We can learn a lot about climate change from Venus, our sister planet. Venus currently has a surface temperature of 450℃ (the temperature of an oven’s self-cleaning cycle) and an atmosphere dominated by carbon dioxide (96 percent) with a density 90 times that of Earth’s.
Less than one billion years ago, the climate dramatically changed due to a runaway greenhouse effect. It can be speculated that an intensive period of volcanism pumped enough carbon dioxide into the atmosphere to cause this great climate change event that evaporated the oceans and caused the end of the water cycle.
Since the early 1990s, my Carleton University research team—and more recently my Siberian team at Tomsk State University—have been mapping and interpreting the geological and tectonic history of Earth’s remarkable sister planet.
Our search for geological evidence of the great climate change event led us to focus on the oldest type of rocks on Venus, called tesserae, which have a complex appearance suggestive of a long, complicated geological history. We thought that these oldest rocks had the best chance of preserving evidence of water erosion, which is a such an important process on Earth and should have occurred on Venus prior to the great climate change event.
Given poor resolution altitude data, we used an indirect technique to try to recognize ancient river valleys. We demonstrated that younger lava flows from the surrounding volcanic plains had filled valleys in the margins of tesserae.
The LIP analogs on Venus include individual volcanoes that are up to 500 kilometers across, extensive lava channels that reach up to 7,000 kilometers long, and there are also associated rift systems—where the crust is pulling apart—up to 10,000 kilometers long.
If LIP-style volcanism was the cause of the great climate change event on Venus, then could similar climate change happen on Earth? We can imagine a scenario many millions of years in the future when multiple LIPs randomly occurring at the same time could cause Earth to have such runaway climate change leading to conditions like present-day Venus.
Citation: Venus was once more Earth-like, but climate change made it uninhabitable (2020, December 14) retrieved 14 December 2020 from https://phys.org/news/2020-12-venus-earth-like-climate-uninhabitable.html
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