TM JONES of Hazlemere (March 3) asks if something has changed in relation to carbon dioxide (CO2) emissions since he was at school, and states that "CO2 is far less dangerous than some gases and particles".

The confusion is understandable we are not often presented with the facts of the carbon story.

I don't know when she/he was at school, but since 1960 background CO2 levels in the world's atmosphere have risen from 325 to 380 parts per million (ppm) in just 45 years.

In all the previous 400,000 years CO2 has never before exceeded 320 ppm.

This rapid rise is not surprising really given the rate we humans release CO2 when burning fossil fuel: seven million tonnes of CO2 each day, or seven kilos each day for each person on the planet. Nature was just about coping with this until the 1950s but we are now releasing two to three times more "new" CO2 than nature can absorb.

Remember the Buncefield (Hemel) smoke stack?

In the UK we burn the equivalent of four Buncefields each and every day.

As for how dangerous it is, it is true that other pollution and particles can present a more immediate local health threat.

However, CO2 is now widely regarded as the greatest ever threat to human survival, via the climate chaos we have unleashed.

Fortunately, we can all save money and reduce our personal CO2 "footprints" quite easily thereby leading the way for the rest of the world in the process. And in Hollywood and Notting Hill, it is rapidly becoming drop dead cool to lead a carbon-lite lifestyle.

Dave Hampton, The Carbon Coach, Marlow