Tag: volcano

Merapi, volcanoes and cooling

Back in April, when Eyjafjallajökull in Iceland was erupting and causing much disruption to air travel in Europe and the North Atlantic, there was some concern that the volcano’s ash and aerosols could cause global cooling. As I said at the time, there was little chance of that happening because volcanoes need to be near the equator to cause global cooling events. However, we now we have an eruption in Indonesia that has the potential to cause a noticeable global cooling. Merapi is Indonesia’s most active volcano, and the eruptive sequence which began at the end of October has already killed at least 153 people and emitted a considerable amount of sulfate aerosols as this NASA Earth Observatory image shows:

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At the time of writing the eruption was showing signs of easing off, and the amounts of sulfur emitted to date haven’t been sufficient (or reached high enough altitudes) to cause a significant cooling. However, as Jeff Masters notes, Merapi’s volcanic history indicates that it is capable of very powerful eruptions which could mimic or exceed the Pinatubo eruption in 19941991 which caused a 0.5ºC cooling over the following 18 months. As ever, the best place to follow events is at vulcanologist Erik Klemetti’s Eruptions blog (note: new web address). Definitely one to watch.

Garth goes off the deep end

Another week, another load of tripe from Garth George in the Herald. He emerges from his sulphurous lair stirred by stories of volcanoes in Iceland to lend his weight to calls for the suspension of the Emissions Trading Scheme. He makes so many egregious errors that he not only makes himself look foolish, but also calls into question the editorial standards of the Herald. Opinion is opinion (and Garth is entitled to his) but facts are facts, and the nation’s leading newspaper should not allow him to simply invent his own.

Let’s take a closer look…

 

Here’s his opening error:

…more and more evidence is available that gases such as carbon dioxide and methane have absolutely no effect on global temperatures.

What evidence would that be, one wonders, because Garth provides no clue. I haven’t heard of any major revisions in basic physics that would allow greenhouse gases not to warm the planet. I suspect Garth is just making stuff up, interviewing his typewriter (which, for all I know, may be about to win a Nobel prize for rewriting quantum physics).

I suspect that the eruption of Mt Eyjafjallajokull in Iceland shot more gases into the atmosphere in five minutes than New Zealand would in five years.

No need for suspicion. The figures are available, and even Garth could have Googled an answer to his rhetorical question. Leo Hickman at the Guardian has done the digging: Eyjafjallajökull has been emitting somewhere in the range of 150-300,000 tonnes of CO2 per day. New Zealand, on the other hand, emitted 74.7 million tonnes of CO2e in 2008 according to the latest MfE report. Garth could have argued that Eyjafjallajökull’s peak daily emissions were about the same as New Zealand’s, but they were also being more than offset by the cancellation of so many long distance flights.

The increasing scepticism over global warming throughout the world is not surprising after the shocking sub-zero weather which created chaos all over Britain, throughout Europe and in the United States in the depth of their winter.

It was the fourth warmest winter since records began.

There is increasing scepticism here, too, after one of the coldest winters in decades, which started early and finished late, afflicted much of New Zealand.

Wrong. New Zealand’s winter started early, and was quite cold, but it also ended early and August was the warmest in the record.

But the deception continues among the global warming scaremongers.

The chutzpah is breathtaking. A Biblical phrase about logs and eyes springs to mind.

Climate has been in a constant state of flux since God created the heavens and the land and the sea and placed the sun and the moon in their orbits.

When was that, Garth?

And I am persuaded absolutely that it is the sun, not the harmless, essential trace gas carbon dioxide, that drives climate change. So our emissions trading scheme will not just be a colossal waste of time and effort but an unaffordable waste of money.

Garth’s absolute certainty is ridiculously unpersuasive, based as it is on shoddy research and made-up “facts”. The Herald, if it wishes to retain any vestige of credibility in its opinion section, should apologise for foisting such ignorant and ill-informed ramblings on its readers.

Smokestack lightning

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Not much to do with climate, I’m afraid, given that the Eyjafjallajökull eruption seems to have slowed down for the moment, but this spectacular picture from Marco Fulle at Stromboli Online shows that there’s still a lot going on up there. One of a series of night shots, it shows lightning flashing through the lava and ash erupting from the vents at the top of the volcano. There are other wonderful images to be found at Stromboli Online — Jeff Masters uses one in his latest roundup of ash movements. For the view from space, take a look at this picture from NASA’s Earth Observatory. Normal climate service will resume shortly…

[Howlin’ Wolf]

An eyeful of Eyjafjallajökull: no cooling threat (yet)

eyeful.jpg

NASA’s Terra satellite captured this spectacular image of a plume of volcanic dust from the ongoing eruption of the Eyjafjallajökull volcano in Iceland. It’s blowing south and east from Iceland (top left) towards Scotland and Norway, and has caused the cancellation of most aircraft movement over Western Europe, with knock-on disruption around the world. New Scientist explains why here. It’s well known that large volcanic eruptions can cause the earth to cool, as they can push large amounts of sulphur aerosols into the stratosphere, reflecting away incoming solar radiation. The eruption of Mt Pinatubo in 1991 is the most recent example. It caused a global cooling of about 0.5ºC over the 18 months following the eruption. Artificially creating the same effect by injecting sulphur into the stratosphere has been suggested as one possible method of geoengineering a response to global warming.

Could the current eruption cause significant global or regional cooling? That question is already being asked, but the answer seems to be no — at least for the time being. Jeff Masters has a good post discussing the issue, and points out that volcanic eruptions in the tropics have the biggest effect because the atmospheric circulation tends to rise and spread dust and aerosols both south and north of the equator around the whole planet. At mid or high latitudes, the circulation tends to be moving polewards and sinking, and this limits the effects to one hemisphere. However, truly massive eruptions, such as that of Eyjafjallajökull’s neighbour Laki in 1783-4, can cause dramatic regional effects. There are good descriptions of the disruptions to European and North American weather at the time at the Wikipedia page: it quotes British naturalist Gilbert White’s journal for summer 1783:

The sun, at noon, looked as blank as a clouded moon, and shed a rust- coloured ferruginous light on the ground, and floors of rooms; but was particularly lurid and blood-coloured at rising and setting. All the time the heat was so intense that butchers’ meat could hardly be eaten on the day after it was killed; and the flies swarmed so in the lanes and hedges that they rendered the horses half frantic, and riding irksome. The country people began to look with a superstitious awe, at the red, louring aspect of the sun.

Eyjafjallajökull’s current eruption has not approached the scale of that 18th century event, but there are fears that it could trigger new eruptions in neighbouring volcanoes. A good place to monitor what’s going on is Dr Erik Klemetti’s Eruptions blog at Scienceblogs. If you want to know how to pronounce the name, try this, and this recent video of the eruption is well worth a look.