Earlier this year Google launched the Timelapse project,  a global interactive map that uses three decades of Landsat imagery to show how our world is changing. One stunning example of human impact on the planet is the rapid buildout of Powder River Basin coal mines in the Thunder Basin National Grassland.

In addition to domestic power production, coal exports are an increasingly controversial issue as demand in Asia increases. Exporting coal means even more mining here at home, long coal trains transporting it to ports through busy cities, increased train derailments, and more dirty coal terminals that spill and flood.

View the larger version on Google Earth Timelapse.

Be sure to check out past posts on this issue to see mines like this one compared with more familiar features like San Francisco, and get an idea how big the trains are that carry all this coal to foreign markets.