CANNES, France, July 11 (Reuters) - Documentary makers and environmental activists including British teenager Bella Lack on Sunday said they hoped to inspire more efforts on climate change, including through several films with hopeful messages presented at the Cannes Film Festival. The world"s biggest cinema showcase is back after a 2020 hiatus due to the COVID-19 pandemic, and has this year highlighted productions with an environmental focus in a special selection. The festival, which has attracted people from around the world, including big hitting Hollywood stars like Adam Driver and Matt Damon, has also tried to cut back on waste, using some hybrid or electric cars to shuttle people around and replacing its red carpet, which it used to change three times a day, with recyle-friendly material, organisers said. The world of film could also be an example in other ways, said 18-year-old activist Lack, who appears in "Animal" along with chimpanzee expert Jane Goodall, in a documentary by Cyril Dion shown at the festival. "People believe that all young people are terrified and motivated by fear... I"ve actually been motivated by hope and by imagination," Lack told a news conference. "That"s what the cinema industry and Cannes can act as, as a vehicle to catalyse the imagination of adults." Other films being presented include "Bigger Than Us", produced by Oscar-winning actress Marion Cotillard and which features young campaigners from Indonesia to Malawi. Director Flore Vasseur said the activists had pressured the crew to take steps such as cutting out plastic on set. "This industry does not have an extraordinary track record on this issue," Vasseur said. "We"re all on a learning curve, we"re all looking for solutions." The green selection also included French actor and director Louis Garrel"s "The Crusade", a fictional comedy about children who sell their parents" jewellery in their quest to save the planet.