And this was one year ago already!

begin partial quote from:

Killer Robots Are Coming And These People Are Trying To Stop Them

A very, very small quadcopter, one inch in diameter can carry a one- or two-gram shaped charge. You can order them from a drone manufacturer in China. You can program the code to say: “Here are thousands of photographs of the kinds of things I want to target.” A one-gram shaped charge can punch a hole in nine millimeters of steel, so presumably you can also punch a hole in someone’s head. You can fit about three million of those in a semi-tractor-trailer. You can drive up I-95 with three trucks and have 10 million weapons attacking New York City. They don’t have to be very effective, only 5 or 10% of them have to find the target.
There will be manufacturers producing millions of these weapons that people will be able to buy just like you can buy guns now, except millions of guns don’t matter unless you have a million soldiers. You need only three guys to write the program and launch them. So you can just imagine that in many parts of the world humans will be hunted. They will be cowering underground in shelters and devising techniques so that they don’t get detected. This is the ever-present cloud of lethal autonomous weapons.
They could be here in two to three years.
— Stuart Russell, professor of computer science and engineering at the University of California Berkeley

end partial quote.

If you can build millions of very very small quadcopters one inch in diameter and can carry a one or two shaped charge the only thing that might stop something like this leveled at a city out of several semi truck vans would be either an EMP to fry the electronics in all these devices at once or high winds blowing these things against buildings and setting off the charges prematurely. But, either way it is possible that some might get through to their targets anyway because of flukes and just dumb luck or not.

So, this is a very real potential threat now to especially 3rd world cities where governments don't have nuclear weapons to train on adversaries who do things like this. So, I'm thinking rich terrorists like ISIS and tyrannical oil nations some places would be rich enough to take out whole cities of people with these things that they don't like for whatever the reason. So, I expect it is likely weapons like this will be used on large groups of people who are mostly civilians as time goes on now during the rest of this century.

However, it is also possible to use nanobots to kill people that were put in foods worldwide too that would be autonomous as watchers or as killers or as maiming devices too. The problem with Nanobots is that they could be completely undetectable to anyone but the governments that made them.

All these things from the size of a predator Drone to a nanobot are here now in actuality this century, so these are the weapons that will kill millions of people this century along with Global warming which is a part (25% to 50%) of secret weather warfare waged by the larger nations of earth who are capable of this.

So, it is very likely we will see a major depopulation of earth during this century and centuries in the future from all these weapons and even worse ones than these.

The ones we know about as the general public worldwide might be stopped. The ones we don't know about might not be.

Note: By the way I-95 goes from Miami north along the east coast to the Canadian border through cities like Washington DC , Philadelphia, and New York City and many more.