fuel poverty

From midnight tonight the duty imposed on a litre of petrol or diesel rises by 2p. Add on to that the VAT and the price at the pumps tomorrow will be 2.3p higher than it is today (assuming that the forecourts haven't adjusted their prices a day early). This 'green tax' will encourage us all to use less fuel and in doing so help us save the planet.

Apparently.

I don't want to get bogged down in the AGW argument but I do want to contrast the attitude to petrol with this.

How is it that rising fuel costs, reducing the ability of people to use fossil fuels, is fantastically good in one instance but terribly bad in another?