Difference between revisions of "Super Greenhouse Gases"
(Discussion of normal greenhouse gases. Start of section on SGG.) |
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== Super Greenhouse Gases (SGG) == | == Super Greenhouse Gases (SGG) == | ||
| + | If megatonnes of gases are to be created then we want to create compounds which will be stable in the Martian atmosphere for many decades or centuries. Mars is bombarded by ultraviolet light which has energies sufficient to break molecular bonds. Fluorine has the strongest chemical bonds, so its compounds are ideally suited for SGG in Mars' atmosphere. Unfortunately, fluorine is fairly rare. Chlorine (Cl) is chemically similar and much more common and cheaper, so some fluorine atoms may be replaced with Cl, as a cheaper, less long lived substitute. | ||
| − | + | The following table shows several chemicals, their greenhouse gas warming potential (relative to CO2), and their expected lifetime in the Martian air. | |
Revision as of 15:26, 8 May 2021
Super Greenhouse Gases (SGG) are hundreds or thousands of times more powerful than CO2 in warming planets, and are highly regulated on Earth for that reason. On Mars, which is too cold, long lived Super Greenhouse Gases (SGG) are considered an economic and desirable way to warm the planet. Types of gases which are long lived under Martian conditions are especially valuable for this purpose.
Discussion of Greenhouse Gases
Planetary atmospheres warm planets by allowing light to hit the world, but slowing the radiation of infrared (heat energy) leaving the world. Without our atmosphere, Earth would have a sub freezing temperature of -10 C. However, not all gases warm planets equally. Some such as oxygen (O2), and nitrogen (N2) are transparent to heat energy. Some slow the radiation of heat to space. Carbon dioxide (CO2) is a greenhouse gas which is causing the Earth to warm as it concentration increases in Earth's atmosphere. The strength of other green house gases are measured relative to carbon dioxide. So we might that that methane is 80 times more powerful than CO2 during the 20 years it is expected to remain in the atmosphere. Water (H2O) is a powerful greenhouse gas, but it rapidly leaves the atmosphere as rain and snow. Carbon dioxide remains in the air for a long time.
Many gases will help retain heat, but each is best at trapping specific wavelengths of infrared radiation. To warm Mars, we would wish to pick gases which block 'windows' where heat can escape from Mars. (There is plenty of CO2 on Mars, and if it warms water (H2O) will also be more common in the air. So gases which block wavelengths that these two compounds don't are of especial interest.
Super Greenhouse Gases (SGG)
If megatonnes of gases are to be created then we want to create compounds which will be stable in the Martian atmosphere for many decades or centuries. Mars is bombarded by ultraviolet light which has energies sufficient to break molecular bonds. Fluorine has the strongest chemical bonds, so its compounds are ideally suited for SGG in Mars' atmosphere. Unfortunately, fluorine is fairly rare. Chlorine (Cl) is chemically similar and much more common and cheaper, so some fluorine atoms may be replaced with Cl, as a cheaper, less long lived substitute.
The following table shows several chemicals, their greenhouse gas warming potential (relative to CO2), and their expected lifetime in the Martian air.
