Here is what I do when I'm feeling down about the country: I load up the Wikipedia page for the BBC Natural History Unit and click on the "In Production" link. Happy sighs ensue.

The unit's latest product, aired on Wednesdays, is Frozen Planet, a majestic tour of Arctic and Antarctic wildlife ably narrated by Sir David Attenborough, an 85-year-old man who insists on travelling to the south pole while people many decades his junior make a small noise whenever we sit down.

On the screen, polar bears mate and fight, wolves run down herds of bison and lunging whales create concentric ripples of fleeing fish. It would take several thousands of pounds to see these sights in person, but for £145.50 a year, I can recline on my sofa and watch the world's jammiest penguin escape from the world's most incompetent sea lion. From the screen, that velvety voice: "Never have the roles of hunter and hunted been played with so little skill." Fortunately, the same can't be said for the people behind the cameras.

Frozen Planet's first episode attracted 6.8 million pairs of eyes, and it's just part of the BBC's prodigious output of science and nature documentaries, each one bringing science to massive audiences. The last few weeks alone have seen Alice Roberts telling the story of human evolution, Jim Al-Khalili narrating the history of electricity, and Marcus du Sautoy discussing the possibility of faster-than-light neutrinos. In the wings, the likes of Brian Cox, Adam Rutherford and Kevin Fong are at work on upcoming shows. With such a diverse menu on offer, it is not difficult to believe that we're in a "glorious new age of science on television", of a type that places genuine education over cheap sensationalism.

The technology behind the visuals has undoubtedly improved, but for all the time-lapse, slow-motion, geo-stabilised, infra-red, high-definition camerawork, the craft behind the BBC's science programmes is delightfully old-fashioned. When you have footage of killer whales pummelling seals with waves, there is little need for manufactured dramas. Even when the presenter is a celebrity – and Attenborough is surely the pinnacle of the A-list – everyone from the directors to the composers seem to know well enough to let the visuals and the content do the heavy lifting. Attenborough is the guide, not the centrepiece. He tells, but only to supplement what he shows.

Even Planet Dinosaur, unusual in placing soulless spectacle over substance, managed to insert fascinating segments about fossil evidence between the oddly weightless CGI and John Hurt repeating the word "killer" a lot. And, if anything, that series' limitations show why Frozen Planet and the others are so valuable. Even with a completely blank canvas, you cannot dream up dramas as intense as those you get when you actually send filmmakers to opposite corners of the Earth on a four-year shoot. The results of these ambitious projects surely provide the best evidence of the BBC's value as a public service broadcaster.

But these shows are not just about describing and inspiring, but also discovering. New species, populations and behaviours, never before seen, are captured on film and brought to home screens before they debut in scholarly publications. Elizabeth White, one of the directors for Frozen Planet, tells me that the series has already yielded five papers on new behaviours, such as a proper description of the killer whale wave attack seen in Wednesday's episode. White says: "The scientists we worked with did so well because they got to spend 24/7 watching the killer whales while we filmed, access they'd never get from a big research ship or other type of vessel that they usually have to work on."

The scenes in the actual films are surely the tip of the iceberg. Consider the footage that must lurk in the BBC's archives, enough probably to make hundreds of lesser documentaries, and entice hundreds of salivating zoologists. Consider also that this footage may eventually be our only surviving record of a delicate and disappearing world (Frozen Planet's final episode will look at the changes afflicting the polar regions). Even Attenborough himself sounds older, his voice slower and rougher than the sprightly tones from Life on Earth. As we watch, we are constantly reminded of the fragile natures of both the world being filmed and the people filming them.

But enough of such melancholy: the next episode of Frozen Planet features narwhals. On primetime television, we get to watch giant unicorn-whales with lance-like tusks sprouting from their heads. That is why I pay my licence fee.