The full impact of the Mt. Toba eruption of about 73,000 years ago will never be known, but there’s no question that it was a major event, which blew most of a mountain into space. The explosion created a crater lake over 60 miles (96 km) long. Huge ash clouds rose high into the atmosphere and fell over much of the South China Sea and far north and west over Southeast Asia and India. In places, the ash deposits were up to 30 feet (9 m) deep. The eruption blanked the sun and caused the equivalent of a 6-year nuclear winter. The details of this devastating scenario are still being debated, especially its global impact on humanity.

         Mt. Toba vanished into space at a critical moment in human history, when Homo sapiens, anatomically modern humans, ourselves, were flourishing in sub-Saharan Africa. Some hypotheses claim there was an evolutionary bottleneck that humanity almost became extinct, and that India was effectively depopulated, but these notions are by no means universally accepted. As always with sensational discoveries, the hype mounts immediately and even minor finds are magnified by University PR departments into huge scientific advances. For instance, a joint Indian and Oxford University expedition has spent seven years excavating a Stone Age living site in India’s Andhra Pradesh, removing layers of volcanic ash, in which stone tools survive. The artifacts occur above and below the Toba ash, tools that are said to be identical to ones made in southern Africa at the same time, proving, we are told, that some modern humans in India survived the cataclysm.

         Casting aside the hype, what does this interesting find tell us? It certainly shows that there were humans living in India before and after the eruption, but there are, as far as I can tell, no precise dates for the tools found above and below the ash. How long after the ash fell did people resettle the area? Was this a group of immigrants or survivors of the ash fall? And how can one possibly claim that simple artifacts found in Africa were made by the same kinds of people in India? One cannot. All that the Andhra Pradesh site tells us that human occupation resumed after the eruption. Almost certainly, some people survived the catastrophe, perhaps in areas sheltered from ash, or spared its onslaught by shifting winds. But to claim more than this, in the absence of more accurate dating and of human fossils, tells us little beyond confirming that some folk occupied the area at some moment after the eruption.

         So the Andhra Pradesh find moves the pieces on the archaeological chessboard slightly, but, in the absence of more precise dates and human fossils, it is but a straw in the archaeological wind. Claims like those made by the excavators, and one can sympathize with their need for publicity as part of the fund-raising game, require much more data, laid out systematically for fellow-specialists to evaluate. But it’s good news to learn that another five years of excavations are planned. India is one of the big gaps on the human evolution map, and more finds like this one are likely to revolutionize what we know about our ancestry.