The Prince of Wales has announced the finalists for his Earthshot Prize, rewarding ideas designed to help the environment.
The shortlist for the competition, which is in its second year, features 15 innovations from across the world.
Two UK-based entries have been selected for the first time.
The ideas include a “Great Bubble Barrier” to catch plastics before they reach the ocean, a zero-waste city and a new type of leather made from flower waste.
Five winners will be chosen from the shortlist and announced in Boston in the US next month, with each receiving £1m to develop their projects.
The first British entry is Notpla Hard Material, a London-based start-up run by Pierre Paslier and Rodrigo Garcia Gonzalez that makes packaging from seaweed and plants as an alternative to single-use plastic.
It has already created more than one million biodegradable takeaway food boxes for Just Eat, the takeaway company.
The other UK finalist is Low Carbon Materials (LCM) based in Co Durham. They use unrecyclable plastic waste to make traditional concrete blocks carbon-zero.
Dr Natasha Boulding, one of the co-founders of LCM, said: “Until now, construction has been one of the hardest industries to decarbonise.
“With LCM, that could all change. We’ve turned concrete net-zero and now we need the world to start using it.”
Please use Chrome browser for a more accessible video player
10:41
Major glaciers to disappear by 2050
‘Reasons to be optimistic’
The prince described the finalists as “innovators, leaders and visionaries” and said they proved there are “many reasons to be optimistic about the future of our planet”.
“They are directing their time, energy and talent towards bold solutions with the power to not only solve our planet’s greatest environmental challenges, but to create healthier, more prosperous and more sustainable communities for generations to come,” he added.
Prince William’s inspiration for the ambitious 10-year £50m prize was John F Kennedy’s Moonshot project, which eventually resulted in the Moon Landing in 1969.
The prince said he was “so excited” to celebrate the finalists and meet the winners when he and the Princess of Wales head to Boston – Kennedy’s hometown – on 2 December for the awards gala.
Among the other finalists are the Great Bubble Barrier, from the Netherlands, where air is pumped through a perforated tube to create a curtain of bubbles, which directs plastic up to the surface and into a waste collection system.
Another Dutch entry is the City of Amsterdam Circular Economy, a city-wide initiative to establish a fully circular economy by 2050, wasting nothing and recycling everything.
Read more: Everything you need to know about the Egypt climate talks World ‘so far off global warming targets’ it will destroy economies Sigh of relief as Sunak reinstates fracking ban
Daughter’s burns inspired mother
Mukuru Clean Stoves from Kenya provides cleaner-burning stoves to reduce unhealthy indoor pollution and provide a safer way to cook.
The initiative was started by Charlot Magayi, who grew up in one of Nairobi’s biggest slums, Mukuru, and who used to sell charcoal for fuel.
Ms Magayi suffered from repeated respiratory infections due to the charcoal pollution, and then sought an alternative solution after her daughter was severely burnt by a charcoal stove in 2012.
Her eco-stoves use processed biomass made from charcoal, wood and sugar cane and cause 90% less pollution than an open fire, and she plans to create an even cleaner version which burns ethanol.
Other finalists include Fleather, a leather made of floral waste in India; Oman-based 44.01, which eliminates CO2 by mineralising it in rock; Hutan in Malaysia, a conservation organisation that creates wildlife corridors to give orangutans safe passage to new habitats; and the Indigenous Women of the Great Barrier Reef group from Australia, which uses ancient knowledge and digital technologies to protect the land and sea.
There are five Earthshot categories: protect and restore nature; clean our air; revive our oceans; build a waste-free world; and fix our climate.
