14 DAY TRIAL // Investigators with the University of East Anglia in the United Kingdom and the Chinese Academy of Sciences (CAS) in Lanzhou, China, say that areas in northeastern Tibet have received significantly more precipitations over the past few decades than any time over the past 3,500 years.
The exact mechanisms through which this semi-arid region receives so much rain are unknown, the climate science team says. The readings used in this study were collected from tree rings in Tibet. These rings can reveal moisture levels in the area spanning back thousands of years.
Overall, scientists collected data from around 1,000 trees. Some of these trees are known to live up to 2,000 years, so the team in essence developed the most comprehensive tree ring database for this part of the world, PhysOrg reports. These records revealed that moister conditions began in northeastern Tibet around 50 years ago.
“The most recent few decades have, on average, the widest rings in the 3,500-year record which suggests that this may have been the wettest period, perhaps associated with global warming during the last century,” says Dr. Tim Osborn, who is based at the UEA Climatic Research Unit. Details of the work appear in this week's issue of the journal Proceedings of the National Academy of Sciences.