Mars Is Emerging From an Ice Age

Could the planet one day be warm enough to sustain life?

NASA/JPL/Arizona State University, R. Luk

The question of whether Mars once was a warmer, habitable planet or if it’s always been a cold wasteland is a question scientists have been trying to answer for … forever.

But the future for the red planet might actually be clear and bright. A study published today in the journal Science suggests Mars is currently in the midst of an ice age — and that it is potentially en route to exit that cyclical state, and perhaps warm up.

“We have indeed identified the record of the most recent Martian glacial period and the regrowth of the polar ice since then,” says planetary scientist Isaac Smith, the study’s lead author from the Southwest Research Institute in San Antonio, Texas

A warmer Mars, of course, means the planet could become more amenable to sustaining or even evolving some forms of life.

Like Earth, Mars goes through seasonal and epochal cycles in which the climate systems change over very long periods of time (hundreds of thousands or even millions of years). One of the important factors that shapes what these changes will look like is the planet’s tilt on its axis. Earth’s tilt is about 23.5 degrees and varies about 2 degrees over millions of years. Mars’ tilt? About 25 degrees but fluctuates by as much as 60 degrees during the same time span. Yikes. It’s a consequence of the red planet’s proximity to Jupiter and the latter’s gravitational effects, as well as the lack of a moon as big as Earth’s.

The top 100- to 300-meter layers of ice show a stark change in properties between an ice age and an inter-glacial period. In the highlighted boxes, layers below the blue line show migration of spiral features toward the left (yellow and orange lines). Above the blue line, those features disappear or reverse migration direction, an indication of changes in accumulation rate and wind patterns associated with climate change.

Southwest Research Institute

And that tilting means the amount of sunlight that hits a certain spot of the surface changes much more radically.

“Because the climate on Mars fluctuates with larger swings in axial tilt, and ice will distribute differently for each swing, Mars would look substantially different in the past than it does now,” Smith said in a news release. “Furthermore, because Mars has no oceans at present, it represents a simplified ‘laboratory’ for understanding climate science on Earth.”

Smith and his team have mapped the ice deposits on the north and south poles for the first time ever, and found that an ice age on Mars began about 400,000 years ago. The research team also found that such accelerated accumulation had occurred and that there was enough ice to cover the entire planet under a two-foot layer.

Mars seems to be coming out of its ice age and could warm up.

More intriguing, however, is what happens next. With such a capacity to change climatic activity so quickly, Mars seems to be quickly coming out of its ice age and could potentially warm up. The poles will probably lose some of that ice, and the surface of the rest of planet could warm up considerably.

The problem, of course, is that Mars still doesn’t have an atmosphere that could keep liquid water on the surface in large quantities. The prospect that Mars could naturally retrieve its once-vast reserves of lakes and oceans is almost impossible unless the planet miraculously gets a robust atmosphere back. Life might have a better chance of surviving, but there’s no way the environment will be anything as vibrant or diverse as what we find here on Earth.

Nevertheless, if we fast-forward a couple-hundreds of thousands of years, Mars will probably look like nothing we’ve ever seen.

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