if 10 nukes are detonated in less than 4 minutes local temperature drops and causes local nuclear winter

if 100 nuclear bombs are detonated in less than 16 minutes it will cause big local nuclear winter and absolute dark fog that will make everyone get radiation poisoning

if 1000 nukes are detonated in less than 1 hours it will cause global nuclear winter that will last for 3 minecraft years
1 no animals spawn only animals inside of buildings or bunkers survive
2 no farms outside of bases with airlocks
3 everything freeze outside
4 player die without warm clothing outside if he outside for 1 - 2 minutes
5 random building ruins appear
6 creepy sounds
7 absolutly no alive objects spawn only player is alive in entire world

total hell 5000 nukes detonated in less than 5 hours
player die outside if he dont have very warm clothing with insulation and heat source in half minute
nothing spawns
total hell
radiation over 200 outside
every block outside is radiactive
world later after total hell type nuclear winter
atmosphere pressure becomes much lower so player have to wear spacesuits
meteorites fall constantly because no atmosphere
every biological block becomes non biological like grass into stone or moon like regolith
oxygen nitrogen snow
and after this nothing protects earth from solar radiation so earth heat up again but will be venus like planet instead
only way to survive is just get out from planet to another planet

I approve of this idea

i think it should scale with nuke power, for example, more powerful nukes require less detonations in a longer timespan to cause a nuclear winter

i think it should scale with nuke power, for example, more powerful nukes require less detonations in a longer timespan to cause a nuclear winter

fusion bombs less radiactive

Adding ontop of this, the Planet-Killer weapon dropped by the construction satellite should have a far greater global implication. Perhaps an eternal winter would suffice, but something of such scale may call for even greater consequences than just that alone. Maybe unique mobs / spawns? Falling debris around the globe that sets massive lava-filled fires? Earthquakes?

eternal winter will exist only untill dust is in air
temperature will be insanely low like -30 or even less what u mean by lava and everything alive will die due to nearly unbreathable air with radiactive cobalt dust

And to perhaps put the already stated ideas into a more concise format:

Local Brownout Caused by a high number of powerful explosions within a roughly 30x30 chunk area. Causes a localized temperature gradient drop, but otherwise inconsequential. Can probably be caused by any explosive that throws enough particles into the air. Electrical machines (running off of KW or RF) malfunction.

Widespread Blackout Caused by a very high number of powerful explosions within a larger chunk area (50x50?). Even greater localized temperature gradient drop spread out across a far more vast area, producing fog and a constant radioactive snow until the soot has had enough time to dissipate (maybe passing like rain.) Electrical machines (running off of KW or RF) malfunction.

Nuclear Winter Natural spawning for peaceful mobs is disabled. The entire global temperature gradient shifts to frigid conditions and the sky becomes completely clouded by dark soot, with falling radioactive ash being the only common weather event outside of black rain in deserts or other hot regions. Due to the temperature and radiation, crops that aren't already shielded are likely to die off.

Other described effects of the cold are probably best left to other mods like Tough As Nails, which have native support for freezing to death. The sound of howling wind is your only companion in a brave new world, as every chunk both old and newly generated becomes progressively permeated with radiation for many in-game years.

Nuclear Summer An idea of my own design, which happens after the Nuclear Winter passes. As the name suggests, the exact opposite begins to happen; due to the radioactive debris eroding Minecraft's natural ozone layer there is nothing to shield the surface from harmful solar rays. While the sky is bright and sunny, radiation still abounds and the harmful ultraviolet beams make growing anything a very difficult task - not to mention, weakening and harming those who stay out too long. Looking directly at the sun blinds you for a long time.

Peaceful mob spawns return, albeit highly reduced and weak. Electrical machines (running off of KW or RF) can randomly malfunction.

Armageddon Caused only by the Planet Killer. Once it impacts the surface, the entire world is rung like a bell with Earthquakes that cause nausea and make blocks randomly fall down en-masse. Superheated debris from the initial impact floats high in the sky for a brief while before it all starts raining back down unto the surface as a devastating meteor shower that also makes the entire planet reach hundreds of degrees - setting anything above a certain Y-Level on fire and killing all plantlife / water supplies.

Once all is said and done, the effects are identical to Nuclear Winter with the added caveat that it never ends. Additionally, Meltdown Elementals spawn naturally.

if temperature will be cold enough due to high albedo caused by dust atmosphere may just turn into snow - fluid and it will be nuclear winter with insane solar radiation

Adding ontop of this, the Planet-Killer weapon dropped by the construction satellite should have a far greater global implication. Perhaps an eternal winter would suffice, but something of such scale may call for even greater consequences than just that alone. Maybe unique mobs / spawns? Falling debris around the globe that sets massive lava-filled fires? Earthquakes?

And to perhaps put the already stated ideas into a more concise format:

Local Brownout
Caused by a high number of powerful explosions within a roughly 30x30 chunk area. Causes a localized temperature gradient drop, but otherwise inconsequential. Can probably be caused by any explosive that throws enough particles into the air. Electrical machines (running off of KW or RF) malfunction.

Widespread Blackout
Caused by a very high number of powerful explosions within a larger chunk area (50x50?). Even greater localized temperature gradient drop spread out across a far more vast area, producing fog and a constant radioactive snow until the soot has had enough time to dissipate (maybe passing like rain.) Electrical machines (running off of KW or RF) malfunction.

Nuclear Winter
Natural spawning for peaceful mobs is disabled. The entire global temperature gradient shifts to frigid conditions and the sky becomes completely clouded by dark soot, with falling radioactive ash being the only common weather event outside of black rain in deserts or other hot regions. Due to the temperature and radiation, crops that aren't already shielded are likely to die off.

Other described effects of the cold are probably best left to other mods like Tough As Nails, which have native support for freezing to death. The sound of howling wind is your only companion in a brave new world, as every chunk both old and newly generated becomes progressively permeated with radiation for many in-game years.

Nuclear Summer
An idea of my own design, which happens after the Nuclear Winter passes. As the name suggests, the exact opposite begins to happen; due to the radioactive debris eroding Minecraft's natural ozone layer there is nothing to shield the surface from harmful solar rays. While the sky is bright and sunny, radiation still abounds and the harmful ultraviolet beams make growing anything a very difficult task - not to mention, weakening and harming those who stay out too long. Looking directly at the sun blinds you for a long time.

Peaceful mob spawns return, albeit highly reduced and weak. Electrical machines (running off of KW or RF) can randomly malfunction.

Armageddon
Caused only by the Planet Killer. Once it impacts the surface, the entire world is rung like a bell with Earthquakes that cause nausea and make blocks randomly fall down en-masse. Superheated debris from the initial impact floats high in the sky for a brief while before it all starts raining back down unto the surface as a devastating meteor shower that also makes the entire planet reach hundreds of degrees - setting anything above a certain Y-Level on fire and killing all plantlife / water supplies.

Once all is said and done, the effects are identical to Nuclear Winter with the added caveat that it never ends. Additionally, Meltdown Elementals spawn naturally.

The 1.7.10 versions of NTM have the planet killer cause an extinction event on impact. It begins with the impact forming a gigantic crater flooded with lava that is lined with tektite and rare osmiridium-induced tektite blocks. Once the crater is complete, a global firestorm begins that burns away all exposed vegetation while the atmosphere fills with dust and smoke. After a full MC day (20 minutes), the firestorm ends, and a 600 day long period of darkness begins. At the beginning of this period, the sky is completely black with debris and the world is completely dark. As time passes, the atmosphere gradually clears, and light slowly returns to the world. The final effect is that all mobs larger than one block in size go extinct and can no longer spawn.

I suggest there should also be a form of "Balefire Winter", where, if enough balefire bombs and balefire missiles detonate, they turn the atmosphere a toxic green, any exposure to the sky will apply contamination and wither to any entities, and everything will receive a small dose of digamma radiation.

sounds awesome, maybe all water would slowly evaporate?