Although one of the aims of the research school is contribute to the building of a detailed, complex Earth system model we will also build Earth system models of intermediate complexity and even simple Earth system models so as to highlight and generate an understanding of particular elements of the problem. We will ensure consistency with regard to concepts as well as data between the simple, intermediately complex and complex models of this model hierarchy. By these means, the School will address scientific questions related to the integral Earth system as for instance:

• How will human activities, as there are economic development, population growth, policy implementation etc., affect climate in the future?

• Will the percentage of additional carbon removed from the atmosphere grow or shrink in the 21st century?

• What physical / chemical / biological mechanism(s) stabilize the greenhouse effect of the atmosphere in the long term?

• Are we approaching a bifurcation in the climate system, will we experience abrupt climate change, and to what would be the consequences for society?

• Is the Earth system manageable at all in terms of long term "climate steering"?