What a difference a lot of humans make

The focus on global warming and changes in climate and greenhouse gases is too narrow. The arguments between scientists befuddle the rest of us. In polls, opinions hover, and around 50 per cent do not believe there is trouble ahead. Most of us do not believe that we make any perceptible difference to the world, judging by the feedback on blogs and articles on the web, and the casual attitudes of politicians. The economy is the real world, and measurements are made in money.

Yet facts that we can see for ourselves can be summed up and shown that they matter. The planet needs saving from many imminent dangers that are clearly mostly man-made - the waste, wrecking and exhaustion of essential resources for food, power and quality of life; extinctions of fauna and flora; madmen in control of nuclear bombs and weapons of horrible destruction; the devastation of wars, pollutions, diseases and new viruses, populations of three billion added to the present consuming six billion by the year 2050, and the extent of mega slums visible from space.

Nature is not averse to adding to catastrophes with earthquakes, tsunamis, volcanic eruptions and other effects from her arsenal. We can argue who is to blame for diverting the warming Gulf Stream, or melting the glaciers and tundra.

A little look around tells us what a difference humans have made to the world in the past 150 years.

There are steep graphs of vast changes since the Industrial Revolution, from resources used, land used, to the steepest graph of all, population, only six million up to 1760, six billion now, and nine billion predicted in 2050. The denser our cities and the more of them there are the more it is to the detriment of the less well off. There is even a book, Planet of the Slums, about the megacities where the poor live in crammed hovels. Mudslides are more frequent, with homes perched in dangerous places, and the trees that could have saved them, gone.

Australia is a large and empty continent. We live on the edge of a saucer surrounding mostly desert. To fill it up is like populating the Sahara. Where will our growing population live and what water will they use? There is a determined push to make people throw away their dreams, and be glad to live in tower blocks or tenements. We are persuaded to like recycled water, when once we were used to crystal-clear tap water. Our traffic jams are multiplied a million times across the world, as developing countries catch up with the developed. See Google maps for what is happening across the world.

Our cities take ever more farmland and bushland. The south of England with its historic countryside now turns to urban sprawl - it needs no more people, despite the specious arguments for ever more young people to prop up the older.

The more people there are, the more factory farming of animals is needed to feed the developed world, and the more bush-meat is taken for the developing world. Species are becoming extinct around the world. Even road kill contributes to a significant loss of wildlife.

Getting rid of our waste takes ever more ground. And anyone who sees the ruinous marks made by motorbikes in parks can imagine the ruinous marks that any number of four-wheel-drive vehicles leave behind as they crash down riverbanks and raise the dust or mud on open ground. Recently, comfortable Sydneyites felt the dust storms fall around them from the drought-stricken farming hinterlands as winds blew their eroded soil away.

We can see from afar the rising glow from cities, like sunsets.

At night from space the electricity shines bright across the world.

Our footprint is mostly not seen by the Western people who make them. Our imports of fuel including biofuels, of food, of goods, all leave their mark on other countries.