Stephen Hawking tends to exaggerate, using hyperbole – exaggerations for emotional effect. In this talk he takes our exponential population growth and extrapolates it forwards to 2600 and predicts that human beings will cover the globe shoulder to shoulder and that our electricity consumption will turn the surface of Earth red hot through the waste heat. Actually, we have already stopped exponential growth (as we have reached peak child) and the middle of range projections by population experts have our population level off by around 2100. This story is scaring people and that’s my motive for debunking it here.

http://www.science20.com/robert_walker/stephen_hawking_predicts_earth_to_glow_red_hot_by_2600_due_to_population_growth_could_it-228187