Recent work challenges view of early Mars, picturing a warm desert with occasional rain

May 3, 2018, Tokyo Institute of Technology
The simplified surface energy balance for early Mars showing the decrease in surface temperature with increasing amounts of surface ice. The resultant increase in surface reflectivity is represented by a widening blue arrow. Credit: Ramirez and Craddock (2018), Nature Geoscience

The climate of early Mars is a subject of debate. While it has been thought that Mars had a warm and wet climate like Earth, other researchers have suggested early Mars might have been largely glaciated. A recent study by Ramses Ramirez from the Earth-Life Science Institute (Tokyo Institute of Technology, Japan) and Robert Craddock from the National Air and Space Museum's Center for Earth and Planetary Studies (Smithsonian Institution, U.S.) suggests that the early Martian surface may not have been dominated by ice, but might instead have been modestly warm and prone to rain, with only small patches of ice.

While there is little debate about whether water previously existed on Mars, the debate regarding what the of Mars was like around 4 billion years ago has persisted for decades. Mars has a surprisingly diverse landscape made up of valley networks, lake basins and possible ocean shorelines. These ancient fluvial features all provide clues that early Mars may have had a warm and , similar to Earth's (Figure 1).

However, this idea has challenges. First, the amount of solar energy entering the atmosphere at the time was considered to be too low to support a warm and wet climate. Secondly, recent climate studies have argued that Mars' ancient fluvial features can be accounted for with an icy climate, where widespread surfaces of ice promoted cooling by reflecting solar radiation (Figure 2). Occasional warming events would have triggered large amounts of ice-melt, and fluvial activity as a result. However, Ramirez and Craddock suggest that early Mars was probably warm and wet, and not so icy, after a careful geological and climatological analysis revealed little evidence of widespread glaciation.

The Grand Canyon (a) versus a Martian dendritic river system (b) (Arabia quadrangle; 12 degrees N, 43 degrees E). Slight morphologic differences between terrestrial and Martian comparisons may be attributed to the great differences in age. Scale bar is 60 km long. Credit: Google/Landsat/Copernicus (a) and Google/NASA/JPL/University of Arizona (b). Images adapted from Ramirez and Craddock (2018), Nature Geoscience

Recently, their study, published in Nature Geoscience, argues that volcanic activity on a relatively unglaciated planet could explain Mars' fluvial features. Volcanic eruptions releasing CO2, H2, and CH4 may have contributed to the greenhouse effect, which in turn may have promoted warming, precipitation (including rain), and the flow of water that carved out the valleys and fluvial features. However, this climate would not have been as warm and wet as Earth's, with precipitation rates of around 10 centimeters per year (or less), similar to Earth's semi-arid regions. This drier climate suggests that small amounts of ice deposits could have also existed, though these would have been thin, and liable to melt, contributing to the fluvial system.

In the future, the authors will be using more complex models in their analysis to investigate their warm, semi-arid climate hypothesis further. They will also be aiming to find out what the climate was like before these fluvial features formed on Mars. This will involve investigating the earliest history of Mars, which is a mysterious subject since little is currently known about it.

Explore further: New studies of clay formation provide clues about early Martian climate

More information: Ramses M. Ramirez et al, The geological and climatological case for a warmer and wetter early Mars, Nature Geoscience (2018). DOI: 10.1038/s41561-018-0093-9

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Mark Thomas
not rated yet May 03, 2018
Volcanic eruptions releasing CO2, H2, and CH4 may have contributed to the greenhouse effect, which in turn may have promoted warming, precipitation (including rain), and the flow of water that carved out the valleys and fluvial features.


If that is true, perhaps we could duplicate the effect by redirecting icy comets into the icy polar caps of Mars. Logically, if enough of the ices were vaporized, we should get a similar warming in very short amount of time. On general principals, this is better than nuking the polar caps or waiting 10,000 years for plants to transform Mars on their own. Comet impacts can be much more powerful than nuclear weapons and generally don't cause radioactive fallout.
rrwillsj
2.3 / 5 (3) May 03, 2018
But Mark! You would have Human efforts causing Climate Change and Global Warming....

The horror of it all.

Bitch slapping the denier cultists.
Mark Thomas
5 / 5 (2) May 03, 2018
Bitch slapping the denier cultists.


Yes, as they so richly deserve.

It is worth pondering the incredible irony of global warming ultimately becoming one of the human race's greatest allies on numerous worlds.
Joker23
1 / 5 (3) May 07, 2018
Start reading about the history of earth. It has had literally millions of thermal cycles over it's 4 billion years and guess what? Humans have only been here and able to affect the climate, if you believe we can, for at most 200 years at the most. I guess those stone age SUV's caused all of those. SlaP BACKq!
Scolar_Visari
5 / 5 (1) May 07, 2018
Humans have been affecting climate far, far longer than the industrial era.

Since the Neolithic revolution, for example, vast amounts of trees have been cleared for crops and livestock, with much of that often done in the slash-and-burn style with no subsequent fertilization. Even non-agrarian societies have been known to burn enormous stretches of land as part of their game management strategies.

With the removal of trees comes a diminished capacity for carbon dioxide removal and an increased rate of carbon release from their use as fuel. While deforestation is dwarfed by modern fossil fuel usage in terms of carbon generation, it still is a very important factor with deeper ecological and land management concerns.

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