An incredible twist of fate: we now understand how Earth acquired its icy caps.

The History of Earth spans over 4.5 billion years, during which the planet has undergone remarkable transformations. Despite the planet's current state, for most of its history, Earth existed in what is referred to as a "greenhouse" state—meaning it lacked ice caps. But why is this the case? It seems that scientists have finally found an answer, as reported by PHYS.org.

In a new study, a team of researchers from the University of Leeds focused on understanding how the planet's ice caps formed and why the conditions we experience today are so rare in Earth's history.

The findings suggest that the current icy state of the planet is atypical and has been achieved only through a fortunate coincidence. The cool conditions that allowed Earth's ice caps to form are rare events in the planet's history and require numerous complex processes to work simultaneously, according to the new research.

Many ideas have previously been proposed to explain the known cold intervals in Earth's history, including:

• a decrease in CO2 emissions from volcanoes;
• an increase in carbon storage by forests;
• the reaction of CO2 with certain types of rocks.

The researchers conducted the first-ever combined testing of all these cooling processes using a new type of long-term 3D Earth model, which was developed for the first time at the University of Leeds. This type of "Earth evolution model" has only recently become feasible due to advancements in computational technology.

The study's authors concluded that no single process can account for such a cold climate—the results indicate that cooling actually requires the combined influence of several processes occurring at the same time.

According to the lead author of the study, Dr. Andrew Meredith, the results will help settle the debate among scientists regarding which processes are responsible for these cold periods. The authors also believe their findings could explain why glacial states are rare.

The authors note that the reason we live on a planet with ice caps rather than one free of ice is due to a random combination of very low levels of global volcanism and widely dispersed continents with large mountains that provide substantial precipitation. All of this together enhances reactions that remove carbon from the atmosphere.

No less important is the conclusion that the natural mechanism regulating Earth's climate appears to favor a warm world with high CO2 levels without ice caps, rather than a partially ice-covered world with low CO2 levels like the one we have today. It is suggested that the overall trend toward a warm climate helps prevent catastrophic global glaciations, known as "Snowball Earth," which have occurred very rarely in the planet's history.