We’re on the road to nowhere: An exhibition of molecules to transport us
The rays of the Sun, and the motions of the Moon and Earth, provide energy in abundance. Light from the Sun is absorbed by plants on land and algae in the sea and is used to convert carbon dioxide into high energy carbohydrates, which in turn become oils. Together these provide most of the food energy for animals like ourselves. We can also harvest plants and trees and burn them to release this energy as heat. The sunlight which falls on barren terrain, or on the roofs of buildings, we can also gather by using solar panels to heat water or to make electricity. The sunlight which falls on the oceans leads to evaporation of water which is precipitated on land, and this too we can use to generate hydroelectricity. The Earth itself is a vast reservoir of heat below the crust, but this is not so easily tapped—although in parts of the world, such as New Zealand, hydrothermal heat is an important source of power. We can extract energy from the effects of the Earth’s daily rotation, partly through the weather systems this produces, by using windmills, and possibly through the rise and fall of sea levels, by using tidal barriers and wave power. These sources of clean energy should be able to provide all the fuel and electricity for a sustainable human population of several billion, provided we did most of our travelling on foot or by bicycle. How much these natural renewable sources could really provide is debatable, but we have the means to utilize them so they could supply enough food and energy for a world population of two or three billion, and at a level which allows for most of the high-tech living that we now take for granted. It might even be possible for most families to run a car, provided they were content to travel only a couple of thousand miles a year in it. The trouble is that there are already six billion of us, and forecasts are that this will reach ten billion by the middle of the next century. Most of these people will no doubt aspire to owning a car.