The aim of this study was to examine the activities associated with climate change before and during the COVID-19 pandemic based on G-20 countries. The climate change performances of the G-20 countries were considered within the framework of four criteria (greenhouse gas emissions, renewable energy, energy usage, and climate policy). The PROMETHEE method, one of the MCDM methods, was employed for the analysis. The weights of the criteria were calculated with the MEREC method. Climate change performances of countries have changed during the pandemic process. The UK showed the best performance before and during the pandemic. Consequently, in this study, it was aimed to raise awareness by emphasizing climate change, which is one of the crucial problems of the age. Thus, an idea was obtained about the extent to which the countries implemented their climate change policies and activities during a crisis such as the COVID-19 pandemic.