Modern warfare is creating a new and largely overlooked form of environmental pollution. Across battlefields, particularly in Ukraine, fibre-optic drones are leaving behind vast quantities of extremely thin cable that may remain in the landscape long after the fighting has stopped.

Drones have transformed modern warfare, but conventional radio-controlled drones are vulnerable to electronic jamming. One solution has been the development of fibre-optic drones. These carry reels containing many kilometres of cable, which unwinds behind the aircraft as it flies. Commands travel to the drone through the fibre and video images return to the operator along the same connection.

The technology is ingenious, but it creates an environmental problem. Once deployed, the cable remains where it falls.

A typical fibre-optic cable used by a drone is only a fraction of a millimetre thick. At its centre is a tiny glass fibre surrounded by protective layers of plastics and synthetic polymers. The finished cable is light, strong and exceptionally difficult to see once it has fallen into grass, woodland, farmland or water.

There is an intriguing historical parallel. The battlefields of the First World War were also covered with communication wire. Telephone and telegraph systems required enormous quantities of cable, with a single British field army potentially needing thousands of miles. Yet much of that wire had value. It could be recovered, repaired and reused.

Modern drone fibre is different. It is scattered across the landscape, often with no practical means of locating or retrieving it.

Nobody currently knows how much fibre-optic cable is being deposited. As an illustration of the potential scale, if 500,000 fibre-optic drones were deployed globally in a year and each carried 15 kilometres of cable, they would leave behind approximately 7.5 million kilometres of fibre. That would be enough cable to circle the Earth almost 190 times.

The environmental significance lies not simply in the weight of material but in its extraordinary dispersal. A relatively modest mass of plastic becomes something quite different when shredded into almost invisible threads and scattered across forests, fields, rivers, wetlands and settlements.

There are already reports from Ukraine of birds incorporating discarded fibre-optic cable into their nests. That raises uncomfortable parallels with abandoned fishing line and nets. Conservationists describe discarded fishing equipment as “ghost gear” because it can continue trapping and injuring wildlife long after it has been abandoned.

Fibre-optic drone cable may eventually prove to be a terrestrial equivalent - ghost gear on land.

The material has several characteristics that make this possibility concerning. It is thin, strong, difficult to see and potentially persistent. Birds and mammals may encounter it, vegetation may grow around it, and fragments may eventually enter soils and waterways. Yet the long-term ecological consequences remain poorly understood.

Nor is this simply a Ukrainian issue. Military technologies spread rapidly. If fibre-optic drones become standard equipment in conflicts around the world, every future battlefield could potentially acquire the same environmental legacy.

That raises questions that have received remarkably little attention. Who will remove this material once a conflict ends? Who will pay for the clean-up? How can almost invisible fibres be located across thousands of square kilometres? And what happens when recovering them is simply impractical?

Wars leave environmental consequences long after armies have departed. Trenches soften, vegetation returns and wildlife recolonises damaged landscapes, but some remnants of conflict can persist for decades.

A strand of fibre-optic cable hanging between two young trees may appear insignificant. Multiplied millions of times, however, it could represent an entirely new category of battlefield litter.

The environmental impact of fibre-optic drones is still uncertain. It may ultimately prove relatively minor, or it may become a significant conservation problem. At present, there is insufficient evidence to know.

What is clear is that enormous lengths of synthetic fibre are now being deposited across landscapes as a direct consequence of modern warfare. As history repeatedly demonstrates, what conflicts leave behind can matter almost as much as what happens while they are being fought.

The New Battlefield Litter considers whether the technological revolution in drone warfare may be creating an environmental legacy that could remain hidden in the landscape for decades.