Some of us actually know what we're talking about, as opposed to just idly speculating. You're welcome to play devil's advocate, but just quoting Einstein isn't going to get you far.

We can put a rover on Mars. We can make a desert bloom. I'd like to think we can pick up some radioactive dust.

You don't have kids, I see.

I wasn't the one quoting einstein.

Okay fair enough. I had the impression that air can become radioactive as well, but if I was wrong and it settles into the ground after awhile, my apologies.

Never said you were, just pointed out it's the only thing the pro-armaggeddon crowd has brought up so far.

Air itself, not so much. Dust in the air is what carries the radioactivity.

The moisture in the air too I believe.

If that dust remains mobile then it can be hard to predict where it is and where to pick it up, no?

Meaning it can rain radiation whenever that moisture evaporates into the clouds.

No, but it's okay because I don't have the responsibility of looking after them either.

If I wanted kids, I'd look to adopt some.

Radioactive fallout is comprised of Uranium or other fissionable materials from the bomb not consumed in teh explosion. In fact over 60% of the uranium that was in a bomb before it explodes is still Uranium afterwards, and much of the other 60% has been converted to new radioactive isotopes (new compared to what they were before) the dust remains airborne for some time, and subject to weather patterns, due to the force of teh explosion, but it is heavier than air and will settle to teh ground eventually. At that point their may be some gaseous radioactive isotopes that are generated by the decay of radioactive particles, but these are short lived- the most well known of these is Radon and can occur in a domestic household without the use of nuclear weapons in the vicinity when naturally occuring radioactive dust settles into the carpets of relatively undisturbed rooms. In most cases a vacume cleaner with a good filtration system is enough to clean up the problem.

Your math doesn't add up.
You've got over 120% of your radioactive material accounted for.

I think the problem with overpopulation is mostly present in third world countries (especially Africa, the continent which will mostly likely have a population of 1 billion soon enough), and this is partially to blame to the West. No, I'm not going to hang up a teary story about how the West supposedly ruined Africa during the colonial era, but quite the contrary: foreign aid is destroying Africa. Let me explain how.

Imagine that there's a farmer in Senegal who cultivates rice and also happens to own a few chickens, so he earns his living by selling rice (a staple food in West Africa), eggs and poultry. Now imagine that, suddenly, the west starts sending massive food packs for free. Not only is all of this food completely free of charge, but due to the use of hormones, antibiotics etc. etc. this food will be vastly superior to anything our friend the farmer can produce on his own. This means that he can't earn his living and thus also becomes dependent on thse food packs. These food packs allow Africans to eat and quickly reproduce which doesn't only not solve the hunger problem, but only gives the West more mouths to feed. Personally I think the West shoud cut off this kind of aid as soon as possible, since even not helping is better than this. If the West absolutely, positively NEEDS to get involved (which they have absolutely no obligation to, mind you), then the only kind of aid they should give should be constructive aid, ie. Belgian and French Canadian farmers going to Senegal to explain our farmer friend how he can increase his rice output, what kinds of chickens he should breed for maximum egg production etc. etc.

This will solve most of the problems, because:
1. Our farmer friend only has 'fair' competition, ie. other farmers that have more or less the same tech level as himself.
2. The existant farmers will no longer have any reason to quit their work, since they don't get any foreign aid for simply existing
3. Because they no longer receive free food packs, Africans will actually have to do some family planning, which will result in (relatively) smaller families. These families will most likely still be bigger than western families, but most likely lower than the current 5-7 children per family rate*.

The West hardly has an overpopulation problem. Countries like China have a massively decreasing population due to the 1 child policy, and western countries have very small families that are belowe the 2.11 child/family replacement rate. My country, the Netherlands, for example, only has a growing population due to immigration rather than birth rates.

*This might be a bit of a problem in Africa though, since polygamy is completely common in some societies there. I don't want to start a religious discussion here but for (among others) this reason I think Christian missionairy work in Africa is a good thing, even if only to promote monogamy.

To a lesser extent. This isn't exactly my field of expertise, but from what I understand the contamination that's a concern after the initial span is the radioactive material from the bomb itself - the uranium dust. It's a fine point of difference in the field, but actually radioactive water would be nigh-impossible to clean (only dilute); water contaminated with radioactive dust is much simpler to clean.
That's not to say you can't get water made from radioactive isotopes. Tritiated water is lightly radioactive, whereas heavy water is simply toxic if ingested in large quantities.

Wind patterns are fairly well-understood.

Me neither - well, that and I can't stand kids. That wasn't my point, though. My point was that you said there was no benefit to an increased population. I'm sure every parent with three or more offspring would disagree.

"Can" and "will" are two very different things. Also keep in mind that those amenities will also facilitate population increase - more roads make it easier to leave home, so you don't have to worry about feeding that last kid, just send 'em on their way. Bigger cities are a direct result of population increase, as well - no point in building a city if there aren't people there. The old adage is wrong; it should say "When they come, you will build it."

Edit: Also, Solaris is right about the child thing. I'm not a huge fan of a massive population boom, but I still plan on having a child or two in order to continue my genetic line. As the last reproducing male of my family, I feel a bit of an obligation to keep the line going.