At a time when the Earth’s oceans are rising due to melting glaciers, the exact opposite is what happens in closed seas and lakes, as heat and drought deplete their precious water.
According to a new study published in the journal Communications Earth and Environment on December 23, the Caspian Sea – the largest closed water body on Earth – is experiencing a particularly sharp decline.
And scientists warn that if emissions continue, salt seawater will drop from 9 to 18 meters by the end of this century.
The researchers say that this significant drop in the water level means that almost the entire northern shelf of the Caspian Sea and some Turkmen shelf to the southeast will evaporate. The eastern shore would also be “completely dry.”
In the worst-case scenario of an 18-meter drop in sea level, models show that 34 percent of the sea’s surface area will shrink.
The size of the crisis
Scientists consider the closed Caspian Sea, which is located in western Asia, as a sea, not a lake, due to its size, which reaches about 371 thousand square kilometers, and due to its high levels of salinity.
And it overlooks the Caspian Sea on 5 countries, which are Russia, Iran, Azerbaijan, Turkmenistan and Kazakhstan.
According to the press report published on the “Science Alert” website, despite the tremendous crisis it is facing, the scientific community is largely unaware of what is happening.
For example, the International Panel on Climate Change did not address the issue of sea evaporation caused by climate change in any of its reports, nor did the United Nations address this issue in its Sustainable Development Goals.
This problem is not specific to the Caspian Sea alone. Some recent studies have shown lower water levels in closed seas and lake systems, largely due to continental droughts caused by climate change.
Because the lakes have no outflow, they are particularly vulnerable to higher temperatures. Its water level is roughly determined by precipitation, river flow and evaporation. The same applies to the Caspian Sea, which depends on the Volga, Europe’s longest and richest river, for its flow.
Is it too late?
Scientists argue that accurate models for the retreat of lakes around the world are urgently needed to save these precious ecosystems and the economies and societies that support them.
As for the Caspian Sea, it may unfortunately be too late to save it. The inland water body is actually declining at a rate of 6 to 7 centimeters each year.
Based on the state of the Caspian Sea, the study authors call for a global campaign to raise awareness and improve research about the shrinking lakes and inland seas of the world, which have long been neglected.
Part of the problem is the sheer lack of research. The risks and vulnerabilities of the Caspian Sea due to water loss have not been studied at all.
“Many people don’t even realize that an inland lake could be drastically shrinking due to climate change, as our models suggest,” said Matthias Prang, co-author of the study, who created climate models at the University of Bremen in Germany.
“This must change. We need more studies and a better understanding of the consequences of global warming in this region,” he adds.
The authors say there is an urgent need for global task forces. Immediate and coordinated action, because if nothing is done, the consequences for the environment are enormous. The projected decline in sea level will severely affect this unique ecosystem, and the loss of shallow waters in the south will deprive endemic fish, birds and seals of invaluable habitats, spawning areas and food sources.
The new paper concludes that “the projected escalating effects of sea level decline in the Caspian Sea are likely to lead to a comprehensive reorganization of ecosystems and threaten the unique organisms in the Caspian Sea that have been developing in the basin over millions of years.”
According to the study, the geopolitical consequences are very worrying, as local economies that depend on fishing and maritime trade will be affected irreversibly, as will coastal ports, which will suddenly find themselves far from the water.
The loss is also likely to exacerbate water scarcity issues in the arid region, undoubtedly causing international conflicts.
Experts predict that “since the livelihoods and food security of millions of people depend on the Caspian Sea, the loss of these ecosystem services will have dire social and economic consequences and may lead to local and regional conflicts in an ethnically diverse and already tense region.”