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Could Aviation be part of the climate change solution?

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Could Aviation be part of the climate change solution?

Old 13th Oct 2019, 08:33
  #21 (permalink)  
 
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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.
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Old 13th Oct 2019, 09:22
  #22 (permalink)  
 
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Not sure about contrails but;



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 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 and cumulus 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/im...-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/fe...sols/page1.php

Last edited by OPENDOOR; 13th Oct 2019 at 09:36. Reason: More information
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Old 13th Oct 2019, 13:06
  #23 (permalink)  
 
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Originally Posted by tdracer View Post
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?
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Old 14th Oct 2019, 08:14
  #24 (permalink)  
 
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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/g...ere-and-oceans
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Old 14th Oct 2019, 11:17
  #25 (permalink)  
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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.
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Old 14th Oct 2019, 16:36
  #26 (permalink)  
 
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Originally Posted by StraightLevel View Post
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 . Another way of seeing it is that a hurricane releases more than a megaton yield nuclear weapon every 10 seconds 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

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.

Last edited by Ian W; 14th Oct 2019 at 16:42. Reason: spelling
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Old 14th Oct 2019, 17:05
  #27 (permalink)  
 
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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.
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Old 14th Oct 2019, 21:12
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Originally Posted by TURIN View Post
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.
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Old 15th Oct 2019, 02:16
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Old 15th Oct 2019, 03:50
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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
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Old 15th Oct 2019, 09:36
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Originally Posted by TURIN View Post
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!!

Originally Posted by TURIN View Post
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. .
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Old 15th Oct 2019, 10:54
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Originally Posted by Lord Farringdon View Post
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.
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Old 15th Oct 2019, 11:17
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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

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Old 15th Oct 2019, 12:41
  #34 (permalink)  
 
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Originally Posted by Ian W View Post
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.
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Old 15th Oct 2019, 17:05
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Originally Posted by 20driver View Post
Originally Posted by Ian W 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.

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.



There's a lot more such as disregard of atmospheric enthalpy, but you are probably bored already.
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Old 15th Oct 2019, 22:17
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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.
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Old 16th Oct 2019, 15:39
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Originally Posted by VFR Only Please View Post
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!

&
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Old 16th Oct 2019, 16:07
  #38 (permalink)  
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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.
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Old 16th Oct 2019, 19:21
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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?
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Old 16th Oct 2019, 19:29
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Originally Posted by Reluctant Bus Driver View Post
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........

Last edited by gearlever; 16th Oct 2019 at 19:46.
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