... <more at

link

>

[Edtharan]

CO2 absorption by old forests. Sadly, your earlier statement was incorrect. I used to believe, as you do, that old forests do not sequester carbon. Now I realise I was wrong. Old forests are continuously adding to carbon in soils, and discharging carbon down waterways. All this from plant fragments that fall to the ground. Some become humus, and sequesters carbon in the soil. Some washes to the sea, and a small fraction ends up as deep sea sediment, which is a long term carbon storage. Some gets buried downriver.

I had heard that there was still a bit of debate, but from what I had heard the data was mostly pointing towards (ie measurements of the CO2 released from old growth forests vs the amount of carbon in the organisms and soils). If you have a link to this alternate data set I would be interested in reading it.

 

Methane is a relatively short term contaminant in the atmosphere. It has a half life of 12 months. This means that, of all methane released today, 75% is gone in 2 years. It oxidises to CO2 and water vapour.

However, both CO2 and Water vapor are both greenhouse gases as well, not as bad as Methane but not without their problems either.

 

And forests, old and new, are sequestering carbon into soils. With the world growing more verdant, more carbon gets sequestered. Obviously this is not enough to stop CO2 increase, or to stop warming, and I have never suggested it was. But it may be one reason why warming remains linear, even though CO2 emissions continue to increase.

This is one of the Negative feedback effects. However, it is not without limit.

 

We are clearing land at an high rate due to logging and for food crops. Logged forests are definite greenhouse gas emitters and food crops, although they grow and take a bit of carbon form the air, they also take most of their carbon from the soil (yes, plants tend to get a lot of carbon, not from the air, but from the soil), this means that they reduce the carbon in the soils and much of this actually ends up in the atmosphere (and a lot converted to methane).

 

I have never argued that negative feed-back mechanisms act to stop warming, at this point in time. My arguments are simply pointed to the uncertainty of future predictions. Since no-one knows what will happen in the future with respect to the balance between positive and negative feed-back mechanisms, how can anyone try for a prediction?

I think you are falling for the Nirvana fallacy. Yes, it is true that we can not be 100% accurate or certain of our predictions, but this does not mean that there is actually a problem.

 

The uncertainties lie in the degree and the timing, not the consequences. The uncertainty of the accuracy is not about whether the predictions are correct or not, it is actually the resolution.

 

The models used for these predictions don't have the resolution to describe the fine scale effects of global warming. But this does not mean that they are inaccurate.

 

It seems to me that you are unwilling to accept the conclusions of these models unless they can provide a fine scale resolution for the short, medium, and long term predictions.

 

As I have explained. This kind of thing is impossible. But it also does not mean that the models are not useful.

 

Yes, the models can't predict if the effect on storms with certainty, but they aren't designed to model storm intensity precisely. They do, however, state that the temperature of the surface water will increase and that the amount of water vapor will increase. Then using the short term models some people have tried to predict that this means that storm intensity will increase.

 

The thing is, the errors crop up because the data provided by the long term models do not give enough resolution for the short term models to have the accuracy they have with today's measurements of sea temperatures and atmospheric water vapor.

 

Its that resolution thing again. Because the long term models do not have the high resolution of today's data sets, the predictions made using the short term models used to predict storm intensity have errors.

 

Because these short term modelings have errors, you seem to think that this means the long term models that produced the data for them must also be incorrect.

 

The uncertainty comes about from a low resolution data source. But just because the conclusions of the short term models are uncertain, it does not mean that the long term models must also be uncertain because of it. It is this whole non-linear systems thing that we have been talking about all this time.

 

Small errors in the initial data can lead to large errors over long periods of time. Due to the low resolution of the long term models output data, this means that naturally the short term models that use this data will have errors.

 

These errors exist because the resolution of the input data (the ones form the long term models) is of a lower resolution than they require.

 

You keep persisting on these misconceptions that have already been addressed and shown to be wrong. This is either because you really don't understand what we have been saying, or that you are not taking in what we have been saying.

[JohnB]

John - I'm only half paying attention right now, but IIRC the link you shared can be countered by this:

I'm not really paying attention either, however my link was to the Hadley Centres graph showing the recent plateau. Personally I regard the drop of early 2008 in the same light as the 1998 peak. Weather noise. That's why looking at a 10 year period is spurious ATM, it starts with a non-representative peak and ends with non-representative cooling, distorting the whole picture.

[SkepticLance]

To Edtharan

 

I have never said that models are not useful. I have said that they do not permit accurate predictions, which is a different thing. The reason is mainly due to the fact that there are still a whole lot of unknown factors not accounted for in models.

 

An example I gave some time ago was the prediction of ice melt at the Arctic. The models predicted an amount that was 100% out (the actual melt was double what the model suggested), and the reason was that a warm oceanic current was carrying heat north. This current was slow and was not detected until recently. That is : an unknown factor was present that caused the model to be wrong.

 

I regard models at this point in time as research tools. They help to increase our knowledge by permitting a kind of predictive test. As in : "My model as it currently exists predicts that in ten years something will happen." We wait ten years and see if the model is right. If not, we can modify the model. Eventually, the models will become much more reliable.

[iNow]

Models don't make predictions. Models just "model" what will happen given a various set of inputs.

 

If this, then that.

If this other thing, then that other thing.

 

You're misframing the issue by suggesting that they are somehow supposed to be the climatological equivalent to a crystal ball.

[SkepticLance]

iNow

You are nit picking. A conditional prediction is still a prediction. A model may say, if condition A is met, then result B will occur. That is still a prediction.

 

If there was no prediction, then the model would be useless. Just as a hypothesis that does not permit predictions for testing is also useless. That is the basic reason why super-string theory has got nowhere.

[iNow]

iNow

You are nit picking. A conditional prediction is still a prediction. A model may say, if condition A is met, then result B will occur. That is still a prediction.

 

If there was no prediction, then the model would be useless. Just as a hypothesis that does not permit predictions for testing is also useless.

 

It's not nit picking when I am calling you out for misrepresentations and spinning the facts. However, we've covered this multiple times already in this thread, yet you continue making the same claims as if they were never rebutted.

 

Since you openly conceded that you didn't read it the first time around, I can understand why you continue making the same mistakes. However, I covered your objections regarding models already here:

http://www.scienceforums.net/forum/showthread.php?p=421600#post421600

 

 

 

I then summarized that post into the parts specific to accuracy and repeated it for you again here:

http://www.scienceforums.net/forum/showthread.php?p=422371#post422371

[swansont]

iNow

You are nit picking. A conditional prediction is still a prediction. A model may say, if condition A is met, then result B will occur. That is still a prediction.

 

However, it becomes a problem when condition A is later omitted from the discussion. And you can't conclude that the model is wrong if condition A never materializes.

[SkepticLance]

I used the example earlier of a new oceanic current making models inaccurate. It appears that oceanic currents are quite a problem. Recently it has become clear that giant ocean circular movements called gyres have a very strong impact on climate.

 

http://www.sciencedaily.com/releases/2008/09/080909094745.htm

 

These have not been well enough understood to be part of climate models up to the present.

[iNow]

These have not been well enough understood to be part of climate models up to the present.

Not true.

 

The understanding is quite strong, it's just that computers are often not powerful enough to account for all of our knowledge and understanding. However, with new computers, the ability to add our knowledge of more variables into the system dynamics is growing.

 

 

 

 

EDIT: I knew I'd find the article where I'd recently read about this. Enjoy.

 

 

http://www.nsf.gov/news/news_summ.jsp?cntn_id=112166&org=olpa&from=news

 

"The limiting factor to more reliable climate predictions at higher resolution is not scientific ideas, but computational capacity to implement those ideas," said Jay Fein, NSF program director in NSF's Division of Atmospheric Sciences. "This project is an important step forward in providing the most useful scientifically-based climate change information to society for adapting to climate change."

 

Researchers once had assumed that climate can be predicted independently of weather, that is, with weather having no impact on climate prediction. Now they're finding that weather has a profound impact on climate, a result that's integral to the drive to improve weather and climate predictions and climate change projections.

 

With this boost in computing capabilities, research team member Ben Kirtman, a meteorologist at RSMAS, has developed a novel weather and climate modeling strategy, or "interactive ensembles," designed to isolate the interactions between weather and climate.

 

These interactive ensembles for weather and climate modeling are being applied to one of the nation's premier climate change models, NCAR's Community Climate System Model (CCSM), the current operational model used by NOAA's climate forecast system (CFS).

 

The CCSM is also a community model used by hundreds of researchers, and is one of the climate models used in the Nobel Prize-winning International Panel on Climate Change (IPCC) assessments.

 

The research serves as a pilot program to prepare for the implementation of more intense computational systems, which currently remain a scientific and engineering challenge.

 

"This marks the first time that we will have the computational resources available to address these scientific challenges in a comprehensive manner," said Kirtman. "The information from this project will serve as a cornerstone for petascale computing in our field, and help to advance the study of the interactions between weather and climate phenomena on a global scale."

 

While this research focuses on climate science, he said, by-products of the work are applicable to similar modeling challenges in other science and engineering fields, particularly the geosciences.

Edited September 12, 2008 by iNow
multiple post merged

[Edtharan]

EDIT: I knew I'd find the article where I'd recently read about this. Enjoy.

iNow, that is exactly what I was saying. It is a matter of resolution. Due to computing power (and measurements), the output of one model does not give as high a resolution as needed for other models.

 

For the example that SkepticLance has brought up about the ice melt in the Arctic, the model that was used to determine the warming of the Arctic was not of a high enough resolution for use in the model of Arctic melting for the result to be perfect.

 

What SkepticLance is also missing is that the model predicted the melting, it just (because of resolution effects), missed the amount that melted.

 

But it still predicted the melting.

 

The other thing is that the actual melting was worse than the model predicted.

[iNow]

Oh, stop nitpicking Edtharan.

[SkepticLance]

I really do not care whether you believe that climate models are inaccurate because of poor computer resolution as iNow said, or because of unknown factors as I have been saying. The point is that climate models are not accurate. If you agree with that point, I am happy.

 

I am off to Australia tomorrow for a week, so won't be able to continue your debate for that period.

Cheers.

[iNow]

I really do not care whether you believe that climate models are inaccurate because of poor computer resolution as iNow said, or because of unknown factors as I have been saying. The point is that climate models are not accurate. If you agree with that point, I am happy.

 

Post #467 was the third time I responded to this assertion of yours, and as any reasonable person can see, my posts had nothing to do with "belief."

 

What I shared was quantitative data which clearly evidenced the vastness of climate model accuracy.

 

You are really getting quite tiresome repeating points which have already been repeatedly rebutted, skepticlance.

[Mr Skeptic]

SkepticLance, do you know the difference between accuracy and precision? I think what you are arguing is that the models are not precise enough.