Pet theory

GIVEN that the carbon footprint of a medium- size dog has been estimated to be twice that of a 4x4 car, we could achieve a real reduction in CO2 emissions by limiting households to one pet each.

MICHAEL LYNCHEHAUN,

Wallasey, Merseyside. IN All the debate about climate change, there is very little mention of overpopulation. In 1970, the population of the world was 3.7 billion. It is now more than eight billion, which must have a huge ecological impact. I would like to see world leaders at least discuss the issue.

ALAN CORLETT, Ringwood, Hants.