Catastrophe modellers use complex IT models to estimate losses from natural hazards and terrorism in particular. They often work with underwriters in an insurance company to ensure that probable losses are kept within specified limits.
Unlike the majority of roles in insurance, those wanting to get into catastrophe modelling are likely to have a specific degree in geography, maths or statistics.
There are very few graduate schemes with a catastrophe modelling specialism (Willis Towers Watson is the only major player with one). Most people who work in the area started either in a direct entry role or have transferred from a role such as Underwriting Assistant.