SUPER-ERUPTIONS POSE GLOBAL THREAT “5-10 TIMES MORE LIKELY THAN ASTEROID IMPACT” March 8, 2005
Society publishes evidence to Government to coincide with media launch of forthcoming BBC dramadocumentary
News Release PR58
The occurrence of a super-eruption would have severe environmental effects and might threaten global civilisation. This is the assessment of a Geological Society of London working group composed of senior Earth Scientists. The effects of a super-eruption would be comparable to those predicted for the impact of a 1km-diameter asteroid with the Earth. In fact, super-eruptions are 5-10 times more likely to occur than such an impact.

Many very large volcanoes on the Earth are capable of colossal eruptions with global consequences. Such eruptions are quite frequent on a “geological” timescale, although not one has occurred on Earth in the short time that an interdependent human civilisation has existed. However, our present civilisation depends on global trade and food production, air travel and space-borne communications, all of which could be at considerable risk if a super-eruption occurred.

There may be several super-eruptions large enough to cause a global disaster every 100,000 years. This means super-eruptions are a significant global humanitarian hazard. They occur more frequently than impacts of asteroids and comets of comparable damage potential.

Prof. Steve Sparks FRS (University of Bristol), co-lead author, said: “Several of the largest volcanic eruptions of the last few hundred years, such as Tambora (1815), Krakatoa (1883) and Pinatubo (1991) have caused major climatic anomalies in the two to three years after the eruption by creating a cloud of sulphuric acid droplets in the upper atmosphere. These droplets reflect and absorb sunlight, and absorb heat from the Earth - warming the upper atmosphere and cooling the lower atmosphere. The global climate system is disturbed, resulting in pronounced, anomalous warming and cooling of different parts of the Earth at different times.

Prof. Stephen Self (Open University) said: “Super-eruptions are up to hundreds of times larger than these, and their global effects are likely to be much more severe. An area the size of North America can be devastated, and pronounced deterioration of global climate would be expected for a few years following the eruption. They could result in the devastation of world agriculture, severe disruption of food supplies, and mass starvation. These effects could be sufficiently severe to threaten the fabric of civilisation.”

The report concludes: “Problems such as global warming, impacts by asteroids and comets, rapid use of natural resources and nuclear waste disposal require world leaders and governments to address issues with very long-term consequences for the global community. Sooner or later a super-eruption will happen on Earth and this issue also demands serious attention. While it may in future be possible to deflect asteroids or somehow avoid their impact, even science fiction cannot produce a credible mechanism for averting a super-eruption. The point is worth repeating. No strategies can be envisaged for reducing the power of major volcanic eruptions.”

The Working Group has recommended:

Investment in research to improve our understanding of regional and global impacts of major volcanic eruptions.
Research to determine more accurately the composition and amounts of volcanic gases and dust released in super-eruptions – these are the major factors governing widespread environmental effects.
An expanded programme to produce a comprehensive inventory of large magnitude explosive eruptions in recent geological times, such as the initiative started under the auspices of the International Association of Volcanology and Chemistry of the Earth’s Interior (IAVCEI) [ [link to www-volcano.geog.cam.ac.uk] on www.iavcei.org]
Initiatives to improve public understanding of the nature of volcanic hazards with regional and global effects.
Establishment of a multidisciplinary Task Force to consider the environmental, economic, social, and political consequences of large magnitude volcanic eruptions. As in the case of impacts by asteroids and comets, these proposed activities will be best developed by collaboration within an international context.
Report of a Geological Society Working Group, comprising:

Prof. Stephen Sparks FRS (Bristol University)
Prof. Stephen Self (Open University)
Dr David Pyle (Cambridge University)
Dr Clive Oppenheimer (Cambridge University)
Dr Hazel Rymer (Open University) and
Dr John Grattan (University of Wales, Aberystwyth)
It’s not a question of “if” - it’s a question of when…

Many large volcanoes on Earth are capable of explosive eruptions much bigger than any experienced by humanity over historic time. Such volcanoes may be termed super-volcanoes and their colossal eruptions super-eruptions. The occurrence of a super-eruption would have severe environmental effects and might threaten global civilisation. Events at the smaller scale end of the super-eruption size spectrum are quite common when compared to the frequency of other naturally occurring devastating phenomena such as asteroid impacts. The effects of a medium scale super-eruption would be similar to those predicted for the impact of a 1 km-diameter asteroid with the Earth, but even super-eruptions of this size are still 5-10 times more likely to occur within the next few thousand years than an impact.