What sort of events could destroy the human race if it stays on one planet? Hawking mentioned the possibility of nuclear war or climate change as being the cause of human extinction. http://news.yahoo.com/stephen-hawking-colonize-space-end-human-race-192615409.html ââ¦One of the most serious consequences of our actions is global warming brought about by rising levels of CO2 from the burning of fossil fuels. The danger is that the temperature increase may become self-sustaining, if it hasnât done so already. Drought and deforestation are reducing the amount of carbon dioxide recycled into the atmosphere and the warming of the seas may trigger the release of large quantities of carbon dioxide trapped on the ocean floor. In addition the melting of the Arctic and Antarctic ice sheets will reduce the amount of solar energy reflected back into space and so increase the temperature further. We donât know where global warming will stop but the worst case scenario is that the earth will become like its sister planet Venus, with a temperature of 250 degrees C and rain sulphuric acid. The human race could not survive in those conditions.â What a dope ! Doesn't he global warming is all big scam perpetrated by Al Gore?