Vapour Trails and Greenhouse Gas
Guest
Posts: n/a
ORAC
No, I don't think I was being disingenuous.
The article quite explicitly states that the results are valid only for this area, and would differ if a larger area were considered.
I quote directly from the original text (my parenthesis):
'The results of this case study predict an annual fuel burn change only for the traffic mix and atmospheric conditions of the five states region in Europe. Other regions would be expected to
have a different seasonal cycle of maximum permitted cruise altitudes dependent on the local atmospheric conditions. The fraction of flights affected by those altitude restrictions would be
dependent on the nature of the traffic mix.'
This is explicitly saying that the results reported here are not applicable more widely.
They do also explictly discuss the problem of long haul aircraft, but note that because this was a Europe based study it is not considered in the article:
'Some long distance flights may also be unfeasible with current aircraft as less efficient operation at lower altitude may reduce their range. These issues are not relevant to this analysis of European airspace, but would be for a global study.'
Pax Vobiscum
Commenting on your two points:
(a) There is incontrovertible evidence that global CO2 levels have increased substantially over the last 150 years (and are continuing to increase, although the rate is slowing). The evidence that this change has resulted in global temperature increases over the same period is much thinner.
I'm afraid that your assertion that the increase in levels of CO2 is reducing is not true as far as I know. This graph is an illustration of global CO2 levels. The acceleration is evident:
Yes, the absolute prrof is still lacking, but the evidence is definitely strengthening all the time. More importantly, many of the problems with the anthropogenic greenhouse effect are now being dealt with. Most (but not all) climate scientists are now pretty convinced.
(b) Models of the earth's climate are still pretty crude. One of the biggest problems is lack of computing power which forces the use of very coarse grids (around 1km square) which can take no account of smaller-scale phenomena such as clouds. Another problem is our lack of understanding of how the climate actually works! Estimates of future global warming amount (IMHO) to little more than a best guess.
If anything, you are being too generous to the modellers! Last I heard (18 months or so ago) the Hadley Centre (UK Met Office) regional simulation worked on grid squares of 50 x 50 km. As far as I know, large scale simulations are not being undertaken on a scale of 1 x 1 km.
However, just with weather forecasting, that level of resolution is not really needed. Climate models have a long way to go, but are definitely getting better, and actually appear to be getting quite good now.
DrDave
No, I don't think I was being disingenuous.
The article quite explicitly states that the results are valid only for this area, and would differ if a larger area were considered.
I quote directly from the original text (my parenthesis):
'The results of this case study predict an annual fuel burn change only for the traffic mix and atmospheric conditions of the five states region in Europe. Other regions would be expected to
have a different seasonal cycle of maximum permitted cruise altitudes dependent on the local atmospheric conditions. The fraction of flights affected by those altitude restrictions would be
dependent on the nature of the traffic mix.'
This is explicitly saying that the results reported here are not applicable more widely.
They do also explictly discuss the problem of long haul aircraft, but note that because this was a Europe based study it is not considered in the article:
'Some long distance flights may also be unfeasible with current aircraft as less efficient operation at lower altitude may reduce their range. These issues are not relevant to this analysis of European airspace, but would be for a global study.'
Pax Vobiscum
Commenting on your two points:
(a) There is incontrovertible evidence that global CO2 levels have increased substantially over the last 150 years (and are continuing to increase, although the rate is slowing). The evidence that this change has resulted in global temperature increases over the same period is much thinner.
I'm afraid that your assertion that the increase in levels of CO2 is reducing is not true as far as I know. This graph is an illustration of global CO2 levels. The acceleration is evident:
Yes, the absolute prrof is still lacking, but the evidence is definitely strengthening all the time. More importantly, many of the problems with the anthropogenic greenhouse effect are now being dealt with. Most (but not all) climate scientists are now pretty convinced.
(b) Models of the earth's climate are still pretty crude. One of the biggest problems is lack of computing power which forces the use of very coarse grids (around 1km square) which can take no account of smaller-scale phenomena such as clouds. Another problem is our lack of understanding of how the climate actually works! Estimates of future global warming amount (IMHO) to little more than a best guess.
If anything, you are being too generous to the modellers! Last I heard (18 months or so ago) the Hadley Centre (UK Met Office) regional simulation worked on grid squares of 50 x 50 km. As far as I know, large scale simulations are not being undertaken on a scale of 1 x 1 km.
However, just with weather forecasting, that level of resolution is not really needed. Climate models have a long way to go, but are definitely getting better, and actually appear to be getting quite good now.
DrDave
Join Date: Jun 2003
Location: London
Posts: 8
Likes: 0
Received 0 Likes
on
0 Posts
Regarding Pax and Dr Dave above,
The resolution of the Hadley Centre Regional Models is 0.44*0.44 lat lon. These models are currently available for a European window, and I think over the Indian Subcontinent as well. The resolution of the global scale models is 3.75*2.75 lat lon, which gives effectively ~7000 grid cells, of which there are around 19 atmospheric levels, and 20 oceanic levels. To give some idea of how this translates into reality, the UK is taken care of by only 6 grid boxes.
All is not lost though for regional climate scenarios - there are a number of downscaling techniques which are available and effective (some of which I have used in research) to resolve the scale mismatch between the output of global climate models, and the needs of the climate change impacts community
The resolution of the Hadley Centre Regional Models is 0.44*0.44 lat lon. These models are currently available for a European window, and I think over the Indian Subcontinent as well. The resolution of the global scale models is 3.75*2.75 lat lon, which gives effectively ~7000 grid cells, of which there are around 19 atmospheric levels, and 20 oceanic levels. To give some idea of how this translates into reality, the UK is taken care of by only 6 grid boxes.
All is not lost though for regional climate scenarios - there are a number of downscaling techniques which are available and effective (some of which I have used in research) to resolve the scale mismatch between the output of global climate models, and the needs of the climate change impacts community
Join Date: Jul 2001
Location: New Zealand
Posts: 254
Likes: 0
Received 0 Likes
on
0 Posts
My initial reply may well have been over simplified, but that does not necessarily signify inaccuracy, Dr Dave.
You have very eruditely produced data and facts to back your stance, and I note your belief in the increase in CO2 levels.
Basic photosynthesis, as you will know, is the process that converts energy in sunlight to chemical forms of energy that can be used by biological systems. Photosynthesis is carried out by many different organisms, ranging from plants to bacteria. All these organisms convert CO2 (carbon dioxide) to organic material by reducing this gas to carbohydrates in a rather complex set of reactions.
All the food we eat and all the fossil fuel we use is a product of photosynthesis, and with a rapidly burgeoning world population, even more of the building blocks of photosynthesis become essential to provide the food and fuel supplies necessary to support this population growth.
Does the increase in CO2 levels not signify that we now see an increased food supply for these plants and organisms, and also that this supply is where it can be used, namely where these biological systems exist?
Weather, and the study of it has been long and involved, but most have agreed that apart from any other factors, weather patterns have always been chaotic, and temperature fluctuations have existed since long before mankind exerted any influences on the atmosphere.
You have very eruditely produced data and facts to back your stance, and I note your belief in the increase in CO2 levels.
Basic photosynthesis, as you will know, is the process that converts energy in sunlight to chemical forms of energy that can be used by biological systems. Photosynthesis is carried out by many different organisms, ranging from plants to bacteria. All these organisms convert CO2 (carbon dioxide) to organic material by reducing this gas to carbohydrates in a rather complex set of reactions.
All the food we eat and all the fossil fuel we use is a product of photosynthesis, and with a rapidly burgeoning world population, even more of the building blocks of photosynthesis become essential to provide the food and fuel supplies necessary to support this population growth.
Does the increase in CO2 levels not signify that we now see an increased food supply for these plants and organisms, and also that this supply is where it can be used, namely where these biological systems exist?
Weather, and the study of it has been long and involved, but most have agreed that apart from any other factors, weather patterns have always been chaotic, and temperature fluctuations have existed since long before mankind exerted any influences on the atmosphere.
Guest
Posts: n/a
Herctorus Rex
Not sure where I implied that your facts were inaccurate? If I did, my apologies. Not my intention.
With regard to biological productivity - yes, it is a little reported by-product of CO2 elevations that biological productivity increases - off the top of my head it has been estimated that increased CO2 has been responsible for a 4% increase in crop yields in temperate areas?
However, it is undeniable that increased productivity is not compensating adequately for increased CO2 production - otherwise levels wouldn't be rising. The fact is that this increase is tiny compared with the growth in world population, and certainly is not the answer to those problems. Add to that the poitential loss of productivity to aridity if, as predicted, climate zones move.
Some calculations have been done of the amount of increased tree planting that would be needed to compensate for the emissions from humans. Generally, the figures come out as follows (from Goreau 1992):
'A major part of global warming could be averted if the addition of CO2 to the atmosphere were accompanied by equal removal. Emitters could pay for planting, growing, and sustaining enough biomass and storage to remove excess carbon permanently. It would require trees that consume 10 tonnes of carbon per ha per year on 4 million km2 of land, to ensure removal of the current carbon increase. The area could be as low as 2 million km2 in the humid tropics, if reforestation stopped, or as high as 8 million km2 if areas with long dry seasons or colder temperatures were planted.'
(I haven't checked these numbers though).
Weather is a chaotic system, but as with many non-linear systems order emerges (that is climate). We are getting better and better at modelling this ordered behaviour from the non-linearity. Of course temperature fluctuations have occurred previously (and my very first post in this thread demonstrated that explicitly). The fact remains that, except during extinction events, the rapid changes in global temperature that we are currently measuring do not appear to occur in the geological record, and that our observations of increased atmospheric temperature are consistent with the results from Global Climate Models when increased CO2 levels are input. Add to that the clear linkage between palaeo levels of atmospheric CO2 and temperature (with the rider that cause and effect are hard to interpret as per bluskis post), and the argument becomes reasonably strong.
DrDave
Not sure where I implied that your facts were inaccurate? If I did, my apologies. Not my intention.
With regard to biological productivity - yes, it is a little reported by-product of CO2 elevations that biological productivity increases - off the top of my head it has been estimated that increased CO2 has been responsible for a 4% increase in crop yields in temperate areas?
However, it is undeniable that increased productivity is not compensating adequately for increased CO2 production - otherwise levels wouldn't be rising. The fact is that this increase is tiny compared with the growth in world population, and certainly is not the answer to those problems. Add to that the poitential loss of productivity to aridity if, as predicted, climate zones move.
Some calculations have been done of the amount of increased tree planting that would be needed to compensate for the emissions from humans. Generally, the figures come out as follows (from Goreau 1992):
'A major part of global warming could be averted if the addition of CO2 to the atmosphere were accompanied by equal removal. Emitters could pay for planting, growing, and sustaining enough biomass and storage to remove excess carbon permanently. It would require trees that consume 10 tonnes of carbon per ha per year on 4 million km2 of land, to ensure removal of the current carbon increase. The area could be as low as 2 million km2 in the humid tropics, if reforestation stopped, or as high as 8 million km2 if areas with long dry seasons or colder temperatures were planted.'
(I haven't checked these numbers though).
Weather is a chaotic system, but as with many non-linear systems order emerges (that is climate). We are getting better and better at modelling this ordered behaviour from the non-linearity. Of course temperature fluctuations have occurred previously (and my very first post in this thread demonstrated that explicitly). The fact remains that, except during extinction events, the rapid changes in global temperature that we are currently measuring do not appear to occur in the geological record, and that our observations of increased atmospheric temperature are consistent with the results from Global Climate Models when increased CO2 levels are input. Add to that the clear linkage between palaeo levels of atmospheric CO2 and temperature (with the rider that cause and effect are hard to interpret as per bluskis post), and the argument becomes reasonably strong.
DrDave
Ecce Homo! Loquitur...
Dr Dave,
We seem to be at cross purposes.
The text you quote is not in the article posted at the beginning of this thread by Thread Bear. It may well be in the paper which you then posted. In which case I reiterate my point, someone (albeit perhaps the NS journalist) omitted the caveats and phrased the article to imply that long-haul flights are/were responsible.
We seem to be at cross purposes.
The text you quote is not in the article posted at the beginning of this thread by Thread Bear. It may well be in the paper which you then posted. In which case I reiterate my point, someone (albeit perhaps the NS journalist) omitted the caveats and phrased the article to imply that long-haul flights are/were responsible.
Thread Starter
Join Date: Jul 2003
Location: No Fixed Address
Posts: 30
Likes: 0
Received 0 Likes
on
0 Posts
Okay, at the end of every good study there must be some conclusions drawn and I have spent so much time reading about this subject over the last few days I am braindead.
Probably the best I can come up with thus far is that this subject is far more extensive than can be discussed in a 1000 word article in a magazine, accompanied by this picture that initially caught my attention.
One ounce of information has led me onto another and another and so on... it is literally neverending. The technical/scientific assessment and results of which must have inspired this article were derived from the studies of the IPCC.
This is by no means a simplified answer or conclusion to this thread...
http://www.grida.no/climate/ipcc/aviation/index.htm - Chapter 2.4 does offer "Conclusions and Overall Assessment of Present Aviation Impacts on Ozone".
Bottom line of what it says (or the top line actually!) is
It is a snippet from a LOT of information.
Probably the best I can come up with thus far is that this subject is far more extensive than can be discussed in a 1000 word article in a magazine, accompanied by this picture that initially caught my attention.
One ounce of information has led me onto another and another and so on... it is literally neverending. The technical/scientific assessment and results of which must have inspired this article were derived from the studies of the IPCC.
This is by no means a simplified answer or conclusion to this thread...
http://www.grida.no/climate/ipcc/aviation/index.htm - Chapter 2.4 does offer "Conclusions and Overall Assessment of Present Aviation Impacts on Ozone".
Bottom line of what it says (or the top line actually!) is
Currently, there is no experimental evidence for a large geographical effect of aircraft emissions on ozone anywhere in the troposphere.
Guest
Posts: n/a
Thread Bear
Good diagram. It is very scary when you start to dig to find just how much research is going into this field. Last weeks INQUA conference, looking just at climate change during the period 2.5 million - 11,000 years ago had over 1,100 scientists attend to present their research. This is only a small proportion (probably <10%) of the total number of climate and atmospheric scientists working on cliate change. Wading through the scientific output is a major challenge!
Unfortunately, the ozone conclusion that you highlight, although highly relevant, is not a conclusion about overall heating as ozone is just one of a range of greenhouse gases.
My feeling is that the key conclusion of the IPCC report in relation to aviation is this one:
http://www.grida.no/climate/ipcc/aviation/008.htm
The climate impacts of different anthropogenic emissions can be compared using the concept of radiative forcing. The best estimate of the radiative forcing in 1992 by aircraft is 0.05 Wm-2 or about 3.5% of the total radiative forcing by all anthropogenic activities. For the reference scenario (Fa1), the radiative forcing by aircraft in 2050 is 0.19 Wm-2 or 5% of the radiative forcing in the mid-range IS92a scenario (3.8 times the value in 1992)
In other words, the best estimate is that aircraft are responsible for 3.5% of the anthropognic greenhouse effect, rising to about 5% over the next 50 years or so.
ORAC - fair enough. In my view the ways in which journalists 'misinterpret' fact is scandalous.
DrDave
Good diagram. It is very scary when you start to dig to find just how much research is going into this field. Last weeks INQUA conference, looking just at climate change during the period 2.5 million - 11,000 years ago had over 1,100 scientists attend to present their research. This is only a small proportion (probably <10%) of the total number of climate and atmospheric scientists working on cliate change. Wading through the scientific output is a major challenge!
Unfortunately, the ozone conclusion that you highlight, although highly relevant, is not a conclusion about overall heating as ozone is just one of a range of greenhouse gases.
My feeling is that the key conclusion of the IPCC report in relation to aviation is this one:
http://www.grida.no/climate/ipcc/aviation/008.htm
The climate impacts of different anthropogenic emissions can be compared using the concept of radiative forcing. The best estimate of the radiative forcing in 1992 by aircraft is 0.05 Wm-2 or about 3.5% of the total radiative forcing by all anthropogenic activities. For the reference scenario (Fa1), the radiative forcing by aircraft in 2050 is 0.19 Wm-2 or 5% of the radiative forcing in the mid-range IS92a scenario (3.8 times the value in 1992)
In other words, the best estimate is that aircraft are responsible for 3.5% of the anthropognic greenhouse effect, rising to about 5% over the next 50 years or so.
ORAC - fair enough. In my view the ways in which journalists 'misinterpret' fact is scandalous.
DrDave
Join Date: Jan 2001
Location: Location, Location
Posts: 642
Likes: 0
Received 0 Likes
on
0 Posts
Comment from Philip Stott (retired prof of biogeography) in today's Times:
Claims about global warming are worse than hot air, they poison the atmosphere
Claims about global warming are worse than hot air, they poison the atmosphere
Join Date: Aug 2000
Location: UK
Posts: 1,914
Likes: 0
Received 0 Likes
on
0 Posts
DR. Dr!, as promised, having had an amenable Flight Planner for our flight on Thursday, he kindly ran through the Big Airways flight planning computer comparison figures for a New York flight limited to 24,000' as compared to the standard altitude requirement. This was for a B747-400 on 07 Aug 2003. The common figures are:
Zero Fuel Weight 220,000 kgs
Payload 31,700 kgs
Planned Fuel remaining at Destination 10,700 kgs
Standard
Step climbs at approximatel quarter points 34,000', 36,000' and 38,000'
Fuel required to destination 62,739 kgs and time 06.48
Altitude Restricted
Limited to 24,000'
Fuel required to destination 72,616(*) and time 06.44
(*) Note. The flight planner was unable to prevent the computer desperately wanting to climb once the Oceanic leg was completed. At 1.45 hrs from New York, the computer assumed a climb in the remaining time to 40,000' to try and save a bit of fuel, so the actual 'all the way figure at 24,000' would have been several hundred kgs higher.
Thus limiting cruise to 24,000' all the way would have consumed more than 10,000kgs extra fuel on top of the 62,739 actually used through a high level cruise. What surprised me was the time factor- actually slightly quicker at 24,000'. The burning question of the day, therefore, is:
"Is it better to reduce contrail pollution by burning an extra 16% (approx) fuel and producing that much extra exhaust pollution?"
Another relevant point- high altitude air is not floating around up there forever- like on surface meteorological charts, it moves horizontally. Over surface high pressure areas, the air subsides from high altitude (thus creating poor visibility hazy conditions that doesn't clear easily as particles are not removed from near the surface), over low pressure areas, air rises, clearing the atmosphere but producing cooling condensation into cloud. Therefore the minute amount of water injected into the atmosphere will eventually find its way back into the water cycle. I'm afraid this research team have been bending facts to make it fit their hypothesis!
Now Dr., about me back.............
Zero Fuel Weight 220,000 kgs
Payload 31,700 kgs
Planned Fuel remaining at Destination 10,700 kgs
Standard
Step climbs at approximatel quarter points 34,000', 36,000' and 38,000'
Fuel required to destination 62,739 kgs and time 06.48
Altitude Restricted
Limited to 24,000'
Fuel required to destination 72,616(*) and time 06.44
(*) Note. The flight planner was unable to prevent the computer desperately wanting to climb once the Oceanic leg was completed. At 1.45 hrs from New York, the computer assumed a climb in the remaining time to 40,000' to try and save a bit of fuel, so the actual 'all the way figure at 24,000' would have been several hundred kgs higher.
Thus limiting cruise to 24,000' all the way would have consumed more than 10,000kgs extra fuel on top of the 62,739 actually used through a high level cruise. What surprised me was the time factor- actually slightly quicker at 24,000'. The burning question of the day, therefore, is:
"Is it better to reduce contrail pollution by burning an extra 16% (approx) fuel and producing that much extra exhaust pollution?"
Another relevant point- high altitude air is not floating around up there forever- like on surface meteorological charts, it moves horizontally. Over surface high pressure areas, the air subsides from high altitude (thus creating poor visibility hazy conditions that doesn't clear easily as particles are not removed from near the surface), over low pressure areas, air rises, clearing the atmosphere but producing cooling condensation into cloud. Therefore the minute amount of water injected into the atmosphere will eventually find its way back into the water cycle. I'm afraid this research team have been bending facts to make it fit their hypothesis!
Now Dr., about me back.............
Guest
Posts: n/a
PaperTiger
I am sorry, but you, like many others, are drawing incorrect conclusions about this research because you have not read the actual source.
The authors of the paper (i.e. the scientists) DO NOT say that contrails do not form between 24,000 and 31,000 ft. Indeed, they say explicitly that they do. What they say is that the height of widescale contrail production varies hugely (and provide a mathematical function to describe this). As a result they are investigating the effects that would occur if cruising altitude were restricted when contrails can be formed at these altitudes.
In their calculations, the suggest the following:
June - September: altitudes up to 31,000 ft would be allowed, as contrail production at lower levels is limited (NOT zero though)
Nov-Jan: altitudes would be limited to 24,000 (or thereabout) as contrail production at higher levels is quite high
Other months: altitude varies between 24,000 and 31,000 ft
There is a graph in the paper to decsribe this
The 3.9% increase in CO2 production as a result of these altitude limitations seems to be quite in keeping with the very interesting figures provided by Notso Fantastic, given that this paper considers predominantly short-haul flights. Again I remind you that the authors explictly recognised that when long-haul flights were considered the figures would change:
'The results of this case study predict an annual fuel burn change only for the traffic mix and atmospheric conditions of the five states region in Europe. Other regions would be expected to
have a different seasonal cycle of maximum permitted cruise altitudes dependent on the local atmospheric conditions. The fraction of flights affected by those altitude restrictions would be
dependent on the nature of the traffic mix.'
Notso Fantastic, I can't work out what your comments about the hydrological cycle are meant to show. No-one is suggesting that once injected at high altitude the water stays there. Of course it is redistributed and rejoins the hydrological cycle. However, under current conditions the water is replaced by further air traffic, meaning that there is a nett long term impact.
This point was beautifully illustrated by the other research that we have been discussing, in which N. America became essentially contrail free during the short period of the Set 11th shutdown.
Oh, and by the way, I'm not that sort of Dr...but my wife is a physio if you need help for your back.
DrDave
I am sorry, but you, like many others, are drawing incorrect conclusions about this research because you have not read the actual source.
The authors of the paper (i.e. the scientists) DO NOT say that contrails do not form between 24,000 and 31,000 ft. Indeed, they say explicitly that they do. What they say is that the height of widescale contrail production varies hugely (and provide a mathematical function to describe this). As a result they are investigating the effects that would occur if cruising altitude were restricted when contrails can be formed at these altitudes.
In their calculations, the suggest the following:
June - September: altitudes up to 31,000 ft would be allowed, as contrail production at lower levels is limited (NOT zero though)
Nov-Jan: altitudes would be limited to 24,000 (or thereabout) as contrail production at higher levels is quite high
Other months: altitude varies between 24,000 and 31,000 ft
There is a graph in the paper to decsribe this
The 3.9% increase in CO2 production as a result of these altitude limitations seems to be quite in keeping with the very interesting figures provided by Notso Fantastic, given that this paper considers predominantly short-haul flights. Again I remind you that the authors explictly recognised that when long-haul flights were considered the figures would change:
'The results of this case study predict an annual fuel burn change only for the traffic mix and atmospheric conditions of the five states region in Europe. Other regions would be expected to
have a different seasonal cycle of maximum permitted cruise altitudes dependent on the local atmospheric conditions. The fraction of flights affected by those altitude restrictions would be
dependent on the nature of the traffic mix.'
Notso Fantastic, I can't work out what your comments about the hydrological cycle are meant to show. No-one is suggesting that once injected at high altitude the water stays there. Of course it is redistributed and rejoins the hydrological cycle. However, under current conditions the water is replaced by further air traffic, meaning that there is a nett long term impact.
This point was beautifully illustrated by the other research that we have been discussing, in which N. America became essentially contrail free during the short period of the Set 11th shutdown.
Oh, and by the way, I'm not that sort of Dr...but my wife is a physio if you need help for your back.
DrDave
Join Date: Jul 2001
Location: New Zealand
Posts: 254
Likes: 0
Received 0 Likes
on
0 Posts
A very recent letter on Climatology and disagreement with the Kyoto Protocol was sent to the Candadian House of Commons.
The link is Here
It provides a contray opinion to Dr Dave.
It merely serves to demonstrate that there is no absolute certainty in this topic, just as weather forecasting is sometimes described as:"Weather forecasts are horoscopes with numbers"
The link is Here
It provides a contray opinion to Dr Dave.
It merely serves to demonstrate that there is no absolute certainty in this topic, just as weather forecasting is sometimes described as:"Weather forecasts are horoscopes with numbers"
There seems to be a lot of 'interpreted statisitics' with reference to global warming. Scientists who seem to be frequently pushing their theory for career furtherment and fame, pick and chose the stats they need to prove or disprove. In the 1970s, some scientists were claiming to have proved with the data they had that there was incontavertable evidence that we were heading for another ice age. I wonder where they are now?
One statistic which we don't hear much about is that volcanic activity pushes out more CO2 into the atmosphere than all the man made activities put together. The fact that volcanic activity has been markedly on the rise since 1980 may have something to do with temp rises.
"Lies, damn lies and statistics". (Disreli).
One statistic which we don't hear much about is that volcanic activity pushes out more CO2 into the atmosphere than all the man made activities put together. The fact that volcanic activity has been markedly on the rise since 1980 may have something to do with temp rises.
"Lies, damn lies and statistics". (Disreli).
Guest
Posts: n/a
Dan Winterland
Lies, Damn Lies and Statistics indeed.
Data from Middleton (1998), amounts in millions of tonnes of carbon per annum
Combustion of fossil fuel: 6000
Land use change (deforestation and biomass burning): 1600
Metamorphism and volcanism 120
Weathering: 220
Probably serves to show how much misinformation there is out there.
DrDave
Lies, Damn Lies and Statistics indeed.
Data from Middleton (1998), amounts in millions of tonnes of carbon per annum
Combustion of fossil fuel: 6000
Land use change (deforestation and biomass burning): 1600
Metamorphism and volcanism 120
Weathering: 220
Probably serves to show how much misinformation there is out there.
DrDave
I suspect a lot of people who describe themselves as so-called "contrarians" on this issue are influenced by the fact that all their arguments tend towards not having to do or spend anything themselves. It's generally a sign of bad thinking when - completely by coincidence, obviously - all your arguments favour your own interests!
PS, Dr. Dave - interesting stuff...
PS, Dr. Dave - interesting stuff...
Join Date: Aug 2000
Location: UK
Posts: 1,914
Likes: 0
Received 0 Likes
on
0 Posts
It's nothing to do with ones own interests, it's to do with believing insufficient or faulty research. Back in the 70s, we were continually being told that the next Ice Age was just around the corner. Now it seems to have disappeared into 'Global Warming' will get us all. Periodically we get things like coffee consumed with bacon creates carcinogens, next coffee is actually good for you. Salt is currently out of favour- what's the betting within a few years salt will be regarded as good again? But when you are presented with scientific 'facts' that present a case, and you see that there are errors in assumptions leading up to those conclusions, then there is a good case to disregard faulty and insufficient research. When Biogenetic companies fund 'independent' research that proves that biogenetic products are harmless, should we necessarily believe them? Without knowing exactly where this theory about contrails comes from, and who funded it, or is it a personal opinion coming from a rabid 'green', then the results are to be treated with great suspicion, especially as this one seems to have made some broad assumptions that are erroneous. It was mentioned back at the beginning it was an old news item?
Guest
Posts: n/a
Notso Fantastic
Fair comments, but surely part of the problem is that people are willing to pass comment based on inaccurate information (look through the thread for a number of examples). This muddies the water to a very high degree. At the end of the day, as a research scientist myself, I continually come back to the feeling that good science is undone by poor (often very poor) reporting by journalists. This seems to be a problem we share with the aviation community.
For information, the original paper openly details the source of the funding:
'This work was supported by the Engineering and Physical Sciences Research Council as part of a feasibility study in the Future Integrated Transport Programme.'
EPSRC is the UK government research funding body for engineering: www.epsrc.ac.uk
DrDave
Fair comments, but surely part of the problem is that people are willing to pass comment based on inaccurate information (look through the thread for a number of examples). This muddies the water to a very high degree. At the end of the day, as a research scientist myself, I continually come back to the feeling that good science is undone by poor (often very poor) reporting by journalists. This seems to be a problem we share with the aviation community.
For information, the original paper openly details the source of the funding:
'This work was supported by the Engineering and Physical Sciences Research Council as part of a feasibility study in the Future Integrated Transport Programme.'
EPSRC is the UK government research funding body for engineering: www.epsrc.ac.uk
DrDave
Last edited by Dr Dave; 12th Aug 2003 at 00:00.
Join Date: Aug 2000
Location: UK
Posts: 1,914
Likes: 0
Received 0 Likes
on
0 Posts
And now they've just found a new oil field near Winchester. They really are finding the stuff as rapidly as it is being used. If ever it starts running short, we haven't even scratched the surface of biological fuels yet.........