Wikipedia:Reference desk/Archives/Science/2020 January 16

= January 16 =

Wow! sushi
What did Wow! sushi do? Can we please correct it. Please see top of the page..." Which of "geometric algebra" or "algebraic geometry" proceeds the other. Wow! sushi (talk) 05:08, 8 January 2020 (UTC) (we don't have so much time...) _ I need to confess, I am multi-personalities. Wow! sushi (talk) 05:12, 8 January 2020 (UTC) Geometric algebra#History 1844 Algebraic geometry#History 16th Century? Graeme Bartlett (talk) 05:50, 8 January 2020 (UTC) Thank you. and for answering to such a rough-cut (or to say, "large-cut") question. Wow! sushi (talk) 01:39, 16 January 2020 (UTC) " Thanks. Anton 81.131.40.58 (talk) 09:05, 16 January 2020 (UTC)


 * Fixed. DMacks (talk) 15:45, 16 January 2020 (UTC)


 * What?? —Tamfang (talk) 01:09, 21 January 2020 (UTC)
 * This, apparently. ←Baseball Bugs What's up, Doc? carrots→ 01:38, 21 January 2020 (UTC)

CO2 warming mechanism
How has the increase in atmospheric CO2 of some 100 parts per million (0.01%) since 1960 had such a seemingly disproportionate impact on global warming? Sandbh (talk) 09:34, 16 January 2020 (UTC)
 * Climate sensitivity. Tigraan Click here to contact me 10:23, 16 January 2020 (UTC)
 * CO2 has increased from 310 to 410 ppm since 1960. That's a 32% increase, so that's quite a lot. Keep in mind that most of the atmosphere is nitrogen and oxygen, which don't contribute to the greenhouse effect. Then there are positive feedback loops like increased water vapour and reduced snow cover. PiusImpavidus (talk) 10:25, 16 January 2020 (UTC)


 * The "seemingly disproportionate impact on global warming" (and also impact on climate) that we are observing is due to all the greenhouse gases, not just CO2. For example, methane is a more potent greenhouse gas than CO2. Methane is produced by large animals like cows. In the past 60 years the Earth's population has increased significantly so, presumably, the number of large animals has also increased, and therefore, presumably, the output of methane has also increased and contributed to global warming and climate change. Dolphin ( t ) 11:27, 16 January 2020 (UTC)
 * It is correct that methane and other greenhouse gases are also contributing to man-made climate change, but long-term (centuries), carbon dioxide is the main driving factor, because of its long persistence in the atmosphere. Methane, nitrous oxide, etc. gradually react with other chemicals, while carbon dioxide is inert, so it persists in the atmosphere for much longer. --47.146.63.87 (talk) 01:26, 18 January 2020 (UTC)
 * Just what is "proportionate" ? If we assumed that the Earth's surface temperature was solely due to the amount of carbon dioxide in the atmosphere (it isn't), and varied linearly with that concentration (it doesn't), we could do the calculations. The average surface temperature is around 15 C or 288 Kelvin, on the absolute scale. So, a 32% increase would take us to 380 K or 107 C, above the boiling point of water. Good thing it's far less than proportionate. The results are even worse using methane levels alone to do the same calculations. NonmalignedNations (talk) 13:17, 16 January 2020 (UTC)
 * I think we are also dealing with a question of "why does a change of 0.01% of atmospheric content lead to such a big impact?" The answer gets into some physical chemistry. CO2 is now 0.04% of atmospheric composition, yet has a large influence on warming. Why? Let's look at the rest of the gases. In order to be involved in global warming, a gas needs to absorb IR radiation (such an absorption causes molecular vibrations, and heat is essentially kinetic motion of molecules, including vibrations). In order to absorb infrared radiation, the proper selection rules must be satisfied, in this case being a change in a molecular dipole moment with respect to the change in nuclear position during vibration. N2 gas is 78% of the atmosphere, but as a homonuclear diatomic molecule, which means it has no dipole moment, and only one molecular vibration (stretching), which does not have a change in the dipole moment. Therefore, N2 does not absorb IR radiation, and plays no role in global warming, even though it is 78% of the atmosphere. Similarly, O2, which is 21% of the atmosphere, is another homonuclear diatomic molecule, and therefore still does not satisfy the IR selection rules and plays no part in global warming. Argon is 0.9% of the atmosphere, but as a single atom, it doesn't have a dipole moment and doesn't have molecular vibrations, and so still does not satisfy the selection rules and will not absorb IR radiation. That means that 99.9% of atmospheric composition plays no role, one way or another, in global warming. CO2 makeups of 40% of the remaining 0.1% of the atmosphere. While it has no permanent dipole moment, several of its vibrations do induce a change in dipole moment with respect to nuclear motion, and therefore absorb IR radiation. So, why does CO2 have a "disproportionate impact on global warming" when it is only 0.04% of the atmosphere? Because 99.9% of the atmosphere isn't doing anything at all regarding global warming. To think of this another way, if you drank a liter of water containing 0.04% of cyanide (DO NOT DO THIS, DO NOT DRINK THIS), you will die. Straight up dead. Why does the cyanide have a disproportionate impact on killing you when it is only 0.04% of the liter of water? Because the other 99.96%, being water, isn't playing a role either way in inhibiting cytochrome c oxidase, while cyanide itself binds to the enzyme and inhibits its function. --OuroborosCobra (talk) 22:49, 16 January 2020 (UTC)
 * Today I learned hat we have three notable groups with songs titled, "A Little Bit Goes A Long Way". DMacks (talk) 04:09, 17 January 2020 (UTC)
 * To be extra pedantic, because it's interesting and might teach people more: regarding cyanide, this only applies to something with free cyanide ions in solution. You can safely consume lots of cyanide as long as it's bound tightly to something, since then the cyanide ions won't become unbound and enter your bloodstream. Prussian blue contains bound cyanide, and it's actually an antidote for poisionings—not of cyanide, but of some other poisons. The name "cyanide" was actually inspired by Prussian blue and its deep blue color. Hydrogen cyanide is also produced in small amounts when burning many organic substances, and tobacco smokers have detectably-elevated blood cyanide levels. This may have some negative effects long-term (and tobacco smoking is terrible for many other reasons), but people obviously don't drop dead after one drag on a cigarette, demonstrating the core principle of toxicology: "the dose makes the poison". Botulinum toxin is the most toxic substance currently known, yet extremely dilute amounts are injected into people all the time. Most famously this is done for cosmetic reasons (which people typically know as the brand name "Botox"), but it has numerous therapeutic applications as well for things like nerve and muscle disorders. In such cases, the toxin's paralytic action is desirable, so just enough is used to affect the intended target. --47.146.63.87 (talk) 01:22, 18 January 2020 (UTC)
 * Oh, and another neat example that didn't come to mind earlier: the most common form of supplemental vitamin B12 is cyanocobalamin. If you guessed from the name that it contains cyanide, you were correct. And this does release cyanide in the body when it's converted to its active forms. But, the amount is much too small to cause any adverse affects. And another cool aspect of this is the reaction works in reverse when there's an excess of cyanide, like when someone suffers cyanide poisoning. Hydroxocobalamin is now considered the first-line treatment for cyanide poisoning; the hydroxocobalamin binds to cyanide to form cyanocobalamin, and the excess cyanocobalamin is then excreted in the urine. --47.146.63.87 (talk) 05:35, 19 January 2020 (UTC)
 * Our greenhouse gas article suggests such gases make up about 5% ppm of our atmosphere and but for their presence the average temperature of the Earth's surface would be about −18 °C (0 °F)[255 K] rather than the present average of 15 °C (59 °F)[288 K]. That's a fall of 33 K. Given CO2 contributes about, say, 20% to warming, I can begin to see that increasing CO2 levels by about one-third since 1960 could have an appreciable impact on the global temperature average. A case of a little bit going a long way. Sandbh (talk) 03:09, 19 January 2020 (UTC)