10 Things That Would Happen if Every Volcano on Earth Erupted at Once

The world would go dark

Following the 2011 Grímsvötn eruption in Iceland, the nearby town of Kirkjubaejarklaustur was plunged into almost total darkness in the middle of the day thanks to the plumes of ash that reached as high as 12 miles into the atmosphere.

In a nightmare scenario of synchronized worldwide volcanic eruptions, experts believe that the ash clouds could travel thousands of miles and block out the sun entirely, remaining in the atmosphere for up to 10 years. This would make the process of photosynthesis very difficult and would have a calamitous effect on all plant life and cause temperatures to drop. A large area of the United States would be covered in ash thanks to the Yellowstone super volcano located in Wyoming.

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