How massive volcanism may have altered Venus’ climate

An artist’s concept of active volcanoes on Venus, depicting a subduction zone where the crust in the foreground plunges into the planet’s interior at the topographic trench. Credit: NASA/JPL-Caltech/Peter Rubin

“By understanding the record of large igneous provinces on Earth and Venus, we can determine whether these events may have caused the current condition of Venus,” said Dr. Michael J. Way, of NASA’s Goddard Institute for Space Studies in New York. Way is the lead author of the Planetary Science Journal paper.

Dimension Volcano Mons Venus

Maat Mons is displayed in this computer-generated three-dimensional perspective of the surface of Venus. The observation point is located 634 kilometers (393 miles) north of Maat Mons, at an altitude of 3 kilometers (2 miles) above the ground. The lava flows stretch hundreds of kilometers across the fractured plains shown in the foreground, to the base of Maat Mons. Synthetic aperture radar data from NASA’s Magellan mission is combined with radar altimetry to develop a three-dimensional map of the surface. The vertical scale in this perspective has been exaggerated 10 times. Credit: NASA/JPL

Large igneous provinces are the result of long periods of large-scale volcanism lasting tens of thousands or even hundreds of thousands of years. They can deposit more than 100,000 cubic miles of volcanic rock on the surface. At the top end, this would be enough to bury the entire state of Texas in molten rock half a mile deep.

Today, Venus boasts surface temperatures of about 864°F (462°C) on average and an atmosphere 90 times the surface pressure of Earth. According to the study, these massive volcanic outpourings may have started these conditions sometime in Venus’ early history. In particular, the occurrence of many of these eruptions in a short geological time frame (within a million years) could have led to a runaway greenhouse effect that kick-started the planet’s transition from wet and temperate to hot and dry. .

In total, 80 percent of Venus’ surface is covered by large fields of solidified volcanic rock, Way said. “While we’re still not sure how often the events that created these fields have occurred, we should be able to narrow it down by studying the history of the Earth itself.”

Dimension Mons Vulcano Venus

Maat Mons, a large volcano on Venus, is shown in this 1991 simulated color radar image from NASA’s Magellan space mission. Credit: NASA/JPL

Since the origin of multicellular life about 540 million years ago, life on Earth has experienced at least five major mass extinction events. Each of these wiped out more than 50% of animal life across the planet. According to this study and previous ones, most of these extinction events were caused or exacerbated by the types of eruptions that produce large igneous provinces. In Earth’s case, the climatic perturbations from these events weren’t enough to cause a runaway greenhouse effect like they were on Venus, for reasons Way and other scientists are still trying to determine.

NASA’s next missions to Venus, scheduled for launch in the late 2020s: the Deep Atmosphere Venus Investigation of Noble gas, Chemistry, and Imaging (DAVINCI) mission and the Venus Emissivity, Radio science, InSAR, Topography, And Spectroscopy (VERITAS) – aim to study the origin, history and current state of Venus in unprecedented detail.

“A primary goal of DAVINCI is to narrow down the history of water on Venus and when it might have disappeared by providing more insight into how Venus’ climate changed over time,” Way said.

The DAVINCI mission will precede VERITAS, an orbiter designed to investigate Venus’ surface and interior from above, to better understand its volcanic and volatile history and thus Venus’ path to its current state. Data from both missions could help scientists narrow down the exact record of how Venus may have gone from wet and temperate to dry and sweltering. It could also help us better understand how volcanism here on Earth has affected life in the past and how it might continue to do so in the future.

Reference: “Large-scale Volcanism and the Heat Death of Terrestrial Worlds” by MJ Way, Richard E. Erns and Jeffrey D. Scargle, April 26, 2022, The planetary science journal.
DOI: 10.3847/PSJ/ac6033

This study was supported by the Goddard Space Flight Center’s Sellers Exoplanet Environments Collaboration (SEEC) and was part of NASA’s Nexus for Exoplanet System Science (NExSS) RCN.

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