When A Volcano erupted long ago on Mars, it created an ice barrier that covered the equator and caused massive global temperature drops
But, also started to dry up the planets continental crust. The planet kept on getting colder for several million years, until a big asteroid strike brought the planet back into a warmer climate. This led to the start of the Ice Age, which experts believe may have been triggered by a volcano eruption long time before. One of the many theories about how this happened is due to the way the planet kept on getting colder as the it came closer to the sun.
The ice sheets would have provided enough heat for the planet to warm up, but without the ice sheets, it would have been much colder than today.
The next time you hear someone ask how volcano eruptions on Mars blocked out the Sun, chances are it was chalked up to myth. The consensus was that no volcano on the Red Planet erupted for millions of years before the Ice Age. and that one thing that did cause an ice age though, was the Moon. When the Red Planet was becoming closer to the Sun, it spun faster, and the resulting gravitational pull may have blocked out the Sun. The slowing of the planet meant that the amount of gas created from volcanic activity was cut down. In turn, it made the planet a little colder, and it spun even faster, getting closer to the red planet in just a few million years.