This is a summary of the Stern Review, which assesses a wide range of evidence on the impacts of climate change, using a number of different techniques to measure costs and risks.The review states that green house gases need to stabilise to 450-550 parts per million carbon dioxide (CO2), which will require a 25% reduction in emissions by 2050. In order to do this Stern estimates that if no action is taken, the overall cost and risks of climate change will be equivalent to losing at least 5% of global Gross Domestic Product (GDP) each year. In contrast, the cost of mitigation could be limited to 1% GDP each year.The review gives the following recommendations for achieving emissions reductions:transform carbon market to support a low-carbon marketstrong deliberate policy choices to reduce emissions which will contain three elements: pricing of carbon through tax, trading, and regulation; policy to support innovation and deployment of low-carbon technologies; action to remove barriers to energy efficiency and inform, educate and persuade individuals about what they can do.The report concludes that it is essential to create a shared international vision of long-term goals, and to build the international frameworks that will help each country to play its part in meeting these common goals. These frameworks should contain the following key features:emissions tradingtechnological co-operationaction to decrease deforestationadaptation through linking climate change with all development policy