This is a extremely user-friendly climate simulation software that is available for download and it also comes with many predefined environmental scenarios:
"The EdGCM Project develops and distributes a research-quality global climate model (GCM) with a user-friendly interface that runs on desktop computers. Anyone can explore the subject of climate change using the same methods and tools that scientists employ. The design of the software allows students to learn and experience the full scientific process including: designing experiments, setting up and running computer simulations, post-processing output, using scientific visualization to display results, and creating scientific reports ready for publishing to the web..."
It has been developed by EdgCM cooperative project at Columbia University.