In the 21st century, the water level in seas and lakes is dropping regarding the impact of climate change and global warming. Lakes, which do not flow into the oceans, are particularly vulnerable to climate change, as the inflow and evaporation of water into the lake define their water levels.
The popular magazine Nature has published an article on the problem that the Caspian Sea may face in the next 60-70 years. The research by Western scientists sounds the alarm bell on the urgent need to act regarding the rapid decline of the Caspian Sea.
The article reads that by the end of 21 st century, the water level of the Caspian Sea is expected to drop by 9-18 m under medium and high emission scenarios. In the 21st century, the water withdrawal rates in the Caspian Sea will be about twice as much as in comparison with the forecasts based on previous climate models. A 9-18 m drop in water level will mean that the Caspian shelf in the north, the Turkmen shelf in the southeast, and all coastal areas will rise below the sea level. In addition, the Kara-bogaz-gol Gulf in the eastern part of the Caspian Sea will dry up completely. In general, the surface area of the Caspian Sea will decrease by 23% -34%.
What does Azerbaijan forecast about the environmental challenges that the Caspian Sea will encounter?
Rasim Sattarzadeh, head of the Department of Ecology and Nature Protection Policy of the Ministry of Ecology and Natural Resources (MENR), said that periodic changes in the water level of the Caspian Sea are inevitable as it is a closed water body. Level fluctuations mainly depend on the elements of the water balance of the sea such as the rivers that flow into it, the amount of precipitation, the level of evaporation. Tectonic motions on the seabed are also among the factors influencing the level change:
We should mention the seasonal changes as well. Therefore, the difference during the year can vary in the range of 30-40 cm. The water level of the sea reaches its peak in June-August when the rivers are overflowing. The lowest level is observed in December-February. If we have a look at historical periods, for instance, in the last 100 years the level difference has changed in the range of 3 m, and 200 years in the range of 3.5 m. According to some sources, the level of the Caspian Sea has risen and fallen in the range of about 15 m for 3,500 years.
Rasim Sattarzadeh stated that the water level of the Caspian Sea rose by 2.5 m in 1977-1995. Until 1975, the Caspian Sea was at the lowest level in the twentieth century. At that time, the water level was 1 m lower than now: “The ministry's hydrometeorological service is researching the Azerbaijani part of the Caspian Sea - on the coast, on the high seas and the islands. According to observations, by 1995 the sea level had risen by 2.5 m. The descent has been observed since 2005, which is 7 cm per year, and the sea level has dropped by 1.5 m so far.
Sattarzadeh notes that there are many assumptions about the level of the Caspian Sea. However, according to scientists studying this field, it is impossible to make long-term forecasts of changes in sea levels: “Such forecasts have been made before and they did not come true. There are different programs, you enter some historical figures in one program and get the overall result, and in another program, the result is more different from other scenarios. Some articles can be considered as one of the many possible scenarios. Many factors lead to water level fluctuations, and they have such uncertainties. Considering all these, we should be careful about the long-term forecasts.
The expert confirms that considering the direction of climate change, we can say that the downward trend at the level of the Caspian Sea is slightly greater than the upward trend. However, in similar situations, historically, the sea level has risen. There are many points. It is difficult to perform fully accurate 5-10- year predictions in advance. Scientists and climatologists of the Caspian littoral states are researching this direction. Along with forecasts of falling levels, there are also forecasts of rising levels.
Sattarzadeh also highlighted that the water level change in the Caspian Sea has an impact on its environment, particularly on the economy, offshore oil and gas operations, maritime transport, and the operation of ports. Therefore, all these should be taken into account while planning these activities: “We regularly conduct hydrometeorological observations at sea level and inform the relevant agencies to consider these issues in their work and future projects. It is necessary to admit that water level fluctuations will always occur. Water level changes are a negative factor for the environment, biodiversity, and human activity but we cannot control it. "
Sattarzadeh stressed that the problems of the Caspian Sea are not only the problems of Azerbaijan but also of 5 countries: "Based on the Framework Convention for the Protection of the Environment of the Caspian Sea, which has been in force since 2006, the Caspian littoral states continue their cooperation on various environmental issues, including joint research and discussions on water level fluctuations in the Caspian Sea, etc. An anthropogenic factor can be mentioned in the sea-level change, but it is not that much. Increasing water demand follows population growth. In addition, agricultural water consumption (including both rainfed and irrigated agriculture) is expected to increase each year. While water consumption increases, the amount of usable freshwater that is easily accessible is rapidly shrinking due to climate change.
If the forecast published in the journal Nature comes true, it will have a serious impact on the ecosystem. In winter, the reduction of ice on the northern shelf of the sea will lead to the disappearance of breeding grounds for endangered Caspian seals. In this case, ecosystems will completely be reorganized threatening the unique Caspian Sea biota that has been developing in the basin for millions of years.
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