What will Latin America's borders look like in 100 years?

Though some borders are obvious due to natural formations (Chile-Argentina), most are simply lines on a map. They started with the Spanish and then were greatly reshaped in the 19th century after independence.

The 20th century was odd in that Latin America's borders barely moved. Sure, there were a few small shifts. There remain several border disputes over relatively small plots of territory. But nothing big.

To think that the borders will remain nearly the same in the coming hundred years is to embrace the 20th century and miss the rest of human history. We're more likely to see big and completely unexpected shifts than to see absolute stagnation for another century.

Here's a few possibilities. These are NOT meant as predictions, but rather to begin thinking about potential ways that borders could move, even if it seems very unlikely today:

• A larger regional structure will form as countries merge under a single federal government. Various countries in Central America may merge into a single unit. Hispañola seems like a likely candidate. Or Colombia, Venezuela and Ecuador could combine back into a Bolivarian unit. Or perhaps UNASUR pulls off the big integration effort and we end up with a president of a United South America.
• Countries break apart and new countries or city-states emerge. Rio and Sao Paulo could become one or even two separate countries, completely split off from Brasilia. Bolivia and Peru could both break into two or three parts. Chile could divide itself into multiple long and skinny countries. Mexico could break up.
• Countries could forcibly take territory. Mexico could take over Guatemala. Venezuela could take over Guyana. Argentina could take over Uruguay and Paraguay. Or perhaps the US takes a new state. While violent armed conflict is off the table today, a worst case scenario in 50 years could have countries fighting each other again and taking territory from each other.
• Countries could cede territory, leaving lawless and (officially) ungoverned spaces or new countries. Brazil could decide it doesn't want all of the Amazon. Colombia could give up some of the states where violent actors remain present. A Central American country could decide a portion of the Caribbean coast is simply owned by the indigenous communities there and give up all claims on it.

As I said, I don't expect any of those predictions to happen, but I do expect some larger movement of borders in the coming hundred years. The map in 2112 will not look like the map in 2012. It's all a matter of how and when.