A warmer and wetter solution for early Mars and the challenges with transient warming

Ramirez, Ramses M.

doi:10.1016/j.icarus.2017.06.025

Cited by 64 publications

(135 citation statements)

References 95 publications

Supporting

Mentioning

125

Contrasting

Order By: Relevance

“…Our results further support the notion that a dense CO 2 ‐H 2 greenhouse could have explained the early Martian climate (Ramirez, Kopparapu, Zugger, et al, ; Ramirez, ). As we have argued before (Ramirez, ; Ramirez & Craddock, ), the high albedo of ice can pose an additional challenge in the deglaciation of an initially cold surface. Deglaciation is not a major issue for surfaces with only modest amounts of ice in many cases (Ramirez, ), although this depends on CIA assumptions and heat transport efficiency (Figure ).…”

Section: Discussionsupporting

confidence: 89%

“…Analogously, we overlay the BPS water continuum over its region of validity (0–~18,000 cm − 1 ) (Paynter & Ramaswamy, ). We also implement CO 2 ‐CO 2 CIA (Baranov et al, ; Gruszka & Borysow, , ; Wordsworth et al, ) and N 2 foreign‐broadening (e.g., Ramirez, Kopparapu, Zugger, et al, ; Ramirez, ). A standard Thekeakara spectrum is used for the Sun (e.g., Thekaekara ).…”

Section: Methodsmentioning

confidence: 99%

“…However, our study differs from that one in several key ways. First, von Paris et al () only assessed CO 2 ‐H 2 O atmospheres and were unable to obtain warm solutions (as explained above) whereas we assess the CO 2 ‐H 2 hypothesis of Ramirez, Kopparapu, Zugger, et al () and Ramirez (), which covers a very different temperature and pressure regime. Second, von Paris et al () had used a 1‐D radiative‐convective (RC) climate model whereas our advanced energy balance model (EBM) can also compute latitudinal quantities and include additional aspects like oceans, clouds, the ice‐albedo feedback, and seasonal effects.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Climate Simulations of Early Mars With Estimated Precipitation, Runoff, and Erosion Rates

2020

Self Cite

View full text Add to dashboard Cite

The debate over the early Martian climate is among the most intriguing in planetary science. Although the geologic evidence generally supports a warmer and wetter climate, climate models have had difficulty simulating such a scenario, leading some to suggest that the observed fluvial geology (e.g., valley networks, modified landscapes) on the Martian surface could have formed in a cold climate instead. However, as we have originally predicted using a single‐column radiative‐convective climate model (Ramirez, Kopparapu, Zugger, et al., 2014, https://doi.org/10.1038/ngeo2000), warming from CO2‐H2 collision‐induced absorption on a volcanically active early Mars could have raised mean surface temperatures above the freezing point, with later calculations showing that this is achievable with hydrogen concentrations as low as ~1%. Nevertheless, these predictions should be tested against more complex models. Here we use an advanced energy balance model that includes a northern lowlands ocean to show that mean surface temperatures near or slightly above the freezing point of water were necessary to carve the valley networks. Our scenario is consistent with a relatively large ocean as has been suggested. Valley network distributions would have been global prior to subsequent removal processes. At lower mean surface temperatures and smaller ocean sizes, precipitation and surface erosion efficiency diminish. The warm period may have been approximately <107 years, perhaps suggesting that episodic warming mechanisms were not needed. Atmospheric collapse and permanently glaciated conditions occur once surface ice coverage exceeds a threshold depending on collision‐induced absorption assumptions. Our results support an early warm and semiarid climate consistent with many geologic observations.

show abstract

Section: Discussionsupporting

confidence: 89%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Climate Simulations of Early Mars With Estimated Precipitation, Runoff, and Erosion Rates

2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…This has critical implications for understanding the Noachian climate: if the observed clays can be produced through transient heating and rainfall events, such as those explored here and in Palumbo and Head (), at least some of the observed clay deposits may not be suggestive of a long‐term ambient warmer and wetter climate or episodic warmer and wetter periods (e.g., Craddock and Howard ; Bishop et al. , ; Ramirez ).…”

Section: Consequences and Testable Hypotheses Of The Baseline Seguramentioning

confidence: 86%

Impact cratering as a cause of climate change, surface alteration, and resurfacing during the early history of Mars

Palumbo

Head

2017

Meteorit & Planetary Scien

View full text Add to dashboard Cite

Ancient valley networks (VNs) and related open‐ and closed‐basin lakes are testimony to the presence of flowing liquid water on the surface of Mars in the Late Noachian and Early Hesperian. Uncertain, however, has been the mechanism responsible for causing the necessary rainfall and runoff and/or snowfall and subsequent melting. Impact cratering has been proposed (e.g., Segura et al. 2002) as a process for temporarily raising temperatures and inducing conditions that would produce rainfall, snowmelt, runoff, and formation of the VNs and associated lacustrine features. We refer to the collective effects of this process as the ICASE model (impact cratering atmospheric/surface effects). In this contribution, we assess the proposed impact cratering mechanism in order to understand its climatic implications for early Mars: we outline the step‐by‐step events in the cratering process and explore the predictions for atmospheric and surface geological consequences. For large and basin‐scale impacts, rainfall should be globally and homogeneously distributed and characterized by very high temperatures. Rainfall rates are predicted to be high, ~2 m yr−1, similar to rates in tropical rainforests on Earth, and runoff rates are correspondingly very high. These predicted characteristics do not seem to be consistent with the observed VNs, which are mainly equatorial and not homogeneous in their distribution. Prior to the Late Noachian, however, we predict that basin‐scale impact effects are very likely to contribute significantly to degradation of crater rims and regional smoothing of terrain, implying vast resurfacing and resetting of crater ages following large crater and basin‐scale impacts. Furthermore, the high temperatures of impact‐induced rainwater and snowmelt and the pervasive penetration of heat into the regolith substrate are predicted to have a significant influence on the mineralogical alteration of the crust and its resulting physical properties. We conclude by describing a case example (Isidis basin) and describe how the ICASE model provides an alternative scenario for the interpretation of the layered phyllosilicates in the Nili Fossae and NE Sytris regions. We outline specific conclusions and recommendations designed to improve the ICASE model and to promote further understanding of its implications for the geological, mineralogical, and climate history of early Mars.

show abstract

“…Laboratory experiments do not allow for studying the long accumulation of doses of relatively low intensity in the microbial biomass of natural soil. The main question of the present study is how long the biosphere of Mars could be maintained after the supposed catastrophic change in planetary conditions [24][25][26][27][28][29], the gradual loss of the atmosphere [30], and the formation of a modern climate.…”

Section: Introductionmentioning

confidence: 97%

Survivability of Soil and Permafrost Microbial Communities after Irradiation with Accelerated Electrons under Simulated Martian and Open Space Conditions

et al. 2018

View full text Add to dashboard Cite

Abstract:One of the prior current astrobiological tasks is revealing the limits of microbial resistance to extraterrestrial conditions. Much attention is paid to ionizing radiation, since it can prevent the preservation and spread of life outside the Earth. The aim of this research was to study the impact of accelerated electrons (~1 MeV) as component of space radiation on microbial communities in their natural habitat-the arid soil and ancient permafrost, and also on the pure bacterial cultures that were isolated from these ecotopes. The irradiation was carried out at low pressure (~0.01 Torr) and low temperature (−130 • C) to simulate the conditions of Mars or outer space. High doses of 10 kGy and 100 kGy were used to assess the effect of dose accumulation in inactive and hypometabolic cells, depending on environmental conditions under long-term irradiation estimated on a geological time scale. It was shown that irradiation with accelerated electrons in the applied doses did not sterilize native samples from Earth extreme habitats. The data obtained suggests that viable Earth-like microorganisms can be preserved in the anabiotic state for at least 1.3 and 20 million years in the regolith of modern Mars in the shallow subsurface layer and at a 5 m depth, respectively. In addition, the results of the study indicate the possibility of maintaining terrestrial like life in the ice of Europa at a 10 cm depth for at least~170 years or for at least 400 thousand years in open space within meteorites. It is established that bacteria in natural habitat has a much higher resistance to in situ irradiation with accelerated electrons when compared to their stability in pure isolated cultures. Thanks to the protective properties of the heterophase environment and the interaction between microbial populations even radiosensitive microorganisms as members of the native microbial communities are able to withstand very high doses of ionizing radiation.

show abstract

A warmer and wetter solution for early Mars and the challenges with transient warming

Cited by 64 publications

References 95 publications

Climate Simulations of Early Mars With Estimated Precipitation, Runoff, and Erosion Rates

Climate Simulations of Early Mars With Estimated Precipitation, Runoff, and Erosion Rates

Impact cratering as a cause of climate change, surface alteration, and resurfacing during the early history of Mars

Survivability of Soil and Permafrost Microbial Communities after Irradiation with Accelerated Electrons under Simulated Martian and Open Space Conditions

Contact Info

Product

Resources

About