“Earth: Art of a Changing World”, at the Royal Academy, hovers somewhere between a display of contemporary art and a list of New Year’s resolutions, or perhaps that should be commandments. Thou shalt not pollute. Thou shalt recycle. Thou shalt reduce thy carbon footprint. Or else.

The show’s mission statement appears on page one of its pocket-sized, eco-friendly catalogue (printed, of course, on recycled paper): “In this exhibition the Royal Academy sets out to explore the challenges posed by climate change by bringing together works of art by 35 leading contemporary artists from around the world. Many have addressed climate change directly; others have allowed the subject to find a resonance within their work”. As a rule, the less preachy the art, the more effective it turns out to be.

 
Upstairs, the eco-messages and meditations multiply. Mona Hatoum’s Hot Spot is a wire mesh globe with the different continents picked out in buzzing red neon – a 3D diagram of points of potential future eco-conflict. Next door, whole room has been filled with the rudimentary miniature clay figurines of Antony Gormley’s Amazonian Field. The spectacle is familiar, in that the trope of the mini-crowd has been one of Gormley’s signature devices for years. But in the present context, the piece acquires a touching pathos. Each of the figures was made by a native of the Amazon basin, using local clay. The multitude of homunculi starse up accusatorily or perhaps pleadingly, a proxy for the peoples of the developing world, wondering if anything will ever be done on their behalf.

Like most mixed exhibitions on a given theme, this is a curate’s egg of a show. But despite its inevitable unevenness, there are plenty of good things in the mix. Gary Hume’s ingeniously delicate drawing on marble, entitled The Industrialist, shows a wonkily phallic factory chimney exhaling filigree lines of diagrammatic smoke. The artist has compared the image to “an epitaph drawn by a child”, which seems just about right. Nearby, Edward Burtynsky’s striking chromogenic colour photographs, monumental in scale, offer disturbingly lovely images of processes such as the refining of oil. Alberta Oil Sands #6, Fort McMurray, Alberta, 2007 is a beautifully composed image of an oil refinery at dusk, last gleams of light reflected in a slick marbled lake of effluvia – a repulsive yet alluring report from the front line of climate change. Sophie Calle’s very different and personal work, North Pole,also stands out among the photographic contributions in the show. The piece takes the form of a quirkily melancholic pictorial journal of a voyage taken by the artist to the pole itself, to bury a reliquary containing some of her late mother’s jewels.

The exhibition reaches its climactic conclusion with a series of works assembled under the rubric of “Destruction”. Kris Martin’s 100 Years gets the ball rolling. The piece is a dry, wry Conceptualist’s emblem of the threat of global warming. It consists of what seems to be a simple gold sphere roughly the size of a croquet ball. But the accompanying text reveals it to be a kind of anarchist’s bomb, lobbed into the art gallery: “The title this diminutive gold-coloured sculpture, 100 Years, refers to its internal mechanism, which is primed to explode one hundred years after its creation.” There is no way of checking whether the assertion is actually true, but the suspicion lingers that Health and Safety might have had something to say about it if so.

In an immediately adjacent video display space – a cubbyhole geared for continuous-loop broadcasting – Tracey Moffatt contributes the sole work in the entire exhibition that can be said to speak for climate change sceptics. Doomed is a wonderfully manic and hilariously entertaining essay in the fashionable new medium of film-splicing. The Australian artist has ingeniously and seamlessly edited together a truly tidal flood of scenes of catastrophe, panic and mayhem drawn from a mass of cheesily apocalyptic disaster movies. Tsunamis rain down on New York, as volcanoes shower molten lava on unsuspecting multitudes. Dams collapse, rivers burst their banks and people die in their millions. It is an exhilaratingly amusing essay in the absurd, with a soundtrack that keeps the mood of hysteria ticking along perfectly from start to crashing end. Implicit in the whole thing is a mischievous little question. Is it possible that that all the doomsday scenarios are just a little overdone?

Perhaps the most striking work in the show, a piece by Cornelia Parker, brings it to a more solemn conclusion. The work is called Heart of Darkness, which alludes to the title of Joseph Conrad’s famous novella while simultaneously expressing Parker’s own strong feelings of political disllusionment. A thousand pieces of charred and fractured wood – blackened branches, twigs, mute remains of timber – have been arranged in the form of a mobile that fills an entire gallery. The charcoal was gathered from the remnants of a forest fire that swept through Florida a few years ago. According to a statement by Parker herself, “This forest fire seemed to be a metaphor for the disastrous consequences of political tinkering. From the hanging chads in the US elections, to the cutting down of rainforests to grow biofuels to power Hummers”. But the piece itself transcends such overt and precise symbolism. It is solemn, grand and memorable – a cautionary memorial to the loss and destruction of the natural environment.