Cosmology: snowball Earth possible cause (Introduction)

by David Turell , Monday, February 19, 2024, 19:00 (67 days ago) @ David Turell

Low CO2:

https://www.sciencedaily.com/releases/2024/02/240207194410.htm

"Inspired during field work in South Australia's Flinders Ranges, geoscientists have proposed that all-time low volcanic carbon dioxide emissions triggered a 57-million-year-long global 'Sturtian' ice age.

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"'We now think we have cracked the mystery: historically low volcanic carbon dioxide emissions, aided by weathering of a large pile of volcanic rocks in what is now Canada; a process that absorbs atmospheric carbon dioxide."

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"The extended ice age, also called the Sturtian glaciation after the 19th century European colonial explorer of central Australia, Charles Sturt, stretched from 717 to 660 million years ago, a period well before the dinosaurs and complex plant life on land existed.

"Dr Dutkiewicz said: "Various causes have been proposed for the trigger and the end of this extreme ice age, but the most mysterious aspect is why it lasted for 57 million years -- a time span hard for us humans to imagine."

"The team went back to a plate tectonic model that shows the evolution of continents and ocean basins at a time after the breakup of the ancient supercontinent Rodina.

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"They soon realised that the start of the Sturtian ice age precisely correlates with an all-time low in volcanic CO2 emissions.

"In addition, the CO2 outflux remained relatively low for the entire duration of the ice age.

"Dr Dutkiewicz said: "At this time, there were no multicellular animals or land plants on Earth. The greenhouse gas concentration of the atmosphere was almost entirely dictated by CO2 outgassing from volcanoes and by silicate rock weathering processes, which consume CO2."

"Co-author Professor Dietmar Müller from the University of Sydney said: "Geology ruled climate at this time. We think the Sturtian ice age kicked in due to a double whammy: a plate tectonic reorganisation brought volcanic degassing to a minimum, while simultaneously a continental volcanic province in Canada started eroding away, consuming atmospheric CO2.

"'The result was that atmospheric CO2 fell to a level where glaciation kicks in -- which we estimate to be below 200 parts per million, less than half today's level."

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"Dr Dutkiewicz said: "Whatever the future holds, it is important to note that geological climate change, of the type studied here, happens extremely slowly. According to NASA, human-induced climate change is happening at a pace 10 times faster than we have seen before.'"

Comment: So, in view of the fact that CO2 is an important friend who keeps us warm, CO2 is not an enemy. Obviously volcanic outgassing plays a major role in CO2 levels along with the human input. We certainly do not want another glacial period. And we must understand all the simulations of future climate temperatures are extremely inaccurate. Is current alarmism necessary?