In the third programme in the series, Inside Money looks at the carbon offsetting industry and asks whether it delivers what it promises.
It has become fashionable to worry about our so-called "carbon footprint", the amount of carbon which our activities generate.
A growing number of companies and individuals are tempted to try to "offset" their carbon emissions by investing in environmentally positive projects such as tree planting and providing solar panels to villagers living in poorer countries.
But there is concern that some offset projects are not providing any additional benefits to local communities and in some cases could even create further damage to the environment.
The number of companies offering offset schemes has more than tripled in the last year.
According to government figures, Britons spent £60m on such schemes last year - an amount which is forecast to grow to £250m a year by 2009.
Will offsetting help to cut aeroplane carbon emissions?
These arrangements are currently voluntary and critics argue much tighter regulation is necessary to prevent confusion and standardise this new and burgeoning industry.
Listener Simon Mallett is an IT consultant from Kent and very environmentally conscious.
He plans to take his family to Florida on holiday, and wants to find out if he should offset the carbon their flights will generate.
He joins Inside Money to investigate how carbon offsetting works, and whether the government needs to do more to ensure consumers can be confident about the money they spend in this way.
Inside Money: Carbon Confusion was broadcast on BBC Radio 4 on Saturday 4 August at 12.04 BST.
A longer version of the programme was broadcast on Monday 6 August at 15.02 BST.
Presenter: Lesley Curwen
Listener: Simon Mallet
Producer: Smita Patel