Researchers from York University have found that the expansion of palm oil plantations, even in areas previously cleared for agriculture, could lead to the extinction of 25% of rare species and increase greenhouse gas emissions. The researchers, from the UK, South Africa, and Germany, identified around 167 million hectares of land that could be used for palm oil cultivation while adhering to a 'zero deforestation' policy, most of which is located in dry forests and grasslands in Africa and South America. However, they discovered that palm plantations would significantly reduce habitats for 34% of rare animals and birds, and decrease the population of about 25% of endangered bird and mammal species.