Could Aviation be part of the climate change solution?

[StraightLevel]

Hi Folks,

i cant help wonder if Aviation could be part of the climate change solution as opposed to the perceived problem.

Would it be practically possible fo fuel jet engines on aircraft with hydrogen so that the water exhaust actually formed high level clouds which in turn would possibly provide an element of shade to the earth below and maybe slow down global warming?

I appreciate that there are a lot of gaps in the thought process there but still can’t help but think that this could definitely maybe possibly be a better Aviation emissions solution than electric aircraft.

Yours hopefully,

StraighrLevel

[Meester proach]

Dunno,
I’m too busy making sure the chemtrails are deploying properly

[nonsense]

No.
Water vapour is itself a potent greenhouse gas.

https://www.ncdc.noaa.gov/monitoring-references/faq/greenhouse-gases.php#h2o

[ldo]

To amplify from (google "increasing cloud cover in upper athmosphere effect on global warming" and look for the "Clouds and Global Warming - NASA Earth Observatory" entry, sorry cannot post links).

If more high clouds were to form, more heat energy radiating from the surface and lower atmosphere toward space would be trapped in the atmosphere, and Earth’s average surface temperature would climb.

[Capt Scribble]

As the climate has changed radically over the millennia, has aviation ever been a factor.

[Busbuoy]

Using hydrogen instead of hydrocarbons would certainly eliminate the CO2 production but burning the fuel mostly used today, JET A-1, already produces about 1.4 tonnes of water vapour per tonne of fuel burned. Atmospheric O2 contributes the additional mass. The process also creates over 3 tonnes of CO2. Variations in existing atmospheric water vapour content determine whether contrails form and indeed whether they persist. Interestingly if the right conditions exist for contrails to persist, vast amounts of additional atmospheric water vapour will condense and freeze on the ice crystals that make up contrails. Some measurements have determined that 1 tonne of burnt jet fuel can lead to 200 tonnes of contrail forming.
I'm still researching this next statement but...my understanding of contrail formation is that the formation process is dependent on the presence of particles of soot in the exhaust plume that act as condensation nuclei. No hydrocarbons, no soot, no contrail.

[OMAAbound]

Dunno,
I’m too busy making sure the chemtrails are deploying properly

Braco Sir, Bravo!!

[Grebe]

Using hydrogen instead of hydrocarbons would certainly eliminate the CO2 production but burning the fuel mostly used today, JET A-1, already produces about 1.4 tonnes of water vapour per tonne of fuel burned. Atmospheric O2 contributes the additional mass. The process also creates over 3 tonnes of CO2. Variations in existing atmospheric water vapour content determine whether contrails form and indeed whether they persist. Interestingly if the right conditions exist for contrails to persist, vast amounts of additional atmospheric water vapour will condense and freeze on the ice crystals that make up contrails. Some measurements have determined that 1 tonne of burnt jet fuel can lead to 200 tonnes of contrail forming.
I'm still researching this next statement but...my understanding of contrail formation is that the formation process is dependent on the presence of particles of soot in the exhaust plume that act as condensation nuclei. No hydrocarbons, no soot, no contrail.
my understanding of contrail formation is that the formation process is dependent on the presence of particles of soot in the exhaust plume that act as condensation nuclei. No hydrocarbons, no soot, no contrail.

Nope - they ( engines ) may help or hinder certain contrails , but contrails form from other areas of the airplane- dependent on local conditions. Wingtips re a prime area along with some protrubances which change ' local ' air pressure ( slipstream) . They can be ' stopped' by certain chemicals introduced in the slipstream or also by changing altitude and speed.

[tdracer]

The data is very limited and largely circumstantial, however there is some evidence that - in the immediate aftermath of 9/11 - the grounding of virtually all commercial air traffic over the continental US resulted in slightly lower temperatures. Some researchers suspect the reduction in water vapor being injected into the upper atmosphere by all those grounded aircraft was responsible.
That the average ground temperatures dropped slightly is pretty much certain, cause and effect is rather more questionable (particularly with a single data point).

Besides, "practical" and H2 powered aircraft don't belong in the same sentence given current technology. There is simply no practical way to contain the volume of hydrogen necessary for long range flight - the density of even liquid H2 is far less than Jet A - and keeping a large volume of cryogenic fuel on a commercial aircraft wouldn't leave much room for passengers and cargo (you're not going to be putting it in the wing).

[boisbrule]

Some decades ago I read an article that seemed technically respectable (can't remember where, possibly Scientific American) which said that liquid hydrogen fueled aircraft would start to become economical around 1.4 million pounds. There was a tradeoff between fuel weight savings and fuel tank weight and bulk/drag (cylinder on top of fuselage). Lower fuel consumption per unit of payload might compensate for the greater greenhouse effect of water vapour and clouds (I'm not up to the data and math). However if the A380 is too big then immediate prospects for hydrogen fueled aircraft don't look good. In any case it would only be feasible for very high-traffic routes.

[Busbuoy]

Grebe:
The type of condensation you describe is not generally called a contrail in my experience. When it formed in the reduced pressure areas around the lifting surfaces of a manouevring fighter we used to call it "ecto"-plasm but that was just a colloquillalism.
In any case my research leads me to believe that the ice crystal contrails to which the OP refers require a condensation nucleus to form.

[Grebe]

Grebe:
The type of condensation you describe is not generally called a contrail in my experience. When it formed in the reduced pressure areas around the lifting surfaces of a manouevring fighter we used to call it "ecto"-plasm but that was just a colloquillalism.
In any case my research leads me to believe that the ice crystal contrails to which the OP refers require a condensation nucleus to form.

Sort of splitting hairs- suggest you do a bit of research on contrail issues and stealth bombers eg B2- some claims/articles are phony, and some are ' probably' correct, and whether from wings and major pressure- temp changes at low alt re fighter or at high alt, the physical requirements are essentially the same- rapidly expanding air causes a temp drop- and the local humidity does the rest. IF one can make the necessary measurements in the right areas, then one knows at what altitudes and speeds contrails can be expected or practically nil.
granted, most " contrails " are from engines ( jet or prop ) and the easiest way to avoid is to change altitude and speed. Airliners dont care, but military does. And then if one wants to get real picky, other than the ' straight line ' - how does one determine the real diff between clouds a˜d contrails say with a physical measurement of a cloud and ditto for a contrail ? The net effect is the same.

And then there is your breath in cold weather or walk in freezer or on a cold mountaintop ..

[Busbuoy]

At the risk of this becoming a thread-distracting pi55ing match, more research has confirmed that "exhaust" contrails are the predominant (I would like to say "only" but I honestly haven't read every peer-reviewed scholarly article on the subject) type of ice crystal based contrail and as such are the only persistent form of contrail. I have learned that the other type (for me "ecto") is an "aerodynamic" contrail and requires that the atmosphere be above freezing and reasonably close to saturation. As no energy is removed from the air parcel on aircraft passage the temperature will rise again above the saturation point and the localised condensation will evaporate hence be non-persistent.
I can say with relative certainty that I never saw an "aerodynamic" contrail form above the freezing level but I sure as hell formed a few "exhaust" ones when I didn't pay proper attention to the met man's morning brief.
But hey, contrails can be useful.
A 4 ship of Eaglejets in wide combat4 coming beak to beak at 50,000ft M1.5 and conning, accompanied by Eagle lead's gravelly voice on the back radio saying "Gentlemen, the Claw!!!" focusses your survival instincts sharpish!!!

[Easy Street]

For the energy density problem already mentioned, consider that greater fuel volume = more drag = less efficiency. There is also accident safety to consider. But most pertinently in climate change terms there is the question of how the hydrogen is generated in the first place. It does not occur naturally in significant quantity and has to be produced. Whatever process is adopted, it will be less than 100% efficient so additional energy is needed from the first stage. Burning fossil fuels to generate electricity to do this, typically at lower efficiency than a jet engine can achieve, is clearly a nonsense unless all pollutants can be captured, in which case why the current angst? Nuclear fission might be credible in capacity terms but has cost and political issues; good luck getting the green lobby on board. And renewables need to get closer to existing electrical power demand before it becomes conceivable to add another huge requirement. The received wisdom in futurist writing used to be that nuclear fusion power would be the step which unlocked a ‘hydrogen economy (https://en.m.wikipedia.org/wiki/Hydrogen_economy)’ but that seems as far away as ever...

[Smythe]

As anyone who lives in northern latitudes can attest, it is significantly colder on clear days/nights, than cloudy.

Unfortunately, I spent quite a bit of time in Norfolk, VA, which has a lot of air traffic over it. It was easy to see how all of the "chemtrails" :oh: come together on many, many days and by early afternoon, it was all hazed over...I was not enthused about this observation.


https://cimg6.ibsrv.net/gimg/pprune.org-vbulletin/768x510/gettyimages_548029033_58d6c48c3df78c5162f87517_05f2d9128b6cd 71bbd7d59a2c3ca56ae853e0e44.jpg


Stuff like this is common

[GS-Alpha]

Water vapour is not just a greenhouse gas, it is responsible for a considerably larger proportion of the greenhouse effect than all other greenhouse gasses on Earth combined! The funny this is everyone gets so exited about greenhouse gasses, and the greenhouse effect, yet we would not even be here in the first place without them!

[Mac the Knife]

Problem is too many people in the greenhouse

(and yes, Africa & India, I'm looking at you)

Mac

[sprite1]

The data is very limited and largely circumstantial, however there is some evidence that - in the immediate aftermath of 9/11 - the grounding of virtually all commercial air traffic over the continental US resulted in slightly lower temperatures. Some researchers suspect the reduction in water vapor being injected into the upper atmosphere by all those grounded aircraft was responsible.
That the average ground temperatures dropped slightly is pretty much certain, cause and effect is rather more questionable (particularly with a single data point).

Besides, "practical" and H2 powered aircraft don't belong in the same sentence given current technology. There is simply no practical way to contain the volume of hydrogen necessary for long range flight - the density of even liquid H2 is far less than Jet A - and keeping a large volume of cryogenic fuel on a commercial aircraft wouldn't leave much room for passengers and cargo (you're not going to be putting it in the wing).


Only quoting your post tdracer as you were the only one to reference 9/11.

I always wondered about those temperature claims made over the years about the days immediately following 9/11.

This report is well worth the read. It’s just 4 pages long yet accurately describes their reference points around the US, the average Diurnal Temperature Range over the period ‘71 to ‘01, the actual change in airmass over the NE US that week, etc.

Basically, the witnessed change in temperature would’ve happened anyway.

Do read it. Very interesting.


https://www.int-res.com/articles/cr2002/cr2004/26/c026p001.pdf

[nonsense]

Problem is too many people in the greenhouse
Yes.

(and yes, Africa & India, I'm looking at you)
So sod off all you third world people; there isn't enough room in the greenhouse for you to burn coal, drive cars, and fly places, we got here first?

[boisbrule]

Water vapour is not just a greenhouse gas, it is responsible for a considerably larger proportion of the greenhouse effect than all other greenhouse gasses on Earth combined! The funny this is everyone gets so exited about greenhouse gasses, and the greenhouse effect, yet we would not even be here in the first place without them!

Yes, water vapour is the most powerful greenhouse gas in one sense. John Tyndall discovered the basics in the 1850s. The Wikipedia article "greenhouse gas" says that water supplies 36-72% of the warming effect, varying with location. CO2 is number 2. However. the average water molecule stays in the atmosphere for 9 days, while the residence time for CO2 molecules is thought to vary from 30 to 95 years. Evaporation of water varies with temperature. Therefor we call CO2 the "driver." Water vapour content of the atmosphere follows the CO2 content.

Regarding "we wouldn't be here without them"; yes, Joseph Fourier brought to notice in 1824 the fact that the Earth is considerably warmer than the physics of his time could explain, and proposed as one possible explanation that some property of the atmosphere caused it to retain heat. "The dose makes the poison." Recently the Earth's temperature has been like Goldilocks' third bowl of porridge, just right. We don't want it hotter, especially as the Sun's radiation has slowly increased over its lifetime, and the disposition of the continents right now is helpful for cooling.

[GS-Alpha]

A comparison between how long a CO2 molecule remains in the atmosphere compared to a water molecule is kind of irrelevant, as the water vapour molecule is replaced by another one. This is the beauty of the system. I personally think it is highly arrogant of mankind to believe that it will ultimately win against nature. Worrying about CO2, as MAC says, is not the answer here. In nature, population sizes are controlled. We have used our technology to fight nature, and have artificially enhanced the size of human populations, and indeed the animal populations we feed upon, or keep as pets. At some point, nature insists we will come up against a population size barrier which cannot be broken using our science.

CO2 and the greenhouse effect is a red herring. The real problem is over population, but that is a far more difficult problem to address.

[OPENDOOR]

Not sure about contrails but;

https://cimg5.ibsrv.net/gimg/pprune.org-vbulletin/2000x1429/atlantic_amo_2018016_lrg_2c1bc19f3b0c8e60d45acc8c043125a03e7 effe0.jpg

Ships churning through the Atlantic Ocean produced this patchwork of bright, criss-crossing cloud trails off the coast of Portugal and Spain. The narrow clouds, known as ship tracks, form when water vapor condenses around tiny particles (http://earthobservatory.nasa.gov/Features/Aerosols/page1.php) of pollution that ships emit as exhaust or that form from gases in the exhaust. Ship tracks typically form in areas where low-lying stratus (https://www.metoffice.gov.uk/learning/clouds/low-level-clouds/stratus) and cumulus (https://eo.ucar.edu/webweather/cumulus.html) clouds are present.

The high reflectivity of ship track clouds means they shade Earth’s surface from incoming sunlight, which produces a local cooling effect. However, determining whether ship tracks have a global cooling effect is challenging because the way particles affect clouds remains one of the least understood and most uncertain aspects of climate science.

See NASA page; https://earthobservatory.nasa.gov/images/91608/signs-of-ships-in-the-clouds

Overall, clouds are thought to cool Earth’s surface by shading about 60 percent of the planet at any one time and by increasing the reflectivity of the atmosphere. Given that, just a 5 percent increase in cloud reflectivity could compensate for the entire increase in greenhouse gases from the modern industrial era in the global average. Likewise, long-term decreases in cloudiness could have major impacts.

Source; https://earthobservatory.nasa.gov/features/Aerosols/page1.php

[Lord Farringdon]

The data is very limited and largely circumstantial, however there is some evidence that - in the immediate aftermath of 9/11 - the grounding of virtually all commercial air traffic over the continental US resulted in slightly lower temperatures. Some researchers suspect the reduction in water vapor being injected into the upper atmosphere by all those grounded aircraft was responsible.
That the average ground temperatures dropped slightly is pretty much certain, cause and effect is rather more questionable (particularly with a single data point).


Interesting stuff td. Perhaps worthy of more research by scientists.

Aircraft and engine manufacturers have come a long way in reducing emissions but the capability to keep doing this without some radical new technology that is both practical and economically viable, means any future reductions are likely to incrementally much smaller than has currently been the case. But despite all that has been done to reduce engine emissions the contribution to greenhouse gases from aviation continues to climb as a result of increasing demand for air travel. Calls by the environmentalists to effectively ban air travel or heavily tax it are just not the answer. You cant un-invent the wheel (or in the case the wing!). Asking business and liesure sectors to limit their travel is more sensible and more doable. However voluntary buy-in is hard and limited. So, if scientists could actually prove a connection between the 9/11 grounding event and reduced temperatures, and could quantify what that would actually mean to temperatures across the big emitters of China, the USA and Europe, then aviation could in fact be part of the climate change solution. How? By mandating flightless days!

Imagine no fly days across the world on for example Wednesday and Sundays. In big hairy audacious numbers that's about a 30 percent reduction in greenhouse gasses caused by aviation activity. This doesn't require new technology, alternative fuels, onerous carbon taxes, elimination of incentives to fly such as air points programmes or complete bans on flying. It would of course have an impact on world economies and certainly airline economies. But that would be in the form of a one off adjustment, albeit a bit painful in places. Yes, all the Wednesday and Sunday travelers would book on the other days and initially create chaos but adjustments would eventually be made. That thrice weekly meeting that required air travel would eventual settle down to Monday and Friday meetings with a video conference on Wednesdays. The world and it's economies would slow but not stop because they would simply adapt to the longer leads times. That Fedex carton is going to be six days away, not four!

Asking business and holiday makers to reduce their travel is not new. But realistically, relying on voluntary personal choices and social pressure just doesn't seem to do it. So this cannot be voluntary and it cannot be done unilaterally since that would give immediate economic advantage to non-participants. It must be a UN agreed solution and then implemented by ICAO and its treaties. It's either everyone, or no one.

So, huge political hurdles and many practical issues to overcome if this was to work but, we are either serious about human activity causing undesirable climate change .. or we're not.

Other than offering a cloudless night which is always a little cooler, I'm not sure how the 9/11 event would achieve measurable cooling in 1 day across the US when aviation is only contributing about 4 percent of carbon emissions globally. But whether this is true or not, and in answer to the question that the title of this thread raises, mandated flightless days would almost instantly create and achieve significant contributions to the reduction of aviation induced greenhouse gases.There is nothing else radical enough to do it.

But if the question is, what cost to our economies would such a radical action be, then the answer may be in a corollary question. What is the cost to the planet if we don't take such action?

[Whenwe]

I am a better reader than a contributor but I have to say something!
Its happening; have been for millions of years and a few thousand liters of Jet A1 is not going to change evolution.
Just another cash cow to milk!

See this: https://www.britannica.com/science/geologic-history-of-Earth/Development-of-the-atmosphere-and-oceans

[StraightLevel]

Some interesting responses and links, however it still looks to me like there is a vast vast amount that science and certainly us don’t know about the climate and how it gets influenced both naturally and by us as a species.

There was some interesting info provided in one of the links that states that CO2 lasts in the atmosphere for years while H2O only lasts for a mater of days which I found very interesting. This could be a very significant difference between hydrogen and carbon based fuel exhaust emissions which could possibly warrant further scientific study.

At the risk of appearing stupid, I think it’s very easy to overly simplify things by saying that on a cloudy day it’s warmer and vice versa, however that’s not always the case. On a cloudy day during the day it blocks some sunlight and keeps the earths surface and therefore local atmosphere cooler, however at night a cloud layer insulates and keeps the air warmer.

Thinking completely outside the box, maybe rather than ban flying on certain days maybe it would be better to ban night flights when contrails could keep the atmosphere warm.

I hope that most of us on this forum want to continue having the benefits of flying, and aviation is a unique form of transport in the way that we go up into the upper atmosphere rather that stay on the earths surface.

I just hope that science will find a way for this to be turned into an advantage as opposed to the perceived negative that it is at the moment in certain circles.

[Ian W]

Some interesting responses and links, however it still looks to me like there is a vast vast amount that science and certainly us don’t know about the climate and how it gets influenced both naturally and by us as a species.

There was some interesting info provided in one of the links that states that CO2 lasts in the atmosphere for years while H2O only lasts for a mater of days which I found very interesting. This could be a very significant difference between hydrogen and carbon based fuel exhaust emissions which could possibly warrant further scientific study.

At the risk of appearing stupid, I think it’s very easy to overly simplify things by saying that on a cloudy day it’s warmer and vice versa, however that’s not always the case. On a cloudy day during the day it blocks some sunlight and keeps the earths surface and therefore local atmosphere cooler, however at night a cloud layer insulates and keeps the air warmer.

Thinking completely outside the box, maybe rather than ban flying on certain days maybe it would be better to ban night flights when contrails could keep the atmosphere warm.

I hope that most of us on this forum want to continue having the benefits of flying, and aviation is a unique form of transport in the way that we go up into the upper atmosphere rather that stay on the earths surface.

I just hope that science will find a way for this to be turned into an advantage as opposed to the perceived negative that it is at the moment in certain circles.



There was some interesting info provided in one of the links that states that CO2 lasts in the atmosphere for years while H2O only lasts for a mater of days which I found very interesting. This could be a very significant difference between hydrogen and carbon based fuel exhaust emissions which could possibly warrant further scientific study.

A turning propeller blade in only there intermittently but a wall stays in place permanently therefore ......

The thing with water (the hydrologic cycle) is that it is continually being replaced at a huge rate. The hydrologic cycle is very powerful so for example in extremes a Cat 3 type hurricane in a day dissipates as much energy as 200 times the daily world electricity generation capacity (https://www.aoml.noaa.gov/hrd/tcfaq/D7.html) . Another way of seeing it is that a hurricane releases more than a megaton yield nuclear weapon every 10 seconds (https://wattsupwiththat.com/2019/08/29/nuking-hurricanes/) imagine the amount of energy from a frontal system across the entire US. All this is convective energy is based on latent heat release by water molecules and becomes radiant energy and leaves to space. The atmosphere contains very little energy compared to the oceans with the top 6 meters or so of the oceans having a heat content that is more than the entire atmosphere. It is the continual evaporation that maintains the humidity of the atmosphere and cools the surface of the oceans as does transpiration from plants. There is a hypothesis that as the atmospheric and ocean temperatures rise this causes more convective clouds and the clouds are not only evidence of evaporative/convective cooling but also raise the albedo reflecting solar radiation back to space. (Sometimes called the Iris Hypothesis)
It does appear that there is more correlation between atmospheric temperatures and the solar activity - we will find that out in the next decade or so as even NASA is expecting some cooling from the quiet sun (https://www.nasa.gov/centers/langley/news/releases/2009/09-101.html)

There are two things to be concerned about with graphs watch what is being done with the Y axis normally this exhibits a degree (cough) of precision in temperature measurement that would not be achieved by the accuracy of a met observer in howling sleet reading a temperature from a thermometer in a Stevenson Screen. The comparisons with 'global temperatures' from the past when in the Southern hemisphere a hundred years ago there were very very few observations - are extremely shaky as the much of the temperatures are based on guesswork but then expressed with a precision of hundredths of a degree (ever seen error bars on those graphs? No nor have I),

The other issue is correlation and causation all that can really be said is that if there is NO correlation between one value and another then there probably isn't causation. But two values closely correlating over a period definitely does not mean there is causation - see https://www.tylervigen.com/spurious-correlations

We are currently at the cold end of the Holocene - there is nothing special about the temperatures or their variance. So I wouldn't sell your coats. Definitely I wouldn't limit aviation as it is the most efficient transport in terms of miles per gallon per paying passenger. Work it out you'll find in those terms an A320 (and most other aircraft) has better consumption than a Prius and doesn't need road infrastructure between departure and destination.

[TURIN]

Globally aviation contributes about 6% of the total man-made carbon emissions. Or so we are told.
You could stop every aircraft in the world flying tomorrow and it would not make a blind bit of difference.

Why there is this obsession with reducing air travel I just do not understand.

Fine, if man made global climate change is a thing, then target those that contribute the most to it, not the family going on a jolly to Spain for a week or two.

[etudiant]

Globally aviation contributes about 6% of the total man-made carbon emissions. Or so we are told.
You could stop every aircraft in the world flying tomorrow and it would not make a blind bit of difference.

Why there is this obsession with reducing air travel I just do not understand.

Fine, if man made global climate change is a thing, then target those that contribute the most to it, not the family going on a jolly to Spain for a week or two.

In fairness, the aviation contribution to high altitude carbon and H2O emissions is a lot more than 6%. There just are not that many fires at Everest altitudes.
That said, the current models have a hard time coping with clouds and the daytime/nighttime impacts, so it is unlikely that they can model high versus low altitude emissions.
We are doing an experiment on the only environment we have. Hopefully the results will be benign.

[cessnaxpilot]

https://news.yahoo.com/climate-change-group-recommends-banning-112055148.html

[Grebe]

interesting re carbon emissions by jets. years ago, most jets left a trail of black ( carbon ) smoke. but for a variety of ' non scientific ' reasons re carbon emissions, the carbon smoke disappeared. One reason was efficiency, one reason was military - smoke trail make a good pointer as to where you are. one reason was the ' appearance ' of evil carbon.

OK- but to eliminate the carbon smoke trail, absent some real expensive methods- and generally impractical for airplanes - the easiest way was relatively simple - raise the combustion temperature. ( simplified explanation ). OK but when you do that, you create more Nitrous oxide ( disassociation of the 72 percent N2 in the air ). Nitrous oxide and related combustion products mixed with moisture- becomes ..."acid " rain . And in the extreme ( industrial ) process, can be made into Nitric Acid.


carbon is essential for life, nitrous ..... is NOT

[Lord Farringdon]

Globally aviation contributes about 6% of the total man-made carbon emissions. Or so we are told.
You could stop every aircraft in the world flying tomorrow and it would not make a blind bit of difference.

Well, actually it would. By your own statement it would reduce human made carbon emissions globally by 6%...overnight!!

Why there is this obsession with reducing air travel I just do not understand.

Shipping contributes some 2.5 % to global carbon emissions. Compared to air travel, that's a drop in the ocean really (see what I did there?). Even so, calls are being made to reduce cruise ship travel. So its not just air travel. .

[Australopithecus]

Well, actually it would. By your own statement it would reduce human made carbon emissions globally by 6%...overnight!!



Shipping contributes some 2.5 % to global carbon emissions. Compared to air travel, that's a drop in the ocean really (see what I did there?). Even so, calls are being made to reduce cruise ship travel. So its not just air travel. .


Within the next ten years I expect carbon shaming to apply to all private aircraft, pleasure boats, snowmobiles, jetskis etc. So it's a cinch that all discretionary internal combustion will be seen as very anti-social, and carbon offsets will be de rigueur.

[Imagegear]

Things are getting more complicated:


The Committee on Climate Change has called for Air Miles schemes to be axed. Greg Dickinson says we should go one step further and penalise frequent flyers

I have been guilty of both being a frequent flyer and using airmiles so I am not in a position to criticise however, the potential impact on prices and passengers makes for an interesting discussion.

Behind a paywall but: Axing Air Miles (https://www.telegraph.co.uk/travel/comment/frequent-flyer-air-miles-scrapped/)

IG

[20driver]

There are two things to be concerned about with graphs watch what is being done with the Y axis normally this exhibits a degree (cough) of precision in temperature measurement that would not be achieved by the accuracy of a met observer in howling sleet reading a temperature from a thermometer in a Stevenson Screen. The comparisons with 'global temperatures' from the past when in the Southern hemisphere a hundred years ago there were very very few observations - are extremely shaky as the much of the temperatures are based on guesswork but then expressed with a precision of hundredths of a degree (ever seen error bars on those graphs? No nor have I),


This encapsulates is so much of my objection to the current state climate science. The rules of evaluating and presenting data in a manner that accounts for precision do not apply.

[Ian W]

Originally Posted by Ian W https://www.pprune.org/images/buttons/viewpost.gif (https://www.pprune.org/rumours-news/626264-could-aviation-part-climate-change-solution-post10594189.html#post10594189)There are two things to be concerned about with graphs watch what is being done with the Y axis normally this exhibits a degree (cough) of precision in temperature measurement that would not be achieved by the accuracy of a met observer in howling sleet reading a temperature from a thermometer in a Stevenson Screen. The comparisons with 'global temperatures' from the past when in the Southern hemisphere a hundred years ago there were very very few observations - are extremely shaky as the much of the temperatures are based on guesswork but then expressed with a precision of hundredths of a degree (ever seen error bars on those graphs? No nor have I),
This encapsulates is so much of my objection to the current state climate science. The rules of evaluating and presenting data in a manner that accounts for precision do not apply.

This NASA GISS graph is what is normally shown in all the 'climate emergency' media reports note that the display is in 10ths of a degree centigrade for a 'global mean estimates on land and ocean data'. In 1880 there would be less than 100 observer thermometers in the entire Southern Hemisphere most of those in Australia. Some sea temperatures would be being taken by a disinterested boat crew using a canvas bucket dunked into the sea and a handheld thermometer. Even in the Northern Hemisphere before the 1940's it is unlikely that there was any precision in meteorological observations. It is only relatively recently that rules were applied internationally for rounding up or down to the nearest degree. Yet this inaccurate data is averaged (The 'average' is built from a daily 'average' which is actually the mean of the highest and lowest temperature. So if the lower temperatures have not been as low - this will be claimed as warming.) Comparing observations at hourly intervals by a bored meteorological observer to the recent automated observation systems that record transients of a few seconds is a statistical nonsense due to change in sampling rates. (The Heathrow automated observation system just North of the Northern runway at the express exit where it sits in jetwash much of the time. ) The error bars on the Y axis below would probably be +/- a degree - or outside the graph. Note that this is an 'anomaly' metric so is based on how much warmer than the standard temperature of the Earth the temperature is - and that is a whole different argument.
https://cimg8.ibsrv.net/gimg/pprune.org-vbulletin/885x497/nasagraph_d24b19cdf4b63ea3155ed982092d0b13d9dfb1ca.jpg
You will see why those who want to report a crisis prefer to stretch the Y axis and show unreal precision reporting a very inaccurate input especially values reported before 1940. As said much of the southern hemisphere is 'estimated'. [or to be blunt " In [url=https://realclimatescience.com/2015/12/southern-hemisphere-temperature-fraud/]Climategate E-Mails, Phil Jones admitted that much of his southern hemisphere temperatures were made up, because there is no actual data. "]

So should we panic? Well below are the global average land/ocean temperature series shown by a line of red-alcohol thermometers.

https://cimg2.ibsrv.net/gimg/pprune.org-vbulletin/962x544/dw9pnyxwsacudex_e36346fa70a6992f0e58b3e9a62a09c67860c9ea.jpg

There's a lot more such as disregard of atmospheric enthalpy, but you are probably bored already.

[VFR Only Please]

Lots of interesting posts here.

My understanding of the 911 business is – current consensus – that contrails and often-ensuing stratus (same with ship exhaust) do more to prevent heat radiating outwards than they shade the Earth's surface.

Yes, let's face it: overpopulation is the Big Daddy of our problems every which way. We're choking the whole works. But lay off Africa, hitherto relatively lightly populated. India yes, scary, and when combined with China will, in a few years, amount to Three Billion people, far higher than total world population the day I was born – and I'm 64. Those two Industrial Giants ain't stoppin' for nuthin'.

So, after staying just one jump ahead of our own extinction for hundreds of thousands of years, we now have runaway overpopulation which spells ... our extinction. Along with that of millions of other species.

[Sholayo]

Lots of interesting posts here.

My understanding of the 911 business is – current consensus – that contrails and often-ensuing stratus (same with ship exhaust) do more to prevent heat radiating outwards than they shade the Earth's surface.

Yes, let's face it: overpopulation is the Big Daddy of our problems every which way. We're choking the whole works. But lay off Africa, hitherto relatively lightly populated. India yes, scary, and when combined with China will, in a few years, amount to Three Billion people, far higher than total world population the day I was born – and I'm 64. Those two Industrial Giants ain't stoppin' for nuthin'.

So, after staying just one jump ahead of our own extinction for hundreds of thousands of years, we now have runaway overpopulation which spells ... our extinction. Along with that of millions of other species.

Hehe, but note that right now we have less hungry people than we had back then, when you were young. That's one thing.
Second - population is not an issue anymore.
Current Big Thing is climate change.
There will be something else in decade or two from now, do not worry.

And about aviation and CO2 - now think of banning flights and impact on economy of all those places which are destinations of all these flights? Me myself? I prefer if my place would get warmer by 2-3 Celsius rather than economy collapse.
Sorry!

&

[a_q]

Whatever your take on climate change (personally I think it's inevitable, and if we spike the atmosphere with CO2 now, we'll get it over and done with quicker...)

As the efficiency of aircraft increases, so does the aviation industry's CO2 emissions. This seems counter-intuitive at first, but the reasoning is:

1. Aircraft become more efficient
2, Price of air travel comes down (as it's dominated by the fuel cost)
3. Demand then goes up - in excess of the efficiency saving.

The only way to break this cycle is to impose a carbon tax, perhaps on each ticket.

[Reluctant Bus Driver]

Since C02 is a very very wimpy temperature driver there is no real climate emergency, only one that is manufactured. So Aviation, together with the entire fossil fuel economy has little to nothing to do with climate change so who cares?

[gearlever]

Since C02 is a very very wimpy temperature driver there is no real climate emergency, only one that is manufactured. So Aviation, together with the entire fossil fuel economy has little to nothing to do with climate change so who cares?

Wow, the well known Trumpmenistan Mantra.
And 97% of worldwide climate scientists are wrong........:ugh:

[b1lanc]

Within the next ten years I expect carbon shaming to apply to all private aircraft, pleasure boats, snowmobiles, jetskis etc. So it's a cinch that all discretionary internal combustion will be seen as very anti-social, and carbon offsets will be de rigueur.

And from CNN, eliminate frequent flier miles and tax frequent fliers. Steamships anyone?

https://www.cnn.com/travel/article/air-miles-ban-report-scli-intl/index.html

[Raffles S.A.]

Wow, the well known Trumpmenistan Mantra.
And 97% of worldwide climate scientists are wrong........:ugh:

Could just be, the mainstream, Anyone who disagrees is ostracised immediately. Climate change is an ongoing process,thugs are trying to profit from it. Man doesn't have a snowball's hope in hell of changing the climate. When I see 100 or more large jet aircraft at the COP summit, it immediately trashes any credibility.

[73qanda]

The psychological impact this subject is having on people aged between 12 and 30 is significant. I stopped and talked to a 19 year old girl on the street in Melbourne a couple of days ago who was raising money for Doctors Without Borders. She was a bit emotional about kids being bombed in Hospitals overseas and I agreed that things like that were terrible. She was so down that I told her to remember to look on the bright side of things at least a couple of times a day, I reminded her that there are less people living in extreme poverty than ever before, that there are less school age children ‘not in school’ than ever before, and that if she had kids they were much much more likely to survive than any other time in history and that women and racial minorities are more equally compensated for work, have more education opportunity, and are afforded more rights than at any other time in history. She looked at me sort of sideways, like she was figuring out how to deal with a crazy person. My statements hung in the air as if I had just used the C word in a public address.
Eventually she said “ But we have the climate”. I am pretty sure she thought I was nuts and that the idea that not everything was doom and gloom was completely foreign to her.
I told her to make sure she looks on the bright side of life at least a couple of times a day and carried on my way.
Thinking about it now, I wonder if her news feed ever pops up positive news or if she and her mates just get continuously bombarded with negative opinion pieces and then engage each other in deadly serious conversations about how the future of mankind rests in their hands? I wonder if me suggesting that we’re doing ok is met neurologically in the same way as someone suggesting to me that Santa is going to give me a waterfront property for Christmas? Ie it just doesn’t compute as a possibility.
Anyway, our young folk are pretty worried and are not getting a balanced view of things which will cause problems that nobody seems to be talking about. Pretty irresponsible from the vast majority of our leaders IMO.

[Lookleft]

I think you have raised a very good point. The young are that stressed by all the doom and gloom being presented to them through SM and the education system that they really believe that the world is coming to an end. The perfect expression of that was Greta Thunberg's emotional address to the UN. I have no doubts about her sincerity but I also don't believe that she hasn't been manipulated by the adults around her. Much like the young girl that you encountered in Melbourne. In any flight deck discussion about CC it is very much a demographic divide. The younger pilots arent as sceptical as the older pilots. One of the big diferrences is that this is the first big issue that the younger generation have faced and accept it at face value. The older generation have seen it before with acid rain, nuclear winter, Y2K, crippling and irreversible environmental pollution, the hole in the ozone layer etc etc. The only way the current "crisis" will go away is it will be superseded by another threatening scare.

[Smythe]

Forget CO2 or other emissions....

look at the contrails creating cloud cover... (posts 15 and 22)

[Ian W]

Wow, the well known Trumpmenistan Mantra.
And 97% of worldwide climate scientists are wrong........:ugh:

Well it is actually 97% of 79 responses to a survey that claimed climate science expertise out of 3,146 scientists that responded to a survey.

The "97 percent" figure in the Zimmerman/Doran survey represents the views of only 79 respondents who listed climate science as an area of expertise and said they published more than half of their recent peer-reviewed papers on climate change. Seventy-nine scientists—of the 3,146 who responded to the survey—does not a consensus make. (https://www.wsj.com/articles/joseph-bast-and-roy-spencer-the-myth-of-the-climate-change-97-1401145980)

There is a lot more in that link on similar claims. The entire field of climate 'science' is riddled with wild claims that have no support in reality but make extremely good press releases.

[Reluctant Bus Driver]

Well it is actually 97% of 79 responses to a survey that claimed climate science expertise out of 3,146 scientists that responded to a survey.

The "97 percent" figure in the Zimmerman/Doran survey represents the views of only 79 respondents who listed climate science as an area of expertise and said they published more than half of their recent peer-reviewed papers on climate change. Seventy-nine scientists—of the 3,146 who responded to the survey—does not a consensus make. (https://www.wsj.com/articles/joseph-bast-and-roy-spencer-the-myth-of-the-climate-change-97-1401145980)

There is a lot more in that link on similar claims. The entire field of climate 'science' is riddled with wild claims that have no support in reality but make extremely good press releases.
Exactly right.
And that isn't even the tip of the ice berg. Every single climate prediction has been wrong. C02 has never been a temperature driver on this planet. In our own interglacial we have had at least three periods where it has been warmer than today with less C02. We have had ice ages during times when C02 were 4000 PPM. All 3 known interglacials prior to this one have been warmer with less C02. After glacial periods temperature increases first then C02 follows with a 800 year lag as the oceans warm.
Sea levels are not rising any faster than they have been. Arctic Ice is not at an all time low. Antarctic ice is growing, polar bears are thriving, heat waves were much worse in the 1930's here in the United States. An inconvenient fact that NOAA, NASA and IPCC conveniently neglect to show on their graphs, in line with the now infamous hockey stick graph of " professor" Michael Mann fame..

So if we can figure out that AGW is mostly B.S. you don't think establishment science, media and politicians can too? Of course, but saving the world is obviously not on the agenda, but keeping a multi billion dollar a year gravy train certainly is. Collateral damage of brain washed Swedish teens be damned. A very sad and scary state of affairs since we have an abundance of actual problems to solve...

[Lord Farringdon]

Well it is actually 97% of 79 responses to a survey that claimed climate science expertise out of 3,146 scientists that responded to a survey.

The "97 percent" figure in the Zimmerman/Doran survey represents the views of only 79 respondents who listed climate science as an area of expertise and said they published more than half of their recent peer-reviewed papers on climate change. Seventy-nine scientists—of the 3,146 who responded to the survey—does not a consensus make. (https://www.wsj.com/articles/joseph-bast-and-roy-spencer-the-myth-of-the-climate-change-97-1401145980)

There is a lot more in that link on similar claims. The entire field of climate 'science' is riddled with wild claims that have no support in reality but make extremely good press releases.


Seems like click bait to me with subscription required to access it. Not saying it isn't authoritative or peer reviewed but just cant tell behind a paywall.

Edit. Had to wiki Zimmerman/ Doran to get any information and you will see quite a lot that discounts your propersition Ian. Essentially you have selected supportive quotes and there are plenty within the wiki article regarding the many surveys on this topic that have been conducted, that provide an alternative and supportive view by researchers who have researched over 11000 peer reviewed papers related to climate change. An interesting comment is that unlike the researchers comprehensive works, offhand criticisms of this research designed to nullify this overwhelming consensus has not been peer reviewed. So do we accept it ahead of peer reviewed work?. Why would anyone do that? On this forum we are quick to waive off non pilot comments especially when they criticise pilot actions. I would like to see references to peer reviewed criticisms of this subject...if we can find them in abundance...in which case I would certainly be prepared to have another view. Although, if they existed, I doubt this thread would! 😊

[Reluctant Bus Driver]

Here is an unrestricted link to the 97% non sense. https://cei.org/sites/default/files/IQA_NASA_97_Percent_Final.pdf

Furthermore, there is no consensus in science. There are only theories that you can or cannot prove. Anything else falls under politics and religion. Since the climate establishment cannot prove AGW they simply make stuff up, like the debunked 97% or erasing the Medieval warm period ​​​​​, or adjusting temperature data to make it look like it is warmer than it actually is. Yes this has happened and is still happening which can be verified by a simple Google search. Climate " science" is totally rotten and in my humble opinion will one day be exposed as the greatest fraud in scientific history.

[Lord Farringdon]

Here is an unrestricted link to the 97% non sense. https://cei.org/sites/default/files/IQA_NASA_97_Percent_Final.pdf



I note the following regarding this libertarian movement:
"Academic research has identified (CEI) as one of the Conservative think tanks (https://en.m.wikipedia.org/wiki/Conservatism_in_the_United_States) central to promoting climate change denial (https://en.m.wikipedia.org/wiki/Climate_change_denial).[3]" (https://en.m.wikipedia.org/wiki/Competitive_Enterprise_Institute#cite_note-DryzekNorgaard2011-3)

Not sure why I would accept their clearly political based research over more scientific and peer reviewed research.

To be fair. The title of this thread is not about climate change and whether you or I agree with it not. It's really for those who accept that our body of scientists show consent not dissent toward the proposition and that if you accept that, what can aviation do to help.

[StraightLevel]

Whether we like it or not, or even whether it is or it is not, aviation is seen as a major contributor to climate change and as such I initially wondered if there is anything that could be done to turn a perceived negative into a positive.

From the thread it’s obvious that it’s not so straight forward, however if the climate models are really as incomplete as some replies suggest I still think that there just might be a way in which we could use our high level emissions to humanities advantage.

i also still think that there may be a possibility that high level clouds would be beneficial as they might provide an element of shade but still have enough atmosphere below them to allow the energy absorbed into the earth to be dissipated into the air immediately below the clouds and have less effect on the lower atmosphere, and surely high level H2O emissions would be better than CO2.

Hopefully as climate modelling advances we will be able to accurately asses this and find a better way forward for aviation.

[fab777]

Hehe, but note that right now we have less hungry people than we had back then, when you were young. That's one thing.
Second - population is not an issue anymore.
Current Big Thing is climate change.
There will be something else in decade or two from now, do not worry.

And about aviation and CO2 - now think of banning flights and impact on economy of all those places which are destinations of all these flights? Me myself? I prefer if my place would get warmer by 2-3 Celsius rather than economy collapse.
Sorry!

&

If your place, whichever it is, get 2-3 C warmer, there is a strong chance economy WILL collapse.

Think agriculture productivity, for instance... most of western europe had reduced crop yield due to drought this summer, and we are not even at plus 1 deg.

[rotorwills]

Along with many threads the reflection appears again as clueless individuals bleating.

These forums used to have a reasonable level of common sense. I really trust that they do not reflect upon the present body of flight crew. They obviously have been infiltrated by others.

[etudiant]

There are certainly signs of a potential 'hydrogen economy'. Apparently there is a well-understood industrial process for producing hydrogen.
As has been pointed out, water vapor is by far the earths most potent greenhouse gas, so not sure hydrogen would give much benefit to aviation, even if using it removes the CO2 stigma.

[jimmievegas]

Perhaps those wishing to comment on climate science would like to, to put it politely, actually read what the scientists say before commenting. Just because you have an opinion does not make it a reality, and it is highly discourteous to rubbish the work of scientists without even reading or understanding it. These people are experts for a reason: They have a detailed understanding of the subject and suitable training in the field.
That doesn't make them right, but it does mean that, unless you are also an expert in the subject and have read extensively on that subject, they're more likely to be right than you.

[Eclectic]

Very many scientists do not believe in MMGW. In fact if you take out those scientists who are on the MMGW gravy train then there are almost certainly more "deniers" than "warmists".
Here is one reference: Global Warming Petition Project (http://www.petitionproject.org/index.php)
And here is another: https://www.youtube.com/watch?v=GpVBH-HY5Ow

As has been pointed out earlier there was the Medieval warming period, 1.5C warmer than the current one. The coast of Greenland was farmed successfully by the Vikings, you can still see the remains of their farms. And there was no fossil fuel use then.
The Roman warming period was as much as 4C warmer than the current one. They grew exotic Mediterranean fruits at Hadrian's Wall. And this was well before Ryaniar existed.

Two bits of science to add clarity. Firstly there are an infinite number of ways of measuring the earths temperature, even producing trend graphs going in opposite directions. "Scientists" tend to select the graph that fits their theory. Secondly climate change is experienced more the closer you get to the poles, with far less effect near the equator.

There is no scientific proof that CO2 has a greenhouse effect on our planet. Many scientists say that it doesn't. Here's one: https://principia-scientific.org/chemistry-expert-carbon-dioxide-cant-cause-global-warming
In fact you could say that the use of fossil fuels is only returning to the atmosphere carbon that used to be there but which has been trapped underground. That we actually currently have a historic shortage of CO2.
The only provable scientific effect of burning fossil fuels that every scientist agrees on is that has massively greened the planet. Providing food for our burgeoning population. Preventing famine. Because CO2 is plant food. So those turbines on Ryanair's fleet are feeding children in Africa. This fact would confuse Greta.

Unfortunately the MMGW debate has nothing to do with science. It is pure politics with the UN using it as an excuse for globalisation. So those who believe in globalisation, such as the BBC, force the MMGW mantra down our throat at every opportunity, having sacked their scientists, such as David Bellamy, who did not agree with it.

Finally take a look at Milankovitch Cycles. The earth does not follow the same orbit round the sun every year because it is puled slightly off course by the gravitational pull of the planets. In the 1920s Milankovitch showed that this created cycles that had an effect on the climate. Scientists have now calculated Milankovitch Cycles going back hundreds of thousands of years and they are a perfect fit for the climate records.

And yes we do have climate records going back that far from looking at isotopes in glacial layers and in lake bed deposits.

[Propellerpilot]

Eclectic - absolutly correct.

Apart from that, Earth's atmosphere can not even be compared to a "greenhouse" - it is not a closed off container and the heat is not trapped - as mentioned water vapour manages to absorb some of the heat (infra red) and hold it in suspension for a while - the rest radiates into space - all dependend on solar insolation. If insolation increases, temperature rises and more CO2 and other gases such as methane is gased out of the oceans as a delayed result, more giga tonnes CO2 that could be produced by man in a decade. The concentration of CO2 is so minute in the atmosphere and it only proved heating properties in a closed container at a 100% concentration. A higher CO2 is better for plants and trees as photo- synthesis can not occur without.
SO the human induced CC by CO2 emmision is a hoax to impose taxes.

Other gasses induced by humans, such as certain Krypton isotopes which have rising levels, do not change the climate but are far more lethal to life on earth. SO2 is also a problem (acid rain). We do need to become cleaner in this regard for sure - we as pilots do see much of the plastic being dumped in the 3rd world and oceans being plastic polluted - this is a real visible problem - that is were the industry should start, but not blame everything on an invisible gas. Come On... it's BS.

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