From ice cores extracted from the Tibetan Plateau, scientists recovered the equivalent of 1,705 virus species. Reading their genomes tells the story of 41,000 years of climate change.

As humans alter the planet’s climate and ecosystems, scientists are looking to Earth’s history to help predict what may unfold from climate change. To this end, massive ice structures like glaciers serve as nature’s freezers, archiving detailed records of past climates and ecosystems – including viruses.

One key finding was that viral communities varied significantly between cold and warm climatic periods. The most distinct community of viral species on the glacier appeared about 11,500 years ago, coinciding with the major transition from the Last Glacial Stage to the Holocene. This suggests that the unique climate conditions during cold and warm periods profoundly influenced the composition of viral communities. We hypothesize that these influences were likely due to viruses from other places being blown in by changing wind patterns and subject to selection pressures from changing temperatures on the glacier.