If only

[woodburner]

http://www.thenakedscientists.com/HTML/ ... tion/2599/

However there are loadsof links to articles saying the contrails are worse than the CO2 emissions for causing global warming.

[biffvernon]

Biff, you may not be rgr but a reference would be really useful here.

Now, now, you can google as well as the next man. Start, of course, with Wikipedia:

Contrails, by affecting the Earth's radiation balance, act as a radiative forcing. Studies have found that contrails trap outgoing longwave radiation emitted by the Earth and atmosphere (positive radiative forcing) at a greater rate than they reflect incoming solar radiation (negative radiative forcing). Global radiative forcing has been calculated from the reanalysis data, climatological models and radiative transfer codes. It is estimated to amount to 0.012 W/m2 for 2005, with an uncertainty range of 0.005 to 0.0026 W/m2, and with a low level of scientific understanding.[4] Therefore, the overall net effect of contrails is positive, i.e. a warming effect.[5] However, the effect varies daily and annually, and overall the magnitude of the forcing is not well known: globally (for 1992 air traffic conditions), values range from 3.5 mW/m2 to 17 mW/m2. Other studies have determined that night flights are mostly responsible for the warming effect: while accounting for only 25% of daily air traffic, they contribute 60 to 80% of contrail radiative forcing. Similarly, winter flights account for only 22% of annual air traffic, but contribute half of the annual mean radiative forcing.[6]

http://en.wikipedia.org/wiki/Contrail

But a moment's thought should suffice. Burning paraffin produces CO2+H2O, the two most important greenhouse gasses. I think it behoves the deniers to demonstrate why aircraft should not add to global warming.

[emordnilap]

In 1963, a young woman from county Waterford got on her bike and cycled to India. She went on to be a prolific, honest, incisive and endearing writer, travelling in such diverse places as Cuba and the Balkans in the '90s. I believe she still cycles today.

i'd love to do a trip like that (well, just across europe or something), but figured (a) I would waste far too much money staying in hotels (b) whilst i can consistently cycle good distances on a daily basis, i tend to be quite clumsy/disorganized and struggle with lifes' practicalities.. I'm sure I'd have some major catastrophes along the way.

It might be worthwhile getting hold of her account of the journey to India. It might inspire you to try the same.

[woodburner]

But a moment's thought should suffice. Burning paraffin produces CO2+H2O, the two most important greenhouse gasses. I think it behoves the deniers to demonstrate why aircraft should not add to global warming.

Make up your mind

So it makes no difference to global warming whether you fly or not.

.

[Tarrel]

I am being bullied by the other half into flying to Cyprus next year to visit aged aunt before she pops off, and I have run out of excuses.

This is the way I'd prefer to do the journey.

In 1963, a young woman from county Waterford got on her bike and cycled to India. She went on to be a prolific, honest, incisive and endearing writer, travelling in such diverse places as Cuba and the Balkans in the '90s. I believe she still cycles today.

I recommend her writing. Read a couple of them. Certainly an intrepid traveller. (Some good tips on bush cycle maintenance as well!)

[Tarrel]

Biff, you may not be rgr but a reference would be really useful here.

Now, now, you can google as well as the next man. Start, of course, with Wikipedia:

Contrails, by affecting the Earth's radiation balance, act as a radiative forcing. Studies have found that contrails trap outgoing longwave radiation emitted by the Earth and atmosphere (positive radiative forcing) at a greater rate than they reflect incoming solar radiation (negative radiative forcing). Global radiative forcing has been calculated from the reanalysis data, climatological models and radiative transfer codes. It is estimated to amount to 0.012 W/m2 for 2005, with an uncertainty range of 0.005 to 0.0026 W/m2, and with a low level of scientific understanding.[4] Therefore, the overall net effect of contrails is positive, i.e. a warming effect.[5] However, the effect varies daily and annually, and overall the magnitude of the forcing is not well known: globally (for 1992 air traffic conditions), values range from 3.5 mW/m2 to 17 mW/m2. Other studies have determined that night flights are mostly responsible for the warming effect: while accounting for only 25% of daily air traffic, they contribute 60 to 80% of contrail radiative forcing. Similarly, winter flights account for only 22% of annual air traffic, but contribute half of the annual mean radiative forcing.[6]

http://en.wikipedia.org/wiki/Contrail

But a moment's thought should suffice. Burning paraffin produces CO2+H2O, the two most important greenhouse gasses. I think it behoves the deniers to demonstrate why aircraft should not add to global warming.

There's a difference between global warming and local temperature rise. I also read that a temperature rise was noted during the closure of US airspace in 2001. But you would expect to see this, just as you would in your garden if you stepped out from the shade into full sun. This is quite different from the chronic and progressive trapping of energy within the atmosphere, oceans and land that is occurring as a result of an ever more potent "greenhouse" effect.

[biffvernon]

Make up your mind

So it makes no difference to global warming whether you fly or not.

.

It makes no difference to global warming whether you fly or not. If you don't fly then somebody else will take your seat on the plane, or if the plane doesn't fly then the oil not burnt in the plane will be burnt somewhere else.

If it's taken from the ground it will be burnt.

[Tarrel]

http://www.youtube.com/watch?v=TQlHaGhYoF0

[woodburner]

There's a way of dealing with the weather.

[Tarrel]

There's a way of dealing with the weather.

Technology meets medieval superstition!

[ceti331]

It makes no difference to global warming whether you fly or not. If you don't fly then somebody else will take your seat on the plane.

Defeatist

If everyone stops flying, the airlines would go out of business and shut down.

the outcome is dictated by the majority, which is a sum of individuals.

its more powerful to say "follow my example" to convince the next person.

of course i'm pessimistic, although we can reduce waste I think we'd quickly run into activities that we can't eliminate, because despite all the waste fossil fuel use is what supports the current population.

[woodburner]

We sit comfortably posting on PS and elsewhere, trawling the internet, and think it's everyone else who isburning fuel. It would b useful to have a "power consumed" indicator on web page displays to show what was being devoured by data servers for all these activities. Then we might not be so smug.

[biffvernon]

It makes no difference to global warming whether you fly or not. If you don't fly then somebody else will take your seat on the plane.

Defeatist

If everyone stops flying, the airlines would go out of business and shut down.

You didn't quote the whole of what I said. I went on to point out that if the planes don't fly then the unburnt oil will be burnt by someone else. If the oil is unsold at a price, the price will drop and it will then be sold - and burnt. It's a supply issue and CO2 emissions will not cut until supply is restricted.

Of course demand destruction is an important element in allowing supply restriction, necessary but not sufficient. I don't fly, but I don't pretend that this will have any effect on its own.

[AndySir]

I rather liked Sean Lock's comment about doing your bit for the environment being like turning up to the scene of a major disaster with a dustpan and brush and saying "Can I help?"

[SleeperService]

It makes no difference to global warming whether you fly or not. If you don't fly then somebody else will take your seat on the plane.

Defeatist

If everyone stops flying, the airlines would go out of business and shut down.

You didn't quote the whole of what I said. I went on to point out that if the planes don't fly then the unburnt oil will be burnt by someone else. If the oil is unsold at a price, the price will drop and it will then be sold - and burnt. It's a supply issue and CO2 emissions will not cut until supply is restricted.

Of course demand destruction is an important element in allowing supply restriction, necessary but not sufficient. I don't fly, but I don't pretend that this will have any effect on its own.

Sit back a second and go back to basics.

Aeroplane flies from A to B using X amount of energy. Creating Y amount of noise and heat.

Contrails reflect Z amount of sun's energy back to space before it can warm the atmosphere.

Is X plus Y or Z the bigger number? If the former net contribution if the latter net deduction.

If the planes always flies half empty the airline will share with another on the same route. One plane replaces 2. Second plane put on a different route. If we all cut back air travel there will be no second routes thus a contraction in the numbers flying. Depending on the answer above this could be a good or bad thing.

BTW the grounding of air transport saw daytime temperatures rise and night temperatures fall. This was only two days so the effect at other times of year is unknown. It was definitely covered by the Herald-Tribune at the time.