The big bang theory
Mark Twain famously observed: “Everyone talks about the weather, but no one does anything about it.” That’s true, unless you are a volcano. Volcanoes know how to do something about the weather, especially really big ones. Nigel Calder, in his 1974 book and BBC TV series told us about the effect of Bali’s Mt Agung blowing its top in 1963. Volcanic dust was spread by stratospheric winds, and by intercepting the sunlight it cooled the world. The surface temperature of the Earth was apparently reduced by a third of a degree in 1964 and 1965.
Then in 1991 we had an even bigger one in our part of the world. Mt Pinatubo in the Philippines helped create amazing sunsets and extraordinary weather. It was aided by another eruption in Chile that same year. In 1992, like now, we suddenly had some big late winter and early spring rains in South Australia. We had flooding from Gawler to Langhorne Creek. The Torrens became a torrent. Tragically, it swept through the Cudlee Creek caravan park and two people were killed.
The Pinatubo eruption was so big it changed the world’s weather for the next couple of years. It reminded us that nature has its own arsenal that can rival anything we can stockpile. We might be able to create a nuclear winter but nature can create a volcanic one.
There are other blasts from the past. The Indonesian Tambora eruption of 1815 created the famous “year without summer”. And before that, the Icelandic eruption that began in June 1783 and lasted eight months. The ash and gases from the Laki fissure helped create another bitterly cold winter. Work by the University of Oregon shows it caused temperatures in the US to fall by 4.8C below the 225-year average.
In Iceland itself, acid rain killed crops and livestock. The famine that followed wiped out a quarter of Iceland’s population. The gases and material spewed into the atmosphere acted as a global coolant. Millions of lives were affected around the world. Historians now say the famines that followed in France helped create the conditions that led to the French Revolution. A big bang in Iceland didn’t just change the world’s weather, it changed the world’s history.
So, has the recent almost unpronounceable Eyjafjallajokull eruption – once again in Iceland – changed the world’s weather? It started in April and lasted five weeks. It threw dust up to 9km into the atmosphere. It’s estimated 250 million cubic metres of volcanic material was pumped into the sky. Most experts say although this bang was big enough to disrupt air travel it wasn’t big enough to have any real effect on the world’s weather. But there has been a lot of other volcanic activity recently. Could there be a cumulative effect? Could there be a link to the exceptionally wet weather here, the return of big snowfalls in the alps, and the flooding in Victoria and the Outback?
I am not a global warming sceptic. I don’t say it is nature not man that drives the Earth’s warming and cooling. Like many things in life, it’s possible both sides are right. When we are burning billions of tonnes of fossil fuel we are acting like an industrial volcano. We just take 200 years rather than two months to push the stuff out. We can’t stop volcanoes but we can stop what we are doing. Let’s learn from nature, and in the meantime, enjoy the change in the weather.