Thousands of years ago, the barren sands of the Libyan Sahara were fertile pastures filled with lush grass. Then the climate changed dra matically – as the region’s ancient rock art testifies. Malcolm Smith considers the evidence

In the scorching desert heat, the sandy wadi as dry as dust and the nearby rocks too hot to touch, I am admiring walls covered in artistic images of crocodiles, giraffes, elephants, herds of antelope and hunters giving chase with spears and clubs. It’s a pretty unlikely location. Here in Libya’s Akakus Mountains in the very centre of the Sahara, there is no chance of a giraffe surviving today’s arid conditions and there are no streams for many hundreds of miles that could possibly sustain a crocodile.

But the ancient presence of a huge range of animals typical of a tree-dotted savannah, interspersed with flourishing marshes and rivers, has been intimately recorded here as a cornucopia of vibrant rock drawings and carvings. There are amazing images of people herding domesticated livestock, of chariots, of adults and children, of a couple holding hands as if attending some ritual – even of a young woman having her hair combed by another, getting ready for her wedding, perhaps.

These exquisite images date from a time, between 8000 and 5000 BC, when the Sahara was not a desert but a lush, fertile land capable of supporting a vibrant and extensive human community. But this incredible resource of rock art, distributed over about 1,300 scattered sites, is not solely a unique record of early life in the Sahara but documentation of a past era of climate change and its human impact that has resonance for life on our planet today.

Who were the people with these primitive artistic skills? What do their drawings tell us about everyday life before the North African climate dried out so catastrophically, causing its wetlands and lakes to evaporate and its grasslands to wither?

Today’s Akakus presents an arid scene of dark, barren rocky mountains interspersed with gravel plains and terracotta-coloured, sandy wadis with a scattering of shrubs. Massive, wind-carved dunes sit in a landscape where very few people have been able to eke out a difficult nomadic existence. The present desert inhabitants, the Tuareg – a few families of which are still semi-nomadic in the Akakus – are incredibly proud of the rock drawings, which they treat as a precious inheritance handed down to them by their forebears.

Arid and inhospitable, with summer temperatures approaching 50°C and an annual rainfall so low that it all but defies measurement, the Jebel Akakus – eroded sandstone desert mountains in the far south-west corner of Libya – is a demanding environment today. It is also a fascinating place. Sandstone pillars, arches, chasms and monster-cut shapes eroded by sandstorms crouch high over wide wadis – the pancake-flat valleys of pale terracotta sand and stones where water flows when it rains – with their viciously thorny acacias, scrubby bushes and inedible, ground-creeping wild gourds.

But not all experts agree that this dramatic change took 2,000 years. Some climate scientists think it happened much more suddenly, at least in parts of North Africa.

‘We detected an abrupt end to this humid period at around 3500 BC in Mauritania [about 2,500km west of the Akakus],’ says Peter deMenocal, associate professor at the Lamont-Doherty Earth Observatory of Columbia University, New York. ‘And there’s evidence that many African lakes dried up abruptly then too, perhaps as rapidly as over the course of a century. But in other places the transition would have been more gradual.’

But how could the climate change so rapidly? There are several possibilities. Perhaps the changing tilt of the Earth relative to the sun – a cyclical process that occurs naturally – could have reduced the amount of heat hitting the ground, thereby causing less hot air to rise and not suck in as much moisture-laden air from the Atlantic. Or maybe changes in solar pulses had a similar effect. Deprived of water, the vegetation would soon have died.

Evidence for a slow change is based on a very subjective comparison of the artistic styles of the drawings and by comparing the ages of pottery fragments and other artefacts found at associated habitation sites. But most sites have a range of drawing styles, maybe done at very wide time intervals.

For rock carvings, a rough idea of their date can be gained from the darkness of the rock on which they are carved. The Saharan rock, mainly a reddish-brown sandstone, becomes very dark over time and almost black on surfaces long exposed to the air. It is a natural process in which oxides form on the surface. So darker drawings or carvings are likely to be older.

The rock carvings were designated by Unesco as a World Heritage Site in 1985, and there are signs erected by the Libyan government at their main locations, showing they are protected by its Department of Antiquities. But the sites are isolated, well away from any roads or habitation so, in practice, protection relies on guides acting responsibly and the few local Tuareg keeping an eye on their heritage.

Visitors to the Jebel Akakus have to be accompanied by an authorised guide, a measure introduced and enforced by the Libyan Government after some amateur European archaeologists attempted to make silicon rubber replicas of drawings about six years ago. They almost obliterated the rock images they targeted.

There are other examples of damage. At some sites, pieces of rock have been removed, presumably with their drawings intact. At Wadi Matkhandush, a few of the exquisite animal carvings have modern, chiselled hacking marks nearby as if someone has tried to deface them. At Tin Chalaga, one of the protected rock drawing sites, someone has carved his sweetheart’s name in Arabic next to a painted rhino – odd animal to choose.

In the recent past some guides have wetted the painted images so that they show up better. ‘The wetting leads to a slow removal of the colour pigment and fading of the images,’ says Mattingly. ‘Images that were crystal clear 30 years ago are now practically invisible.’

He also lists oil prospecting as a problem, especially where sound-vibration equipment is being used to check for deposits. In some places, he says, rock carvings are cracking. In the past few years, the Libyan government has issued a large number of oil-prospecting concessions in the southern desert, including some in the Akakus, in a move to re-invigorate the country’s economy after the long sanctions era.

While not directly affecting the art, tourist four-wheel-drive vehicles motoring around and parking close to the drawing sites are unwittingly damaging a great number of associated artefacts, such as pieces of pottery, tools and the location of former walled enclosures.

‘Protection is much better now than it was five or 10 years back,’ says Exeter University’s Keenan. ‘There’s far greater awareness of how precious this rock art is. The guides are acting more responsibly. I suppose about 40 sites have sustained some damage out of the 1,300 locations. Ultimately I think their protection will need to rely on local Tuareg.’

Italian archaeologists – many of whom have followed in Mori’s footsteps – are proposing the Libyans designate the Akakus a national park and introduce better practical protection using local Tuareg, by training responsible guards and by controlling any developments that could cause damage.

‘There is more evidence of natural climate change here in the Sahara than anywhere else in the world, and these thousands of rock drawings and carvings illustrate it. It’s an invaluable resource,’ says Keenan.

Perhaps we will never be sure whether the Saharan climate flipped suddenly or gradually, but change it did – and drastically. The rock art of the Akakus offers a lesson of which we would be well advised to take heed.

Two German explorers, Heinrich Barth and Gustav Nachtigal, were the first Westerners to find the drawings in the late 19th century. Unfortunately, the view at the time was that only Europeans – and not ‘barbarians’ as they bluntly put it – could have drawn them. That myth was then dispelled by Professor Fabrizio Mori, a palaeoethnologist at Rome University, who began the first systematic studies of them in 1955.