Tuesday, 03 September 2024.
Today we conclude the yesterday’s article, when we discussed the so-called “weathering thermostat”, according to geologist Howard Lee.
Basically, it relates to chemical reactions over millions of years, through which silicate minerals remove atmospheric CO2 and capture it in the form of limestone rock, with much of the atmospheric CO2 being generated from the weathering of metamorphic rocks and the oxidation of carbon in eroded sediments. Oceans can also help this absorption, if there is no overload. Otherwise, they will acidify.
The balance between these processes would work like a thermostat, since when the climate heats up, chemical reactions become more efficient in removing CO2, slowing warming and as the climate cools, reactions become less efficient, facilitating cooling.
In other words, a relatively stable terrestrial climate, providing a habitable environment.
But since the burning of fossil fuels currently emits about 100 times more CO2 than volcanoes, too fast for the oceans and weathering to neutralize it as described above, the concentration of atmospheric CO2 is increasing, our climate is warming and our oceans acidifying.
This is one of the 10 factors that paleoclimatologists indicate as related to climate change in the past.
See the complete list below:
Solar cycles, when solar activity slows down between 30 and 160 years. Magnitude: 0.1 to 0.3°C of cooling.
Volcanic sulfur, 1 to 20 year fluctuations. Magnitude: Approximately 0.6 to 2°C cooling.
Short-term climate fluctuations, from 2 to 7 years. Magnitude: Up to 0.15°C.
Orbital oscillations, in regular and overlapping cycles of 23,000, 41,000, 100,000, 405,000 and 2,400,000 years. Magnitude: varies over geological time and was approximately 6°C in the last 100,000 year cycle.
Young (and weak) sun, practically constant. Magnitude: Increasing solar brightness over time, although the effect is neutralized by the next item.
CO2, Earth's natural thermostat with geological cycles of 100,000 years or more. Magnitude: Neutralizes other changes.
Tectonic plates moving very slowly. Magnitude: Approximately 30°C in the last 500 million years.
Asteroid impacts, causing centuries of cooling and 100,000 years of warming (Chicxulub, which vaporized part of Mexico 66 million years ago, killing the dinosaurs). Magnitude: Approximately 20°C of cooling followed by 5°C of heating.
Evolutionary changes over millions of years. Magnitude: Variable, was about 5°C cooling 445 million years ago.
Large igneous provinces, volcanism for hundreds of thousands of years. Magnitude: About 3 to 9°C of warming.
All of these situations were mentioned and detailed in the article “How Earth’s Climate Changes Naturally (and Why Things Are Different Now)” by Howard Lee for Quantamagazine, which you can read by clicking on the image below.
We conclude with another quote indicated on our portal, from the chemical scientist Madame Marie Curie:
“Nothing in life is to be feared, it is only to be understood. Now is the time to understand more, so that we may fear less.”
