Levent Kurnaz: the Caspian Sea will dry out if we don’t change agricultural practices

"There is nothing you can do but use water smartly. Efficient is one thing. Smart is quite another," says Professor Levent Kurnaz.

A physicist by training, Professor Levent Kurnaz is the Director of the Climate Change and Policy Programme of the Bogazici University, in Istanbul, and one of the few climate experts focusing on the understudied region of the Caucasus and Central Asia. At the heart of climate negotiations, the region does not have access to the water that covers three quarters of the planet. Human activity has already exhausted valuable water resources, with the destruction of the Aral Sea. The question for many is whether the Caspian Sea will follow.

Shared by Iran, Azerbaijan, Uzbekistan, Kazakhstan, Turkmenistan, and Russia, this body of water is critical for food production, transport, energy, and the livelihood of millions. Home to unique species like the famous caviar-producing sturgeon and the Caspian seal, this water system fed by the Volga River has lost a surface equal to the territory of Belgium since the 1990s. In terms of depth, the Caspian Sea is at its lowest point since the 1970s. And because this part of the world does not have a “Plan B” in terms of access to water, there is a sense of urgency. Iran produces two-thirds of its calories by farms in the region.

We find Professor Kurnaz in Baku, where this discussion and sense of urgency do not seem to dominate the agenda. Generally, he considers himself “an optimist.” However, the window for action has closed and the point now is to mitigate the challenge. That is not happening.  If we did have the resolve to act, we should start from agriculture, he argues.

European Interest: How do we know what we know about climate change in the region?

Professor Levent Kurnaz: In climate science, there are basically two kinds of modelling. First, you can look at the whole world, but at a rough-coarse resolution. Secondly, one takes this coarse resolution modelling as a baseline and then refine the model.

For the first global approach, you need supercomputers because it takes a huge amount of computing power. This is not a matter for individual researchers any local researcher can take on. There are very few groups in the world with this climate modelling capacity. The global research data pool is called CORDEX. This global data pool is the foundation for our local work. What we do is take the global data and use the same modelling to increase the resolution. It’s the same physics fundamentals.

At the moment, I’m in Baku {at the COP29}. One can you say I just care about Azerbaijan, or you can easily say I just care about the environment around New York City. So, any region anywhere may be the object of our focus.

European Interest: So, within the CORDEX framework, you focus on the Caspian Sea and Central Asia. What does that include?

Professor Levent Kurnaz: The coordinates of the broader region are quite broad: from Finland to Manchuria down to Thailand and the Arabian Peninsula. I have been focusing more closely on the Caucasus-Central Asia region for the last 13-14 years.

European Interest: Do you look at what is happening now or do you focus on future projections?

Professor Levent Kurnaz: Fundamentally, you factor three physical parameters: first, how much energy is coming from the sun; secondly, what is the composition of the atmosphere; three, what’s the composition of the surface, whether it is desert or ice, for instance. If you give these three parameters, you can basically model the climate of Earth the same way you would model the climate of Venus. Of course, the more the data, the better the model, and we know more about Earth than we know about Venus. On Earth, we have surface layer data, such the specific colour and composition of the sand in the Gobi desert and how much light it reflects. So we put all the physics into this story.

European Interest: Okay, and so with the current data what do you see? What are the projections for the Caspian Sea?

Professor Levent Kurnaz: If you look at the broader Central Asian region, what we predict is an increased flow of water will increase before it is reduced, quite dramatically. The Himalayan glaciers are melting, and that’s increasing the amount of water that’s coming into the Central Asian plateau at the moment. That will not last long. If all of the economies in the region assume that is the water they have available, “forever,” then they will squander a capital that is about to fall. If they go into water-intensive agriculture, that will be a problem.

In time, the farmers will need to supplant the water they are “missing,” and they will use groundwater. When you use groundwater, you eventually deplete groundwater.

There is a similar dynamic in the Caspian Sea, which sipes underground to replenish reservoirs. It flows through your farm, and you just drain it one cup at the time.

European Interest: However, the main tributary to the Caspian Sea is the Volga River on the North.

Professor Levent Kurnaz: Yes, in the North, you have the Volga, which produces more torrential rain when it rains and more prolonged and extreme periods of drought. Climate change is bringing these two things together.

Whenever we have rain, we have heavy precipitation and whenever we don’t have rain, it’s just basically drought. And this is bad because drizzling or not-so-intense rain penetrates the surface and humidifies the soil. Therefore, torrential rain is less good for agriculture. Therefore, you would use more ground water. And more ground water usage means the level of the Caspian Sea will be dropping.

The southern part of the Caspian Sea, along Iran, will definitely need more water than the Volga flow supplies, because they won’t get any rain.

Plus, the temperature is rising, and evaporation is increasing.

European Interest: I have interviewed scientists who argue that if you can do something about the flow of the Volga, you get more water into the Caspian Sea. Is this a solution or just delaying the inevitable?

Professor Levent Kurnaz: I basically do not understand how they can get more water into the Volga or get the Russians to exploit less the water. If you stop the flow of the water to farming upstream, you can increase it downstream. That is possible. 

European Interest: So, essentially, the only thing you can do is increase the efficiency of water usage. But I wonder: mining uses water, tourism uses water, and agriculture uses water. Why are we only talking about faming?

Professor Levent Kurnaz: Yes, there is nothing you can do but use water smartly. Efficient is one thing. Smart is quite another.

For example, in Turkey, we are growing tomatoes, and we are selling these to Russia. We are very happy about it; the Russians are very happy about it. But we are not selling just tomatoes to the Russians. We are sending them water. This is a water-intensive produce. Therefore, in agriculture, we have to be smart and produce more of different kinds of produce, which use less water. That means we won’t grow these many tomatoes anymore. Instead, we’ll grow wheat.

In Turkey, 77% of our water reserves or three quarters are used in agriculture. If we make a difference there, we make a difference.

European Interest: So, you wouldn’t encourage cheese making or pastoral farming.

Professor Levent Kurnaz: These are minor things depending given the big picture. Of course, when you connect cheese, milk, cows, and corn to feed them, then yes, there is a connection. We need to decrease animal-based production worldwide.

European Interest: So, if human activity changes, does modelling give different predictions? I mean does any of this make a difference. It looks like the climate is a bit like it’s more like driving a ship than driving a car. It takes time to accommodate the course from the moment you change behaviour. Meanwhile, for Caucasus and Central Asia there is no sea, you cannot desalinise, and there is no “Plan B.” Does anything we do make a difference?

Professor Levent Kurnaz: There is no plan B, exactly.

Theoretically, we can always dig a canal from the Black to the Caspian Sea. That’s always a solution. It will take trillions of dollars. It’s cheaper to prepare to stop climate change and manage water resources.

We can change the face of the Earth, but it takes a lot of money. I suppose it’s more cost effective than Elon Musk’s plan of going to Mars. Spending the money here is probably a better investment.

We have to put a price tag on water, more or less in the way we put a price tag on carbon emissions. Now, when we are selling tomatoes to Russia, we are calculating how much diesel is being used and how much you pay farmers and fertilisers. But, you do not factor in water. If you did, many things would be a lot more expensive and people would think twice about growing them and consuming them.

European Interest: Aren’t you describing a dystopia in which water is more expensive for millions of people?

Professor Levent Kurnaz: How much are we paying for our cellular phones compared to how much are we paying for tomatoes? In the future, food will be more expensive.

You can live without cellular phones, but you can’t live without water. We will need to learn to use fewer “things” and price food properly. I’m not saying that water should be expensive, but there should be a price tag on it, especially in agriculture.

Of course, we take the world as we have known so far. That means we assume the methane underneath the glaciers in Siberia stays underground. If permafrost melts, and we have all that methane seeping out of Siberia, all bets are off. We have to prepare ourselves for way worse.

Under normal circumstances, the next 20 years shouldn’t be a problem, but after 20 years, we will have serious changes coming for everyone globally.

European Interest: So, in the future, wearing jeans will be very expensive because they are made of cotton, which is water-intensive.

Professor Levent Kurnaz: Exactly. Cotton shorts will be maybe, much cheaper than wearing jeans. And everybody will say, “I don’t have enough money to buy jeans.”

Levent Kurnaz is a climate scientist attending the 29th edition of Climate Change (COP29) in Baku, Azerbaijan.

Explore more