Earth's total population reaches 10 billion, with estimates of it reaching 12-12.5 billion by the end of the century. Heavy pollution and global warming, along with overpopulation has stretched resources on Earth very thin. Sea levels have risen by over a meter since the year 2000, and are projected to hit 1.5m by the end of the century. Millions have been displaced by coastal flooding, while others are fighting water wars as freshwater resources have started to dry up. However, groundwater is not the only resource that has been running out - fossil fuels are nearly all but depleted. The UN takes action and issues a project to counter the damaging factors. Coastal seawalls are constructed around the world in major cities, such as New York, Baltimore, London, Naples, Barcelona, and many others. The world is forced to switch to renewable and nuclear power sources.
All this increases the UN's power grip over its member nation states.