Parky at the Pictures (In Cinemas 31/5/2014)

Opening proceedings is Dane Daniel Dencik, who reveals sights that have not been seen since prehistoric times (if at all) in Expedition to the End of the World, a lively mix of adventure and scientific investigation that informs, amuses and humbles. Following such recent Polar pics as Werner Herzog's Encounters at the End of the World (2007), Sebastian Copeland's Into the Cold: A Journey of the Soul (2010), Jeff Orlowski's Chasing Ice and Greg MacGillivray's To the Arctic (both 2012), this voyage in a three-mast schooner to the fjords of north-eastern Greenland has plenty to say about mankind's past, present and future and its fraught relationship with the natural world. But Dencik never forces the issues and, as a consequence, has produced a film that works just as well as a travelogue as an eco polemic.

Among those joining Captain Jonas Bergsøe on the Activ are geologist Minik Rosing, zoologist Jeppe Møhl, environmental geochemist Bo Elberling, geographer Morten Rasch, archeologist Jens Fog Jensen, marine biologist Katrinbe Worsaae, photographer Per Bak Jensen and artists Daniel Richter and Tal R. Their banter is witty and intelligent (if sometimes a touch self-conscious and glib), but their expertise is even more impressive, as they provide accessible explanations of their findings in and around Ella Island and place them in a wider context so that the significance of glacial deposits, rock strata, thawing rates, rising water levels and the exposure of land masses frozen over 750 million years ago is always evident.

Perhaps the most notable moment surrounds the discovery of a worm that lives in the permafrost and prompts a discussion of the microbes that once populated the planet before the first animals appeared. However, Dencik is aware of the thrills that polar bears can generate and pocks the action with close encounters with these majestic, but ruthless creatures. Even more terrifying, though, are the shots of the disintegrating ice cap, which are made all the more disconcerting by Per Nyström's sound design.

But Dencik and fellow writers Michael Haslung-Christensen and Janus Metz (for whom Dencik edited the 2010 Afghan War documentary, Armadillo) might have provided more to the expedition (which appears to have been staged for the cameras rather than as part of a more concerted scientific study). They also wrap things up a little brusquely, as Bergsøe decides they need to beat a retreat before the frosts entrap them. But such is the stunning imagery captured by cinematographer Martin Munch and associates Adam Philip, Torben Forsberg and Valdemar Cold Winge Leisner that this often takes the breath away, as the beauty and fragility of the planet is revealed with a sense of epic pathos at how close we may be to destroying it.

The precarious balance between ecological reclamation and human necessity is laid more shockingly bare in Annie Eastman's Bay of All Saints, which is set amidst the stilted palafitas shacks of Bahia in north-eastern Brazil and focuses on the struggle endured by three single mothers to save their homes and give their children a future. The World Bank presented the town of Salvador with $49 million to clear these slums, which teeter above waterways that have been used for so long as dumping grounds for sewage and refuse that they have almost become solid ground. But, despite promises that new accommodation would be built, not a single house was completed during the six years that Eastman was filming.

She relies on jovial refrigerator repair man Norato Moraes Trindade to guide viewers through the maze of rickety shanties where he was raised. Everyone seems to adore him and he has a word of advice or encouragement for all he meets. But some problems seem intractable, as Genilza Lima Ferreira is worried that she will have to travel too far to her work if she is relocated to social housing, while Maria de Jesus Souza is concerned that her new neighbours will not be willing to offer her the laundry work on which she depends to feed herself and 15 year-old daughter, Rafaela, who is heavily pregnant after being abandoned by her boyfriend. Yet their problems seem minor compared to the woes facing widow Maria de Paixao dos Santos Marques, who has 15 children to support (four others have already died) and has no idea where she will be able to find somewhere big enough to keep the family together.

Eastman's camera never flinches, as she captures the grim realities of poverty, as old ladies forage in the filth for recyclable bottles they can sell for a few vital coppers and residents teeter along flimsy walkways to point out the holes in the plywood floors and walls made by hungry rats. Norato shrugs at each new indignity, as no one expects life to be easy. But the lack of respect accorded the unofficial mayor of the slum when he challenges city bigwigs about the lack of progress in ameliorating their conditions is shameful. Once seen, this putrefying landscape can never be forgotten. Yet, while misery seeps through every frame, Eastman also captures the fortitude and optimism of a community whose best hope seems to be the filling in of the bay, even though such a development would be environmentally ruinous.

German Markus C.M. Schmidt turns the focus on an issue that presses closer to home in The Last Catch, a disturbing exposé of the global fishing industry and the plight of the bluefin tuna. Although the blame lies squarely with those who serve and eat the species (as without a demand, there is no need for a ruinous chain of supply), the film points the finger at the International Commission for the Conservation of Atlantic Tunas, whose failure to impose restrictions has led to giant refrigerated warehouses in Japan hoarding twice the annual quota that conservationists consider sustainable.

Each year, schools of tuna migrate from the Atlantic to spawning grounds in the Mediterranean. It was once customary to allow breeding to occur without interference. But such are the prices that impoverished fishermen can command for their hauls that this natural cycle has been disrupted and stocks are no longer being replenished at the required rate. In particular, the waters off Libya are being fished to the point of exhaustion and Schmidt seeks to shame piscivores into thinking twice before ordering bluefin dishes.

Aiding his cause is Roberto Mielgo, who became an activist after he quit fishing on falling behind on the payments on his boat. He accompanies the crew to Japan (destination of 80% of the catch) to witness the scandalous indifference of producers and consumers to the looming crisis. But this is much safer than monitoring trawlers off the African coast, as there are those prepared to kill to prevent the EU imposing a moratorium on bluefin fishing. Raphael Scannapieco may not be ready to go to such extremes, but he has five boats based at the French port of Sète and he is happy to operate them under the Libyan flag and will trawl off West Africa to maintain his profits and keep his crews employed. By contrast, Roger del Ponte and his son David restrict themselves to EU waters and spend an entire season criss-crossing the Mediterranean in a desperate search for the weight of catch that will enable them to stay in business.

Pulling few punches in his depiction of Scannapieco, Mielgo and the Del Pontes, Schmidt and cameraman Axel Schneppat capture some dramatic and deeply disconcerting images. The shooting of tuna as they rise to the surface is barbaric and few will be able to watch this gruesome sequence without flinching. But, for all his anger, Schmidt also betrays a certain resignation, as if to suggest that the big corporations in Japan cannot be reined in and that humanity will have to foot the bill for their greed. It's a sobering thought and one that should prompt administrators to act before it really is too late.

The French duo of Yann Arthus-Bertrand and Michael Pitiot provide a handsome, but only fitfully thought-provoking companion piece in Planet Ocean. Narrated by Josh Duhamel, this draws on the traditions established by Jean Painlevé in his pioneering underwater studies and by Jacques-Yves Cousteau in the Oscar-winning documentaries, The Silent World (1955; which he co-directed with Louis Malle) and World Without Sun (1964). Consequently, for its first half, this is a mesmerising glass-bottom boat tour of our oceans and seas that combines memorable images with quotable facts about every aspect of marine life. The imagery respectively photographed by Andy Casagrande, Denis Lagrange and Nel Boshoff on land, under the sea and in mid-air is often stunning and Armand Amar's score adds to the sense of wonderment without quite turning the experience into a theme park son et lumière show.

But Duhamel's first-person narration does seem (like the restless editorial style) as though it has been pitched at a youthful audience, with the unfortunate consequence that older viewers may feel both patronised and browbeaten during the segment on the ways in which waters have been polluted, exploited and taken for granted. Eco-documentaries tend to wield a heavier stick than nature programmes produced for the small screen and Arthus-Bertrand and Pitiot are to be commended for including grim evidence of the damage human society is wreaking. But this one takes a turn for the preachier in the closing segment, as a raft of solutions for addressing some of the issues raised are hurled at the audience at a pace that eschews complex science and precludes in-depth analysis. Thus, while this may be a decent introduction to the wonderful and mysterious world in the waters occupying some 71% of the planet's surface, its ideas of spoliation and conservation have been expressed with greater clarity, intensity, intelligence and pragmatism elsewhere.

NB This bonus theatrical slot means there won't be a DVD column this week.