Uneasily blending an examination into the global effects of climate change with dysfunctional family drama, British playwright Nick Payne’s dark comedy If There Is I Haven’t Found It Yet hasn’t quite found its footing in its American premiere by the Roundabout Theatre Company.  One can only imagine the befuddled reactions the play will induce among the many young female fans of Jake Gyllenhaal, here making his New York stage debut.

The heartthrob actor plays Terry, the unkempt, slacker uncle of obese fifteen-year-old Anna (Annie Funke). Arriving for an unexpected family visit, Terry quick ingratiates himself to the troubled teen even if he proves ultimately ill-equipped to solve her myriad emotional problems.

Proving equally unhelpful to the oft-bullied girl are her parents. Her father George (Brian F. O’Byrne) is a writer/activist endlessly distracted by the book he’s working on about the devastating results of global warming, while her mother Fiona (Michelle Gomez) is a teacher who has transferred Annie to the school in which she teaches in a misguided attempt to protect her.

At first glance Terry would seem to be little help as well. Verbally maladroit except for his constant use of profanity, he’s also still deeply torn up over a recent break-up. But the friendship and attention he provides his niece at first seems to prop her up, albeit with the unintentional effect of awakening a sexual desire for her uncle.

The dramatically thin family dynamics on display are gussied up with a stylized staging by director Michael Longhurst. The stage is separated from the audience by a large moat, with the actors periodically flinging pieces of scenery into the water to ever lessening effect. And a climactic coup de theatre, while visually stunning, doesn’t justify the enormous trouble and expense it must have taken to produce it.

Gyllenhaal delivers an ingratiating turn as the prodigal uncle, and displays a convincing Cockney accent to boot. Funke is highly impressive as the body and soul-baring Anna, and O’Byrne and Gomez do the best with their underwritten roles. But despite their efforts, the evening still feels diffuse. If there any deeper meanings to be gleaned from this earnest drama, I haven’t found them yet.

Laura Pels Theatre at the Harold and Miriam Steinberg Center for Theatre, 111 W. 46th St. 212-719-1300. www.roundabouttheater.org. Through Nov. 25.