We've Dug a Pretty Damn Big Hole for Ourselves

Your article on resilience.org is a very fine read - the kind of big picture layout that can help me get my mind around issues that are just too boggling to take in piecemeal.I have a new job that leaves barely time to read, much less post, but rest assured I will be re-reading and deeply considering what you wrote.
A question - rather key since I'm starting the gardening aspect of my micro-homestead - why does food production in an unstable climate have to be perennial-based?  Is the problem with the annuals, or with agribusiness?  If annuals are being grown by me on a human scale, can they be part of food production despite climate issues?  Already I'm having to adapt to cold, heavy rain here where in my childhood we had gorgeous summer-y Junes, but the adaptations are working for annuals so far.  If one assumes a soil-friendly, water-wise, non-fossil-fuel dependent kind of gardening, what is it that makes annuals unsuitable and perennials suitable to future food production?
Again, Thanks!
Susan