Last Night's Television: How Reading Made Us Modern, BBC4<br />Nature's Great Events, BBC1

Here's a nagging thought I'd never encountered before. What do you do if you're a beluga whale and you get an itchy back? There you are, stuck in mid-ocean with the nearest scratchy rock hundreds of nautical miles away, and there's not a lot of point in asking your neighbour to help you out because flippers don't have a very high coefficient of friction anyway. The answer, it turns out, is that you have to wait until the Arctic ice melts and you can roll around in the shingle of a fresh water estuary. We saw a group of belugas doing just that in Nature's Great Events and David Attenborough assured us that they were having a whale of a time. They "whistle with pleasure," he said, which made me wonder where the Natural History Unit had found a fluent speaker of Belugese. It's true that they looked to be enjoying themselves, but can we be sure that they aren't saying, "Bloody hell it's crowded... I know I say this every time but I'm definitely going to a quieter estuary next year"?

Some questions didn't get answered. We were told that a walrus can vacuum up to 4,000 clams off the sea bed in just one 10-minute dive, but not how it gets the shells off. Perhaps it simply doesn't bother, and that's why a walrus beach is such a dyspeptic, bad-tempered place. "Spitting, stabbing and bellowing iron out any disagreements," said Attenborough, which made it sound like Aldershot on a bad Saturday night. Adding to the charm is a miasma of fishy flatulence, conjured for us here by a shot of a walrus breaking wind – not exactly a discreet affair given that the walrus is already nature's whoopie cushion. I don't think any of those disagreements are about who's responsible for a silent but deadly.

It wouldn't really be fair to dwell on the walrus fart, because the money shot here, the trophy that featured in the making-of diary at the end, was a lovely sequence showing narwhals swimming along a lead in the sea-ice, one of the narrow pathways of open water that begin to appear as the annual thaw sets in. And that wasn't the only picturesque aspect of the Arctic summer the team had captured. There was film of guillemots diving 80 metres to the sea-bed and then surfacing like fireworks, leaving a trail of silver bubbles behind them. And footage of guillemot chicks taking their first flight, an all-or-nothing induction that either ends in a safe but undignified arrival in the sea or a shortfall that leaves them easy prey for the Arctic foxes. A crash-landed guillemot is also a sitting duck.

It isn't possible to make a film about the seasonal melting of the Arctic without acknowledging that it isn't just part of the natural cycle anymore. The melt of 2007 broke all records and there are some who predict that in 20 or 40 years the Arctic will be entirely ice-free in summer. One hopes this is an excess of gloom, ultimately to be filed alongside those respectable scientists who, in the early Seventies, predicted that we would be enduring another ice age by the turn of the century. But if not, the polar bears are going to have a very hard time indeed, apparently the one animal in this eco-system that prefers it when the sun eventually goes down and it can get out on the ice to stake out a seal's breathing hole. One melancholy shot showed 200 polar bears marooned on an iceberg, like shipwrecked mariners on a raft, the prospect of landfall dwindling with every passing year.

I found a faint sense of ecological transformation carried over to How Reading Made Us Modern, John Mullan's account of how Britain was transformed from an essentially illiterate society into one where virtually everyone can read and most people do. The first big ecological shift was the obvious one: the explosion of literacy itself, ignited by the end of the Licensing Act (which allowed anyone to set up as a publisher without fear of having their entrails whipped out) and then fuelled by the arrival of the first mass media– newspapers and chapbooks – which allowed even the poor to escape from life into alternative worlds. But a second ecological shift lay just behind it, unacknowledged. "Our appetite for the printed word is insatiable," said Mullan at one point, and you couldn't help but wonder whether that could always be relied on – like the winter sea-ice – or whether his celebration of literacy arrives at precisely the moment when that appetite is beginning to melt away, as YouTube and video downloads and online news erode the supremacy of print. Mullan is so passionate about the pleasure of reading that I suspect he'll be perched on the last ice floe with a book in his hand. I'll be with him, reading a newspaper, but I fear the sea of not-print is encroaching.