Currently, climate change is considered to be one of the most severe threats to ecosystems around the world. Lake ecosystems are sentinels for change as they provide indicators of climate change either directly or indirectly through variables such as lake level and temperature increase.Researchers in China have conducted a long-term study (1961-2012) on Qinghai Lake measuring the changes in lake level over time. The principal goals of this study were to investigate the monthly and annual variations of lake level, identify the reasons for lake level variation and to discuss future possible variation of the lake level.
Data was obtained from meteorological and hydrological stations in the region and monthly lake level records and river runoff records were collected as well.
Qinghai Lake is the largest lake in China with a surface area of 4,400 square kilometers. Average precipitation is roughly 13 inches annually, with more than 65% occurring in the summer. Though this may seem like enough water to sustain the lake, the rate of evaporation is four times higher than that of precipitation. There are more than 50 rivers or streams flowing into Qinghai Lake, but most of the rivers are seasonal, so come dry months the lake’s hydrological in-puts reduce drastically contributing to a decrease in overall lake level.
Data suggests that the levels of Qinghai Lake were divided into two stages: decreasing from 1961-2004 and increasing from 2004-2012. During the decreasing stage, reduced river inputs along with a decrease in precipitation were noted whereas during the increasing phase, there was a substantial increase in river runoff combined with increased rainfall (especially in the summer months). Moreover, thawing permafrost, due to climate warming, also increased the amount of water coming into the lake.
Overall, Qinghai Lake water levels were extremely sensitive to climate, changes in river runoff, and evaporation. This trifecta had direct effects on lake volume whereas temperature, humidity and wind speed had indirect effects on lake volume. It will be fascinating to see how the lake responds in coming decades with climate changing as rapidly as it is.