Now our two 'GHG guinea pigs' are old enough for infant school, they both qualify for a free bus service. However, the Prescotts decide against using this service and opt to continue using their four-wheel drive, despite these infant school trips (10km total) being around twice the distance of those to the nursery (5km). This decision costs the Prescotts about an extra £176 on petrol and produces about 677 kg of GHG each year. The Bellamys do make use of the free bus service and so pay no extra money. The bus only produces about 53kg of GHG to carry the young Bellamy to and from infant school over the course of the year, a saving of more than half a tonne of GHG.
Now our two subjects are getting older their parents decide they are old enough to start going on holiday. As both families live on the outskirts of London they have relatively easy access to all major road, rail and air routes. The Bellamys decide to spend their annual holiday in Plymouth UK while the Prescotts opt for holidays in Paris. Travelling by train from London to Plymouth and back with the young Master Bellamy costs an additional £29 and produces about 12kg of GHG each year. Meanwhile, the Prescotts clock up an extra 100kg of GHG and a bill of around £94 to fly young master Prescott to Paris and back each year.
The Prescotts continue to use their four-wheel drive for school trips, while the Bellamys still make use of the free bus service, so widening the divide in both GHG produced and cost between the two families.
For the first time our young subjects begin to become directly responsible for some of their GHG emissions. Initially this takes the form of Master Prescott leaving the television, video and video games console on for hours at a time when he isn't using them. This extra energy use adds up to an extra 120kg of GHG each year and costs his parents about £6 each year, while young Master Bellamy usually switches off these appliances.
In this last period, before our two subjects will gain complete control of their lifestyle and its associated GHG emissions, they can already make quite an impact on their GHG emissions. Master Prescott now routinely leaves his computer, stereo, TV and video on while they are not being used, so clocking up an extra 160kg of GHG at a cost of £10 each year. He has also got into the habit of turning on the heating at home instead of putting on a jumper. His use of an electric radiator in his room for an extra 2 hours each day, compared to Master Bellamy, results in 700kg of extra GHG emissions at a cost of about £35 to his parents every year. For holidays during this period the Bellamys travel to Chester each year by train, at a cost of £22.20 and producing 17.6kg of GHG each time. The Prescotts, on the other hand, fly to Cairo every summer with the flights for teenage master Prescott costing £225 and producing over 1 tonne of GHG.
Both our subjects have also moved on to senior school in this period. Master Bellamy again takes advantage of the fee bus service to school, a journey that produces around 211kg of GHG over the course of each year. The Prescotts persist with using their car for these longer school runs, at an extra annual cost of some £706 and producing around 2707kg of GHG.
So, beyond 18 our two subjects now