The WRI report shows that the water level has had a downward trend in recent years, IRNA reported.
Last year’s measurement put the Caspian Sea’s water level at -27 meters (relative to that of the Baltic Sea), according to Financial Tribune.
The Baltic Sea datum is used as a reference point to measure fluctuations in the Caspian Sea water level.
Morteza Eftekhari, head of WRI, attribute the worrying decline to prolonged droughts and climate change.
“Precipitation, inflow of rivers and evaporation are the main causes of change in the level of the Caspian Sea,” he said.
The Caspian Sea is a closed water body which was separated from the Black Sea in the Pliocene Epoch (around five million years ago) and has experienced numerous cycles of fluctuation ever since.
Its area has constantly changed between one million and 150,000 square kilometers and its water level is estimated to have fluctuated within a range of over 300 meters.
It experienced a massive drop in water level in the late 1970s but went back to normal in 1991. However, the water level has been gradually dropping since then.
Caspian water level has decreased by 1.3 meters since 1996 and more decline is expected in the future.
Experts and environmentalists believe that if the shrinkage continues, adverse environmental consequences may occur in Iran’s coastal areas.
The Caspian Sea is the largest enclosed inland body of water on Earth by area. It is bounded by Kazakhstan to the northeast, Russia to the northwest, Azerbaijan to the west, Iran to the south, and Turkmenistan to the southeast. The sea has a surface area of 371,000 square kilometers and a volume of 78,200 cubic kilometers.