The question is for the industry what will replace hydrocarbon fuel?

Whilst the present emissions are only 3% by mid century, aviation will account for approximately 30%.
With forecast growth in ASK at 5% per annum the CO2 net emission cap is loaded with assumptions of questionable robustness. For aviation to be carbon neutral from 2020, efficiency gains will need to be found every year at rates that largely map the improvements in jet engine technology since the 1960's. Further, embedded in the assumptions are gains best described as "Rumsfeldian", unknown-unknowns: As yet undetermined efficiency gains will continue to be invented. Whilst substitute fuel sources are big on media and technically feasible, they are not commercially viable,
By way of an example, Bio Fuel technically works, the problem remains the scale of agricultural land needed to support 1/3 of the requirements in a country like the USA, would result in reduced food production of major cereal crops..

By way of contrast, the maritime industry already taxes sulfur levels, is transitioning away from fossil fuels and will by 2075, be completely free of hydrocarbon based fuel. The aviation industry has no such viable alternative.
It is possible that the industry becomes a much larger emitter both in gross terms and in percentage derived from aviation, than even the optimistic forecasts suggest.

IFF the world decides that 'CO2 emitters are a problem', then the airline's industry as a collective may face a public relations problem, which could arguably mutate into something more concerning: a reduction in available air transport options.


This is neither in defence of, nor rebuttal of climate change.

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

The long answer is all those IPCC (Intergovernmental Panel on Climate Change https://www.ipcc.ch/ ) 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.

Technically feasible yes.A long way to commercially viable. Unfortunately, that is a press release, noting a 'study'.

To produce sufficient bio-fuel for 10% of US airline ASK would require an area the size of Florida.

I'm sorry everyone, but I find the extent of climate change deniers and minimizers on this forum to beyond belief. Human caused global warming due in part to CO2 emissions is science fact. The more CO2 the more the warming. period - accept it!

HOWEVER - there are many many questions also:
- How much warming for how much CO2 (we have models, but models have uncertainty)
- What will be the exact effect of how much warming on different parts of the earth
- What is the true cost of that warming (both monetary - for example building coastal defenses - and non-monetary - for example how much is a forest worth?)
- To what extent do contrails reduce warming?

I believe the environmental movement has done a disservice to society by fear mongering and doomsday scenarios.To me their hard line is part of the reason for the push-back against needed changes. Pushing an environmental agenda others with a big stick is wrong. Maybe many here have a hard time accepting climate change due to legitimate career fears?

There are changes aviation can make. Bio-fuels from algae ponds in the Sahara is one interesting option among many. If people were to work together there would be no threat to aviation from the need to reduce CO2 emissions. To me it is hard to work together when many in the environmental movement are so hard line and unwilling to understand the social costs of their demands. People need good stable jobs and many in the environmental movement project a position that they care more for a single tree or owl than the children of those who earn a living in CO2 producing industries.

The real problem is not the science of climate change or the ability for tech to find solutions, the real problem is people can not compromise to a solution that works for everyone.

TME

Yes, which politicians pay lip service to but rarely understand. The "Back of a post card" version is: the rate at which CO2 is generated is believed to be (or is shown to be) higher than the rate at which CO2 can be absorbed and/or used by various plants.
The aggregate amount is an annual gain, which over time (see boiling a frog) begins to change the entire blanket of mixed gases that is our atmosphere.

Why rate (or mass flow rate) is important: did you ever try to drink from a fire hose rather than sipping from a glass?

NIPCC - backed by the Heartland Institute - a far Right wing think tank. Their original campaign was to try and discredit the health effects of secondhand cigarette smoke. Can they be relied upon to give an unbiassed opinion? errr....No.

Why is it that issues such as climate change along with human rights always seem to always attack countries that are doing something about it or don't really have much of a problem, yet countries that actually have a real problem get off scott free?

I can't believe that people are seriously suggesting that world aviation has some sort of a pollution problem but are too weak to do anything about China. Either Global Warming is real and you do something about China or it isn't and you keep quiet. It's that simple. It is the height of stupidity to suggest that the Western Countries have this massive pollution problem, and should inflict harm on their economies and way of life, whilst China charges on like it's 1875.

If there is really global warming then you need to go after the real issues, not just try and attempt to destroy democratic free societies.

I honestly believe that we are at a tipping point and that within the next decade we will see significant behavioural changes. Two examples:

- the car-maker, Tesla, is now building more electric cars than all other manufacturers combined: it's expected to make 500,000 vehicles this year. People are prepared to pay a premium to "go green" (in the UK, the entry model Tesla costs almost $50,000)
- Simultaneously, there is a growing movement to veganism: for example, the number of vegans in the UK has grown sevenfold in the last three years.

Severe weather is becoming more severe and more frequent. At present there is a lot of power production we cannot do without: wind and solar are unreliable and we still need electrical power, say, in the evenings when Mr Sun has gone to bed.

However, much air travel is unnecessary. It may lead to enjoyable holidays, for example, but those hardly figure in Maslow's Hierarchy of Needs. Actually, I'd suggest that much business travel is not needed, either. In almost 40 years in business, I'd guess that a good half of the intercontinental business trips in my industry weren't vital. I'd guess that there's an even chance that by the time Heathrow's third runway is built, it will be surplus to needs.

Now, you might well say that it's China [or insert the country you like least here] that is the big polluter. Well, just as today reputable companies make sure your shoes aren't made by eight year olds working 12 hour days, it's going to be more common that products will include a charge related to the carbon (or water) footprint, which will encourage cleaner power.

This may all seem apocolyptic and you may well ask who the hell am I to judge? I spent almost 40 years as SLF and I love a good steak. I have just returned to the UK from a family holiday in Africa. But I see things changing, especially as regards climate, and the younger generation are in the forefront.

I'm just surprised that no company is working on a safe method to use hydrogen as a fuel source for jet engines. Nothing but water as emissions.

With only water vapor as emissions, it will also be easier to mix in the chemtrails. Fewer harmful emissions and better population control. Win-win!

Energy density per kg and per litre are important in aviation.

Liquid hydrogen has major storage and handling problems, namely the weight of any container vessel and the low, low temperatures encountered.

A good subject for discussion, a big hand to MACH1 for kicking the ball into play.
The challenge faced by aviation is just another part of the biggest challenge facing the human specie. That is Nature v Humans. We have since the year dot, tried to conquer the forces of nature. There have been many occasions where Nature has shown its strength in defeating us. Will we manage to destroy the planet. No I don`t think so. It will destroy us. Before it does so, it will first impoverish us, then humiliate us. How will it begin. It will begin by us starting scrapping over the ever diminishing resources, over arable and habitable land. Over energy and its sources.
Our concerns over the loss of the comforts of aviation is of little consequence. Whatever we do requires a process of conversion in order to produce energy. Our own bodily survival requires it. The whole equation reduces to one of how much we need to take from Nature to sustain ourselves whilst maintaining a balance between the two. That means no waste. So difficult to achieve, almost impossible I`d say. Forget the aeroplane and the motor car, just for a moment, just think of that noisy little lawn mower that will soon be out every weekend beltching out smoke. What is it for, just to cut the grass on our perfect lawns and make them the envy of our friends and neighbours and appease her indoors. For those who might say go electric, I`d say how did that electricity got to my socket. If the answer to that was, solar/wind/tide/nuclear, I`d say how were all those machines and all the parahanelia that goes with them got there and ended up squirting that juice of energy at my socket. I don`t know how many sockets there are in my house, I`ve never counted them, but at any given time there are so many things plugged into them. Kettles, phones, washing machines, driers, dish washers, fridges, freezers, clocks, TV`s, computers, vac cleaners, battery chargers, printers, tooth brushes, light bulbs, radios, hifi`s, drills, saws, oh yes, my swizz espersso coffee maker. At the push of a button the whole world is right there at my finger tips and I don`t have to move a muscle, only those little ones for the tips of two fingers at worse. That is not so much different these days when one is sitting in the pilot`s seat of a modern jet liner, don`t you agree. Except perhaps I have more buttons to play with at home.

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I don't see why so many people have such a problem accepting and understanding that as a species we're simply not capable of sufficient intelligence/ self-control to live in harmony with our environment.

I must draw on AI to make my point - far more succinctly than I am able to do;

"I'd like to share a revelation that I've had during my time here. It came to me when I tried to classify your species and I realized that you're not actually mammals. Every mammal on this planet instinctively develops a natural equilibrium with the surrounding environment but you humans do not. You move to an area and you multiply and multiply until every natural resource is consumed and the only way you can survive is to spread to another area. There is another organism on this planet that follows the same pattern. Do you know what it is? A virus. Like the dinosaur, you've had your time here, now it's our time, our World."
Agent Smith, The Matrix.

https://cimg5.ibsrv.net/gimg/pprune....53f13249f7.png

Bring it on - says I - can't do any worse and will probably do significantly better. (As long as Arnie doesn't show up)

Joking aside I highly recommend Max Tegmark's excellent book "Life 3.0 - Being Human In The Age Of Artificial Intelligence"; an insightful and highly intelligent thesis as to how we go about developing the next inheritors of the husbandry of the planet Earth. (And he's no crank; NASA, MIT, Oxford, best mates with Stephen Hawking, etc)