Thursday, March 25, 2010

Are you scared yet?

Into the Climate arguement comes this little prize offering from MeteoGroup a private weather forecasting outfit owned by the people behind PA,
Who publish this today,

Yes and I could get hit by a metorite.
In 1815 there was a massive volcanic eruption on the island of Sumbawa
in Indonesia when Mount Tambora ejected millions of tonnes of dust, ash
and gas into the atmosphere.

It was the biggest volcanic eruption ever known, and the ejected
particles could have filled more than 100 cubic kilometres. Instead they
were spread by winds widely around the globe and had a devastating
effect on the weather in the northern hemisphere.

The culprit was not the cloud of dust and ash but sulphur dioxide, which
volcanoes can belch forth in vast quantities. It combines with water
vapour in the atmosphere to form a mist of sulphuric acid which reflects
a lot of sunlight away from the Earth.

The consequent drop in temperatures caused what became known as "the
year with no summer" in 1816. Crops failed due to low daytime
temperatures, late frosts and abnormally high rainfall, provoking food
riots, famine and disease. In Ireland rain fell on 142 days that summer,
and across France the grape harvest was virtually non-existent.

In North America there was snow in June, and lakes and rivers froze as
far south as Pennsylvania during July and August.

The role of vulcanism on the weather and short-term climate is sometimes
overlooked. Although this is an extreme example, something similar had
occurred just 32 years previously and rather closer to home.

In 1783 Laki volcano in Iceland erupted. The effects were less
widespread and seem to have been confined to the northern half of the
northern hemisphere. The thick pall of gases virtually wiped out the
summer of that year across much of Europe and North America, and a
particularly harsh winter followed.

The great naturalist Gilbert White wrote that "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."

Benjamin Franklin - statesman, polymath and "America's first
meteorologist" - also remarked upon these occurrences in 1784. "During
several of the summer months of the year 1783," he said, "when the
effect of the sun's rays to heat the Earth in these northern regions
should have been greater, there existed a constant fog over all Europe
and a great part of North America".

Geologists, seismologists and vulcanologists are currently monitoring
events in southern Iceland very closely, following the eruption of
Eyjafjallajokull for the first time in nearly 200 years. Although
dangerous to those nearby, this was a relatively small event but
geophysicists fear that it could trigger a much larger explosion of
nearby Mount Katla.

Katla is described as "enormously powerful", and because it lies under a
glacier its eruption would cause a huge glacial outburst flood - a
jokulhlaup in Icelandic. Moreover, it is possible that it could spread
its shadow over a much larger area, even though the last major
eructation in 1918 had no clear influence on the weather.

It is therefore not possible to say that it would have anything like the
ramifications of Laki or Tambora. Even so, anybody wishing for a hot
summer this year or next might hope that Katla does not blow. More
pertinently, so will the people of southern Iceland.

Run to the hills.

1 comment:

Sultan said...

"In Ireland rain fell on 142 days that summer". I don't think summer lasts that long...