Guardian: Alistair Darling will use this week’s budget to announce an extra £500m of government spending on reducing carbon emissions, including a pledge of £40m to top up and keep open a grants programme for renewable energy technologies. The chancellor has been coming under increasing pressure from Britain’s fledgling renewables industry not to allow a key part of the controversial Low Carbon Buildings Programme to come to an end this summer, nearly a year before a new support system known as …