42 replies to this topic

[JayMark]

BFB, on 06 April 2012 - 10:42 AM, said:

That graph is incorrect.

Times the contails effect by 8. Also stratospheric water vapor plays a far more importen role than indecated in the graph. In the 80's and 90's stratospheric water vapor caused one third of the observed warming and have caused surface temperatures to increase about 25 percent more slowly since 2000.

How do you know it is incorrect? Do you have a source?

As far as I understand about stratospheric water vapor, you are right, in the 80's and 90's it was pretty bad. But after year 2000, there was a significant drop of it's concentration especially in the lower-stratosphere. So since the graph shows the diffrence between 1750 and 2005, it might very well (and most probably) be less important than if it was between let's say 1750 and 1990.

Now for the contrails, I know that they both reflect incoming radiations and trap outgoing radiations. Since the lastest is more important, the net result is an increase in forcing. But since it also reflects incoming radiations as said, the positive effect is diminished.

But I haven't gotten to deep in both these mechanisms yet.

Here's what I found about it in the IPCC report (graph comes from it).  

STRATOSPHERIC WATER VAPOR

"The TAR noted that several studies had indicated long-term increases in stratospheric water vapour and acknowledged that these trends would contribute a significant radiative impact. However, it only considered the stratospheric water vapour increase expected from CH4 increases as an RF, and this was estimated to contribute 2 to 5% of the total CH4 RF (about +0.02 W m–2).

Section 3.4 discusses the evidence for stratospheric water vapour trends and presents the current understanding of their possible causes. There are now 14 years of global stratospheric water vapour measurements from Halogen Occultation Experiment (HALOE) and continued balloon-based measurements (since 1980) at Boulder, Colorado. There is some evidence of a sustained long-term increase in stratospheric water vapour of around 0.05 ppm yr–1 from 1980 until roughly 2000, since then water vapour concentrations in the lower stratosphere have been decreasing (see Section 3.4 for details and references). As well as CH4 increases, several other indirect forcing mechanisms have been proposed, including: a) volcanic eruptions (Considi ne et al., 2001; Joshi and Shine, 2003); b ) biomass burning aerosol (Sherwood, 2002); c) tropospheric (SO2; Notholt et al., 2005) and d) changes in CH4 oxidation rates from changes in stratospheric chlorine, ozone and OH (Rockmann et al., 2004). These are mechanisms that can be linked to an external forcing agent. Other proposed mechanisms are more associated with climate feedbacks and are related to changes in tropopause temperatures or circulation (Stuber et al., 2001a; Fueglistaler et al., 2004). From these studies, there is little quantification of the stratospheric water vapour change attributable to different causes. It is also likely that different mechanisms are affecting water vapour trends at different altitudes.

Since the TAR, several further calculations of the radiative balance change due to changes in stratospheric water vapour have been performed (Forster and Shine, 1999; Oinas et al., 2001; Shindell, 2001; Smith et al., 2001; Forster and Shine, 2002). Smith et al. (2001) estimated a +0.12 to +0.2 W m–2 per decade range for the RF from the change in stratospheric water vapour, using HALOE satellite data. Shindell (2001) estimated an RF of about +0.2 W m–2 in a period of two decades, using a GCM to estimate the increase in water vapour in the stratosphere from oxidation of CH4 and including climate feedback changes associated with an increase in greenhouse gases. Forster and Shine (2002) used a constant 0.05 ppm yr–1 trend in water vapour at pressures of 100 to 10 hPa and estimated the RF to be +0.29 W m–2 for 1980 to 2000. GCM radiation codes can have a factor of two uncertainty in their modelling of this RF (Oinas et al., 2001). For the purposes of this chapter, the above RF estimates are not readily attributable to forcing agent(s) and uncertainty as to the causes of the observed change precludes all but the component due to CH4 increases being considered a forcing. Two related CTM studies have calculated the RF associated with increases in CH4 since pre-industrial times (Hansen and Sato, 2001; Hansen et al., 2005), but no dynamical feedbacks were included in those estimates. Hansen et al. (2005) estimated an RF of +0.07 ± 0.01 W m–2 for the stratospheric water vapour changes over 1750 to 2000, which is at least a factor of three larger than the TAR value. The RF from direct injection of water vapour by aircraft is believed to be an order of magnitude smaller than this, at about +0.002 W m–2 (IPCC, 1999). There has been little trend in CH4 concentration since 2000 (see Section 2.3.2); therefore the best estimate of the stratospheric water vapour RF from CH4 oxidation (+0.07 W m–2) is based on the Hansen et al. (2005) calculation. The 90% confidence range is estimated as ±0.05 W m–2, from the range of the RF studies that included other effects. There is a low level of scientific understanding in this estimate, as there is only a partial understanding of the vertical profile of CH4-induced stratospheric water vapour change (Section 2.9, Table 2.11). Other human causes of stratospheric water vapour change are unquantified and have a very low level of scientific understanding."

CONTRAILS

"Aircraft produce persistent contrails in the upper troposphere in ice-supersaturated air masses (IPCC, 1999). Contrails are thin cirrus clouds, which reflect solar radiation and trap outgoing longwave radiation. The latter effect is expected to dominate for thin cirrus (Hartmann et al., 1992; Meerkötter et al., 1999), thereby resulting in a net positive RF value for contrails. Persistent contrail cover has been calculated globally from meteorological data (e.g., Sausen et al., 1998) or by using a modified cirrus cloud parametrization in a GCM (Ponater et al., 2002). Contrail cover calculations are uncertain because the extent of supersaturated regions in the atmosphere is poorly known. The associated contrail RF follows from determining an optical depth for the computed contrail cover. The global RF values for contrail and induced cloudiness are assumed to vary linearly with distances flown by the global fleet if flight ambient conditions remain unchanged. The current best estimate for the RF of persistent linear contrails for aircraft operations in 2000 is +0.010 W m–2 (Table 2.9; Sausen et al., 2005). The value is based on independent estimates derived from Myhre and Stordal (2001b) and Marquart et al. (2003) that were updated for increased aircraft traffic in Sausen et al. (2005) to give RF estimates of +0.015 W m–2 and +0.006 W m–2, respectively. The uncertainty range is conservatively estimated to be a factor of three. The +0.010 W m–2 value is also considered to be the best estimate for 2005 because of the slow overall growth in aviation fuel use in the 2000 to 2005 period. The decrease in the best estimate from the TAR by a factor of two results from reassessments of persistent contrail cover and lower optical depth estimates (Marquart and Mayer, 2002; Meyer et al., 2002; Ponater et al., 2002; Marquart et al., 2003). The new estimates include diurnal changes in the solar RF, which decreases the net RF for a given contrail cover by about 20% (Myhre and Stordal, 2001b). The level of scientific understanding of contrail RF is considered low, since important uncertainties remain in the determination of global values (Section 2.9, Table 2.11). For example, unexplained regional differences are found in contrail optical depths between Europe and the USA that have not been fully accounted for in model calculations (Meyer et al., 2002; Ponater et al., 2002; Palikonda et al., 2005)."

[JayMark]

Doug1o29, on 06 April 2012 - 12:31 PM, said:

Those graphs look familiar, but I can't think of where I saw them.  Where did you get them?
Doug

Mine (radiative forcing between 1750 and 2005) comes from the AR4 (IPCC) report.

As for the past T° vs CO₂, I don't know as I didn't post it originally.

[Essan]

Alienated Being, on 05 April 2012 - 04:29 PM, said:

I would agree with man-made global warming if the world hadn't gone through warming/cooling periods in the past...

You'd not be very popular on a jury "I would agree that the man died after being shot 9 times if it wasn't for all the people who have died without being shot at all"

Which is what you - and many others - are effectively saying.

Conversely, others of us point out that just because people die naturally/the Earth's climate changes naturally it does not follow that humans cannot kill people/change Earth's climates through their actions, deliberate or otherwise.


Anyway, back on subject, this new papers shows that:

1) Antarctic ice cores are not a good proxy for global temperature, because at the end of the last ice age the temp rise there lagged behind that in the rest of the world

2) CO2 acts as a positive feedback in a warming environment, regardless of the initial cause of warming

And it also dispells that oft held yet strangely illogical myth that in the past CO2 rises followed temp rises and therefore CO2 rises cannot cause warming.

Edited by Essan, 06 April 2012 - 02:15 PM.

[JayMark]

Doug1o29, on 05 April 2012 - 06:29 PM, said:

Solar and wind can probably meet most of the need, but it will take a major conversion effort to get us there.  Wind and solar cannot produce base load - the minimum power needed to keep the system running at night when the wind's not blowing.  But nuclear can.  Fast breeders can re-use waste from old thermal plants, producing products with much shorter half-lives (300 yrs. vs. 5000 yrs.); that will cut down on the storage problem.  AND, Uncle Sam has enough to supply the US with power for the next thousand years.  Not to mention the $50 billion that would go to the US treasury.  New reactor designs eliminate many of the safety problems of the older designs.  Could we have a Chernobyl-style release from one?  The experts say no, but they also said a long list of other plants were safe, too.  At any rate, I don't think there's a choice - we have to go nuclear, sit in the cold, or destroy our life-support system.

Bio-fuels?  Right now, they're not efficient enough to be practical except in limited local situations - corn oil diesel in a corn-growing area, or crude from turkey processing waste.  There may be hope for cellulose-based alcohol, but that needs more research.  Grain is needed for food, so using good farmland to produce alcohol doesn't make much sense.

The problem with waiting for a disaster is that by then, we may not be able to fix the system.
Doug

Fair enough.

But I still am hesitant towards nuclear. Could you tell me more about those new plants that re-use thermal plant waste? What do they use, what is the process and what are the waste products?

I also know they are actively working in fusion reactors and I guess this would be safer and would generate less crap to deal with. Time will say I guess. I do not have so much knowledge in nuclear physics.

Solar and wind can be very usefull and could supply a lot if we invested in them. We are also developing wind and solar power here in Québec. And I've seen europeen countries also developing crazy solar technologies like this train circulating in a tunnel-like structure covered in solar panels.

I also think a major player would be to simply reduce our energy consumption to begin with by stopping abusing it and find ways to save it (be more efficient). There are literally LOTS of ways to do this than many of us aren't even aware of. Simple things. Should be the same with water.

The only bio-fuel that would be very good would be bio-methane. You trap methane that would've been released in the atmosphere anyways and use it. If we did that with all of our appropriate waste, we could probably supply a great amount of the natural gas needs instead of going the shale way which is just plain disgusting.

Making fuel from corn like ethanol is just wrong in my opinion. Using food as fuel is not so nice to begin with. Also cultivating corn on very large scales has a negative impact on the atmosphere with the change in land use and production of methane. Then producing the ethanol requires a lot of energy thus leading to even more greenhouse gas production so in all, it's not so much better.

Since cars are a major carbon source, we should keep focusing in alternatives like hybrid and electric cars. The Tesla car is 100% electric and car do up to 480km on a single load. Yes, the car is very expensive but what I'm saying is that the technology is there.

[Doug1o29]

JayMark, on 06 April 2012 - 03:13 PM, said:

Fair enough.

But I still am hesitant towards nuclear. Could you tell me more about those new plants that re-use thermal plant waste? What do they use, what is the process and what are the waste products?

I'm a bit hesitant, too, but I think we're reaching the point where it is riskier to continue with business as usual.  The reactors I'm talking about are fast breeders.  I'm no expert, so you probably ought to look them up on Google.  They use a different isotope (element?) that produces decay products with shorter half-lives.  They're still radioactive, but the time we'd have to store them is a lot shorter.  Fast breeders are about 100 times more efficient than thermal plants, so they take a lot less fuel.  They can re-use waste from thermal plants and weapons, but it has to be re-manufactured into a form they can use.  Detroit Fermi demonstrated the economic feasibility of these plants, even if it had a meltdown caused by a piece of titanium pealing off the inside of the vessel and getting caught in the coolant outlet.  Modern designs place the fuel inside ceramic coatings that keep the pellets from getting close enough to have a meltdown and there are other safeguards, such as a gravity-system that scrams the reactor if the power goes off.

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I also know they are actively working in fusion reactors and I guess this would be safer and would generate less crap to deal with. Time will say I guess. I do not have so much knowledge in nuclear physics.

Fusion power is the dream, but it hasn't happened yet.  In the mean-time, fast breeders will give us about a thousand years to come up with a fusion technology and/or make improvements to wind/solar.

I saw the ultimate in wind power:  a windmill driving an oil well.  It's up near Elkhart, Kansas on the Cimarron National Grassland on the north side of the "river" about two miles west of the bridge.  It has a 20-foot fan and drives the well's pump.  I've GOT to get a picture of it.

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I also think a major player would be to simply reduce our energy consumption to begin with by stopping abusing it and find ways to save it (be more efficient). There are literally LOTS of ways to do this than many of us aren't even aware of. Simple things. Should be the same with water.

That's needed.  Again, by itself, it's not enough, but it can make a contribution.

Quote

The only bio-fuel that would be very good would be bio-methane. You trap methane that would've been released in the atmosphere anyways and use it. If we did that with all of our appropriate waste, we could probably supply a great amount of the natural gas needs instead of going the shale way which is just plain disgusting.

There's a dairy farm in Pennsylvania that generates all its own power from manure.  Almost any organic material can be used.

I lived in Durango during the oil shale boom at Piceance Basin.  When govt subsidies ran out, they shut it down.  Not economically feasible they said.  There isn't a big move afoot to start up oil shale again unless uncle finances it, so I don't think it is feasible for the present.

I suspect the reason nobody is building fast breeders is that you could fill up an electric car for about 50 cents.  It costs around $50 to fill up a gas tank.  Doesn't take a rocket scientist to see Big Oil shaking in its boots.

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Making fuel from corn like ethanol is just wrong in my opinion. Using food as fuel is not so nice to begin with. Also cultivating corn on very large scales has a negative impact on the atmosphere with the change in land use and production of methane. Then producing the ethanol requires a lot of energy thus leading to even more greenhouse gas production so in all, it's not so much better.

At the present, it takes about a gallon of fuel to make a gallon of bio-fuel.  Not much savings there.  Better to shut down grain-based ethanol and use the land for food.  But cellulose-based ethanol can be made from wood waste and the US has about 100 million acres in need of thinning.  Abandoned fields could be harvested without even having to plant anything in them - just run a harvester over them.  And then there's millions of acres of road-side borrow ditches.  The shortage seems to be imagination.

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Since cars are a major carbon source, we should keep focusing in alternatives like hybrid and electric cars. The Tesla car is 100% electric and car do up to 480km on a single load. Yes, the car is very expensive but what I'm saying is that the technology is there.

Mass production can bring the cost down.  New products always cost more at first, until they learn the best designs and best ways to make them.  And, the original investors want to recover their cost ASAP, so they hike the price.
Doug

[JayMark]

and then, on 05 April 2012 - 09:10 PM, said:

It's just human nature to put off painful solutions to problems for as long as possible.

In this case, it's just a question of time before we pass a point of non-return and face a major global crisis. On one side you have us that say that we need to massively cut our carbon emissions but since this will have an impact of the profits of oil and gas companies for instance, they do whatever they can to prevent this, hence the big misinformation campains. If these companies are forced to reduce their activities, prices will go up and it will be a mess. I understand that. But frankly, this mess will be due to those companies refusing to lose money despite the fact that they already make rediculous profits. Pure greed and lack of concern.

Quote

When the costs of inaction eclipse the cost of trying to deal with the problems then we will get serious about a solution.  

I think it's already the case. If we did deal with the problem in an intelligent and fair way, it wouldn't be such a problem. It's all a matter of choise. My opinion.

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People will not willingly give up their comfort or convenience until it becomes so expensive that they must choose to.

That is good mostly for people who live in industrialized countries. Many people are already forced out of their (already low) comfort because of climate changes. It will only be worst with time. And even many of us will eventually have to give it because nature dosen't give a damn about our convenience. It only reacts. Since most people already live on costal areas, that alone could be a problem to begin with. And many areas will dry up and force people out as well.  

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This is why the alternatives like wind and solar have not been tried to greater degree.  Just too expensive versus carbon.

I agree. But then again, it's a matter of choise.

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And governments trying to artificially tax carbon to the point of pain will only harm the world's economy.

I understand. But that also because people are irresponsible in their choises.  

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When/if droughts and floods begin to cause mass displacement of populations then we'll find the courage to change.

It's only a matter of time.

Don't forget that there's always a delay of response from nature. What it means is that even if we cut 100% of our carbon emissions tomorrow, the temperature will keep raising for a long time. Carbon dioxide has a pretty long lifetime in the atmosphere from several hundread of years to thousands. So in other words, we are already doomed to a certain extand. So the more we wait, the simply more devastating it's going to be.

I think that responsible industries (fossil fuels) should be those who have to pay first because that's where all the money is and they are the main carbon source. They simply don't want to. They have no heart.

My thoughts. I know that not everyone agree with this.

Peace.

[cerberusxp]

Their time scale in the ice core samples are flip flopped to fit their agenda! Alas more junk science.

[cerberusxp]

Essan, on 06 April 2012 - 02:14 PM, said:

You'd not be very popular on a jury "I would agree that the man died after being shot 9 times if it wasn't for all the people who have died without being shot at all"

Which is what you - and many others - are effectively saying.

Conversely, others of us point out that just because people die naturally/the Earth's climate changes naturally it does not follow that humans cannot kill people/change Earth's climates through their actions, deliberate or otherwise.


Anyway, back on subject, this new papers shows that:

1) Antarctic ice cores are not a good proxy for global temperature, because at the end of the last ice age the temp rise there lagged behind that in the rest of the world

2) CO2 acts as a positive feedback in a warming environment, regardless of the initial cause of warming

And it also dispells that oft held yet strangely illogical myth that in the past CO2 rises followed temp rises and therefore CO2 rises cannot cause warming.

I love it when people OMIT factors in research. As warming occurs what happens? Plants grow more abundant thus EATING more CO2. = More forage, more food, more oxygen. Lets ju8st get rid of CO2 altogether alright? Then no one would have to worry about anything ever again. Famine, the earth would turn into a climate much like MARS no more plants.

[Essan]

cerberusxp, on 07 April 2012 - 12:04 PM, said:

I love it when people OMIT factors in research. As warming occurs what happens? Plants grow more abundant thus EATING more CO2. = More forage, more food, more oxygen. Lets ju8st get rid of CO2 altogether alright? Then no one would have to worry about anything ever again. Famine, the earth would turn into a climate much like MARS no more plants.

None of those straw men are in any way relevant to this particular discussion   


But, back on subject, it seems that there are questions on the validity of Shakun etal's conclusions - as Willis Eschenbach has raised on WUWT.  There should be an article on Skeptical Science shortly to further address this.

(none of which changes the fact that the argument that "because ice cores show CO2 following temp, then CO2 cannot cause temp to rise", is one of the funniest fallacies of the 21st century )

[Doug1o29]

cerberusxp, on 07 April 2012 - 12:04 PM, said:

I love it when people OMIT factors in research. As warming occurs what happens? Plants grow more abundant thus EATING more CO2. = More forage, more food, more oxygen. Lets ju8st get rid of CO2 altogether alright? Then no one would have to worry about anything ever again. Famine, the earth would turn into a climate much like MARS no more plants.

Research projects can't physically encompass everything at once.  Those who are interested in the subject have to do a LITTLE digging on their own.

Only about half the CO2 emitted by humans since 1960 is still in the air.  Plants can't account for that much.

But that's only half.  Look at a graph of Keeling's CO2 measurements.  It shows the seasonal effect of plants.  But CO2 levels continue to rise in spite of plants.  Plants are not absorbing the extra CO2.  Your thesis is flawed.

And I love it when deniers OMIT pertinent research.
Doug

[Doug1o29]

cerberusxp, on 07 April 2012 - 09:34 AM, said:

Their time scale in the ice core samples are flip flopped to fit their agenda! Alas more junk science.

What is your basis for this conclusion?

I may be touring the Lamont-Dougherty facilities in a few months.  If you have a question about their work, I can ask it for you.


While we're on the topic, how do you assess the time scales in dendrochronology?
Doug

[BFB]

JayMark, on 06 April 2012 - 01:58 PM, said:

How do you know it is incorrect? Do you have a source?

Because the IPCC's report is full of embarrassing and wrong research.

Regarding startospheric water vapor. A 10% decline in startospheric water vapor since 2001 would not be able to account for the low raditaive forcing the IPCC issued in their graph.

Bottom line stratospheric water vapor has a bigger impact than the IPCC thought.

As for contrails, its not really the contrails which is the big problem. Its the large cirrus clouds they produce.

http://www.nature.co...limate1068.html

[JayMark]

cerberusxp, on 07 April 2012 - 12:04 PM, said:

I love it when people OMIT factors in research. As warming occurs what happens? Plants grow more abundant thus EATING more CO2. = More forage, more food, more oxygen. Lets ju8st get rid of CO2 altogether alright? Then no one would have to worry about anything ever again. Famine, the earth would turn into a climate much like MARS no more plants.

The thing is, you are right about more CO₂ = increased plant groth = more food, oxygen etc. But vegetation is dying in many places as a concequence of global warming which is mainly due to anthropogenic CO₂ emissions. This leads to less uptaken CO₂, more methane, even more CO₂, less food and less oxygen. At the rate at which it is changing, we will see more trees diying than growing for quite a long time. Not to mention the problems with current agriculture. You need to look at both sides of the coin in everything. More CO₂ also acidifies water which can result in the loss of algae for instance which is a major oxygen source and carbon sink. And heat waves will dry more places up and flood others more as well both leading to vegetation loss. The densiest places on the earth are right now part of the most endangered.

Global warming will surely have positive concequences but the negative ones will be by far greater for us, humans. Billions will suffer from it before we can adapt it. And billions could die from it as well. It all depends on what we decide to do with it. If we reach 5°C+ of warming in 2100 (which is a possible scenario) we will face possible extinction.