To start growing my own food, in my garden, before peak oil depletes the supermarket shelves.

I believe a tipping point is a credible phenomenon. Indeed, there are things we may do to aid the process, that is to say, become a "tipper".
1. Refrain from despair - even though we are about to nudge against extinction.*  Do whatever you need to do - cry, pray, take SSRI's, whatever, but get well enough to be a "tipper".
2. Become an activist and dispell self-defeating behaviours. This involves great change. But take it from me, change can happen.  Four years ago I was a chain-smoking, cynical, lazy, binge drinking, nihilist. Today, I am a reverential, kind, non-smoking, environmentally conscious man on a spiritual path. I still like the odd glass of cabernet now and again, and, to this end, I admit it: I am very, very human. Still, I am now heading in an okay-ish direction. 

Sorry folks. Bad news on the Horizon. Circumstance may be about to shave a couple of billion people off of the global population figures. When considering change, we have to factor in several scenarios. We have to prepare for "the big 3" - the potential US dollar collapse, peak oil and climate change; what activists and academics call "The Perfect Economic Storm."