IIRC the earth had at one point (probably not anymore) enough nukes to obliterate the whole surface and ptw ably coat the planet in huge craters. And there are very few things that can survive that kind of radioactive environment (the only one that really comes to mind is that weird goop growing around/in the Chernobyl reactor, which actualy lives off the radiation) and when I said kill all life I should have probably said all complex life? Would that have fit the description better?
Obliterate the surface? Not even close. This is going to be realtively simplified, because precise figures are hard to find for obvious reasons.
Now, let's look at the maths here. Around ~60% of russian nukes and ~90% of american nukes are below or at the 475 kt range. 77% of Chinese nukes are below 300 kt. That's kilotons of TNT. Mt, megatons. A 475 kt nuke produces approximately 64 square miles of 3+ psi destruction - using the blast pressure, effectively, to demolish things.
So let's assume overall, nukes average out to 475kt. THis might be high, or it might be low, but it's an acceptable basemark. Assume a variance of +/- 50%. Looking at it, it's probably high. The bomb that hit Nagasaki was 21kt. The one that hit Hiroshima was a
mere 15kt. Bombs have certainly got the capacity for more power since then, hence the high number, but having several smaller bombs tends to be more effective than a single huge one.
First, let's work out how many nukes exist at the moment.
China: About 250 total warheads.
France: 290 deployed warheads.
Russia: According to the September 2014 New START numbers, Russia has 1,643 strategic warheads deployed on 528 ICBMs, SLBMs, and strategic bombers [1]. The Federation of American Scientists estimates Russia has several thousand nondeployed strategic warheads and approximately 2,000 tactical nuclear warheads. An additional 3,700 are awaiting dismantlement.
United Kingdom: About 120 strategic warheads, of which no more than 40 are deployed at sea at any given time. The total stockpile is up to 225 weapons.
United States: According to the September 2014 New START declaration, the United States has 1,642 strategic nuclear warheads deployed on 794 ICBMs, SLBMs, and strategic bombers [1]. The Federation of American Scientists estimates that the United States' nondeployed strategic arsenal is approximately 2,800 warheads and the U.S. tactical nuclear arsenal numbers 500 warheads. In total, the U.S. has about 4,800 nuclear warheads [2], including tactical, strategic, and nondeployed weapons. Additional warheads are retired and await dismantlement.
In total, ~8860, give or take a few, if you also include Israel, India, and Pakistan, who aren't part of the non-proliferation treaty. That doesn't include weapons that are awaiting dismantlement.
567,232 square miles of 3+ psi damage.
1,474,803.2 km˛.
China is 9,596,961 km˛.
The current nuclear armament of the world, could, roughly, destroy 15% of china.
The earth has 148940000 km˛ of land. You would need ~100 times as many active nuclear weapons as currently possessed on Earth in order to hit the entirety of the Earth's landmass. Even if my maths is a bit shaky here, I would like to think it's still enough in the ballpark it makes my point.
It's really cool seeing how picturesque and lush the areas around Chernobyl are, whilst being inhospitable to human life.
I mean, plants and grass and important stuff can grow or thrive, just none of those pesky humans.
Nonsense.
People can and do live in the Chernobyl Zone of Alienation. What's stopping more people living there is government, not radiation.