Carbon Neutral Company executive director Jonathan Shopley said the issue of rapidly expanding populations was 'the elephant in the room that no one wants to talk about'.
Oakdene Hollins director of waste David Fitzsimons told NCE that Lovelocks Gaia theory says 'global warming should be allowed to run riot and through massive destruction will eventually return the planet to a state of harmony'.
The 'one planet' theory says that if the world's population was to live as western society does it would need the resources of three planets to support it.
One suggestion raised from the floor was to enforce legislation to reduce the population.
Fitzsimons agreed that population was an issue but said that 'as countries become more sophisticated they find ways of controlling the population through education and often just as a result of wealth'.
Speaking after the hearing, panel member and Shefeld University professor Richard Ashley said: 'It was shocking to think they were talking about controlling the world's population.'