Asked by: Terry Pomroy, Croydon


Whether halving the population would help to reduce the production of man-made CO2 and other greenhouse gases is open to doubt. We contribute about 20,000 megatonnes per year. Even if 3.5 billion bodies needed to be cremated to stop the spread of a viral pandemic, this would only add an extra one hundred megatonnes of CO2 to the atmosphere, far short of our current annual contribution.

Halving the population wouldn’t necessarily reduce the output. If developing countries raised their energy usage to those of most Western countries, this would more than make up the difference. The long-term solution is for all of us to reduce our emissions.


Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.