The homeworld and capital of humanity is entering a new golden age. The resource wealth of a dozen settled colonies and a hundred industrial outposts flows back to Earth, fueling great works of industry, commerce, and art. The great cities are greening as arcology skyscrapers and telecommuting allow more efficient use of land.
Earth is still divided among nation-states, though all are affiliated beneath the overarching banner of the Systems Alliance. While every human enjoys longer and better life then ever, the gap between rich and poor widens daily. Advanced nations have eliminated most genetic disease and pollution. Less fortunate regions have not progressed beyond 20th century technology, and are often smog-choked, overpopulated slums.
Sea levels have risen two meters in the last 200 years, and violent weather is common due to environmental damage inflicted during the late 21st century. The past few decades, however, have seen significant improvement due to recent technological advances.
Mass Effect 3
Earth, the homeworld and capital of humanity, was enjoying a new golden age before the Reapers attacked. Disease, pollution, and other social ills were on the decline thanks to technological advances and a wealth of resources from the colonies. Earth was an inspiration even to alien cultures, resulting in influence out of proportion with humanity's brief time on the galactic stage.
The Reaper attack has put an end to any semblance of this former life. The great cities of Earth are storehouses of human DNA for the Reapers to harvest. Reaper gunships, capable of megaton-scale firepower, annihilated industrial centers in seconds. The militaries of Earth's disparate nation-states have retained only partial communication with the Systems Alliance fleets, leaving the planet's resistance efforts uncoordinated and vulnerable. The loss of the comm-buoy network has cut off Earth's economy from the rest of the galaxy, sending shockwaves across galactic markets--and a significant obstacle to receiving aid.