North Yorkshire libraries and the Reading Agency is running the challenge for children aged four to 11, encouraging them to read six library books over the summer holiday period.
Wild World Heroes aims to educate youngsters on what we can do to make a difference to the environment and stand up for the planet.
To take part children need to sign up at Whitby Library, where they will be given a colourful fold out map of an imaginary place called Wilderville.
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As they read their chosen books, they will receive stickers to fix an environmental problem and make Wilderville a better, greener place to be.
There are more free incentives to collect along the way and those who complete the challenge will receive a medal and a certificate to celebrate their achievement.
Outreach Librarian Adele Duffield said: “We would love children to come in and sign up, and find out what’s on over the summer to get involved with.
"If they want to like and follow Whitby Library on Facebook or Twitter, they can do that too.
“Do bring your children in.
“The challenge is brilliant this year – all about the environment and nature – very topical and hopefully of interest to lots of children.”
County Cllr Greg White, Executive Member for Libraries, said: “It is wonderful that we can run the challenge in libraries again this year.
"Children really missed the free incentives and the advice and encouragement of staff and volunteers last year.
“Signing children up to the Summer Reading Challenge is a great way for parents and carers to help them to maintain their reading levels.
"The Wild World Heroes theme could not be more relevant as we need all our young people to know how to care for our precious planet.”
Children can choose from a range of books at the library or download them as an eBook from the catalogue.
Although there are new books about wildlife and looking after the planet, they can choose any six books to take part in the challenge.
A programme of online events for families will also support the challenge, including a cartoon workshop, a story hunt, finding out why rubbish isn’t rubbish and how to be a North Yorkshire Rotter.
More details of the events and great reading recommendations will be posted on the @nycclibraries Facebook page and local library pages.
Karen Napier, CEO of the Reading Agency, said: “We hope that this year’s theme of Wild World Heroes will help to open up important conversations and inspire children and adults across the country.”
Children can sign up from Saturday July 10.
Visit www.summerreadingchallenge.org.uk to find out more about this year’s Summer Reading Challenge.