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Global Catastrophic Risks, SCENARIO - Coggle Diagram
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SCENARIO
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Supervolcano
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Narrative
Over the last few years, researchers at the US Geological Survey have been raising the alarm about the Yellowstone Caldera. After a period of quiescence, satellite measurements have shown the land surface above the caldera has been rising at an accelerating rate, with more than a 30 cm rise in 2040 alone.
Unlike previous periods of movement, seismologists have also recorded a series of tremors in the northeast of the region, reflecting subterranean fracturing of rock under growing magma pressure. On 21st October 2041, the USGS issues a statement that the probability of Magnitude 8 eruption is higher than at any point in the last 100,000 years. The state government begins contingency planning for mass evacuation of residents within a 100 km radius.
After two more years of apparent calm, the tremors resume on 28th March 2043 and the planned evacuation commences. As the country holds its breath, the feared eruption finally comes on the morning of 8th April. Later analysis estimates that more than 1,300 cubic kilometers of rock, ash and volcanic gases were released in a hot plume that rose more than 20 km into the atmosphere.
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Consequences
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A combination of fine dust particles and sulphate aerosols released into the upper atmosphere spreads over the following weeks to cover much of the globe. People report a hazy or "milky" quality to the sky in the months following the eruption, along with spectacular, deep red sunsets.
Overall sunlight reaching the Earth's surface, however, is reduced by more than 15%, slowing photosynthesis and causing disruption to food crops and ecosystems.
The haze also has wide-ranging impacts on the climate. Average summer temperatures are 5-10 degrees Celsius cooler than normal, and rainfall is 25-50% lower in major breadbasket regions.
Staple crops of wheat and rice fail, leading to food shortages.
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