Snowball Earth
Multiple equilibria and tipping points of the Earth's global mean temperature in a simple climate model.
Move the red handle to control the solar insolation. The green dot and line show the global mean temperature. At the lower (left) tipping point, the whole Earth glaciates and temperature drops to -50 °C. The reason is the ice-albedo feedback: Ice growth and cooling amplify each other. At the right tipping point, the Earth melts again and suddenly warms to approx. 55 °C.