While summer on the coast of Maine is defined by outdoor activities such as boating and hiking and tanning, for much of the rest of the state – and indeed the country – the most popular seasonal activity is going to the movies. If nothing else, the theater offers an air-conditioned reprise from the heat.

And yet this summer, genres associated with younger audiences – Pixar productions and superhero stories – offer little in the way of relief from hot global issues and bleak outlooks about our country’s choices and future.

Take “WALL-E,” the story of the last trash compactor on Earth. WALL-E is a Waste Allocation Load Lifter Earth-Class whose mission for the last 700 years has been to compress an endless supply of detritus into tidy blocks and stack them into towers rising up to a smog-filled sky.

He also collects items for a personal museum – a VHS of the musical “Hello Dolly!” for instance – that distinguish his hydraulics from his human heart. While those among us who love musicals may have a particular appreciation for the bot’s taste and for the role of art even in the life of a battery-operated junkyard denizen, those who work dead-end jobs might have a deeper understanding of the reasons WALL-E perks up out of his Sisyphean boredom when a sleek robot named EVE – an Extra-terrestrial Vegetation Evaluator – blasts to Earth one day.

Disney calls the film a comedy – and indeed, above all it is a love story – yet the backdrop to the romance is anything but funny. WALL-E works on an utterly wasted planet, strewn with mountainous remains of rubbish discarded by a consumer culture that indeed does not give a hoot. By the time WALL-E inherits the Earth, humans have long ago evacuated to a space resort where obesity, inertia and atrophy rule.

You could argue that the story has a happy ending. I won’t reveal more than to say the Greens take a victory on this one and the triumph of the human heart – or computer chip – takes technology to an all-time high.

And yet I felt terribly low at the end. Call me a bad sport, but after two hours of watching postverbal characters communicate about a postinhabitable Earth, I had a hard time coming back up for air. The movie takes place far into the future, and I began to feel the doom and precatastrophe guilt of a bad-deed doer. Yes, the story has a happy ending, but I was hung up on the calamitous implications for our times. I have redoubled my recycling efforts but not because the love story inspired me. It downright scared me.

So did “The Dark Knight.” I won’t parse all the imagery lurking in this frightful adaptation of the Batman comic book series. But the film has more to do with vigilante heroism, prisoner torture and the attacks of Sept. 11, 2001, than it does with boyish imagination. Or maybe it posits that the horrors of our time are simply one boy’s imagination gone awry.

Whatever your take on the film, Batman, a superhero from the last century, is a failed, ineffectual crusader in this century. He arrives too late, with too little technology and too little information – and he ignores the advice of his experienced advisers. So people die. A lot of them. Sound familiar?

Worst of all in the end, the joke – or rather the Joker – is on him. Without being too simplistic: Is it possible the Joker is a pure 21st century villain, beyond Rambo, beyond the Terminator, beyond any of the sociopaths – garden variety or state-sanctioned – whose stories fill headlines? The Joker is Beetlejuice with guns, bombs and a nasty habit of carving smiles on to people’s faces.

When Cormac McCarthy creates a new breed of destructive outlaw, it’s a warning. But when a terrorist-style Joker shows up in a Batman movie, you know the world has changed drastically from the 1966 TV series in which the Joker was merely a prankster who got a well-deserved “Ka-Pow!” from time to time.

“WALL-E” is rated G. “The Dark Knight” is rated PG-13. And yet these two films plumb the depths of our collective anxieties. The very stuff we like to avoid in the headlines comes back to us on the big screen this summer, packaged in familiar children’s techniques: cartoons and comics.

It’s enough to make you go see “Mamma Mia!” Or better yet, go to the beach.

Alicia Anstead is a senior correspondent for the BDN. She spent the last year as arts and culture fellow at the Nieman Foundation for Journalism at Harvard University.