I live in a small Highland village close to one of our ski areas. During stable weather conditions, we are overflown by numbers of aircraft flying at high altitude between Europe and North America. But during the current lockdown their numbers have fallen drastically and our skies are almost empty.

After 9/11 the US closed their airspace for three days. It was apparent that daytime temperatures then rose whilst those at night-time fell. This effect was attributed to a lack of aircraft con trails. These are, in effect, bands of high level cirrus clouds which give rise to a phenomena now termed "global dimming".

In our latitudes in winter, with long hours of darkness, the absence of con trails and dimming might be expected to lead to a fall in temperature during anticyclonic or stable weather. As temperatures around 0C. are common in winter, even a small drop in temperature could have an effect upon precipitation type.

At home, I have cross country skied almost every day since mid-December. There has been snow in my village at 240m asl every day. Snow is, of course, not unusual in winter but snow lying for over 5 weeks is very uncommon.

Could it be that an absence of global dimming increases snowfall? Thinkng back, last May saw me swimming in local lochs, no wetsuit, during a sustained period of very warm weather. With our long summer days the absence of aircraft might be expected to produce higher temperatures during anticyclonic weather.

Like others on the forum, I am passionate about skiing. In winters I ski locally and travel overseas for training and racing. But is it possible that this activity has led to climate change? We can ski locally on great snow, or we can travel by aircraft seeking snow at ever high altitude and on snow with ever increasing unreliability.

We might have to decide. Ski at home, or travel by aircraft and lose home snow.

I have seen a very compelling argument to contradict this. Contrails are high level fine water vapour clouds which easily disperse, especially late afternoon, which mitigates against any affect they may have in retaining heat overnight. However, they arguably act as a good reflector of sunlight, thereby reducing daytime surface level temperatures. By contraast, lower level rain clouds have the affect of retaining generated heat at lower altitudes because of the 24 hour blanket affect. The reasoning is therefore that contrails are actually beneficial in the battle against global warming!

I remember the BBC horizon doc on global dimming in 2005 where they discussed the lack of haze in the sky with the US flight ban after 9/11

Interesting (if long) transcript of the documentary here, discussing the reduction in global warming effects caused by dimming

[www.bbc.co.uk]



Edited 1 times. Last edit at 11.25hrs Fri 29 Jan 21 by geoffers.

I blame it on 5G masts

I've been wondering for a few years when someone would bring this up on here.
I can only point to this
[www.ipcc.ch]

And this..

[climate.nasa.gov]

And this...

[www.eesi.org]

I think the time for debate on this is long passed, almost 100% scientific consensus, by arguably better minds than most, if not all on here.
Personally I haven't flown and wouldn't fly anywhere particularly for a holiday and am reluctant to drive much either these days to tell the truth.

Irrespective of dimming effect, directly injecting carbon dioxide/monoxide etc into the high atmosphere is a total no brainer.

I should imagine like myself most on here have children/grandchildren, I am truly dreading the day when my granddaughter asks me what i did to try and stop the shit show that is inevitably going to hit her, given that we've been warned about it since the early 80's
The oil industry were aware of this since early 70's and spent millions on the cover up.. Exon Mobil are a prime example.


Honestly if all we're worried about are our ski trips we are truly f****d

Tyndrum will be the new sea port soon sending grapes n weed all round the world,

I've still more a problem with toxins than sea level rises n snow loss though I still think history will repeat n the cold will come back. I'm in the process of building a rain garden tae sook up shit before it ends up in the Clyde and in talks to get a load of waste turned back to compost. Got folk to give up clearing areas with machines and mulching instead and been working with a charity to get more market gardens started..

I've been finding a black layer of carbon under some ground and seen a fair bit up the hills in deep cuts for paths etc. Took me ages to find out wtf it was and the cause . Anyone any ideas?



Edited 1 times. Last edit at 12.46hrs Sat 30 Jan 21 by growwild.

I remember seeing a photo of earth from satellite or perhaps the space station of earths outer atmosphere showing a brown ring of polloution at the edge of the atmosphere. This turned bright clean white in another photo days after 9/11 .Tried to find these photos again online but they seemed to have been removed.
My theorey is that this mass of particals at the edge of space prevents heat being radiated to space in the Northern Hemispheres winter so making it warmer but now with much less ground and air based pollution we are seeing a cooler winter. My thoughts have been that we would see the cold building to February as in the winters of my childhood in the sixties. If its any consolation a private jet pilot I know has said that governments round the world have had a very expensive lesson and air traffic levels will never be the same again because of disease spread and climate change. The price of air travel too will never be so low again either according to him.

Found this on the web re:impact of aviation on warming, so looks like research is ongoing...

[www.climatechangenews.com]

Most low clouds such as cumulus are made up of tiny water droplets and reflect sunlight back into space from their white tops. That helps to keep the planet cool.

By contrast, icy, high-altitude clouds formed by contrails have an overall warming effect because they trap more heat escaping from the Earth’s surface than they reflect back into space.



Edited 1 times. Last edit at 07.35hrs Thu 4 Feb 21 by geoffers.

A reasonably un-biased view of greenhouse gas warming and cooling effects (and mostly in simple English):

[www.bgs.ac.uk]

Wrt contrails, they are mostly ice crystals formed by disturbance of the water vapour gas that is already there in the atmosphere (so that reduces warming very slightly). Note that contrails also form from the disturbed airflow at the wing tip, not just the engines. However, a smaller portion of the contrail is formed from water vapour generated from the hydrogen production which is a by-product of combusting aviation fuel.

Much more concerning for global warming though is the amount of CO2 generated by burning aviation fuel.

Equally worrying is the amount of CO² from shipping, which seems mainly to escape the media discussions

Shipping and aviation represented around 3.2% and 2.1% respectively of global CO2
emissions in the mid-2000s.

[www.transportenvironment.org]





Edited 2 times. Last edit at 11.16hrs Thu 4 Feb 21 by geoffers.

On the face of it, without researching the weather patterns further it does appear a linked coincident that many parts of Britain had a great Spring with long spells of clear blue skies and now a pretty consistent cold winter period so far. And there was and is minimal aircraft traffic/traffic volumes across some parts the world.

I looking forward to reading the verdict in the coming years, to the impact on weather and lack of lockdown traffic.





Edited 1 times. Last edit at 20.55hrs Sat 6 Feb 21 by raddays.

A key scientific motto is "correlation does not necessarily indicate causation".

As Geoffers states, aviation is "only" 2.1% of global CO2 Emissions, and it has not totally ground to a halt. Yes, the euro short haul passenger market is way down, but the big polluter long-haul is still surprisingly active, with many "heavy" passenger aircraft being used solely as freight flights. Also have a look at [www.bgs.ac.uk] and you may be surprised at some of the big emmitters - eg cement manufacturing industry between 5% and 8% of global emmissions. Big construction projects have been kept going so far through the pandemic, so cement co2 emmissions are unlikely to have reduced much.

Undoubtedly, there was a drop in emissions worldwide in March-April last year, but very short term, and now the politicos are pushing for more inrastructure big builds to kick start economies, giving a consequent boost to all emmitting industries.

Many thanks, very interesting.

Hopefully, this winter's snow is extra special and lasts until the end of June in vast amounts.



Edited 1 times. Last edit at 16.17hrs Sun 7 Feb 21 by raddays.

One thing you never see mentioned is the amount of CO² attributable to the human population itself (plus animals)

I saw somewhere that "an average" human produces 2lbs of CO² per day and with a worldwide population of 7.8 billion that amounts to 6.96428571E+9 (6,942,857,200)tons

I wonder how many tons transport/industry etc produces

I think CO2 fae coming out humans(animals) and animals mouths don't count as a pollutant so not an issue unless yer rich and into eugenics.

Pretty sure there's numbers out there breaking down the transport industry though they were all over the place when I looked.. Overall transport appears to be accepted as a 1/3 of industrial CO2. Anyone wants tae find out how much CO2 is produced bringing in fruit n veg tae bonnie wee Scotland I'll be happy tae read and use it tae try and cut it doon.

By the time C02 is "sorted" our oceans will be deed anyway and I doubt the rain will be nice, yer food will have enough roundup in it to make all yer health insurance astronomical and you'll need an extra fridge tae keep yer medicine and vitamins produced by fae the same funts that make own roundup and co.

The bit about food aint even the future.............

Lot more worse shit out there than C02, a lotta commercial growers run to waste and its shite they feed their crops with which ends up in the drains, they'll also triple the ppm of C02 by pumping it in to achieve higher yields. Most need heat or cooling too under glass or plastic.