LONDON - A study has warned that using the fat of dead pigs, cattle and chickens to make greener jet fuel will end up being worse for the planet.

Demand for fuel made from animal by-products is expected to triple by 2030, said the BBC, powered by orders from the airline industry.

However, Transport & Environment, a clean transport campaign group based in Brussels, said not enough animals slaughtered are each year to meet demand so industries will use more palm oil - a huge generator of carbon emissions.