An Ice Age on Mars is ending, scientists say. Why is that important for Earth?

Studying the Martian climate can help us better understand our own, say researchers.

|
ESA/DLR/FU-Berlin/Ralf Jaumann
This mosaic image, produced with the High Resolution Stereo Camera on ESA’s Mars Express spacecraft, shows spiral features that were used in interpreting the climate signal of ice age advancement and retreat.

Though it doesn't seem like much happens on Mars – a barren desert of a planet – it does experience seasons and climate change, much as Earth does.

In fact, the Red Planet is going through a change now, as it is coming out of an ice age, say geologists from the Southwest Research Institute.

An analysis of radar data collected by NASA's Mars Reconnaissance Orbiter shows that about 87,000 cubic kilometers of ice have accumulated at the poles since the end of the last ice age about 370,000 years ago, they report in a paper published Thursday in the journal Science. That would be enough to spread a 2 foot thick layer of ice across the entire surface of our solar-system neighbor, a rocky planet that is about half the size of Earth.

The volume and thickness of the Martian ice matches model predictions made by other scientists over a decade ago.

"Turns out the models were pretty good," says Isaac Smith, a postdoctoral researcher at the San Antonio-based research institute and lead author of Thursday's paper, in an interview with The Christian Science Monitor. "This is how we start putting dates on things; combining observations with models," he says.

Dr. Smith didn't set out to prove Martian climate models when he sought to measure ice on the Red Planet.

"I just go where the layers tell me to go," he tells the Monitor. 

But when his team started measuring, they realized their findings validated earlier predictions, which is a boost to the same type of climate modeling that is used on Earth. Smith is now at NASA's Jet Propulsion Laboratory working with glacial modelers who are studying Antarctica, where sea ice is behaving mysteriously compared to Earth's North Pole. 

By Earthly standards, the climate is quirky on Mars. There, polar ice caps actually grow during warmer periods, unlike on Earth, where they melt into the oceans. That is largely because of the tilt of Mars's axis. It can shift by as much as 60 degrees over hundreds of thousands to millions of years, exposing different parts of the planet to the heat of the sun. The Earth's tilt varies by only about 2 degrees over the same period.

When Mars is tilted 60 degrees, its North Pole faces the sun. This kicks off an ice age, as warming at the poles causes polar ice to turn to water vapor, get absorbed by the planet's thin atmosphere, and then be transferred to the cooler mid-latitudes where it condenses into snow or frost.

On Earth, by contrast, ice ages bring polar cooling. Ice sheets build up by drawing water from the oceans, which don't exist on Mars, although they may have billions of years ago.

Right now Mars is tilted about 25 degrees, almost the same as Earth's 23 degree tilt. In radar images, Smith's team is finding ice between 30 and 60 degrees latitude on the otherwise dry and dusty planet.

The icy patch is "kind of like Texas to Canada in size," he says. "There's ice there now, but it's being removed." The ice is moving to both Martian poles, though mostly to the North Pole. Smith's team doesn't know why all the action is there.

"Why does South Pole not exchange the ice with the rest of planet?" Smith wonders. "These are things we want to work on in the future, to figure it out."

You've read  of  free articles. Subscribe to continue.
Real news can be honest, hopeful, credible, constructive.
What is the Monitor difference? Tackling the tough headlines – with humanity. Listening to sources – with respect. Seeing the story that others are missing by reporting what so often gets overlooked: the values that connect us. That’s Monitor reporting – news that changes how you see the world.

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.

QR Code to An Ice Age on Mars is ending, scientists say. Why is that important for Earth?
Read this article in
https://www.csmonitor.com/Science/2016/0526/An-Ice-Age-on-Mars-is-ending-scientists-say.-Why-is-that-important-for-Earth
QR Code to Subscription page
Start your subscription today
https://www.csmonitor.com/subscribe