This is a simple climate model (energy budget) in R that can be used to create some experiments to investigate Earth's climate change. The model considers the albedo of the ocean and land, cloud cover and the greenhouse effect (concentration of carbon dioxide and methane).
By varying the parameters, it's possible to observe how the temperature of the Earth's surface is changed. The model also considers the distance from the sun, so it's possible to verify how the Earth's temperature would change with the planet closer or farther from the sun.