Heavily influenced by Edward Goldsmith, his step-father’s brother and the founder of "The Ecologist", Birley has always maintained a keen interest in environmental matters. In 2002, he set up Envirotrade, a project assisting small farmers in Mozambique through reducing emissions from deforestation and forest degradation (REDD) and agroforestry by generating carbon credits through which they could earn a better living wage. The Sofala Project, in Mozambique, remains the only carbon project to have been awarded gold in all three categories of the Climate Community and Biodiversity Standard. The Sofala Community Carbon Project earned $3,453,228 from carbon offset sales between 2004 and 2013, and the participating communities earned $2,136,744 from agroforestry and avoided deforestation activities directly from the project.