What with the NSA's Prism programme, ubiquitous CCTV and fashionable nerds sporting Google Glass, it seems there's no escape from prying eyes in the hi-tech modern world. But we might look back on this time as a golden age of relative privacy, before the gnat-sized surveillance drones invisibly swarmed in the air, video-recording our every movement and making of the globe a glorious Panopticon. This might sound futuristic, but it's probably not that far off. This week at the TEDGlobal conference in Edinburgh, videogenic scientists and thinkers have been seriously discussing the ethics of drone use, now and in the sci-fi future. Drones can be used to bomb people, but they can also be used to count endangered orangutans in the wild. Assassination or conservation, it's all in a day's potential drone-work.

The word "drone" was probably chosen to describe remote-controlled military craft – formally, Unmanned Aerial Vehicles – so as to sound maximally boring. You don't want to sit next to someone who's droning on. A "drone strike", of the sort that routinely kills civilians in Afghanistan and Pakistan, almost sounds as though a crew of tediously logorrheic raconteurs has decided to shut up, a result for which everyone ought to be grateful. Unfortunately, it has led to the annoying tautology in common use, "unmanned drone". All drones are unmanned. If it's manned, it's an aeroplane.

Future drones will be unmanned by necessity anyway because no human being will fit into them. Scientists at Harvard University have already made a robot modelled on a bee, the size of a fly, which they have christened "RoboBee". It's made of carbon fibre, weighs less than a gram, and flaps little robot wings. At the moment, RoboBee needs to be tethered to a power source, but in a few years it will be able to soar free. Future generations of RoboBee could carry minuscule video cameras for intrusive recording of normal folk and celebrities: the paparazzi won't need to hide in bushes with long lenses, but will sit at home controlling spy-flies from their iPad Nanos.

More potentially alarming than undetectable pap-bots are the military uses of such technology. Especially when attack-drones are given the capability of taking matters into their own hands (or insectoid feelers). Drones that are remotely piloted – in the case of those operating in AfPak, by people sitting safely in the US – are one thing. But US military researchers have, for several years, been working on "robot swarms" that take their own life-or-death decisions, modelling the robots' behaviour on that of flocking birds. The term of art here is Proliferated Autonomous Weapons, or Prawns. (To oblige future reporters to say that people were killed in a Prawns strike adds insult to injury.)

At TEDGlobal, sci-fi author Daniel Suarez said that we need international treaties to limit the use of such autonomous combat drones. Indeed, a report recently presented to the UN human rights council calls for a moratorium on them. (The BBC's story on this referred, with studied rhetorical neutrality, to "so-called killer robots". This seems excessively fastidious, given that we are, after all, talking about robots that kill.) But eliminating the vagaries of human judgment from the wetwork equation is clearly very tempting to some in the military. One US defence researcher told the writer PW Singer a few years ago that "the human is becoming the weakest link in defense systems". And in the highly realistic film Iron Man 3, Pepper Potts' head of security enthuses: "The 'human' part of 'human resources' is our biggest vulnerability. We need to start phasing it out immediately." It's not satire but reportage.

Naturally, autonomous flying weapons are a good thing when they're a) completely reliable and b) on your side. The late, lamented Iain Banks saw this coming a long time ago. In his Culture sci-fi novels, the special-ops agents of the good guys are protected by "knife missiles" that wreak bloody blink-and-you'll-miss-it havoc on anyone foolish enough to mess with them. But spare a thought, if such things come to pass, for the lethal-weapon fetishists of the National Rifle Association, who will have to come up with a new slogan. It won't make sense to say "autonomous killer robots don't kill people … " – because that's exactly what they will do.

But there is a fluffy side to drones, too. Drones are just robots, and robots can be programmed to do evil or good. The father of RoboBee, Dr Kevin Ma, has suggested that such robots could be used for "search-and-rescue operations", navigating tiny spaces in collapsed buildings to look for survivors, or perhaps for "environmental monitoring", equipped to detect chemical traces.

Undoubtedly virtuous, too, is the programme presented at TEDGlobal by Andreas Raptopoulos, which plans to use drones to deliver medical and other supplies cheaply and quickly to people in urgent need in disaster zones (the system was trialled in Haiti after the 2010 earthquakes), or in developing countries with poor emergency infrastructure. (Raptopoulos's company has the inspiring moniker Matternet, implying that a network of such emergency drones will be like the internet, but for physical stuff.)

The challenge with drones is not that we'll need to choose between good and bad uses for them, but that all these uses – and more that no one has yet thought of – will be happening simultaneously, in a near future where drones are thoroughly commoditised. Right now, for less than £300, you can buy a hobbyist's "quadcopter" drone that streams video to your smartphone (which also controls its flight). "It doesn't take a genius to imagine flying one over the neighbours' lawn and capturing photos of them nude," the law professor Kevin Heller recently told the Sydney Morning Herald.

In the coming drone democracy, the possibilities are endless. Sulky Parisians could use drones equipped with electronic-payment systems and little wicker baskets to collect their morning croissants from the bakery. Lazy parents could use more robust load-carrying drones to ferry their children to and from school. On the debit side, it will also be much easier for anyone to blow things up from a safe distance. It used to be said sardonically that a terrorist was someone with a bomb but no aeroplane. But if you have a bomb and a cheap drone, all bets are off.

The skies of the future are looking busy indeed. Perhaps there will be an ambient drone war going on all the time, with antibomb drones targeting bomb drones, and ambulance drones, loaded with robotic surgical equipment, swarming to scenes of an accident or drone-attack aftermath, while privacy activists send hunter-killer drones to take out the surveillance drones. I hope that at least the wildlife-observation drones, like Switzerland, will be considered neutral. And maybe we can even make bee-sized pollinator drones to replace all the disappearing real bees. It's a nice thought. Now excuse me, I have to send my drone out for a second breakfast.