Earth
Walker et al. (1981) argued that atmospheric CO₂ levels on Earth are controlled by the carbonate–silicate geochemical cycle over geological timescales (Gyr) [1]. Silicate weathering also impacts the Earth’s climate and carbon cycle [2], which is a key process for removing anthropogenic fossil fuel emissions over the next 10–100 kyr without human intervention [3–6]. The Earth has been through numerous extreme events — from geomagnetic reversals to super-volcanic eruptions — that have profoundly shaped its history.
Mars
Mars' atmosphere is 95% CO₂ and extremely thin due to low gravity. An H₂–CO₂ greenhouse effect, driving a carbonate–silicate cycle, is proposed as the main early warming mechanism. On Mars, the carbonate-silicate cycle is less understood due to limited experimental verification, requiring space missions for exploration (e.g., NASA’s Mariner 9 and Viking Missions). Nevertheless, the carbonate-silicate cycle, driven by an (H₂ + CO₂) greenhouse effect, is proposed as the primary mechanism for Mars’ early warming, with cycles lasting up to 10 Myr, followed by extended glaciation periods [7].
Seismicity
Mars' atmosphere is 95 percent CO2 and gets earthquakes (called Marsquakes!) everyday. This has been an interesting point of reflection for planetary physics researchers. Read the full paper →
References
- J. C. Walker, P. Hays, and J. F. Kasting, Journal of Geophysical Research: Oceans 86, 9776 (1981).
- D. E. Penman et al., Earth-Science Reviews 209, 103298 (2020).
- D. Archer, Journal of Geophysical Research: Oceans 110 (2005).
- D. Archer et al., Annual Review of Earth and Planetary Sciences 37, 117 (2009).
- G. Colbourn et al., Global Biogeochemical Cycles 29, 583 (2015).
- K. J. Meissner et al., Global Biogeochemical Cycles 26 (2012).
- N. E. Batalha et al., Earth and Planetary Science Letters 455, 7 (2016).