Start with a simple factor which you haven't mentioned involving the Earth's major greenhouse gas: water vapor. Increased temperature obviously encourages evaporation of water. Will that water stay as a gas, or will it cause greater cloud formation? Will those clouds be flat or tall? Look at today's weather satellite pictures -- are clouds an unusual event? What will cloud changes do to climate?

Which is exactly why the first half dozen or so parameters we checked out were cloud-related. Most climate change modellers acknowledge that there are large uncertainties around cloud-climate feedbacks, and these form a central focus of the experimental design.

Dave Frame

climateprediction.net coordinator

University of Oxford

yes, small changes to the initial conditions can significantly effect the result - that's why the mainstream consensus has become that massive parallel simulations like this, with a large number of slightly different starting conditions and slightly adjusted model parameters are the only way to get statistically significant results out of current climate models.

Running such types of experiments has been shown to increase the skill of climate forecasts quite usefully