MY grandparents, born in the horse drawn world of the 1880s, couldn't have dreamt of the indoor toilets, cars, planes, radios, television, mobile phones, the internet and space travel their great-grandchildren take for granted. Add in the advances in medicine, education and working conditions and it would have seemed like a completely different planet.

And it soon will be if we carry on regardless, each in our own little family, city and national bubbles, grabbing what we can, and ignoring what's happening elsewhere in the world. We can't carry on as we have done in the past because:

• In 1 AD the total world population was only about 200 million, similar to Brazil or Indonesia to-day. By 622 AD, (1 AH) it had hardly grown, and it only reached one billion with Queen Victoria in 1837, not even two centuries ago. Two billion arrived in 1930, three in 1960 and since then it's been another a billion every 14 years. It's tripled in my lifetime. We are an infestation!

• Over 95 per cent of all animal life on the planet is domesticated, so needs feeding, including almost two billion cows and 20 billion chickens.

• We barely have two and a half football pitches of land per person to supply all our food, materials, fuel and waste disposal, and this includes deserts, mountains, and ice caps. There'll be even less per person by 2100.

• It's all been made possible by the technical advances in power. My iron is 1,800 Watts, over two horse power, and the vacuum cleaner 2,200 Watts, three horses. Cars average at least 150 horse power, and there are over one billion vehicles. That's some herd!

• Globally we use about 18 billion Watts, but it will be 60 billion when everyone lives like Europe and the States. It's significant that this is more than all the power deep inside the crust that drives continental drift, mountain building, volcanoes and earthquakes. We're now a geological force.

• We're digging up around 100 billion tonnes of minerals, oil and sand and gravel every year, and that's more than young mountains, like the Himalayas and the Andes, add by growth. We're now a serious erosion agent.

• There are already more pieces of plastic in the oceans than fish, and by 2050 it will also outweigh them.

• For the last million years CO2 has varied by about one part per million every hundred years. It's now increasing by one ppm every 23 weeks.

We are changing the world. We now need a future that's not dependent on endless growth but is comfortable with just sufficient for everyone. That's some challenge.