How to Train Your Dragon author and illustrator Cressida Cowell has been named the new Waterstones children’s laureate, and has promised she will use her two-year incumbency to make the magic of books “urgently available to absolutely everyone”.

Following 10 previous laureates, from Quentin Blake to, most recently, Lauren Child, Cowell’s stories about the adventures of timid Viking Hiccup and his dragon Toothless, have sold more than 11m books around the world. They have also been adapted into a popular film series by DreamWorks.

As she was presented with the laureate medal by Child on Tuesday, Cowell unveiled her “children’s laureate charter”: a “giant to-do list” that she will use throughout her tenure. The charter lays out 10 points, asserting that every child has reading rights – from having access to trained librarians and booksellers to reading for pleasure.

Cowell told the audience at Shakespeare’s Globe theatre in London that she had “two super-simple key messages” as laureate: “Point number one: books and reading are magic. Point number two: this magic must be made urgently available to absolutely everyone.”

“The telly is glorious, bookshops are closing, libraries are closing, librarians are disappearing, review space is shrinking, parents are knackered, the kids are on the Nintendo Switch ... Everywhere you look, it’s impossible and getting more impossible by the minute,” she said. “My favourite kind of problem. Luckily, anyone who has read my books will know that I love a quest. A quest is idealistic: there are impossible-seeming obstacles and many people will tell you not to bother trying. A quest is also practical – in order to make progress there must be action.”

Cowell said she had witnessed a discrepancy in the distribution of resources while touring schools around the UK, particularly in libraries, which will be her first focus as laureate. In the face of closures up and down the country, she will be campaigning for school libraries to be statutory, and arguing that public libraries need to be funded properly.

“It really is impossible for a child to become a reader for the joy of it if their parents or carers can’t afford books, they don’t go to a public library, and their primary school hasn’t got a library,” she said.

Her second task will be to argue for more creative space in the curriculum. She launched the Free Writing Friday campaign with the National Literary Trust last year, asking for teachers to let children have 15 minutes every Friday to write whatever they want in a special book, with no fear of marking. She now wants to expand the campaign and is calling on fellow authors and illustrators to spread the word.

“The response to this from teachers and children – drowning in SATs, and losing their love of creation for fear of making a mistake – has been overwhelmingly positive. Emboldened by this, I’m going to be devising a practical plan to offer to schools that helps develop children’s creative intelligence through writing and drawing,” she said.

Cowell, who is also the author of The Wizards of Once series, and the Emily Brown picture books, illustrated by Neal Layton, tackles themes from empathy to the environment. One of the points on her charter is children’s right to have a planet to read on, and she said that environmental advocacy would also be a part of her laureateship.

“Children know that the most important problems facing us all are the environmental challenges facing the world. And while adults often give up when faced with an impossible problem, that doesn’t bother children, and their belief in magic and the impossible just might make it happen,” she told the audience at the Globe.

The laureateship, which is managed by reading charity BookTrust and sponsored by Waterstones, was set up 20 years ago. It is given every two years to a children’s author or illustrator of “outstanding achievement” in their field. Nominations for the new laureate were sought from hundreds of literature and education organisations across the UK. The chair of the steering group, Kate Edwards, said that Cowell was selected for her “impressive canon of work, with broad reach and appeal, coupled with her impassioned advocacy for the right of every child to enjoy a childhood rich in storytelling”.