Human-induced climate change presents grave challenges to society. We have to find ways both to mitigate the changes and adapt to them. However, this is not all, for politics climate change represents a problem with large scientific uncertainties. This is evident in the Intergovernmental Panel on Climate Change (IPCC) assessment reports. In this study, scientific uncertainty is discussed and systematized. Two dimensions of uncertainty are established and used to discuss framings of uncertainty in the summaries for policy-makers of the IPCC assessment reports. It is argued that framings of the uncertain formulated in the space where science meets politics, are important for the process and outcome of the international negotiations on climate change