• Written by Paulo de Souza, Professor, Griffith University
The atmosphere of Mars is thin and very dry. NASA's Mars Reconnaissance Orbiter, CC BY-ND CC BY-ND

Climate Explained is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change.

If you have a question you’d like an expert to answer, please send it to climate.change@stuff.co.nz

If tiny concentrations of carbon dioxide can hold enough heat to create a global warming impact on Earth, why is Mars cold? Its atmosphere is 95% carbon dioxide.

The recipe for the temperature of a planet’s surface has four major ingredients: atmospheric composition, atmospheric density, water content (from oceans, rivers and air humidity) and distance from the Sun. There are other ingredients, including seasonal effects or the presence of a magnetosphere, but these work more like adding flavour to a cake.

When we look at Earth, the balance of these ingredients makes our planet habitable. Changes in this balance can result in effects that can be felt on a planetary scale. This is exactly what is happening with the increase of greenhouse gases in the atmosphere of our planet.

Increased concentrations of carbon dioxide, methane, sulphur hexafluoride and other gases in the atmosphere have been raising the temperature of our planet’s surface gradually and will continue to do so for many years to come.


Read more: Climate explained: why carbon dioxide has such outsized influence on Earth's climate


As a consequence, places covered in ice start melting and extreme weather events become more frequent. This poses a growing challenge for us to adapt to this new reality.

Small concentration, big effect

It is surprising to realise how little the concentration of carbon dioxide (CO₂) and other greenhouse gases has to change to cause such a shift in our climate. Since the 1950s, we have raised CO₂ levels in the atmosphere by a fraction of a percent, but this is already causing several changes in our climate.

This is because CO₂ represents a tiny part of Earth’s atmosphere. It is measured in parts per million (ppm) which means that for every carbon dioxide molecule there are a million others. Its concentration is just 0.041%, but even a small percentage change represents a big change in concentration.

We can tell what Earth’s atmosphere and climate were like in the distant past by analysing bubbles of ancient air trapped in ice. During Earth’s ice ages, the concentration of carbon dioxide was around 200ppm. During the warmer interglacial periods, it hovered around 280ppm, but since the 1950s, it has continued to rise relentlessly. By 2013, CO₂ levels surpassed 400ppm for the first time in recorded history.

This graph, based on samples of air bubbles fro ice cores and direct measurements of carbon dioxide, shows the rise of atmospheric carbon dioxide since the industrial revolution. NASA, CC BY-ND

This rise represents almost a doubling in concentration, and it clear that, in the recipe for Earth’s surface temperature, carbon dioxide and other greenhouse gases are to be used in moderation.

The role of water

Like flour for a cake, water is an important ingredient of the Earth’s surface. Water makes temperature move slowly. That’s why the temperatures in tropical rainforests does not change much, but the Sahara desert is cold at night. Earth is rich in water.

Let’s have a look at our solid planets. Mercury is the closest planet to the Sun, but it has a very thin atmosphere and is not the warmest planet. Venus is very, very hot. Its atmosphere is rich in carbon dioxide (over 96%) and it is very dense.

The atmosphere of Mars is also rich in carbon dioxide (above 96%), but it is extremely thin (1% of Earth’s atmosphere), very dry and located further away from the Sun. This combination makes the planet an incredibly cold place.

The absence of water makes the temperature on Mars change a lot. The Mars exploration rovers (Spirit at Gusev Crater and Opportunity at Meridiani Planun) experienced temperatures ranging from a few degrees Celsius above zero to minus 80℃ at night: every single Martian day, known as sol.


Read more: Curious Kids: What are some of the challenges to Mars travel?


Terraforming or terra fixing

One of the interesting challenges we face while building space payloads, like we do at Griffith University, is to build instruments that can withstand such a wide temperature range.

I love conversations about terraforming. This is the idea that we could fly to a planet with an unbreathable atmosphere and fix it by using some sort of machine to filter nasty gases and release good ones we need to survive, at the correct amount. That is a recurrent theme in many science fiction films, including Aliens, Total Recall and Red Planet.

I hope we can fix our own atmosphere on Earth and reduce our planet’s fever.

Paulo de Souza is a Professor and Head of the School of Information and Communication Technology at Griffith University and collaborating scientist of the NASA's Mars Exploration Rover Project.

Authors: Paulo de Souza, Professor, Griffith University

Read more http://theconversation.com/climate-explained-why-mars-is-cold-despite-an-atmosphere-of-mostly-carbon-dioxide-126337

Switch It Up: What’s the Relationship Between Lighting and Your Work Performance

It’s no secret that light has an immense impact on the way our bodies function on a daily basis. Light is closely linked to our circadian rhythms or our ‘built-in clocks’, and as such, it larg...

Lilly Miller - avatar Lilly Miller

How to Get Rid of Rats?

Do you suffer from scratching noise in the night or find strange signs such as gnawed pieces of wooden furniture or droppings in your house? Then, you have to prepare for an unpleasant fight with ro...

News Company - avatar News Company

VIDEO: Michelle Grattan on an extended travel ban, a royal commission, and zero emissions by 2050

Michelle Grattan talks with Assistant Professor Caroline Fisher about the week in politics, including the extension of the coronavirus travel ban, the royal commission into the bushfires, and labor&rs...

Michelle Grattan, Professorial Fellow, University of Canberra - avatar Michelle Grattan, Professorial Fellow, University of Canberra

I've seriously tried to believe capitalism and the planet can coexist, but I've lost faith

RAJAT GUPTA/EPAThis article is the first in a three-part series on radical ideas to solve the environmental crisis. As the Productivity Commission confirmed this week, Australia’s economy has ...

Samuel Alexander, Research fellow, Melbourne Sustainable Society Institute, University of Melbourne - avatar Samuel Alexander, Research fellow, Melbourne Sustainable Society Institute, University of Melbourne

What is hypnobirthing, the technique the Duchess of Cambridge used?

In a new parenting podcast, Catherine, the Duchess of Cambridge, said she used hypnobirthing techniques to help her get through severe morning sickness – a condition called hyperemesis gravidaru...

Mary Steen, Professor of Midwifery, University of South Australia - avatar Mary Steen, Professor of Midwifery, University of South Australia

Memories overboard! What the law says about claiming compensation for a holiday gone wrong

FRANCK ROBICHON/EPAWhen booking a luxury cruise, you generally expect relaxation and enjoyment, not forced quarantine and distress. Unfortunately, for the thousands of vacationers trapped on cruise s...

Mark Giancaspro, Lecturer in Law, University of Adelaide - avatar Mark Giancaspro, Lecturer in Law, University of Adelaide

Without more detail, it's premature to say voluntary assisted dying laws in Victoria are 'working well'

ShutterstockThe Voluntary Assisted Dying Review Board has this week published a report detailing the first six months of the legislation in action in Victoria. The report reveals 52 people legally e...

Courtney Hempton, Associate Research Fellow, Deakin University - avatar Courtney Hempton, Associate Research Fellow, Deakin University

I've always wondered: who would win in a fight between the Black Mamba and the Inland Taipan?

Wes Mountain/The Conversation, CC BY-NDThis is an article from I’ve Always Wondered, a series where readers send in questions they’d like an expert to answer. Send your question to always...

Timothy N. W. Jackson, Postdoctoral Research Fellow, Australian Venom Research Unit, University of Melbourne - avatar Timothy N. W. Jackson, Postdoctoral Research Fellow, Australian Venom Research Unit, University of Melbourne

Australia, we need to talk about who governs our city-states

Benny Marty/ShutterstockIn 1971, a Time magazine article, titled “Should New York City Be the 51st State?”, observed: States have not only short-changed and hamstrung their cities but a...

Benjamen Franklen Gussen, Lecturer in Law, Swinburne University of Technology - avatar Benjamen Franklen Gussen, Lecturer in Law, Swinburne University of Technology

Sick and Tired of Your Dead End Job? Try Teaching!

Tired of the same old grind at the office? Want an opportunity to impact lives both in your community and around the world? Do you love to travel and have new experiences? Teaching English is the perfect job for you! All you need is a willingness to ...

News Company - avatar News Company

The Impact of an Aging Population in Australia

There’s an issue on the horizon that Australia needs to prepare for. The portion of elderly citizens that make up the country’s overall population is increasing, and we might not have the infrastructure in place to support this. Australians h...

News Company - avatar News Company