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Originally Posted by jantar99
(Post 10477324)
Energy density per kg and per litre are important in aviation.
Storage and safety are legitimate concerns, which is why I mentioned "working on a safe way" :) The effect of water emissions at high altitude are not so great in terms of contrails, that is indeed what some studies have suggested. However, the water formed by hydrogen combustion might just freeze and fall to the ground. I'm not saying that this is happening, I'm saying that it would be worth studying. |
Originally Posted by .Scott
(Post 10477107)
The long answer is all those IPCC (Intergovernmental Panel on Climate Change studies that examine climate change and its causes very, very extensively.
I certainly haven't read all of those studies and reports. But I have read enough to get a good picture. 1) Global warming is a fact. In Physics, something is considered "discovered" if without it, the likelihood of the experimental results it at least 5 standard deviations away from normal. The evidence for global warming goes way beyond that criteria. 2) To go much further, we need a climate model. And we have many of these - none are fully convincing. But there is one sure thing that can be said: CO2 is a major factor. You can create models that include changes in water content, solar effects, contrails, etc - but if you don't include CO2 in your model, your model will not work. 3) You will often hear statements such as: "If we don't keep CO2 levels down, we will loose 1 million species over the next century." In most cases, they are based on good arguments and are good likelihoods. But there are a few problems with these statements. They suggest that if we do control CO2 the bad result will not happen - in most cases, that's just false. In other cases, it is pushing the models well beyond their predictive powers. For example, even if we miraculously brought CO2 level back to what they were in 1900, that might not be enough to end climate change. Agriculture pumps huge amounts of water into the air and water is a far more potent green house gas - though one that is not persistent. They also suggest that what we would need to do to avoid or reduce the consequence would be worth it. In the extinction example, they don't mention that that would leave 2.5 million species. I think most people would be happy with 2.5 million species in exchange for job security. in my lifetime, to date, the human species has doubled. Btw I have no progeny. |
Originally Posted by bzh
(Post 10477096)
Bio fuel will take over as cost is lowered and black oil cost increased, the Arizona desert will be covered by Algae farms, Pacific salt water pumped on way and biofuel the other...
https://www.flysfo.com/media/press-r...aviation-fuels |
Originally Posted by AAKEE
(Post 10477373)
I looked at the OP only two posts... |
Originally Posted by cappt
(Post 10477443)
Some lazy journo doing their "research".
"From small acorns are mighty oaks grown" and all that... |
Originally Posted by cappt
(Post 10477443)
Some lazy journo doing their "research".
I dont post often. But have not seen any professional discussion about this - so here is my 2nd post. But its not about me |
Originally Posted by CargoOne
(Post 10477143)
bio fuel doesnt come for free. It takes large territories to grow thus reducing space available for the food-related agriculture and as far as I remember the process is producing co2 too... it is like Tesla - it doesnt make the world greener it is rather shifting pollutions to a different territories. Out of sight, out of mind. Tesla has tapped in to that part of the human psyche that comforts people thinking they aren't part of the problem. Until base load electricity is generated from renewable energy sources, then plugging a 'green car' into the electric grid is just shifting the pollution to somewhere else. That somewhere else is often a power plant using fossil fuel. Bio-fuel does exactly the same thing for the aviation industry. It provides comfort. The marketing PR release say Airline X bought 30,000,000 gallons of Bio-fuel. Sounds impressive, yet in a few weeks that huge amount of fuel is gone. For the remainder of the year billions more gallons of jet fuel are fueling the aircraft. The industry does not have a viable alternative. Assuming continued efficiency advances into perpetuity is fanciful. Other purported 'alternatives' come at huge opportunity cost and that is ignored in favour of the 'technology will fix it' IFF, the world focuses more attention of big emitters, then the airline industry may face a problem that PR won't fix; declining demand and additional cost pressure. As Emma Thompson found out recently, saying one thing but doing another does get noticed. https://www.dailymail.co.uk/news/art...-New-York.html |
I think it is hilarious that very basic and well understood physics, like the scattering of electromagnetic radiation by gas molecules, can be dismissed as wrong by people whose life depends daily on far more complicated physics, like the interaction of gas molecules at high densities and velocities.
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But this isn’t a very basic and well understood issue we are discussing. There is consensus, and it would be an interesting personality type to happily swim against the tide of scientific opinion at this stage, but climate change is not at all basic and not at all well understood. Why? Because we can’t go into a Lab and reproduce experiments ( too many variables) and instead have to rely on models that in a decade will no doubt be considered crude. The wiggle room for conjecture and argument is what makes this something we debate. If it was straight forward science ( like scattering of electromagnetic radiation by gas molecules) there would be no debate in mainstream society. |
Originally Posted by 73qanda
(Post 10477653)
But this isn’t a very basic and well understood issue we are discussing. There is consensus, and it would be an interesting personality type to happily swim against the tide of scientific opinion at this stage, but climate change is not at all basic and not at all well understood. List of Worldwide Scientific Organizations When I looked at lists of scientists who deny human caused climate change I found no serious bodies prepared to deny it, scientists in other fields apart from climate science, a lot linked to the mining and oil industries and a lot connected to far right politics. And very few overall at that. 97% of scientific papers published recently find human caused climate change to be real. For the remaining 3% they were excluded because, like any good piece of science, their conclusions and methods were found, on peer review, to be flawed or contain significant errors. There’s no debate amongst the credible scientific community, only amongst special interests with agendas: Those 3% of scientific papers that deny climate change? A review found them all flawed |
Originally Posted by 73qanda
(Post 10477653)
If it was straight forward science ( like scattering of electromagnetic radiation by gas molecules) there would be no debate in mainstream society.
2. What is difficult to model is precisely where what will happen as a result, but the thermodynamics are unforgiving in that somewhere something must happen to accommodate the excess energy. |
Dr Dre, I don’t think you understood the intent of my post ( maybe my fault). I’ll try again when I get to the hotel but I wasn’t saying that there isn’t consensus, I was saying it isn’t basic, and it isn’t well understood. It is in fact incredibly complex with many many variables each having an effect on each other. ( as I’m sure you’re aware). If someone agrees that there is man made climate change it doesn’t mean they understand man made climate change, or that it is basic. I was trying to make the point that because you can’t repeat an experiment in a Lab 500 times and say “ see.....global temperatures are going to rise by 2.3 degrees in the next 50 years” , we have a debate in society about whether or not climate change is as big a problem as most are saying it is. The only reason we can’t predict the future climate with certainty is because of the incredible complexity of the interactions that go to make it up. It isn’t basic and it isn’t well understood. TehDehZeh 1. The mechanism behind green house gases literally is exactly that, and it is straight forward to show it experimentally. |
I would say that, to the contrary, precisely because it is very hard to forecast just how nature will dump the excess energy on us, it is vital to keep the amount of excess energy low.
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Originally Posted by 73qanda
(Post 10477715)
we have a debate in society about whether or not climate change is as big a problem as most are saying it is. The only reason we can’t predict the future climate with certainty is because of the incredible complexity of the interactions that go to make it up. It isn’t basic and it isn’t well understood. I don’t know whether Aviation has a big part to play (although new technologies with electric propulsion and fuel reduction are interesting) and I certainly don’t know what the exact solutions to the problems are but it’s now increasingly clear something must be done. |
If the IPCC is correct then the consequences of inaction are horrendous, potentially catastrophic and fatal for our species. If the IPCC is wrong, but we still take their recommendations the consequences are survivable, but society will change.
Are you a gambling man? (rhetorical) |
Originally Posted by cappt
(Post 10477442)
What right do we have to cover the Arizona desert with algae farms? Must every piece of dirt be developed? I suggest covering the LA basin with algae farms if that's where you want bio fuel.
Nuclear - dangerous and “no waste in my back yard” Wind - looks bad and kills birds Sun- looks bad and diverts sun’s warmth from nature Hydro - takes natural land and habitat and causes stress to rock structures Plant solutions - not here etc. Often these are the same environmentalists who object to traditional fuels and methods. Only solution is to give up the rat race and go bush... |
What these tree huggers, and those that naively want is to return to the era of the horse and cart, seem to forget is there are many very poor countries whose only source of income is tourism. By drastically reducing air travel, you cut these people off at the knees and create another crisis. Without travellers dollars, many nations with poor economies will inevitably resort to more nefarious or polluting means to raise income. |
Originally Posted by beardy
(Post 10477760)
If the IPCC is correct then the consequences of inaction are horrendous, potentially catastrophic and fatal for our species. If the IPCC is wrong, but we still take their recommendations the consequences are survivable, but society will change.
https://cimg3.ibsrv.net/gimg/pprune....866be58ef.jpeg |
Without travellers dollars, many nations with poor economies will inevitably resort to more nefarious or polluting means to raise income. |
Originally Posted by BehindBlueEyes
(Post 10477769)
What these tree huggers, and those that naively want is to return to the era of the horse and cart, seem to forget is there are many very poor countries whose only source of income is tourism. By drastically reducing air travel, you cut these people off at the knees and create another crisis. Without travellers dollars, many nations with poor economies will inevitably resort to more nefarious or polluting means to raise income. What can be done is for more research and development in electric propulsion, alternative fuels, more aerodynamic airframes, fuel reduction methods, more efficient flight paths, less holding, etc. Isn’t that something to aim for? |
Originally Posted by dr dre
(Post 10477775)
That’s quite a strawman. No one except extremists are calling for a ban on air travel. What can be done is for more research and development in electric propulsion, alternative fuels, more aerodynamic airframes, fuel reduction methods, more efficient flight paths, less holding, etc. Isn’t that something to aim for? |
When the CFC crisis was recognised and the damage to the ozone layer realised, CFCs were banned and alternatives found. As a result, the ozone layer is slowly recovering. So why not ban CO2 production? Well, obviously because we are currently too dependant on fossil fuels. But are ‘we’ being pro-active enough about alternate forms of energy? We could have had wind farms in the 1960’s - there is nothing particularly technological about a wind turbine driving an electrical generator, and think of all the coal that could have been saved. Is enough being done in nuclear fusion research? Hydrogen production and distribution? Solar cell research - efficiencies are very poor at the moment. Tidal stream generation? Housing insulation and energy efficiency. It is possible to build extremely energy efficient housing, and modern regulations are addressing this, but more could be done. Heat pumps instead of gas/oil powered heating systems. We could ban fossil fuel home heating for all new builds. People need to have realistic alternatives before they can change their behaviour. Why are electric cars so expensive? They have no clutch, no gearbox, no exhaust system, no catalytic convertors, no exhaust filters, no engine cooling system, no oil system - they just have a battery and a motor. They should be way cheaper than the fossil fuel equivalent. . Why are modern cars having more and more energy using, heavy electric motors fitted to open and close doors and windows? The driver’s window does not need to be electric. Doors do not need to be electrically operated. Why are most buses still Diesel powered? Most could be electric, with a brief top-up charge at each stop to keep them going around their route |
Electric cars now. Electric aircraft to come? What on earth are we going to do with all those toxic batteries when the current ‘green’ cars reach the end of their serviceable life ? Just curious Be lucky David |
Hydrogen fuelled aircraft are probably more likely. Batteries will get properly recycled. |
Originally Posted by The AvgasDinosaur
(Post 10477846)
Electric cars now. Electric aircraft to come? What on earth are we going to do with all those toxic batteries when the current ‘green’ cars reach the end of their serviceable life ? Just curious Be lucky David |
There is just too many of us. I find it interesting that the state of the human population and the demands it puts on our one and only home is very rarely discussed. No one wants to touch the subject. As whether climate change is man made or not is a mute point. It will always change, the rate and degree will also vary. In the past, our ancestors had the opportunity to migrate. Why? It was because the population was minimal and the space and resources were available. |
Originally Posted by Uplinker
(Post 10477841)
When the CFC crisis was recognised and the damage to the ozone layer realised, CFCs were banned and alternatives found. As a result, the ozone layer is slowly recovering.
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Tesla’s share price may be an indication that the electric cars time has not quite arrived. Maybe another twenty years or so .. also statements like veganism has increased seven fold, whilst possibly true are , a tad misleading, if the number has gone from say 100k to 700k. It’s an irrelevant amount of people. Tho the direction of travel is of course valid. Don’t forget to factor in the people who say they are vegan but enjoy a burger on the quiet, so knock 50% off the total .. A bit like people who say they will vote Lib Dem or green then tick the brexit party box in the privacy of the booth .. ‘’Nuclear is the only real option if you want to produce a huge constant baseload of co2 friendly Leccy. Maybe dam up the Bristol Channel if you can get over the wildlife changes that will happen .. I think that pollution, litter and destruction of natural environments are bigger problems than co2 at the moment. Nuclear solves a lot of these. By condensing the pollution from power generation into much smaller amounts of highly toxic crap. There is no escaping it.. making the leccy required for the next century will involved making a crap by product. You can either spread it out over the whole planet or bury it somewhere handy. Like er. Scotland �� |
Originally Posted by clark y
(Post 10477863)
As whether climate change is man made or not is a mute point. It will always change, the rate and degree will also vary. The point that every scientific body on earth is making is that it’s that the current rate of change is concerning and critical. Best way to see it is this very long timeline chart explaining the rate of change of temperatures over 20’000 years. Scroll all the way to the bottom and you’ll see why scientists are alarmed: If This Timeline Doesn't Convince You Climate Change Is Real, Nothing Will In the past, our ancestors had the opportunity to migrate. Why? It was because the population was minimal and the space and resources were available. |
Originally Posted by SARF
(Post 10477875)
Tesla’s share price may be an indication that the electric cars time has not quite arrived. Maybe another twenty years or so .. 20 years??? The technology (and the vehicles) exist today. It/they simply need to be made more avaialble ‘’Nuclear is the only real option if you want to produce a huge constant baseload of co2 friendly Leccy. Maybe dam up the Bristol Channel if you can get over the wildlife changes that will happen .. I think that pollution, litter and destruction of natural environments are bigger problems than co2 at the moment. Nuclear solves a lot of these. By condensing the pollution from power generation into much smaller amounts of highly toxic crap. There is no escaping it.. making the leccy required for the next century will involved making a crap by product...........�� I agree that pollution and habitat destruction need to be addressed. Habitat destruction might be contributing to climate change, by removing massive CO2 sinks in the form of forests and jungles. Have a look at nuclear fusion: https://en.wikipedia.org/wiki/Fusion_power |
Originally Posted by John Boeman
(Post 10477173)
May I suggest that as well as studying the writings of the IPCC you take a look over what the NIPCC produces.... Climate Change Reconsidered ? Climate Change Reconsidered I have just read through some of that material. As I said in my previous post, none of the current climate models are fully convincing. This was true in 2011 when the NIPCC did their last overall climate assessment and it remains true to this date. But the NIPCC is using this to toss out all climate models and any revelations that can be gleaned from the attempts to model the climate. The key revelation, as I said before, is that you cannot make a climate model that works without including human-generated (anthropogenic) CO2 as part of your model. None of the other factors have enough influence - and many of those other factors are pulling in the wrong direction (cooling rather than a net warming). On the other hand, the NIPCC is very strong on a couple of the other points I made - that it may not be worth the economic expense to avoid some of the consequences - and that none of the measures proposed to "fix" climate change will reliably (or in many cases "likely") do that. |
it may not be worth the economic expense to avoid some of the consequences |
Originally Posted by bill fly
(Post 10477367)
No it’s not but there are an awful lot of single occupant cars in the roads - realistically... Some aviation is necessary but I'd say most of the trips I've taken, long and short haul, have been luxuries. It wouldn't have killed me to miss that wedding in Boston or that party in KL. So it's not a case of car vs plane CO2. In a lot of cases, we just don't need to go at all. Sure that's a bit less exciting but I'd like to keep this planet habitable if poss. Don't fancy Musk's option of moving to Mars thanks. |
As Woody Allen put it in his 1979 'Speech to the Graduates':
More than any other time in history, mankind faces a crossroads. One path leads to despair and utter hopelessness. The other, to total extinction. Let us pray we have the wisdom to choose correctly. https://www.nytimes.com/1979/08/10/archives/my-speech-to-the-graduates.html |
Nietzsche was under the impression that only by facing and embracing despair and hopelessness could man find a way to overcome. Choosing comfort avoided facing problems and finding answers. He abhorred Nihilism.
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[QUOTE=PerPurumTonantes;10477979 Some aviation is necessary but I'd say most of the trips I've taken, long and short haul, have been luxuries. It wouldn't have killed me to miss that wedding in Boston or that party in KL. So it's not a case of car vs plane CO2. In a lot of cases, we just don't need to go at all. [/QUOTE] Me thinks that saving the world at the cost of non-essential travel ban probably not worth it - let’s keep it as is and we will see. I will start to believe all those climate models the day when a weather forecast for 14 days will become reliable (=never?) |
Originally Posted by SARF
(Post 10477875)
Tesla’s share price may be an indication that the electric cars time has not quite arrived. Maybe another twenty years or so .. also statements like veganism has increased seven fold, whilst possibly true are , a tad misleading, if the number has gone from say 100k to 700k. It’s an irrelevant amount of people. Tho the direction of travel is of course valid. Don’t forget to factor in the people who say they are vegan but enjoy a burger on the quiet, so knock 50% off the total .. A bit like people who say they will vote Lib Dem or green then tick the brexit party box in the privacy of the booth .. ‘’Nuclear is the only real option if you want to produce a huge constant baseload of co2 friendly Leccy. Maybe dam up the Bristol Channel if you can get over the wildlife changes that will happen .. I think that pollution, litter and destruction of natural environments are bigger problems than co2 at the moment. Nuclear solves a lot of these. By condensing the pollution from power generation into much smaller amounts of highly toxic crap. There is no escaping it.. making the leccy required for the next century will involved making a crap by product. You can either spread it out over the whole planet or bury it somewhere handy. Like er. Scotland �� |
Originally Posted by bill fly
(Post 10476871)
Realistically a full aircraft presently uses less fuel than would be used if each passenger drove his car the same distance solo. Realistically, an utterly fatuous statistic, if that's what it is. Each passenger is only travelling by air because the aircraft is available to the desired destination (possibly desired only because it's available). On long-haul there is no realistic alternative so he or she would stay at home if air transport is not possible. On short haul, he or she would probably find a better public transport alternative than the car if the journey were really necessary, or otherwise stay at home. Even if every passenger elected to use a car instead of going by air, the number of cars used is unlikely to be the same as the number of passengers, so the arithmetic is fatally flawed in any event. I'm all for making a case for air transport vs other forms of transport, but nonsensical claims don't help. |
I wonder if there are old timers left who follow this forum. By old timers I mean those who plied their trade high up above the Northern Arctic routes. What would they now see below them, would there not be a remarkable change in the scenery below for them to gaze in sorrowful contemplation. That is of course clouds permitting. More and more of which seem to be rising in our skies with every season, inexorably merging into one, of floods and tempests.
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Originally Posted by .Scott
(Post 10477935)
On the other hand, the NIPCC is very strong on a couple of the other points I made - that it may not be worth the economic expense to avoid some of the consequences -
When you think of farmers with failing crops, coastal cities subject to flooding, mass migrant caused by swamping if low lying areas etc transferring to renewable energy sources now is much cheaper |
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