Armageddon

[Xan]

Exactly how much of a nuclear blast would it take to destroy all life on earth?

[Chez_Guevara]

I don’t know so Armageddon out of here.

[obfusciatrist]

All life or just all human life?

One big bomb or can we strategically place smaller bombs?

[Squink]

We barely have enough nukes to melt the surface in an area the size of Nebraska. The sort of deep heating needed to sterilize the planet is completely beyond our abilities.

[Guy_Propski]

Depends who you’re talking to. A sufficient number of nuclear explosions (or, for that matter, conventional explosions) could eject enough dust in the atmosphere to start a nuclear winter, caused by the dust in the air preventing sunlight from reaching the ground. If the NW was to last several years, that could result in killing all life on earth; shorter periods would “only” cause wide-spread extinctions of species.

Carl Sagan was a big proponent of nuclear winter (he wrote it up for Scientific American several years before he died), but the math is pretty hairy. It’s very difficult to estimate how much dirt and smoke would be lofted by an explosion. For example, you get dramatically different amounts depending on where the explosion takes place. H-Bomb a forest, and you get lots of smoke from burning trees; H-bomb a desert, it’s not so smoky, but you get dust. There’s also the question as to how long the stuff stays up. Weather patterns are hard enough to figure out week to week. Estimating them over a 5 year period is darn near impossible.

[Acco40]

No way. Never. Not all life on Earth.

IANAS, but as far as I know there is a plethora of life on the ocean floor which go on perfectly fine without the energy of the sun; I’d think the ejected dirt in the atmosphere and radiation would have little effect on them.

Also, when you consider just how many bacteria there are (most everywhere!), it becomes obvious that all life wouldn’t die out.

[Guy_Propski]

The problem you run into, Acco40, is that after a certain amount of oxgen producing plant life dies, life that depends on oxygen begans to die to. These plants depend on light for photosynthesis to produce oxygen. The greatest producers of oxygen are the blue-green algae that live in the ocean which, by the way, also provide food for creatures that live in the sea (even those in the lightless depths, both directly and indirectly).

Would there be a couple of bacteria still left alive after 10 or more years of nuclear winter? Maybe. I would bet on it, though.

[Duck_Duck_Goose]

Well, a Google search for “sterilize planet earth” has turned up, so far, ways to sterilize the planet via:

– a giant asteroid impact;
– a giant comet impact;
– the sun going nova in a billion years;
– a star 100 light years away going nova and bombarding us with gamma rays, which would kill everything;
– Marvel Comics’ Yellow Claw sterilizing the planet so that his harem of wives can repopulate it with his offspring;
– and alien angels landing and sterilizing the planet (the exact mechanism is not clear, but it doesn’t seem to matter).

But no mention of nuclear weapons. I think we’re safe in putting “We could destroy our entire planet with the nukes we already have!” on the “worry about this” back burner.

Me, I’m going to worry about the Yellow Claw instead. What if he gets another harem?

[Threadkiller]

*Originally posted by Guy Propski *
Carl Sagan was a big proponent of nuclear winter (he wrote it up for Scientific American several years before he died), but the math is pretty hairy. It’s very difficult to estimate how much dirt and smoke would be lofted by an explosion. For example, you get dramatically different amounts depending on where the explosion takes place. H-Bomb a forest, and you get lots of smoke from burning trees; H-bomb a desert, it’s not so smoky, but you get dust. There’s also the question as to how long the stuff stays up. Weather patterns are hard enough to figure out week to week. Estimating them over a 5 year period is darn near impossible.

You make it sound like he wanted a nuclear winter!

Seriously, Sagan is sort of out there on this one:

Though Dr. Sagan is one of the most frequently cited experts on atmospheric issues by the media, his predictions are often wrong. For example, at the outset of the Persian Gulf War, Sagan warned that if Saddam Hussein delivered on his threat to set fire to Kuwait’s oil wells, so much black soot would be sent into the stratosphere that sunlight would be blocked and a variation of the “nuclear winter” scenario would occur. Hussein followed through on his threat and by the close of the war over 600 wells were on fire. But the fires had little environmental or climatic effect beyond the Gulf region and virtually no ill effects globally. Peter Hobbs, a University of Washington atmospheric sciences professor who studied the atmospheric impact of the fires for the National Science Foundation, said that the fires’ modest impact suggested that “some numbers [used to support the Nuclear Winter Theory]… were probably a little overblown.”

Notice the above site is a bit more of a slam on Sagan than I would normally deliver, but he did seem really far off the mark on the “Gulf War fires = Nuclear Winter” scenario.