Environmental education plays a fundamental role in the fight against climate change and the transformation towards a more sustainable and environmentally friendly socio-economic model. This study shows how to evaluate the effectiveness of a program for compulsory education students in Spain. The subject of the program focused on the effects of climate change in relation to our consumption model and the generation of waste. A mixed research methodology is proposed that combines a quantitative (10 items on the Likert scale, n = 714) and qualitative approach (category construction and analysis on open-ended questions). A study of the reliability and validity of the measure was carried out through a categorical principal component analysis (CATPCA). The multivariate analysis of variance (MANOVA) correlates the gender and educational level of the students to the learning acquired in the program. For example, the results show how students are convinced that adopting minimal pro-environmental habits (turning off lights and unplugging electronics, choosing public transport to get around, or using solar and wind power to produce electricity) can help mitigate climate change. The conclusions show the difficulties and challenges of education for responsible consumption, emphasizing the development of environmental education programs for reducing the effects of climate change.