Most countries use a mix of policy instruments, including carbon pricing (carbon taxes, cap-and-trade emissions trading, fossil fuel subsidy reform), other energy efficiency policies, information-based approaches and innovation policies to foster clean technology. The chapter then looks at what further action is needed by comparing different mitigation scenarios against the Baseline. These include various scenarios to stabilise GHG concentrations at 450 ppm and 550 ppm using different technology options, e.g. carbon capture and storage, phasing out nuclear power, and increasing the use of biofuels, linking carbon markets, and various emissions permit allocation rules. The chapter concludes by outlining how limiting global warming will require transformative policies to reconcile short-term action with long-term climate objectives, balancing their costs and benefits. Timely adaptation policies to limit damage by the already changing climate will also be essential.