The environment is in. Global warming has become a daily news topic. Our carbon footprint is looming ever larger, making us acutely conscious of our wasteful ways.

The problem is that this trend is not a passing one, like mini-skirts, or optional, like high-fibre breakfasts. The rising sea levels and air temperatures are for real. The need to manage (and shrink) our personal carbon footprint will become a legal obligation as soon as science has devised a way to measure it accurately, like our DNA. Our cars, too, will be scrutinized for their CO2 emissions - not just as the car salesman's pitch it has already become, but individually, as our personal responsibility. Already the gas-guzzling SUVs like the Range Rover and the Ford Explorer are attracting derisive hoots - and worse - from environment-conscious urbanites in the West.

We all casually refer to the change in climate when we talk about the cold winters of our youth, and how we used to pelt each other with snow balls on the way to school. I have a photo on the wall of skaters on an Amsterdam canal taken in the 1960s by Ed van der Elsken, a photographer also well known in Japan. When a Dutch visitor saw this photo he laughed. 'It's been a long time since we could do that, skating on the canals!'

For a long time we didn't take any of this seriously, as if these problems did not really concern us. But in just a few years all this has changed. The combined effects of tsunami disasters, yellow dust from the Gobi and the Sahara reaching Japan and Western Europe, and Al Gore's documentary 'An inconvenient truth', have shook up our collective complacency. Add to this the daily diet of dire TV reports about severe droughts, floods and melting ice caps, and the skyrocketing oil prices, and it is no wonder that I am beginning to look over my shoulder when I walk the streets, wondering if anyone notices my shamefully large footprint. And I don't even own a car! I sold my unacceptable Land Rover back in 2003, before anyone had thrown a rotten tomato at it, and never bought another vehicle. Japan's public transport system fully meets any city dweller's reasonable needs.

Where does that leave the average citizen - you and me? What can we do, individually, to help insure that this planet will remain liveable for ourselves, our descendents and the world population at large?

Most of us are aware of the main causes of global warming: the burgeoning world population, and the rising living standards. The former we can do nothing about. The global population has jumped from 3 billion in 1960 to 6.5 billion today, and is projected to reach 9 billion sometime between 2040 and 2050, well within the lifetime of the young among us. Not only will these extra billions make their own contribution to global warming, their production of carbon will be disproportionately higher as global living standards improve - as we can see already in the case of China and other fast-developing areas.

The Showa Spirit

Yet the way we, the earth's human population, live is the only variable amenable to adjustment. Or is it? For the world's deprived masses surely have a basic right to a better life, don't they? How can we ask them to scale back just as they are emerging from misery?

No, we can't do that. Only we, the rich nations, can mend our profligate habits. The sacrifices will have to come mostly from those who caused the problem in the first place: the world's advanced, industrialized countries.

How difficult a task is that? It shouldn't be too onerous if we could only recapture the way we lived 40, 50 years ago. I for one remember the time when, in Japan, most if not all people were naturally careful in their use of resources - water, paper, food, textile fabrics, car tires, heat. Much of it was routinely trapped or recycled. It wasn't a big deal. No talk then about 'saving the planet' - it just made good sense, and it saved money along the way.

Just consider these excellent Showa customs:

- The bathtub needed to be filled and heated only once a day, as the whole family washed outside the tub
- Envelopes of incoming letters were carefully opened, turned inside out, glued back together and reused
- Some food scraps were kept for recycling: onion skins for use as dye; tea leaves to sweep up floor dust; orange peels for flavouring; leftover toast for bread crumbs; bamboo husks for use as shibui 'plates.'
- Shirts and blouses were repaired, socks darned, skirts shortened if fashion required it, with the removed part kept to be sewn back on later, if fashion dictated a reversal
- Worn tires were 'retreaded' with a new glued-on sculptured surface
- The kotatsu was a great way to capture heat at minimal cost, and if your back stayed cold, you put on your quilted kimono or wool vest
- Shopping bags were recycled as rubbish bags, boxes and tins kept for re-use as containers in cupboards and closets

I'm sure every survivor of those homely Showa days can add to this list. Some of us didn't really change our habits greatly even when the economic need for them had evaporated. But the younger generation, having no personal memory of those frugal times, may well laugh at such penny-pinching behaviour. (Though for some, a meager income may be a natural incentive to do some penny-pinching of their own, like shopping at flea markets).

But it is not so much the actual saving achieved by, say, recycling old clothes or resoling your shoes, that is at stake, it is the spirit behind that kind of effort that is worth resurrecting. Once we learn again to value the integrity of things, and to use energy, food and materials intelligently - not to save money but to avoid needless waste - we will be making a real contribution to 'saving the planet'.

And we will be reducing our personal footprint by a size or two.

Next month we will explore this subject further.