Yes…indeed it was. Although “slushball” might be a more fitting name. Wait until you hear about our Earth’s amazing ability to find its way out of an extreme.
During the Neoproterozoic period, around 633 million years ago, the former continent named Rodina started to split apart. The tectonic shifts produced large amounts of basalt rock, which has the special power of capturing large amounts of carbon. The absorption of carbon by basalt rock, as well as the less luminous sun, eventually lowered the temperature on Earth. As the temperature continued to drop, the ocean began to freeze.
The initial freezing of the ocean further intensified because the freezing of ice is a positive feedback. Essentially what this means is that more ice equals more ice and more freezing equals more freezing. This happens because ice is a white surface with a high albedo or reflectivity from that surface, which means that it does not absorb a lot of incoming radiation. In fact, radiation was getting reflected from Earth rather than absorbed. Thus, the solar radiation or heat that normally would have gotten absorbed was not — and this decrease in radiation ultimately meant a cooler climate. Coming full circle, a cooling climate made freezing even easier, which ultimately produced a runaway icehouse effect.
A fascinating thing happened during this icehouse period. Many organisms were able to survive either by living beneath the ice or just above the ice and used sunlight to fuel their photosynthesis. But this is a topic for another time.
So how did Earth ever unfreeze? Well, during this time Earth’s processes were still very much intact. Although the surface of the planet might have been covered in ice or slush, there was still tectonic movement. The Rodinia continent continued to break up because of more shifts in the tectonic plates, and this movement caused several volcanic eruptions.
Along with the magma and other substances produced during volcanic eruptions, large amounts of carbon dioxide are also released. Over time the carbon in the atmosphere began to add up because there were so many eruptions. An increase in carbon dioxide, a greenhouse gas capable of trapping radiation, meant that there was more radiation (heat energy) being stored in the atmosphere. Additionally, since there was no chemical weathering happening since the Earth’s surface was covered in ice, none of the carbon was getting absorbed by the land but rather going straight into the atmosphere. More heat in the atmosphere equals a warmer climate. Eventually, the warmer climate was able to melt the ice that was frozen.
In retrospect, this somewhat preposterous-sounding series of events highlight Earth’s natural response and instinct to balance itself out in whatever (seemingly strange) ways it can. Understanding past climates help us deal with our present climate and predict future ones as we try to understand ways in which Earth might react to our interference of its natural regulating system.
