No more space in outer space? Highly illogical – the universe is expanding. This may be true, but unfortunately until we develop transport that’s a tad more effective than strapping explosives to a titanium can, we won’t be making much use of all that space out there. For the time being, the only space that counts are the orbits which cling to Earth’s gravity, and that space is increasingly congested, contested and competitive.

There are currently some 21,000 known chunks of man-made junk or space debris – abandoned equipment, spent rocket bodies and other fragments –floating around Earth. And by floating, I mean whipping around our planet at speeds of up to 7.7 km a second. At that velocity, even a chip of paint can spell disaster for anything in its path. If we keep polluting Earth’s orbits at the current rate, we’re likely to reach a tipping point at which collisions between objects in orbit become unavoidable. The ensuing domino effect of crashes that produce more pieces of debris, which in turn trigger more crashes, would ultimately result in a “debris belt”. This is fancy way to say that Earth would be adorned with a ring of garbage.

Aside from being a very unsightly welcome mat if other intelligent life forms ever do come to visit, a debris belt would preclude the safe operation of satellites, space stations and any future uses our orbits might have. The day we lose satellite capabilities we instantaneously lose the Internet and cell phone networks. Our critical infrastructures – from electric grids to traffic lights – would lose the ability to synchronize, resulting in blackouts, urban chaos, traffic accidents and train wrecks. News and information flow would slow to a trickle, feeding into panic. Financial markets would be crippled. Global transport would come to a halt. Air traffic controllers would lose contact with flights. If the weather allowed, seafaring ship crews would at least be able to dig out their old sextants and compasses to get home safely, but struggling aircraft would have no such equipment.

How congested are Earth’s orbits now? Bear in mind that we’re not talking about a surface area the size of Earth and extending out as far as Earth’s gravity holds. Due to the unique characteristics of some orbits, there are few altitudes and rings out there that serve our needs. Logically, the debris is concentrated in this prime real estate. Every week there are nearly 200 close calls between active satellites and debris. On average, satellite operators around the world perform three collision avoidance manoeuvres a week. Space debris is also a collision risk for us down here; objects are falling back to Earth all the time. On average, every week there’s at least one re-entry, and many of these objects survive intact and impact on Earth’s surface.

Accidental collisions between satellites and the militarization of space, as seen in the testing of anti-satellite weapon systems, risk greatly increasing the amount of debris, and are perhaps a sign of things to come as more nations and private enterprises begin to exploit space. There is no convincing technology available for the cost-effective removal of space debris, making our best bet to safeguard the orbits we use by reducing the amount of waste that we place there to begin with. Prevention is key because if we lose the use of space, the consequences would be as dire as any science fiction disaster – and it would be no use turning to Scotty to beam us up.

This series of “What if” blog posts is inspired by the findings of the Global Risks 2012 report. The scenarios they depict are far-fetched, but ultimately plausible. The other two posts are What if antibiotics stopped working? and What if a volcano exploded?

Pictured: a view of earth, including the Nile River and the Sinai Peninsula, seen from the International Space Station (Thomson Reuters)