New Madrid earthquakeEdit

See Wikipedia:New Madrid earthquakes for greater details.

Between 1811 and 1812 thousands of quakes, including twenty 6.5 or larger ones, hit areas in the United States along the New Madrid seismic zone.

Solar flaresEdit

See Wikipedia:Solar storm of 1859 for greater details.

The solar storm of 1859 sent an electromagnetic pulse across the world which was powerful enough to take out telegraph lines everywhere, and even cause some electrical fires. If a solar eruption of that magnitude happened again today, the devastation would be massive.

See Wikipedia:Solar storm of 2012 for greater details.

According to NASA [1], in 2012 a solar flare large enough to devastate the world passed by just 9 days away from our orbit. It was only by chance any satellites were around to catch it. There is no telling how many times something that massive happens that we don't know about it. NASA says it would've devastated our infrastructure, and taken trillions of dollars and at least years to fix everything.

Ice caps meltingEdit

Antarctica has 90% of the worlds ice. If all of it melted sea levels around the world would rise about 61 meters (200 feet). If the ice covering Greenland were to melt, it'd add an additional 7 meters (20 feet).[1]

Most of the planet's land is more than 200 feet above sea level. However most of the world's population lives along its coast, so would have to evacuate.

If the planet got hot enough for the entire ice cap to melt, the heat alone would most likely kill most life on the planet already.

If the ice cap melted do to a super volcano under it, an asteroid hitting it, nuclear weapons going off there, or some mad scientist's doomsday device, then the world would be in some serious trouble. Volcanic activity in Antarctica has melted glaciers before, but never enough to cause massive global flooding.