As one of the most comprehensive environmental assessment methodologies, life cycle assessment enables evaluation of the environmental impacts of anthropogenic activities along a supply chain. Its implementation raises many scientific questions. In the case of tropical cropping systems, researchers are working to understand and model environmental emissions based on the diversity of environments and systems. They are also focusing on the relationship between emissions and impacts. Cropping system life cycle assessments show that the impact on climate change varies by crop, environment and type of practice. Life cycle assessment can help guide production methods so as to reduce their environmental impacts. But the choices are not always clearcut.