Forget what Leo DiCaprio said about climate change and global warming. It’s the way governments manage land that threatens us all.
Climatologists say Syria is a grim preview of what could be in store for the larger Middle East, the Mediterranean and other parts of the world. The drought, they maintain, was exacerbated by climate change. The Fertile Crescent — the birthplace of agriculture some 12,000 years ago — is drying out. Syria’s drought has destroyed crops, killed livestock and displaced as many as 1.5 million Syrian farmers. (Source: Scientific American, The Ominous Story of Syria’s Climate Refugees)
Look at the rivers, grasses and forests that fed and formed our first major civilizations (e.g. Mesopotamia). What was urbanization at first but a governed collection of farmers and traders?
Look at the centrality of agriculture and agricultural symbolism to Islam, Judaism and Christianity — making sure people get enough resources from the land, which means managing water, logging, pasture, farms, etc. Look at Christ the Shepherd, Muhammad the Meccan trader (wares including spices, animal products, maybe even wine) and the symbolism of Judaism (wine, the Garden of Eden, Jacob wearing goat hide to win his birthright).
Agriculture and agriculture-related law (including ownership) would drive society, and governments would exert a lot of control over who has what land and what they can do there, e.g. stationary farmers and nomadic herders. Look for a problem in today’s Islamic world that doesn’t strongly involve farmers or getting food to the cities, water, or nomads and the ever-changing migration/grazing patterns of their livestock.
There’s a recurring pattern of disruptive climate fluctuations and human effects on the environment — bad harvests, deforestation, drought/no water in the wells, disease/not enough food for livestock, etc. This makes people move and people fight — this affects governments, armies and the fates of nations.
Then there’s the role of wealth. Trade shapes society and international trade affects what and how people use their land: cash crops (e.g. Turkish cotton) and then oil.
Natural resources attract outside intervention — think of the Mongol desire to control/unify the rich trade of the Silk Road. Think of how oil changed the fate of the Middle East.
These days, all of this comes together. Nations created by environments created by nations. Migration, conflict and commerce on a global scale.