A Libyan rebel sits on the back of a pick up truck (AFP/Patrick Baz)
A warmer planet means more drought, more desertification -- and less land area suitable for human life. More poor people contribute to environmental degradation as they strip drying land bare. Humans became the dominant species on the globe because we move on when our home patch turns on us. A warming world with rising seas is going to push humans to move. A lot of humans.
According a 2009 report in The Economist,
The article takes up the question whether people gradually pushed out of their current habitats must be treated as refugees by more fortunate populations. A few islanders displaced by higher ocean levels may be welcomed, but there's a tendency among rich populations to envision invading dark and dangerous hordes. Here in the US, we still look to the oceans to protect us, but Europeans look south at Africa and worry that they'll be swamped.
The Middle East Research and Information Project (MERIP) sets the current Libyan campaign by France, Britain and the United States in the context of those fears.
The entire analysis is worth a read.