Historical drought on the Tibetan plateau
The last century saw record drought on the Tibetan Plateau. The explanation is a weakened atmospheric circulation that affects precipitation. This is according to a new study from the University of Gothenburg among others.
The Tibetan Plateau is located in Central Asia and is the largest plateau in the world. The area contains the largest layer of frozen water after the North and South Poles. Glaciers, lakes and rivers store and transport water for two billion people in Asia - 30 per cent of the world's population.
The study, published in the scientific journal Nature Communications, shows that the period from 1930 to 2010 was the driest 80-year period in more than 3.000 years on the Tibetan plateau. According to the researchers, the drought is linked to the weakening of both the Asian monsoon and westerly winds. The weakening of atmospheric processes in the area is partly due to the increase in airborne particles, or aerosols, released into the atmosphere over the last century. One example of industrial aerosols is sulphates, which are formed during the burning of coal and oil.
Crises linked to drought
The study also shows that documented historical major societal changes and crises in China could be linked to longer dry periods. This is especially true in the arid areas that were dependent on rainfall for agriculture.
– Today, society has developed a better resilience to droughts compared to earlier times, but in a warmer world, more frequent and prolonged droughts will pose a major threat to ecosystems and society, says Hans Linderholm, Professor of Physical Geography at the University of Gothenburg and one of the study's authors. .
Mapping precipitation 3. 400 years back in time
By analyzing oxygen isotopes from individual tree rings from living and dead trees in the northern part of the Tibetan plateau, the researchers behind the study have produced a more than 3. 400-year record of precipitation in the area. The growth rings of a trees contain information about how the climate has varied at the site over thousands of years. Tree growth is controlled by temperature and precipitation, among other factors.
– Our reconstruction of how the climate has evolved in the area over time is one of the world's longest reconstructions based on oxygen isotopes. It gives us unique opportunities to study how the westerly winds and monsoon have affected precipitation on the Tibetan plateau, says Hans Linderholm.
– It is important to understand both historical and current changes in precipitation and drought, especially in a region that is vital for so many people.
For more information about the study, contact:
Hans Linderholm, Professor of Physical Geography, Department of Earth Sciences, University of Gothenburg, hansl@gvc.gu.se
About the study
The study “Recent centennial drought on the Tibetan Plateau is outstanding within the past 3500 years” is published in the scientific journal Nature Communications.
