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Volcanoes, ash, and grounded planes.

Posted by JLow on Apr 20, 2010

This has been all over the news; how passengers are stranded unable to travel or return home, how airlines are badly affected by cancelled flights, and refunds, or redirecting passengers to alternate destinations.

What about the effect on the environment?

Late last week I saw a comment left by a reader on a news article about the volcano, citing that grounding planes would therefore have an indirect benefit to the environment because of there would be no carbon emissions into the atmosphere. Immediately I thought “What about the plumes?”

I did some research which I am sharing below. The source is wikipedia.

With the massive reduction of air travel occurring over European skies, an estimated 1.3 million tonnes of carbon dioxide, more than the annual emissions of many developing countries, has been saved from entering the atmosphere as a result of the cancelled flights across Europe; however, no calculations have yet taken into account the massive amount of carbon dioxide released by the volcanic ash cloud itself. [119]

Residents of West London under the Heathrow Airport flight path have described the peace as ‘bliss’. John Stewart of the Heathrow Association for the Control of Aircraft Noise said they had been inundated with emails and phone calls and said “The message is that this is what life should be like. The peace and quiet is absolutely wonderful.” Christine Shilling, of the No Third Runway Action Group, who lives in nearby Harmondsworth, said: “I’ve lived here more than 40 years and I’ve never known such peace.”[120] Jenny Tonge, president of HACAN Clearskies, life peer and former Liberal Democrat MP for Richmond Park in London said “Dare we hope that it will finally lay the Third Runway at Heathrow to rest and concentrate government minds on more environmentally friendly and sustainable forms of transport?”[121][122]

No doubt there has been a reduction or temporary cessation of emissions (until flights are allowed into that airspace again), but the plumes from the eruption may actually be quite damaging as well, in more ways than one.

When ash begins to fall during daylight hours, the sky turns hazy and a pale yellow color. The ashfall may become so dense that daylight turns the sky gray to pitch black, with the ash severely restricting visibility and deadening sound. A darkened ash sky lowers temperatures during daylight hours from what would otherwise be expected. Loud thunder and lightning as well as the strong smell of sulfur accompany an ashfall.[11] If rain accompanies an ashfall, the tiny particles turn into a slurry of slippery mud. Rain and lightning combined with ash can lead to power outages, breakdowns of communication, and disorientation.[12]

Very fine ash particles can remain high in the atmosphere for many years, spread around the world by high-altitude winds. This suspended material contributes to spectacular sunsets, as well as an optical phenomenon known as “Bishop’s Ring“, which refers to a corona or halo effect around the sun.[13] High levels of ash high in the atmosphere causes climate change by cooling the globe for a few years following major eruptions. The last episode of ash-induced global cooling followed the Mount Pinatubo eruption of 1991.[14] The most documented case in recorded history of this phenomenon followed the epic eruption of Mount Tambora in 1815, which led to the year without summer in 1816.[15]

Undoubtedly, the airline industry does have a part in overall emissions. But by last official statistics, airlines only contribute 2-3% of the overall emissions, when we take into consideration industries like power generation (coal plants), transport industry such as trucking, etc.

You may also be interested in reading “Air travel disruption after the 2010 Eyjafjallajökull eruption”

John Low
MAS Environment Dept

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