The aim of this paper is to assess the effectiveness on climate change mitigation of the climate-related commitments contained in PTAs. Because of a lack of availability of detailed data on PTAs, the academic literature on the role of PTAs with environmental provisions (PTAwEP) in global climate governance remains limited. A novel and detailed database identifying nearly 300 different types of environmental provisions from more than 680 PTAs since 1947 allows us to establish per country and per year the number of PTAs by distinguishing PTAs with climate-related provisions (PTAwCP) and PTAs with provisions related to other environmental issues. Using panel data covering 165 countries over the period 1995 to 2012, controlling for endogeneity issues, our main result shows that PTAwCP statistically reduce the level of CO2, CH4 and N2O. This suggests that governments seem to comply with the climate-related commitments they made in the PTAs, what potentially helps tackling global warming. Moreover, findings show that to be effective in terms of mitigating climate change, a PTAwEP should contain climate-related commitments.