In the 1970s, the idea of "global cooling" appeared in scientific publications whose influence was magnified through bad science journalism and pop science publications and programming. It was never a scientific concensus and by the early 80s had largely been discarded in favour of the competing hypothesis of global warming as climatology models improved. Regardless, at the time is seemed logical--the years 1940-75 were cold due to a natural climate cycle while the rapid growth and urbanisation of the planet created a huge amount of aerosol emissions that produced "global dimming" which also helped cool the planet. The most recent concern about global cooling comes from the belief that melting ice caps might flood the ocean with freshwater and disrupt natural ocean currents, thus triggering cooling, but this might be overstated.
Given these facts, could anthropogenic global cooling have ever actually become a pressing problem? The most obvious case is a nuclear winter, but the risk of a nuclear winter was severely overstated. To my knowledge without different nuclear weapon design and design of cities, there would not be enough fallout and soot from fires in the atmosphere to cause substantial cooling. Or could it have arisen from a hypothetical early discovery of global warming? Perhaps it is discovered in the early 20th century and the risk of the threat is exaggerated (as in "by 2000 we will all be choking under an inhospitable atmosphere) to the point that early mitigation of greenhouse emissions is actually done, but for whatever reason air pollution is still a prominent issue. I'm not sure if this even makes sense since you'd need to switch emissions to mostly being sulfates rather than CO2 and other greenhouse gases, and a lot of sulfuric acid etc. production is done for processes used in petroleum production and refining. A way to get aircraft to fly higher and thus their emissions occur in the stratosphere might work. Or perhaps a global trend toward white roofs, reflectivity, and urban sprawl while farmers prefer greenhouses--all of this slightly increases the albedo and offsets greenhouse emissions.
More novel ideas that probably aren't feasible with 20th century tech would involve space-based global cooling, but I can't think of any that aren't easily reversible. If you accumulate too much reflective junk at Earth-Sun L1, you also have the tech to clean it up. It also seems easy to melt big chunks of Earth's icecaps from space, be it through a laser or physically smashing it with "rods from god" or other kinetic attacks. It doesn't seem easy to trigger enough melting to disrupt the thermohaline circulation of the Atlantic. Even trying to nuke every submarine hiding under the ice wouldn't do much damage to the icecaps, let alone something vaguely feasible (if uneconomical) like an "iceberg harvesting" industry appearing delivering fresh water to drought-prone regions or those without fresh water.
I would prefer there be no global nuclear war, but a limited nuclear exchange is probably necessary (i.e. Pakistan and India slamming each other with nuclear bunker busters, and some missiles go off track and burn down some of India's forests--because that's in the tropics it would be better at cooling the planet) for the scenario.
If this scenario is too implausible, then the mods can move this to ASB.
EDIT: I meant to post this in post-1900 but pre-1900 works well too. Consider the POD the start of the Industrial Revolution.
Given these facts, could anthropogenic global cooling have ever actually become a pressing problem? The most obvious case is a nuclear winter, but the risk of a nuclear winter was severely overstated. To my knowledge without different nuclear weapon design and design of cities, there would not be enough fallout and soot from fires in the atmosphere to cause substantial cooling. Or could it have arisen from a hypothetical early discovery of global warming? Perhaps it is discovered in the early 20th century and the risk of the threat is exaggerated (as in "by 2000 we will all be choking under an inhospitable atmosphere) to the point that early mitigation of greenhouse emissions is actually done, but for whatever reason air pollution is still a prominent issue. I'm not sure if this even makes sense since you'd need to switch emissions to mostly being sulfates rather than CO2 and other greenhouse gases, and a lot of sulfuric acid etc. production is done for processes used in petroleum production and refining. A way to get aircraft to fly higher and thus their emissions occur in the stratosphere might work. Or perhaps a global trend toward white roofs, reflectivity, and urban sprawl while farmers prefer greenhouses--all of this slightly increases the albedo and offsets greenhouse emissions.
More novel ideas that probably aren't feasible with 20th century tech would involve space-based global cooling, but I can't think of any that aren't easily reversible. If you accumulate too much reflective junk at Earth-Sun L1, you also have the tech to clean it up. It also seems easy to melt big chunks of Earth's icecaps from space, be it through a laser or physically smashing it with "rods from god" or other kinetic attacks. It doesn't seem easy to trigger enough melting to disrupt the thermohaline circulation of the Atlantic. Even trying to nuke every submarine hiding under the ice wouldn't do much damage to the icecaps, let alone something vaguely feasible (if uneconomical) like an "iceberg harvesting" industry appearing delivering fresh water to drought-prone regions or those without fresh water.
I would prefer there be no global nuclear war, but a limited nuclear exchange is probably necessary (i.e. Pakistan and India slamming each other with nuclear bunker busters, and some missiles go off track and burn down some of India's forests--because that's in the tropics it would be better at cooling the planet) for the scenario.
If this scenario is too implausible, then the mods can move this to ASB.
EDIT: I meant to post this in post-1900 but pre-1900 works well too. Consider the POD the start of the Industrial Revolution.