Will our civilisation survive this century?

Roman remains: Extensive ruins such as those of the Roman colony of Thamugadi (Timgad) in modern-day Algeria remind us that civilisations can and do collapse. (Photo: Wikimedia Commons/PhR61.) In 100 AD, the Roman emperor Trajan founded a new colony in Northern Africa, which he called colonia Marciana Traiana Thamugadi or Thamugadi for short. Planned to cover a surface of 12 hectares with its strictly rectangular grid of streets, the new town was located on a gentle slope with fertile soils and ample sources of freshwater. Its theatre measured 63 metres in diameter and could seat 3,500 people. It was settled by veterans of the Roman army as part of the expansion of the Roman Empire. What could have been just another milestone of Roman expansion now looks more like a turning point or a last fanfare for their world domination. Thamugadi was to be the last outpost built in Africa for Roman settlers, and the territorial spread of their empire reached its peak by Trajan’s death in 117 AD. Thamugadi grew and thrived for three centuries, but in the early 5th century, as the power of the Western Roman Empire waned and the Vandals conquered the area, its sunny days were over. A few conquests and reconquests later, the place was reduced to a military outpost of the Byzantine Empire. Its soldiers looted the derelict buildings for materials to build a fort next to the abandoned town. By the 18th century, when the Scottish explorer James Bruce saw the ruins and made drawings, only the tallest surviving structures, including Trajan’s Arch, were still partially above ground. Systematic archaeological excavations starting in 1880 uncovered the largest and best conserved example of a Roman city built on a grid plan. The site located in the Northeast of Algeria is now known as Timgad. It became a UNESCO world heritage site in 1982. With its ruins stretching over 50 hectares and only very few traces of modern life nearby, Timgad is a perfect place to reflect on the mortality of human civilisations. How can a thriving city just disappear from the surface of the Earth? Could our civilisation go the way of the Roman Empire and, if so, is the end nigh? Can an enlightened society recognise and avert its own decline?