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The Martian Mystery: CO2 and the Earth's Greenhouse Effect

Understanding the role of carbon dioxide (CO2) in the Martian atmosphere might provide insights into Earth's own climate dynamics. On Mars, despite an extremely thin atmosphere, the concentration of CO2 is about 15 times that of Earth. One might assume that this would lead to a strong greenhouse effect on the Red Planet, but surprisingly, that's not the case.

So, why doesn't Mars experience a robust greenhouse effect? The answer lies in the specific wavelengths of energy that CO2 can absorb. Unlike what many believe, CO2 predominantly absorbs energy within a very narrow wavelength window, approximately 15 micrometers. Regardless of how much CO2 is present in the atmosphere, the total amount of heat it can absorb is limited.

Now, let's shift our focus to Earth. What truly drives and dominates our greenhouse effect? The answer is water, present in two primary forms: water vapor and clouds. Water contributes significantly, accounting for up to 75% of the greenhouse effect on our planet.

Considering that 70% of Earth's surface is covered by water, one might wonder if we receive an excessive amount of greenhouse effect, causing the planet to overheat. The answer is no, and here's where the magic of atmospheric water comes into play.

You've probably noticed that a sunny day tends to be warmer than a cloudy one during the same season. This is because, during daylight hours, clouds and water vapor act as barriers to sunlight, preventing excess solar radiation from causing the Earth to become excessively hot. It's this natural regulation that keeps our planet within a comfortable temperature range, preventing it from becoming too hot or too cold.

With this everyday knowledge, we can conclude that CO2 isn't the primary contributor to climate change or global warming. In reality, it plays a vital and constructive role in our ecosystem. CO2 is essential for plant life, serving as a key ingredient in photosynthesis, where plants use light energy to convert CO2 and water into organic compounds and oxygen.

While Earth's temperature has risen over the past 150 years, and atmospheric CO2 levels have increased, it's crucial to understand the relationship between these two phenomena. When ocean water warms, even slightly, it releases dissolved CO2 into the atmosphere. This process is akin to the way carbonation in a glass of chilled soda water escapes when it warms up.

So, what is the true driver of climate change? It's essential to acknowledge that the climate has always been subject to change, with various natural factors at play. These include the sun's activity, Earth's orbit, its axial tilt, volcanic activity from thousands and thousands of active volcanoes, both in land and under the oceans, cosmic radiation, and more. While CO2 levels have risen, it's highly improbable that they are the cause of recent climate shifts, as this article has clarified.


References:

https://marsed.asu.edu/mep/atmosphere

https://www.ces.fau.edu/nasa/module-2/how-greenhouse-effect-works.php

https://ei.lehigh.edu/learners/cc/greenhouse/radiationChart.png

https://co2coalition.org/facts/the-warming-effect-of-each-molecule-of-co2-declines-as-its-concentration-increases/

https://www.noaa.gov/news-release/carbon-dioxide-now-more-than-50-higher-than-pre-industrial-levels

https://www.esa.int/Science_Exploration/Space_Science/Venus_Express/Greenhouse_effects_also_on_other_planets


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  • The Martian Mystery: CO2 and the Earth's Greenhouse Effect +1
    • Back in 2005, scientists were thinking about injecting greenhouse gas to Mars

      From space.com:

      The stuff could be shipped to Mars or manufactured there.

      Scientists and science-fiction authors have long pondered terraforming Mars, melting the vast stores of ice in its polar caps to create an environment suitable for humans. The topic is highly controversial.

      Some think earthlings have no right to mess with the climate of another planet. Others see Mars as a refuge for people who might need to flee this world as conditions deteriorate. Another argument holds that Mars was likely warmer and wetter in its distant past, and it might have harbored life, so bringing it back to a previous state makes sense.

      Among the ideas for how to warm Mars: sprinkling stuff near the poles that would absorb more sunlight; or placing large mirrors in orbit around the planet to reflect more sunlight onto it.

      Jumpstart the warming

      The new research suggests that forcing global warming by injecting greenhouse gases may be the best way to terraform, should governments decide to do so. The conditions warming Earth could be harnessed to transform Mars, the scientists determined.

      Jumpstarting global warming in a planet-sized laboratory would be a boon to science in some respects.

      "Bringing life to Mars and studying its growth would contribute to our understanding of evolution, and the ability of life to adapt and proliferate on other worlds," says Margarita Marinova, at the NASA Ames Research Center when the study was done. "Since warming Mars effectively reverts it to its past, more habitable state, this would give any possibly dormant life on Mars the chance to be revived and develop further."

      The research is presented in the February issue of the Journal of Geophysical Research-Planets, published by the American Geophysical Union.

      With a very thin atmosphere and being farther from the Sun, Mars is much colder than Earth. There is no evidence for any liquid water presently on the surface. Liquid water is considered essential to life as we know it.

      The polar regions contain vast stores of water ice and carbon dioxide, or dry ice. Theorists have said in the past that melting the poles might thicken the atmosphere, which like a blanket would insulate the surface and eventually create a more Earth-like climate.

      Studies suggest Mars had surface water and bouts of rain in its early history.

      Gas of choice

      The new research modeled how manmade greenhouse gases would affect Martian temperature and melt water ice and carbon dioxide ice at the poles.

      Artificially created gases could be 10,000 times more effective than carbon dioxide in warming up the Red Planet, the study determined. The gases that would work the best are flourines and could be made from elements readily available on Mars, Marinova and her colleagues found.

      Adding 300 parts per million of the gas mixture into the Martian air would trigger a runaway greenhouse effect, according to the models. The polar ice sheets that would slowly evaporate. The newly released carbon dioxide would cause further warming and melting. Atmospheric pressure would rise.

      The process would take hundreds or thousands of years to complete, the scientists report.