The volume of CO₂ released into the atmosphere is strongly influenced by the amount of energy which man generates to power his lifestyle. The use of electricity, heating and transport all contribute to greenhouse gas emission when coal, oil or gas is used.

A simple but effective step in combating climate change is, therefore, to reduce the amount of energy which we use. Mundane but helpful measures include switching off unnecessary appliances rather than leaving them on standby, as many people do with TVs. Effective insulation will reduce the amount of heating required. The use of telephones and the internet to communicate with people or businesses remotely rather than meeting them in person will cut transportation emissions. All of these measures not only help reduce emissions, they also slash individuals' energy bills, providing a double incentive for them to be implemented.

However these easy reductions are limited in their scope as the vast majority of activities which require energy are absolutely necessary. A more substantial reduction in emissions will emerge from the substitution towards more energy efficient appliances. With developments in technology aimed towards the goal of cutting energy intensity, a new range of products will emerge which will make it possible to maintain our current way of life while cutting energy use at the same time.

Simple items such as energy efficient light bulbs can provide exactly the same benefits as traditional bulbs, at a fraction of the running costs. Hybrid cars can do everything a more traditional car can do but at a much improved miles per gallon ratio. Public transport systems can carry dozens or hundreds of people at significantly lower per person emissions.

All of these measures require more energy efficient substitutes to be in existence, an outcome which will only occur if research and development efforts explicitly include energy intensity as a goal in itself. Many of the new technologies, although they have substantially lower running costs, will require a higher initial investment, so to make them feasible a combination of subsidy and taxation can be used to make them relatively more attractive. These subjects will be discussed in the next sections.