Over the past four decades, global plastics production has quadrupled1. If this trend were to continue, the GHG emissions from plastics would reach 15% of the global carbon budget by 20502. Strategies to mitigate the life-cycle GHG emissions of plastics, however, have not been evaluated on a global scale. Here, we compile a dataset covering ten conventional and five bio-based plastics and their life-cycle GHG emissions under various mitigation strategies. Our results show that the global life-cycle GHG emissions of conventional plastics were 1.7 Gt of CO2-equivalent (CO2e) in 2015, which would grow to 6.5 GtCO2e by 2050 under the current trajectory. However, aggressive application of renewable energy, recycling and demand-management strategies, in concert, has the potential to keep 2050 emissions comparable to 2015 levels. In addition, replacing fossil fuel feedstock with biomass can further reduce emissions and achieve an absolute reduction from the current level. Our study demonstrates the need for integrating energy, materials, recycling and demand-management strategies to curb growing life-cycle GHG emissions from plastics. The life-cycle GHG emissions from plastics are expected to increase. Here, it is shown that an aggressive strategy of decarbonizing energy infrastructure, improving recycling, adopting bio-based plastics and reducing demand is required to keep emissions below 2015 levels.