happened before and the post-war apocalypse.

核戦争以前と 戦後に訪れる終末の世界とに

In the worst case, mass fires consume everything  within tens of thousands of square kilometers,  

最悪の場合 巨大な炎が数万km2にわたり 全てを焼き尽くし

killing hundreds of millions within  hours. But the worst part comes  

数億人を１時間で殺す

after that - nuclear war could trigger a  nuclear winter that might kill billions,  

だが最悪なのはその後だ

maybe even completely collapsing our civilization.  How does it work and what would it look like?

核戦争は「核の冬」を引き起こして 数十億人を殺し

Fire Causes Winter

人間文明を 完全に崩壊させるかも

When a nuclear weapon is detonated, a bubble of  gas hotter than the sun is forced into existence,  

核の冬はどのように生じ 何をもたらすのか

so hot that everything within kilometers  immediately begins to burn. The terror bubble  

【炎が冬を連れてくる】

expands rapidly, filling the sky over its target,  creating a devastating shockwave that causes most  

核兵器が爆発すると 太陽よりも高温な泡が発生する

of the immediate destruction. Basically you  break a lot of stuff and set it on fire – and  

数キロ以内の全てが ただちに燃えるほどの熱さだ

in the worst case this turns into a firestorm that  consumes everything and everyone on the ground.

恐怖の泡は急速に拡大して 上空を埋め尽くし

Right after the explosion a gigantic mushroom  cloud rises over the destruction like a demon  

直接的な被害の大半は 破壊的な衝撃派で生じる

throning over its perverse work, but in  the following hours a far more deadly  

基本は大量の破壊と着火なのだ

cloud forms. The fire burning cities,  forests or fields, heats up so much air  

これは最悪の場合 地上の生物と物質の全てを焼き尽くす

that it creates its own micro climate and  wind system. Hot air and hot smoke rise,  

爆発直後 巨大なキノコ雲が立ち上る

pulling in fresh air from the surroundings,  and fresh oxygen stoking the flames even more.  

人類のご乱心を 悪魔があざ笑うように

This creates an updraft and forms  a colossal pyrocumulonimbus cloud  

だが数時間でさらに致命的な 雲が形成される

that carries the soot and aerosols from  the flames high into the stratosphere.

都市や森林 野原を焼き払われ 空気が過熱し 独自の微気象が形成される

Under normal conditions, the soot rising  from a big fire is quickly washed out by rain.

熱い空気と煙が昇り 周囲の新鮮な空気を引き込み

But a pyrocumulonimbus cloud can  reach altitudes well above the height  

新たな酸素が炎を勢いづかせる

where rain clouds form. Once above the tropopause,  

上昇気流が発生し 巨大な火災積乱雲が作られ

there is simply no weather to remove soot from  the atmosphere, so it can stay aloft for years.

火災によるススやエアロゾルは 成層圏にまで達する

If this happens to a single city, it's a tragedy,  but a fairly local one. But in a full scale  

通常ならススは 雨ですぐに洗い落とされるが

nuclear war, warring nations following the cold  logic of mutually assured destruction, could use  

火災積乱雲は雨雲が作られるよりも 高くに到達しうる

hundreds or even thousands of nuclear weapons all  at once, creating hundreds of fire storms, sending  

対流圏界面を超えると もはや大気から取り除けず

up to 150 million tons of soot, a cube the size  of a skyscraper, directly into the stratosphere.

数年間 上空に留まりうる

In the next few days and weeks the soot  begins to blanket the earth at high altitudes,  

一つの都市なら悲劇だが

absorbing light high above the ground  and preventing sunlight from reaching  

かなり局地的だ

the surface . This is not like science fiction  where the sky turns dark and the sun disappears.  

だが本格的な核戦争では 相互確証破壊の冷徹な論理に従い

Winter is what happens when just a little less  sunlight hits the ground – and now suddenly a  

一度に数百発 あるいは数千発が発射され

lot less sunlight gets through. Yesterday the  world was normal. Today nuclear winter begins.

何百もの火災嵐によるススは1.5億トンにのぼり 集めれば一辺500mの立方体ができる

Winter Causes Hunger

成層圏に直接到達する

How bad nuclear winter would be is still an active  area of research. It all hinges on one thing:  

数日から数週で ススは高くから地球を覆い始め

How much stuff will burn really hot? How many  firestorms would be caused by the heat of the  

太陽光を地表より高くで吸収し 地表への到達を妨げる

explosions? This depends on many factors, from  the materials a city is made of, to the time of  

SFのように空が暗くなったり 太陽が消えたりはしない

the year, if a forest is nearby and so on. So just  keep in mind we are working with some assumptions.

冬になるのは地表に届く太陽光が少し減るからだが それが唐突に激減するのだ

Here is the good news: Nuclear winter is  not permanent, and definitely no new ice age.

昨日まで世界は正常だった

The effects on the climate only last as  long as the soot remains in the atmosphere,  

今日　「核の冬」が始まる

which is at most a decade or so until it  clears out and temperatures normalize.

【冬は飢餓をもたらす】

The bad news is that this causes almost  immediate climate change within a few  

核の冬がどれほど深刻かは いまだに活発な研究分野だ

weeks – it disrupts our climate system  faster than any living being can adapt to.

深刻さのカギを握るのは 業火に包まれる物質の量だ

In this new climate our seasons are suddenly  all wrong. Winters are much longer, summers  

核爆発で どれだけの火災嵐が生じるか

shorter and colder – or gone altogether. This  also means less evaporation over the oceans,  

これには多くの要因が関わる 都市の物質量 被弾する時期 森林の近さなどだ

which means less rain and maybe large scale  droughts. This is bad because our food eats the sun.

だから複数の仮定がある点にはご留意を

Without good summers and enough rain,  growing seasons shrink or even collapse.

いいニュースがある

The majority of humanity lives in  an area called the midlatitudes,  

核の冬は永続せず 新たな氷河期を迎えることもない

a strip of land that has the ideal temperature  for our species – not just because it's not  

気候が変わるのは 大気にススが残る間だけで

too hot or cold, it's also where the plants  we eat grow best. The vast majority of the food  

せいぜい10年で ススは消えて元通りになる

we eat stems from a few highly efficient  crops, that are mostly produced in a few  

悪いニュースは たった数週で気候が変動してしまうことだ

very agriculturally productive regions, like  the US Great Plains or Ukraine. From these  

気候システムの急変に 生物の適応は追いつかない

bread and rice baskets of the world, they  get traded and shipped around the world.

新たな気候では 季節が狂ってしまう

In the worst case of a full scale nuclear  war the temperatures in the midlatitudes  

冬が長くなり　夏は短く寒くなるか 存在しなくなる

will probably stay below freezing for  several years. Nothing at all can grow  

海面からの蒸発が減り

under these conditions and the world's  breadbaskets would suddenly turn empty. 

降雨が減少して 大規模な干ばつもあり得る

If food production crashes, the world's food  producers would very likely ramp up prices or  

作物は太陽が主食なので 厳しい事態だ

even stop selling food to other countries – if  they're still able to farm their fields at all.

暑い夏と十分な降水なしでは 生育期間が縮むか　育ち切らない

It's easy to calculate how many people can be  alive on earth – you take all the calories we  

人類の大半は 中緯度地域に住んでおり

can produce and divide them by what the  average person needs to survive. If you  

この一帯の気温は 人類に理想的だ

have more people than calories, then within a few  weeks you don't anymore. Humanity has only a few  

暑すぎたり寒すぎたりしないし 作物の生育にも最適だ

weeks' supply of crops and food, not enough  to survive this drastic drop in production.

食品の大半は 数種類の優秀な作物に由来し

But the climate is not the only issue: modern  industrialized agriculture is a complex affair  

アメリカのグレートプレーンズやウクライナのような 農業適地で生産される

that relies on functioning supply chains to  provide unthinkable amounts of industrially  

こうした供給源からの貿易や取引で パンや米が世界に行きわたる

produced fertilizer and chemicals to kill weeds  and vermin. Massive numbers of specialized modern  

最悪のケースは 本格的な核戦争で

machinery is plowing, sowing, harvesting  and distributing. After a nuclear war,  

中緯度地域の気温は 数年間にわたり氷点下だろう

especially if the countries that produce the  food were part of the nuclear exchange, there  

この条件下では何も育たず 世界のパンかごは空っぽになる

may simply be no more fuel, fertilizer or machine  parts, because there are no more oil refineries,  

食糧生産が破綻すれば 世界の生産者は値上げをしたり

ports and other essential infrastructure left,  damaging global food production even more.

他国への販売を停止しそうだ

Ok, so now that we set the stage, let's look  

まだ生産ができるならの話だが

at what science says about the  actual wars that could happen.

世界が養える人数は 簡単に計算できる

Actual Nuclear War

生産しうる全カロリーを 1人あたりの必要カロリーで割ればいい

Today there are two main conflicts that scientists  think about when making calculations of nuclear  

需要が供給を上回った場合 数週間で状況が改善される

winter: a nuclear war between India and  Pakistan and one between the US and Russia.

作物や食品の備蓄は 数週分に過ぎず

The most likely smallish nuclear exchange would  be fought today between India and Pakistan,  

この生産量の激減を 乗り切るには不十分だ

with relatively low yield weapons. Even  in a pretty mild nuclear war like this,  

だが問題は 気候だけではない

the immediate explosions would  kill around 27 million people,  

現代の工業的農業は サプライチェーンに依存した複雑な営みで

which is horrible enough. In just a few  hours, more people would die than in all  

想像を絶する量の化学肥料や 殺虫剤や除草剤が不可欠なのだ

of World War 1. The ensuing fires would not cause a nuclear winter,

大量の近代農業機械が 耕起 播種 収穫 流通に必要だ

but a mild 'nuclear autumn'. But even this would disrupt the climate,  

特に食糧輸出国が 核戦争の当事者となった場合

and thereby global agriculture, enough to  starve up to 250 million people worldwide.

燃料も肥料も機械の部品も 手に入らない

Unfortunately India and Pakistan are in an  arms race and have been increasing the number  

石油精製所や港など 基盤的なインフラがないからで

and power of warheads in their arsenal. The next  stage of escalation would be war with hundreds of  

世界的な食糧危機に拍車をかける

nuclear weapons, the bombs and fires destroying  many major population centers and killing over  

よし　前提は共有できたので

100 million people. A war on this scale would  cause a nuclear winter that would damage global  

実際にありえる戦争への 科学的な見解を

agriculture enough to cut the available calories  for humanity in half. The number of people

【実際の核戦争】

that starve to death would be as high as 2 billion.

現在　科学者が核の冬の計算対象とする 主な紛争は2つある

One in four humans alive today.

インド vs パキスタンと アメリカ vs ロシアだ

The worst-case scenario is a full scale global  war between NATO nations and Russia – or China,  

想定される最も小規模な核戦争は インド vs パキスタンで

which also continues to build its nuclear  arsenal. In a war between a former,  

核兵器の収率もやや低いだろう

future and current superpower, thousands  of nuclear weapons could be detonated.

このようにかなり小規模な核戦争でも 2700万人が爆発直後に死ぬだろう

In a scenario with around 4400 nuclear weapons,  360 million people would perish right away. We  

充分に恐ろしいことだ

have no other event to even compare the death  and destruction to. It's like humanity dropping  

たった数時間で 第一次世界大戦以上の死者が出る

an asteroid on itself. The nuclear winter  that follows such an apocalyptic war would  

続く火災は核の冬ではなく マイルドな”核の秋”を招くだろう

tank human calorie production by as much  as 90%. Not only would almost all of our  

それでも気候は乱され 国際的な農業生産は破綻し

agriculture take an immediate and deadly  hit, the climate would take at least a  

2億5000万人が餓死するだろう

decade to recover. Because a war like this would  specifically hit the world regions that produce  

残念ながらインドとパキスタンは軍拡競争中で 核兵器の数も威力も増している

most of the food for humanity – recovery will  be much, much harder than with other conflicts.

さらにエスカレートすれば 数百発の核弾頭が行き交うだろう

Within two years the global death toll from  starvation could rise to about 5 billion.  

爆発と火災で主要な人口密集地の多くが破壊され 1億人以上が死亡する

In mid latitude countries like Russia, China,  Canada, the U.S. and much of Europe only a few  

この規模の戦争は核の冬を引き起こし 農業が受ける損害は

percent of the population might survive.  Humanity will never be the same again.

人類が得られるカロリーを 半減させる

While nowhere is truly safe, some nations in  the southern hemisphere may fare well enough  

餓死者は20億人に達するだろう

to endure, while the rest of the world collapses.  All the nuclear weapon states are in the northern  

現在の人口の4人に1人だ

hemisphere. So a few countries like Australia, New  Zealand, and Argentina may be able to endure for  

最悪のシナリオは ＮＡＴＯ諸国とロシアとの間か

a bunch of different reasons. Their nuclear winter  would be milder, they have a lot of livestock that  

あるいは核を増やし続ける中国との 全面戦争だ

would not be as affected as crops. So they would  probably stop exporting food and focus on keeping  

古今の超大国間の戦争では

their own people alive – assuming they aren't  invaded for their food by other starving nations.

数千発の核兵器が爆発しうる

It's safe to say that the world would become  extremely unpleasant for a long time and it's

4400発の核兵器を想定すると 3億6000万人がすぐに死亡する

impossible to know how many people will have  died when the nuclear winter ends. In the worst  

この規模の死と破壊は 人類史に前例が無い

case human civilization could collapse  and the survivors would be thrown back  

人類が自ら小惑星を落とすようなものだ

thousands of years, slowly trying to recover  a world full of scars and graves. Eventually,  

このような終末的な戦争による核の冬は カロリー生産を90％も低下させるだろう

when they've rebuilt civilization, would  they ever build nuclear weapons again?

農業がただちに致命的な打撃を 受けるだけでなく

We know for sure that we need to do  anything we can to make sure nuclear  

気候の回復にも10年はかかる

war never happens. This video was supported  by Open Philanthropy – if you want to know  

特に食糧生産の大部分を担う地域が 影響を受けるため

what YOU can do to reduce the risk for  nuclear war you can either support expert  

他の戦争よりも 復興ははるかに困難となる

organizations or become a citizen expert  yourself and learn more. We've compiled a list  

2年以内に世界の餓死者は 50億人に達するだろう

of further reading and expert recommendations  in the infobox and our sources doc for you.

ロシア 中国 カナダ アメリカ EUの大部分は 中緯度地域にあり

Thank you so much for helping us clear out  the kurzgesagt warehouse for our big move!  

生き残れるのは数％だろう

But watch out – sometimes creepy  things are hiding behind those boxes. 

人類はもう 元通りにはならない

Wild DREAD appeares! What will you do?  

本当に安全な場所はどこにもなく 南半球の数ヵ国は十分に耐えうるが

Quick! Grab something from one  of the boxes to defend yourself.  

他の地域は崩壊するだろう

You used AWE! It's very effective against DREAD!  Look! You've unlocked some amazing deals! 

核保有国はすべて北半球にあり

Save up to 50% on awe-inspiring  products in our biggest sale ever.  

オーストラリア ニュージーランド アルゼンチンなどは持ちこたえうる

Some of our finest creations are eager to  find a new home - like the Duck Plushie,  

核の冬もマイルドだし 家畜は作物ほどの影響は受けないだろう

our elaborately designed notebook series and  a few of our very best infographic posters. 

だから食糧輸出を控え 自国民を生かそうとするだろう

The birbs will be moving the last boxes to the  new warehouse soon – so grab a notebook,  

飢える他国から 侵略されなければ

plushie, pin or poster before the moving sale  ends – or before dread gets a hold of them.

世界はしばらく 極めて不快な場所になるはずだ

The birbs really appreciate it!

そして核の冬が終わるまでに どれだけ死ぬかもわからない