Large-scale Volcanism and the Heat Death of Terrestrial Worlds

Abstract

Large-scale volcanism has played a critical role in the long-term habitability of Earth. Contrary to widely held belief, volcanism, rather than impactors, has had the greatest influence on and bears most of the responsibility for large-scale mass extinction events throughout Earth’s history. We examine the timing of large igneous provinces (LIPs) throughout Earth’s history to estimate the likelihood of nearly simultaneous events that could drive a planet into an extreme moist or runaway greenhouse, leading to the end of volatile cycling and causing the heat death of formerly temperate terrestrial worlds. In one approach, we make a conservative estimate of the rate at which sets of near-simultaneous LIPs (pairs, triplets, and quartets) occur in a random history statistically the same as Earth’s. We find that LIPs closer in time than 0.1–1 million yr are likely; significantly, this is less than the time over which terrestrial LIP environmental effects are known to persist. In another approach, we assess the cumulative effects with simulated time series consisting of randomly occurring LIP events with realistic time profiles. Both approaches support the conjecture that environmental impacts of LIPs, while narrowly avoiding grave effects on the climate history of Earth, could have been responsible for the heat death of our sister world Venus.

Venus, the Planet: Introduction to the Evolution of Earth’s Sister Planet

“…If temperate conditions existed in an earlier Venusian epoch, then any climatic catastrophe on Venus should probably have a geologic counterpart. A huge amount of the mantle would have needed to undergo partial melting to degass > 90 bars of carbon dioxide (e.g., Way and Del Genio 2020;Way et al 2022a). Such massive melting would presumably cover the vast majority of the surface in thick lava flows.…”

“…Clouds on the dayside of Venus may have kept surface temperatures Earth-like even as the Sun brightened over time (e.g., Yang et al 2014;Way et al 2016;Way and Del Genio 2020). Eventually, perhaps as recently as half a billion years ago, increasing solar input and huge amounts of volcanism caused a climatic catastrophe that led to the current, caustic conditions (e.g., Strom et al 1994;Weller and Kiefer 2020;Krissansen-Totton et al 2021;Way et al 2022a). This transition may have been rapid in geological terms but slow relative to biological generations.…”

The Habitability of Venus and a Comparison to Early Earth

“…An alternative solution that has been suggested is that a global volcanic event, possibly akin to Earth-like Large Igneous Provinces (LIPs), could have both outgassed CO 2 from mantle reservoirs and destabilized carbon crustal reservoirs (such as carbonates and other carbon rich sediments, see Retallack et al 2006;Svensen et al 2009;Ganino and Arndt 2009;Nabelek et al 2014), leading to the accumulation of CO 2 in the atmosphere on a short timescale (Way and Del Genio, 2020;Krissansen-Totton et al, 2021;Höning et al, 2021;Way et al, 2022b) at an undefined date. Such a mechanism and its feasibility are rather difficult to assess in the absence of observation.…”

“…However, such events have been associated with dramatic climate change and global extinction events (Wignall, 2001), making them important enough to affect life on a global scale and planetary habitability. They could possibly trigger a climate transition by overwhelming any volatile cycling in effect hence driving the planet into a moist and then runaway greenhouse (Way and Del Genio, 2020;Way et al, 2022b).…”

“…Even if the overall radiation environment at the surface (as determined by absorption in Venus's early atmosphere) was clement, it may have affected conditions for early life potentially inhabiting water on exposed landmasses or subsea environments, such as hydrothermal vents. Increasing solar luminosity, continuous degassing of CO 2 from Venus' mantle into the atmosphere, or large-scale volcanic eruptions (Way et al, 2022b) may have brought an end to a potential early habitable period.…”