Exorcising the cloud

The Laki fissure eruption in Iceland 1783 was the biggest air pollution event in history; One of the climatic effects was a hot toxic fog which persisted in Britain for several months poisoning people and crops and leading to a death toll so high it is termed a 'mortality crisis'. The connection between the eruption and mortality crisis was made when John Grattan analysed archival data from the 1780s "burial records indicate mainly the young and old suffered and the deaths did not follow accepted annual patterns (usually highest in late winter); indicating the forcing mechanism was environmental." said Grattan. He has been using archived newspapers and diaries to reconstruct the eruption's impacts, they make stark reading -

"The sun is red as blood, with alarming meteors, tremendous thunderstorms, blue mist and intense heat. People are daily falling down in the reigning illness and many die. fever rages which people term the Black Fever."

Reports further show people's fears that Armageddon was upon them, which led them to beg priests to exorcise the noxious cloud. The cloud resulted from particular atmospheric conditions "A high pressure air mass was present over Britain during June and July, concurrently Iceland was experiencing a low pressure system and the Laki fissure was at its most productive. Wind from the low pressure system would have dispersed the volcanic material towards Europe and descending air within the high pressure cell over Britain concentrated the volcanic gases near the ground surface, leading to the acid fog" said Grattan. Sulphur emitted by the volcano combined with water vapour and oxygen in the atmosphere to form 200 million tonnes of sulphuric acid, if an eruption of the same magnitude occurred now, the effects would be far worse due to our poorer air quality "many cities are already at the permissible limit of pollution levels, therefore, even a small injection of volcanic sulphur into the atmosphere could push them over the threshold into levels which are toxic for people and the environment " said Grattan.

To find out about how John's work is progressing and where its leading to -
tune in to the radio show and podcast.

The whole story of the hole in the ozone

Jonathan Shanklin is most famous for discovering the hole in the ozone layer over Antarctica back in the early 1980s which he published in Nature in 1985. In total he's made 16 trips to the Antarctic, visiting all the British bases. He's also responsible for running the operational side of the British Antarctic Survey meteorological observing program. This work includes purchasing, testing and installing new equipment, writing computer software, recruiting Antarctic scientists, training staff, analysing data, solving problems, writing papers and giving public lectures.

This work had massive implications, from raising the issue of global warming and the harmful nature of UV radiation to the eradication of CFCs from many parts of the world. Jonathan will be on the show to explain how although the hole in the ozone is related global warming it is not the single contributing factor. There has been a wide variety of studies of this ozone hole since Jonathan discovered it, has it giot bigger? Will cutting greenhouse gas emissions help fix the hole? To learn more about how the discovery was made and what the hole has been up to since you'll need to tune in to the radio show and podcast.