Biodiesel or biofuel is a fuel produced from plants. It is renewable (unless there is land enough). However, this doesn't mean it is environmentally friendly, exactly because the there is not enough croplands in the world.
The expansion of biofuel production involve additional land use. Even modest usages of biodiesel would consume almost all cropland in some countries in Europe. Switching to biodiesel on a large scale requires considerable use of arable area. And lthis and area is taken up from forests or from food cropland.
When burned, biodiesel emits less carbon than diesel or gasoline, but the damage has already been done. Biofuel became one of the most environmentally damaging commodities on the planet.
The expansion of palm oil production is one of the leading causes of rainforest destruction in south-east Asia. In Indonesia and Papua New Guinea are the Malaysian companies to drain the swamp forests and peat bogs, then burn and then make palm oil plantations, while millions of tons of peat going up in smoke, entering into the atmosphere huge amount of carbon was calculated that, for this reason Indonesia has become the fourth largest emitter of greenhouse gases. Oil palm plantations are now expanding in Africa and South America.
Much rainforest clearance in Indonesia is taking place on peatlands, which yields massive additional carbon emissions as the rich organic peat oxidizes or burns. With the loss of rainforest ecosystems we lose one of the planet's greatest carbon capture and storage systems and best adaptation mechanisms for global warming (up to 300 tons of carbon per hectare).