Greenland, National Theatre: Lyttelton, London

Enter pursued by a (polar) bear. There's a wonderful moment in Greenland where this white ursine creature lopes in, to the consternation not just of the geographers on the Arctic island where, because of global warming, the Inuits are having to invent a noun for "robin", but of the policy wonks with their laptops who are preparing for a global summit on this issue. The piece goes in for that kind of conceptual compositeness. The creature noses around and then exits pursued by no one.

Greenland – co-authored by Moira Buffini, Matt Charman, Penelope Skinner and Jack Thorne – is not so much a play as an intellectual extravaganza about the implications of global warming. It is brilliantly directed by new NT recruit, Bijan Sheibani, and is stunningly well designed by Bunny Christie.

And yet, there is something in me that resists this clever, topical, many-stranded piece. Greenland traverses several plotlines simultaneously. Lisa is a young undergraduate – suspended over the play which, to the sound of "It's Raining Men", is inundated with a flood of unrecycled plastic. She perplexes her parents by becoming an eco-warrior. A smartly suited Miliband-babe endangers her budding relationship with a climate-modelling scientist at the Copenhagen summit. Another thread shuttles us between the patronising Oxbridge interview of a young geographer in the early Seventies and his activist endeavours now.

I have just one problem with all of this. I care about the issues. But I couldn't give a damn about any of the multiply-authored characters. There is a critical moment when the wonk and the climatologist are in bed together. Their intimacy is jeopardised by a newsflash on the television – the Sudanese delegate declaring that it will be a holocaust for Africa if the first-world agenda is carried out. The trouble is that both wonk and climatologist are no more than debating positions. It depletes, rather than augments, one's sense of what is on the debating table here.

The evening is undeniably stimulating. It brings home vividly how the debate is not on a level playing field and comes stuffed with historical baggage. How do you tell China to go easy when she is all systems go for a capitalist future that was once our past? The "play" gives rise to fresh and inventive stage-pictures, as snow and policy papers drift down over an implacably advancing cast of figures from disparate worlds.

And yet. Call me an unreconstructed old Leavisite, but I registered throughout a lack of what used to be called, in such circles, "felt life". As with David Hare's The Power of Yes about the financial crisis, I thought it too much like a public-service broadcast that did not tell one much that is new. At the same time, I would not wish it to be replaced in the NT's repertoire by anything else. It is brave programming. But I would like to draw your attention to a show that outstrips it at its own game. Revived now at the Tricycle Theatre is Filter Company's superb piece Water which interweaves the global and the personal much more suggestively.

In rep to 2 April (020 7452 3000)