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On some otherwise cloudless days, the sky over England is criss-crossed with contrails from high-flying aircraft. These are a rapid accelerator of climate change.

Contrails may last only half a day but they cause as much global heating in that time as the carbon dioxide released on the entire flight, although this exhaust gas will survive in the atmosphere for 100 years.

This startling fact came up in a general discussion about how to cut emissions from aviation with new fuels, hydrogen, biofuels and electric engines.

None of these possible solutions will be developed quickly and all will be more expensive than existing technology, but the Whittle Laboratory in Cambridge believes that reducing contrails on the routes in the northern hemisphere with the heaviest traffic would have an immediate beneficial impact.

Although contrails are common, their formation largely depends on the atmospheric conditions. At different times on different days, flights may produce long-lasting cloud formations or none.

With aircraft travelling so fast, it is impossible for pilots to see the contrails far behind. Flying at lower heights would slightly increase fuel costs but massively reduce contrails.

Scientists are trying to find a workable solution to help governments eliminate the familiar white lines across our skies that are so rapidly warming the planet.

ALAN/ALAN D wrote: ↑Sat Apr 15, 2023 9:48 am What energy is used in a Teleporter. ?

When Star Trek started in 1966 the television had a big glass thing inside where you could warm your hands in the winter by keeping them on the screen.

Joeboy wrote: ↑Sat Apr 15, 2023 9:34 amNope, I'll be first inline when the teleporters have proved themselves though. Until then I'll live the life and offset where I can.

As an aside, I did the drive from Scotland to Turkey a few years ago in my Mazda Bongo. About 1/3rd on veg oil. It was a 12,000km return trip drive and I got about 35kpg. That's 342 uk gallons. 114 veg oil 228 diesel.

I spread money as well as pollution and the smell of chips across the UK and Europe. Would I have been cheaper and less pollution to fly as one person on a flight of 240 souls?

Not sure.

• Edinburgh to Ankara is about 3200 km each way on a great circle route (as flown by airlines, more or less), so assume 7000 km round trip to allow for air traffic control, taxiing and the like and take some margin.
• A320 NEO (about the most efficient narrowbody out there) has a per-seat fuel burn of about 2.2 l/100 km, so you would be looking at about 150 litres of jet fuel burned (34 imperial gallons) for a return trip by one person.
• Rough cut in this case is that flying would have created between 5x and 10x fewer emissions than driving in your Bongo.

Paul_F wrote: ↑Sat Apr 15, 2023 10:46 am

Joeboy wrote: ↑Sat Apr 15, 2023 9:34 amNope, I'll be first inline when the teleporters have proved themselves though. Until then I'll live the life and offset where I can.

As an aside, I did the drive from Scotland to Turkey a few years ago in my Mazda Bongo. About 1/3rd on veg oil. It was a 12,000km return trip drive and I got about 35kpg. That's 342 uk gallons. 114 veg oil 228 diesel.

I spread money as well as pollution and the smell of chips across the UK and Europe. Would I have been cheaper and less pollution to fly as one person on a flight of 240 souls?

Not sure.

• Edinburgh to Ankara is about 3200 km each way on a great circle route (as flown by airlines, more or less), so assume 7000 km round trip to allow for air traffic control, taxiing and the like and take some margin.
• A320 NEO (about the most efficient narrowbody out there) has a per-seat fuel burn of about 2.2 l/100 km, so you would be looking at about 150 litres of jet fuel burned (34 imperial gallons) for a return trip by one person.
• Rough cut in this case is that flying would have created between 5x and 10x fewer emissions than driving in your Bongo.

Stig wrote: ↑Sat Apr 15, 2023 10:44 amI'm confused now, when so many flights were grounded after the September 11th attacks there was a story saying contrails caused 'global dimming' by blocking some of the sun's energy -though a short term effect. The lack of contrails had caused higher daytime but lower nighttime temperatures.
I get it that CO2 in jet exhausts is a greenhouse gas but water vapour? Do clouds keep heat in more than they block it out? Anyone got a link to the science behind this article?

Stig wrote: ↑Sat Apr 15, 2023 10:44 amAs for flying less, I'm planning to visit my sister in France next month. Price by train (my usual route) about £400 return, flight cost is about £150 return. Good luck persuading everyone else to take the green option!