Yesterday I hit a personal “tipping point” that may sounds trivial in the overall scheme of things, but it gave me some useful insights into human psychology. Ever since I arrived in Hawaii on Sept 1, my weight has been creeping up, little by little, pound by pound. Jeans got a bit tighter, my face got a bit rounder – but the change was never dramatic enough from one weigh-in to the next to give me cause for alarm.

Until yesterday.

I stood on the scales in the morning to find that my weight had leaped 4 pounds in 2 days, taking me over 130lb (plenty enough for a narrow-framed 5ft 3in) and bringing my total gain to 23lb in 4 months.

I had hit my tipping point. It was time to get this back under control.

This is not a plea for flattering reassurances that I look fine anyway, or suggestions that I am trying to force my body to be lighter than it wants to be, or recommendations that I stop worrying about such trivial matters and concern myself with the state of the planet instead.

No – this is my own little personal parable, about the part of human psychology that allows us to turn a blind eye to gradual changes – especially if they are unwelcome changes. We don’t see what is happening because we don’t want to see it. We tend to ignore the problem until it has grown into a crisis.

“A stitch in time saves nine”, as my mother used to say. In my trivial example, I now have undeniable evidence of my weight gain, and it will be some time before my jeans and I are seen together in public again. And of course I am wishing I had taken action when I had a 5lb weight issue rather than a 15lb weight issue.

In planetary terms, what has to happen before we take decisive action to reduce our environmental impact? How much evidence is “enough” evidence for us to reach our collective tipping point?

I am optimistic. My perception is that the scales are tipping (forget the bathroom scales now – picture Libra-type scales). The will for change is growing, and the defence of the old status quo is eroding. The question is becoming not so much “if and when”, but “how much and how soon”. And I believe that we, as a species, do have the ability to rise to this challenge, if we can only put aside our illusions of separateness and tackle this global problem together.