Check out this new tool from Google:
This wicked cool tool is called Earth Engine Timelapse. check it out at http://bit.ly/timelapseearth
Explore a global timelapse of our planet, constructed from Landsat satellite imagery. Watch as mines spread across the surface of Wyoming. Each frame of the timelapse map is constructed from a year of Landsat satellite data, constituting an annual 1.7-terapixel snapshot of the Earth at 30-meter resolution. The Landsat program, managed by the USGS, has been acquiring images of the Earth's surface since 1972. Landsat provides critical scientific information about our changing planet.
Here is my first attempt showing some forest changes in the Sierra Nevada