Is there an alternative to Capitalism?

Could Karl Marx be correct in his prediction that Capitalism would ultimately be self-destructive?  If this is the case, is there an alternative to Capitalism keeping in mind the catastrophic failures of Communism?

Why Capitalism needs to radically change is very well explained in this article by Richard Smith.

A Steady State Economy centred on an ecologically sustainable approach to Capitalism could provide the answers to these questions.  Richard Heinberg, Transition Networks, The Centre for the Advancement of a Steady State Economy, Positive Money, Breakthrough Capitalism, The Ellen MacArthur Foundation and the New Economics Foundation, among many other international organisations, are all exploring ways to create more understanding and strategies for necessary and urgent change.