Climate change, and more recently, the risk of fossil fuel production being unable to keep pace with demand (peak fossil fuel) are both considered as risks to civilisation, or global risks. In an initial empirical analysis, this paper attempts to answer the following questions, which have often been posed but have not, to our knowledge, been answered empirically at global level. At which date, if unaddressed, will the risks become critical? Given that the substitution of fossil fuels by wind and solar energy is often proposed as a solution to these problems, what is its current aggregate growth rate and is there a plausible future growth rate which would substitute it for fossil fuels before the risks become critical? The study finds that the peak fossil fuel risk will start to be critical by 2020. If however the future growth rate of wind and solar energy production follows that already achieved for the world mobile phone system or the Chinese National Expressway Network the peak fossil fuel risk can be prevented completely. For global warming, the same growth rate provides significant mitigation by reducing carbon dioxide emissions from fossil fuels to zero by the early 2030s. (C) 2011 Elsevier Ltd. All rights reserved.