1

2

Disaster Risk Reduction for Extreme Geohazards

Hans-Peter Plag, Climate Change and Sea Level Rise Initiative, Old Dominion University, Norfolk, VA, USA Shelley Jules-Plag, Tiwah, Inc., Reno, NV, USA

Seth Stein, Northwestern University, Evanston, IL, USASean Brocklebank, University of Edinburgh, U.K.

Stuart Marsh, University of Nottingham, U.K.Paola Campus, European Science Foundation, Strasbourg, France

Supported by:Geohazards Community of Practice of the Group on Earth Observations (GEO)

European Science Foundation (ESF)

The problem:- extreme hazards occurred in the past, but little exposure often limited the disaster - increased exposure leads to more frequent disasters- complexity of modern societies leads to more indirect effects- sustainability crisis reduces resilience

The growing, interconnected and increasingly exposed global population faces a mounting risk of a global catastrophe caused by extreme natural hazards.

Why Extreme (Geo)Hazards?

White Paper on Extreme Geohazards:• What is the problem?• What do we know and not know?• What are we trying to accomplish?• What strategies are available?• What are the costs and benefits of each?• What is the optimal strategy given various assumptions and the uncertainty involved?• What are the societal and governance processes that could facilitate disaster risk reduction?

Why Extreme Geohazards?

Extreme Events:• Extinction Level Events: more than a quarter of all life on Earth is killed and major species extinction takes place.• Global Catastrophes: more than a quarter of the world human population dies and that place civilization in serious risk.• Global Disasters: global-scale events in which a few percent of the population die. • Major Disasters: disasters exceeding $100 Billion in damage and/or causing more than 10,000 fatalities. Modified from Hempsell (2004)

Extreme events - X-Event: Rare, surprising, high impact events

Terminology

X-ness X: E: total annual death/gross domestic productdelta E: change due to eventU: Unfolding time I: Impact time Modified from Casti (2012)

Measuring Impacts

Tsunami Earthquake Earthquake Cyclone Earthquake

The problems:- knowledge of rare events is limited- know better the “why” and “how” but not the “when”- propability is difficult to assess

In the 20th century we have been very lucky ...

Extreme (Geo)Hazards

- risk assessment is challenged

Poisson distribution; Chance that one or more “1 in N years” events occur in a century:

Earthquakes

Volcanic Eruptions

Volcanic Eruptions

1) Krakatau was similar to Santorini eruption, 1600 BC, although 4 times smallerEyafjallajokull, 2010: VEI 4, 0.25 km3 Laki 1783-85: VEI 6, 14 km3

Several eruptions that happened during the last 2,000 years would be devastating under todays conditions

Extreme Hazards

Toba, 75,000 years ago, VEI 8, 2,800 km3; killed 60% of human population

Cost-Benefit Analysis

Impacts:- ash layer, several million square kilometers- destroying one or two seasons of crops for two billion people- reducing global temperature by 5-15 C- substantial physical damage to infrastructure

Death comparable to other global disasters:- 1918 Spanish flu: 3% - 5% of global population

We assume: - 10% of global population is killed if volcano eruption comes as a surprise

Cost-Benefit Analysis- Value of statistical life (VSL): $9.1 million (U.S. Department of Transportation)- U.S. citizen should be willing to spend $910 to eliminate a 1 in 10,000 risk of fatality

- Global VSL: $2.22 million

Toba-type eruption: 1 in 100,000 years; fatalities 10%:Probability of a random person dying in any particular year: 1 in 1,000,000.

Average person should be willing to pay $2.22 per year to eliminate the risk.

Global population over 7 billion: $15 billion per year.

2014 USGS Budget: $24.7 million for volcano monitoringSame level globally: $370 million

Eliminating half of the risk is worth $7.5 billion per year.

17

The largest volcano eruptions that occurred during the most recent millennia would today threaten an already stressed food supply and challenge the crucial global transportation network and, without rapid preparation, could easily lead to a global catastrophe.

Conclusion

An elaborate, comprehensive volcano observing system needs to be a core element of disaster risk reduction - from a CBA point of view, we should be willing to to spend a lot (> $500 M/year).GHCP is reviewing requirements for this observing system

We need to study how to improve preparedness and what to do with early warnings; we propose a dedicated international institute for this

We have roughly a 20% chance that a major eruption takes place in the 21st century with severe implications for food security, public health, transportation, and global economy.