BBC: How aircraft contrails form cloud (8 January 2010)

[dbt]

At the first link below is a slide show of satellite images analyzed by the UK's Met Office showing how "condensation trails" from aircraft can become clouds. Dr. Jim Haywood and colleagues from the Met Office and from Reading and Leeds universities claim "contrail-induced" cirrus clouds with both a cooling and a warming effect.

They say the cloud cover reflects sunlight back into space and, at the same time, prevents heat from leaving the Earth. They say that there may also be a net warming effect on the Earth.

As far back as 2003, I posted here that jet aircraft were generating artificial cloud cover. Little by little, the border between tinfoil and science is becoming blurry.

http://news.bbc.co.uk/2/hi/science/nature/8309629.stm

More from the BBC here.

[midnight]

1. k&R. For the science crowd.... This report seems to indicate that the

contrails are having the opposite effect at the same time with regard to temp.?

[MercutioATC]

2. I believe you mistyped.

They're not "contrails", they're "chemtrails". :P

:tinfoilhat:

[dbt]

3. One learns not to use Certain Words

at Certain Websites.

:evilgrin:

[lapfog_1]

4. In the days after 9/11

when the passenger jets were grounded over the US, a number of atmospheric scientists started running experiments and taking measurements on the effect. I believe the report was surprising, even to them.

[caraher]

5. From the other BBC links it seems the jury is out

There's a cooling effect in that the clouds do reflect solar radiation back into space (reducing what reaches the ground) and a warming effect due to heat trapping. It's not obvious which effect wins out; it looks like most scientists who've looked atthis are guessing there's more warming than cooling on balance, but it's not certain.

It also appears the 9/11 results are not as robust as many reports lead us to believe. The 1-degree effect observed over the 3 flightless days is apparently well-within natural variations for a typical September, and at least one researcher estimates that the volume of air traffic is insufficient by orders of magnitude to be responsible for the difference.

[igetalong]

6. We had a bunch of 'em in my area earlier this week

I'm not real sure what the deal is, but I'm confident there are plenty of "Amazin' Randi" followers who stand ready to correct any
notions of something funny going on.

[pscot]

7. I recall suggesting this

in conversation back in the late 60's. The reason I remember is that I was shouted down and vilified as a raving lunatic and a stone Luddite bent on ending all progress. It's nice that Science is finally cstching up, but where was it when I needed it?