From Envirowiki

Climate science is a wide category of natural sciences, including meteorology, palaeontology, geology, physics, chaos science, biology, and more. There are also dedicated climate scientists who mesh it all together, to understand how the earth's climate(s) change, and how we might be affecting changes (see climate change).

Climate science is especially concerned with the greenhouse effect, albedo, climate forcings, impacts of climate change, the palaeoclimate record, climate modelling, greenhouse gas emissions, carbon sinks etc.

[edit] Climate science bodies

The Intergovernmental Panel on Climate Change is one of the world's biggest climate science bodies. It does not produce research of its own, rather it collates and synthesises research from climate studies from around the world.

NASA's Goddard Institute for Space Studies has a large climate science division, run by Jim Hansen. Some of it's members post to the RealClimate blog.