This is available to read online at: http://reports.weforum.org/global-risks-2012/ and is where you'll find that they go into these into these five areas more detail, including what they define as 'risk clusters' such as the water-food-energy nexus and the global illicit economy.
There's also some case examples into what's happening in the world at the moment, these are:
While they do discuss risks, one thing to remember that 'through every challenge there is always an opportunity'. So while they do mention that 'no single country, region, sector or industry is likely to be able to confront or prevent on their own', what it does mean is that there is an opportunity for our global communities to become closer together as work towards reducing the risks that we all share.