Pakistan Study Reveals Heaviest Snow in a Thousand Years

A study published today (27 April) in Nature says the region received more snow in the past century than at any other point during the past thousand years. Oxygen locked away inside ancient trees shows that human activities have resulted in a dramatic increase in snowfall in northern Pakistan, say researchers. A senior Pakistani geologist says, however, that the trend could be due to large-scale irrigation schemes that began in the area at around the same time as the West's Industrial Revolution. The researchers took cores from tree trunks, and sampled the individual rings that form with each year's growth to assess the ratio of normal to 'heavy' oxygen. This allowed them to estimate yearly snowfall stretching back more than 1,000 years — the age of the oldest trees in the study area.