Check out the following websites:

 

http://earth.google.com/outreach/env_science.html A collection of KMLs highlighting issues on environment, climate change, science and technology.

http://david.tryse.net/googleearth/ Disappearing Forests of the World: This KML, developed by my friend David Tryse presents a geographical account of the planet's disappearing forests by country. The data can be quickly and easily communicated. Country profiles are also included, providing high quality, accessible information included as pops ups in the pie chart balloons - be sure to check out the live hectare counter in these placemarks!.

http://www.tiles2kml.com/ Where you can buy a useful KML converter to display large volumes of geographic data on Google Earth