Nuclear winter

Thoughts, suggestions, and advice on what to do if the unthinkable happens.
Yingyang
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Tue Mar 06, 2018 7:53 am

Looking for opinions.
Imo for Australia our land mass is huge compared to proxcimity and amount of targets.
My guess is nuclear winter information is generally based on northern hemisphere being the area of most of the planets nuclear targets.
Now taking this into account with global wind patterns I'm guessing it could take months a year or longer for these effects to reach us in Australia? I also believe dicipation will occur when it does meaning we should get more sunlight and heat through this effect. Any thoughts would be appreciated thanks.

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Tue Mar 06, 2018 6:59 pm

Yingyang wrote:
Tue Mar 06, 2018 7:53 am
Looking for opinions.
Imo for Australia our land mass is huge compared to proxcimity and amount of targets.
My guess is nuclear winter information is generally based on northern hemisphere being the area of most of the planets nuclear targets.
Now taking this into account with global wind patterns I'm guessing it could take months a year or longer for these effects to reach us in Australia? I also believe dicipation will occur when it does meaning we should get more sunlight and heat through this effect. Any thoughts would be appreciated thanks.
The movie On the Beach was a fun if ridiculous look at a nuclear war and what would happen to Australia.

My guess is that Australia would see some additional cloud cover, but you'd come through relatively unscathed.

I'm sure there are more knowledgeable people on the subject.

Ein_Kreb
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Tue Mar 06, 2018 8:32 pm

There are two main trains of thought when it comes to nuclear winter:
  1. The model with which we've based our understanding of nuclear winters was a gross overstatement, and the most we can expect is a nuclear "autumn"; in which case Australia doesn't need to worry about it.
  2. The model is real, and nuclear winter will be as horrible as we've come to believe.
If the model is real, then you have to consider wind currents. As you'll see below there isn't a significant air exchange between North and South of the Equator, meaning that most of the effect will primarily affect the North.

Image

In which case Australia probably won't have to worry too much about it. In either case Australia's biggest issue will be the disruption of the supply chain as the rest of the will be plunged into chaos.

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RiffRaff
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Wed Mar 07, 2018 1:51 am

The "nuclear winter" model, as proposed by Carl Sagan and other great scientists of his era was based on a few flawed premises and the nuclear weapons of that time period. I have the greatest respect for Mr. Sagan, and his crusade to prevent mankind from eradicating itself was no less honorable despite his nuclear winter theory all but being disproved in the 21st century. I don't have the energy to go into gory detail here, and the information is freely available for anyone who wishes to search for it, but the short version is that even if every nuclear weapon on the planet were detonated over every one of their targets simultaneously, a huge percentage of the planet surface would remain largely unaffected. Not saying it would not be catastrophic to the human species, but it would not be an extinction level event as popular culture would have most people believe.
"It's in your nature to destroy yourselves." - Terminator 2: Judgment Day

Ein_Kreb
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Wed Mar 07, 2018 3:20 am

RiffRaff wrote:
Wed Mar 07, 2018 1:51 am
The "nuclear winter" model, as proposed by Carl Sagan and other great scientists of his era was based on a few flawed premises and the nuclear weapons of that time period. I have the greatest respect for Mr. Sagan, and his crusade to prevent mankind from eradicating itself was no less honorable despite his nuclear winter theory all but being disproved in the 21st century. I don't have the energy to go into gory detail here, and the information is freely available for anyone who wishes to search for it, but the short version is that even if every nuclear weapon on the planet were detonated over every one of their targets simultaneously, a huge percentage of the planet surface would remain largely unaffected. Not saying it would not be catastrophic to the human species, but it would not be an extinction level event as popular culture would have most people believe.
In a total nuclear exchange where the entire world's arsenal is used, how long would the nuclear winter last and would we survive?

Yingyang, I find that this Quora answer does a great job of explaining Sagan's failure. It's a long read but it's worth it.

Yingyang
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Wed Mar 07, 2018 4:15 am

Ein_Kreb wrote:
Wed Mar 07, 2018 3:20 am
RiffRaff wrote:
Wed Mar 07, 2018 1:51 am
The "nuclear winter" model, as proposed by Carl Sagan and other great scientists of his era was based on a few flawed premises and the nuclear weapons of that time period. I have the greatest respect for Mr. Sagan, and his crusade to prevent mankind from eradicating itself was no less honorable despite his nuclear winter theory all but being disproved in the 21st century. I don't have the energy to go into gory detail here, and the information is freely available for anyone who wishes to search for it, but the short version is that even if every nuclear weapon on the planet were detonated over every one of their targets simultaneously, a huge percentage of the planet surface would remain largely unaffected. Not saying it would not be catastrophic to the human species, but it would not be an extinction level event as popular culture would have most people believe.
In a total nuclear exchange where the entire world's arsenal is used, how long would the nuclear winter last and would we survive?

Yingyang, I find that this Quora answer does a great job of explaining Sagan's failure. It's a long read but it's worth it.
Another great post thankyou . I was under the impression in oz if you can get out of fallout zone we would be one of the survivable countries on the planet. And here we have vast expanses of land out side of these zones.

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Wed Mar 07, 2018 5:00 pm

Yingyang wrote:
Tue Mar 06, 2018 7:53 am
Looking for opinions.
Imo for Australia our land mass is huge compared to proxcimity and amount of targets.
My guess is nuclear winter information is generally based on northern hemisphere being the area of most of the planets nuclear targets.
Now taking this into account with global wind patterns I'm guessing it could take months a year or longer for these effects to reach us in Australia? I also believe dicipation will occur when it does meaning we should get more sunlight and heat through this effect. Any thoughts would be appreciated thanks.
100 missile exchange would render the earth approx 2-3 degrees globally cooler, 9% reduction in global rainfall.
Five megatons of black carbon enter the atmosphere immediately. Black carbon comes from burned stuff and it absorbs heat from the sun before it can reach the Earth. Some black carbon does eventually falls back to Earth in rain.

After one year, the average surface temperature of the Earth falls by 1.1 kelvin, or about two degrees Fahrenheit. After five years, the Earth is, on average, three degrees colder than it used to be. Twenty years on, our home planet warms again to about one degree cooler than the average before the nuclear war.

Earth's falling temperatures reduces the amount of rain the planet receives. Year five after the war, Earth will have 9 percent less rain than usual. Year 26 after the war, Earth gets 4.5 percent less rain than before the war.

In years 2-6 after the war, the frost-free growing season for crops is shortened by 10 to 40 days, depending on the region.

Chemical reactions in the atmosphere eat away Earth's ozone layer, which protects Earth's inhabitants from ultraviolet radiation. In the five years after the war, the ozone is 20 to 25 percent thinner, on average. Ten years on, the ozone layer has recovered so that it's now 8 percent thinner.

The decreased UV protection may lead to more sunburns and skin cancers in people, as well as reduced plant growth and destabilized DNA in crops such as corn.

In a separate study, published in 2013, International Physicians for the Prevention of Nuclear War estimated 2 billion people would starve in the wake of a 100-A-bomb war.
Lee

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Thu Mar 08, 2018 2:38 am

lcurle wrote:
Wed Mar 07, 2018 5:00 pm
Yingyang wrote:
Tue Mar 06, 2018 7:53 am
Looking for opinions.
Imo for Australia our land mass is huge compared to proxcimity and amount of targets.
My guess is nuclear winter information is generally based on northern hemisphere being the area of most of the planets nuclear targets.
Now taking this into account with global wind patterns I'm guessing it could take months a year or longer for these effects to reach us in Australia? I also believe dicipation will occur when it does meaning we should get more sunlight and heat through this effect. Any thoughts would be appreciated thanks.
100 missile exchange would render the earth approx 2-3 degrees globally cooler, 9% reduction in global rainfall.
Five megatons of black carbon enter the atmosphere immediately. Black carbon comes from burned stuff and it absorbs heat from the sun before it can reach the Earth. Some black carbon does eventually falls back to Earth in rain.

After one year, the average surface temperature of the Earth falls by 1.1 kelvin, or about two degrees Fahrenheit. After five years, the Earth is, on average, three degrees colder than it used to be. Twenty years on, our home planet warms again to about one degree cooler than the average before the nuclear war.

Earth's falling temperatures reduces the amount of rain the planet receives. Year five after the war, Earth will have 9 percent less rain than usual. Year 26 after the war, Earth gets 4.5 percent less rain than before the war.

In years 2-6 after the war, the frost-free growing season for crops is shortened by 10 to 40 days, depending on the region.

Chemical reactions in the atmosphere eat away Earth's ozone layer, which protects Earth's inhabitants from ultraviolet radiation. In the five years after the war, the ozone is 20 to 25 percent thinner, on average. Ten years on, the ozone layer has recovered so that it's now 8 percent thinner.

The decreased UV protection may lead to more sunburns and skin cancers in people, as well as reduced plant growth and destabilized DNA in crops such as corn.

In a separate study, published in 2013, International Physicians for the Prevention of Nuclear War estimated 2 billion people would starve in the wake of a 100-A-bomb war.
What is the source of this information?
"It's in your nature to destroy yourselves." - Terminator 2: Judgment Day

Ein_Kreb
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Thu Mar 08, 2018 3:06 am

RiffRaff wrote:
Thu Mar 08, 2018 2:38 am
What is the source of this information?
It's a study done around 2007 by Robock and Toon.

New Scientist Article about it

This is the paper, I think

And an index of publications by Robock

Honestly, I had forgotten about it until it was mentioned by lcurle. I need to reread it, but from what I remember it suffered from one of the flaws of TTAPS, namely that it doesn't take into account that cities are no longer terribly flammable, including Pakistani and Indian cities.

lcurle
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Fri Mar 09, 2018 12:20 pm

Also covered by Popular Science
Lee

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