THIS October, at the age of 90, Sir David Attenborough comes back to our TV screens with one of his natural-history epics, a sequel to 2006’s Planet Earth. Like most kids of the TV age, my internal wiring hums with Mr Attenborough, in ways I couldn’t damp down even if I tried.

Even a mild recall of our family’s watching habits round the televisual hearth – Attenborough’s hooting conversation with a jungle gorilla, or his joy at the seductive ornaments of a bowerbird’s nest – can instantly move me.

Into this hard-working home in a sharp-edged town, Attenborough brought the delicate wonder and variety of the natural world. And all of it explained, in a quiet but utterly consistent way, through the rigours of evolutionary science.

For the philosophically minded, it may be that Nietzsche killed God. But for this wee Coatbridge geek – and don’t tell Father Curley! – David Attenborough was the more direct assassin.

But as TV news items jolt the senses with pictures of slaughtered elephants, or deliver yet another tablet of inexorably worsening climate statistics, I’m a bit disquieted about my old safari-jacketed hero.

The questions start to arise. For all his gushing enthusiasms, has he actually made a damn bit of difference to the protection of natural diversity? What are we really watching, when we watch Sir David Attenborough?

One of the subtleties we have to accept about Attenborough, and nature TV in general, is that we only get up close to these unfolding wonders of nature by means of the most bristling, cutting-edge technologies. In a 90s BBC Radio Scotland interview with me, Attenborough conceded that in order to see a “black cat prowling in the dark”, you needed “night-sight technologies that come from quite dodgy places – military research, for example”.

The first Planet Earth had cameras mounted on helicopters that pounded after birds in flight, like something out of Apocalypse Now. Planet Earth II has made extensive use of camera drones for much of its filming, fitted with the latest high-definition 4K tech. The publicity shots already released depict a snow leopard relaxedly prowling across a high escarpment – a sight unseeable, other than via those buzzing menaces.

The last few Attenborough series have included a few minutes at the end of each episode, where the derring-do or ingenuity of the cameramen in achieving their amazing shots is laid bare.

They look like grizzled army sergeants; Attenborough stands behind them, bearing a dishevelled but gentlemanly authority.

Now for some, this has always been the sneaking problem with the Attenborough phenomenon. Essentially, he’s the British imperial gaze still gazing upon the world, categorising and classifying its contents, and profiting thereby. This time it’s not by the old colony/plantation method but by selling the TV series on to US and global markets, with Sigourney Weaver doing the voiceover.

Is this a tough call on our adored whispering natural enthusiast? Let us say the issue is complicated. There’s no doubt that something Great-Britannic lingers here. Attenborough’s very age and style makes him seem coterminous with the heyday of Britain itself.

There are obvious links between naturalism and empire. If you’re ever in London in summer, go and visit the Chelsea Physic Garden. Someone who looks and sounds like Attenborough’s sister will show you round a beautiful display of natural variety and profusion ... all to the end of developing hardy plants and seeds for those fertile territories, on the old maps, that were once proudly coloured red.

So it’s possible to see, stretching out behind Attenborough, a massive historical fracture, not far below the permafrost. The crack is that our very delight in the way that TV “captures” and “penetrates” nature’s secrets only echoes a much vaster and darker era, one where we in the West could have paid a lot less technical – and more rapacious – attention to the flora, fauna and geology of the planet.

In the early 2000s, the environmentalist George Monbiot took Attenborough to task for presenting the natural world “as a pristine wilderness, unaffected by humanity”.

Sir David’s documentaries portrayed “two planet earths”, wrote Monbiot. One of them is “the complex, morally challenging world in which we live, threatened by ecological collapse. The other is the one we see on wildlife programmes” – which show “an Eden before the sixth day of creation, when God went and messed it up by making Man”.

Attenborough’s response was pithy. “To suggest that every natural history programme should be devoted to the present ecological crisis, or indeed must always make reference to it, is like suggesting that human beings are only interesting or worthy of TV documentaries if they are sick and injured”. (I wonder what Sir David makes of Channels 4 and 5 these days).

IF you read the archive of Attenborough interviews, it’s clear that he feels he’s been playing a canny game with the BBC, science and society. “People are not going to care about animal conservation unless they think that animals are worthwhile,” he said in 2012. “And they will only think that if they think ‘the person on that box is telling us the truth; he is showing us what they are and not telling us too much what to think about them’.”

In short, what David thinks nature programming generally does is to increase our feelings of “biophilia”, to use the term from American biologist EO Wilson. Meaning that if we tap into our love of nature deeply enough, maybe we will then be moved to conserve and preserve it.

But surely we must say – as the climate-warming indicators rise inexorably, despite intergovernmental initiatives aplenty – that this media project has been a crashing failure?

In his latest interview with Monbiot, Attenborough is still exulting like a schoolboy over bioluminescent earthworms.

But if general global warming continues on its path, and ice-melt accelerates in the Arctic, it’s predicted that 1,500 billion tons of land-based carbon and 10,000 billion tons of sea-based methane will be released into the atmosphere. What that would cause is a mass extinction of species.

And the last time that happened – the Permian extinction, 252 million years ago – up to 96 per cent of marine and 70 per cent of land-based species were wiped out. It took the planet seven million years to recover. Humans may not be one of those that make it.

So do we need less of his enthusiasms, more of his militancy? It’s not as if Attenborough hasn’t, in recent years, taken eco-political stances. Yet his chosen angle of attack – we are over-populating the planet – is fraught with its own underlying problems. Shouldn’t we be looking much more at over-consumption – and at the wildly unequal global economic and political structures which underpin that?

We watch nature documentaries on our new 4K domestic widescreens (indeed, in the trade press, Planet Earth II is regarded as a “market maker” for this new display format). We’ll coo and ahh at the snow leopards, from our techno-bubble of affluence and pleasure. But our leading celebrity environmentalist is urging us to worry that billions of other humans have attained the merest foothills of electrification, plumbing, nutrition and connection.

It’s hard to acknowledge, but there seems to have been a kind of escapism at the heart of Attenborough’s nature TV over these several decades. An escape, that is, from thorny political and cultural questions.

How have we even come to adopt that watching position at the edge of our couches? Admiring the filming and editing skills of a “Natural History Unit” – but able to channel-flip at any point to something more glittery, sociopathic or stupefying? For the sake of the “natural world”, doesn’t something need to crash through the glass a bit more rowdily than the nation’s ideal pseudo-grandfather?

He’s too loveable not to enjoy: and I can attest that, in person, he is modest, intellectual and inspiring. But I am snipping away at my childhood bonds with Sir David. Life on earth may now need more robust kinds of defenders than even him.

Sir David Attenborough’s Planet Earth II is on BBC TV this October