Pegminer is on the right track. Jerrod Diamond answered that question in his Pulitizer Prize winning book, Guns, Germs and Steel. It is about agriculture and horticulture. Wheat, Barley, Rye, and Rice do much better on the plains of the US or Europe. These grains allow storage of food throughout the year. In addition, the US and Europe have navigable rivers which allow commerce. In addition Europe and the US have areas where iron ore, and navigable rivers are in proximity to coal reserves which allows for iron and steel production. China too has similar features.

Africa has almost no navigable rivers. They have a hard time growing crops such as wheat that can be harvested in quantities greatly exceeding the expense of planting. Cows and sheep don't do well in Africa.

It has a lot to do with human nature, if you live in a cold climate, you need to think and plan ahead and organize yourself, otherwise come winter you will either starve or freeze to death.

Similar with Egypt, although there it was not climate, but timing the rise and fall of the Nile river.

Humans are clever and ingenious if forced to be so, but lazy and complacent if not.

Think of the hottest most humid day in the middle of summer. Imaging working day in and day out in that heat with no breaks and you tell me how hard you would work. And consider that food plants grow well in that climate so if you do not work one day of 4 you will still eat.'

Contrast that with the north where if you do not work to have food for the winter you die. And where if your home is not in good repair you may freeze. And that it is easier to work hard in the cold than in the heat.

I think at least partly it has to do with agricultural production. Tropical soils are typically poor for agriculture, while midlatitude soilds are often quite rich. I think that's true for ocean fishing, too. The richest areas tend to be regions of upwelling water--because it brings nutrients to the surface--which also makes the climate cool.

I'm sure a lot of it is just an accident of history, though.

Saudi Arabia seems quite prosperous as do other oil-rich middle eastern countries.

Also, why concentrate on now? We have had prosperous areas elsewhere in the past. Think of the Persian empire or ancient Egypt.

Yeah, things are going swimmingly in Detroit and Chicago. It's gotta be the climate.

If anything, climate has the opposite effect on prosperity than denialists claim. Warmer is not always better.

It's true on a international scale and here in the states. The happiest, cleanest, most "green", and the safest countries are northern and western Europe. Canada, Iceland they are all very well off. The same can be said for Minnesota, Colorado, Vermont and other Northern states, so I am curious, why are they so well off, and does it have anything to do with their climate?