Question on the ash clouds over Europe

[OnlinePoker]

Post 9/11, temperatures in the U.S. were up around 1 degree on average for the 3 days aircraft were grounded. One theory given was the contrails weren't reflecting the sun so more light and heat was able to reach the earth (others say it was just sunnier during this period so the temperatures would have been up anyway). Does anybody know if a similar effect is taking place in Europe right now with all the planes grounded, or would the ash clouds work to counter the effect of the missing contrails?

[jpak]

1. Large volcanic eruptions cool global climate

n/t

[Warpy]

2. The brownish grey ash cloud isn't as reflective as contrails

but the net effect is cooling because it prevents sunlight from reaching the surface.

Expect slight cooling if the volcano keeps belching ash over the next 2 years, its pattern in 1830.

[thecrow]

3. The Summer that Never Was

http://www.hewitts.com/Hewitts_Home/The_Summer_that_Never_Was.html

The Summer that Never Was


As anyone who gardens knows, we're NOT enjoying one of the coolest, cloudiest and wet years in memory. I've talked to some experienced gardeners who've been gardening for over fifty years and even they agree that there hasn't been a growing season worse than this. Well, there WAS a worse year nearly two hundred years ago that produced snow and frost in June, frost in July and another killing frost in August. The year was 1816, also known as “The Year There Was No Summer” and “Eighteen Hundred and Froze To Death”.

It seems that a volcano called Tamora explosively erupted in Indonesia in April of 1815. This eruption is regarded by many as the largest eruption in recorded history. On the Indonesian archipelago the impact was, of course, devastating with estimates of up to 90 million deaths. The size and violence of this eruption forced an estimated 100 CUBIC MILES of dust, ash and sulfuric acid into the stratosphere. Many scientists feel that this dust and ash was responsible for “The Year There Was No Summer”. Other theories involve sunspot activity and still other theories revolve around larger cycles of warm and cool climate conditions that occur every 210 years or so. Regardless of the reason or reasons, the tribulations of the summer of 1816 are legend and had a hand in, among other things, the migration of many New Englanders and New Yorkers out of those areas, and a wave of migration out of central Europe and England to the United States.

[OKIsItJustMe]

6. Not likely this time around

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=115&topic_id=242164&mesg_id=242164

[joshcryer]

4. It will have a net cooling effect on the planet. More fuel for deniers.

As far as EU is concerned, EU is going to be cooled pretty significantly. No need to worry about major deaths from the summer we were looking to get.

[bhikkhu]

5. On the explosivity index, it should be minor

It hasn't been rated yet that I know, but definitely a small one compared even to Mount Saint Helen's. I wouldn't expect a measurable effect on global climate.

[Statistical]

7. Net cooling for Europe maybe but net cooling for planet will most likely be unmeasurable.

St Helens was a fraction of the last eruption that actually cause global cooling.
This eruption likely (unless things change in future) going to be smaller than St Helens.

Unless the eruption is powerful enough to get ash into stratosphere (where it will remain for years) it will be rained out rather quickly. Bad news is Europe will be getting a lot of acid rain (sulfur).

[Ready4Change]

8. 3 days is too short a time to consider.

Pick any 3 days and the average temp will be some number of degrees higher or lower than 'average.' So the original claim, that post 9/11 grounding of planes raised temps, isn't valid.

Still, the question of how that eruption might effect our climate is a good one. A BBC report I saw the other day addressed that, asking if this would result in vastly cooler temps, as has occurred in our recorded history. The answer was no. Apparently the clouds from this event aren't hot enough to reach high enough into the atmosphere to have any effect. They are low enough that rain and gravity will cause the particles to precipitate out. Had it been hotter, the particles could have gone higher, where they could have remained for a much longer time and had a stronger effect.

So, no strong temperature effect from the eruption.

I've not heard if, say, two weeks worth of grounded planes in Europe might have any effect at all. I doubt it, but I also admit I'm no expert.