Policies may help to keep the anthropogenic temperature change below some critical temperature thresholds. We apply MERGE in a probabilistic risk assessment framework to assess the risk of action versus inaction on climate change. The method applied gives a probabilistic assessment of the associated economic costs and levels of carbon-values and emissions reduction, as well as the needed technological change to restructure the energy system. The study suggests that a set of low-carbon and carbon-free technologies has to be developed and diffused around the world in order to reduce the risk of serious, adverse climate change. Eventually, a mass deployment of biomass farming technologies for bio-fuels and/or hydrogen production, in conjunction with carbon capture and sequestration options, are needed to satisfy the EU threshold of 2°C average atmospheric temperature rise above the pre-industrial temperature levels by the year 2100. However, because this temperature threshold represents a severe target, the global "willingness-to-pay" (WTP) must be significantly improved in relation with present attitudes.