Azerbaijan's geography: mountains that drain into a sunken sea

Why Azerbaijan's lowest ground lies below sea level

The Caspian Sea covers about 386,400 square kilometres in Britannica's figure, and its surface sits some 27 metres below sea level. Azerbaijan's own record gives the country's lowest point as the Caspian at 28 metres below, and it names no year. The missing year matters more here than for any mountain, because the thing being measured moves.

Britannica's reconstruction runs as follows. Since the first century BCE the level has swung by at least seven metres. Through the first three decades of the 20th century it stood close to 26 metres below sea level. By 1977 it had dropped to 29 metres below, the lowest reading in the previous 400 to 500 years. A rapid rise began in 1978 and put the sea at 26.5 metres below by the mid-1990s; the Wikipedia geography article gives the gain between 1978 and 1993 as 1.5 metres and records that it threatened coastal land. After 1995 the level fell slightly and then rose again in the early 21st century.

The swings follow from the lake having no outlet. Water arrives by river and rain and leaves only by evaporation, which reaches 1,015 millimetres a year from the surface. The Volga, the Ural and the Terek bring about 88% of all river water entering the sea, from the north. The Kura, the Samur, the Sulak and the smaller rivers of the western shore bring about 7%. The level at Baku is therefore set mostly by rain and snow falling over Russia, and the fall between 1929 and 1977 was amplified by reservoirs built on the Volga.

The basin was once open. It connected to the Black Sea through the Manych depression, and a late Miocene uplift closed it; Britannica dates the closure to about 13.8 million years ago in its geology section and to about 11 million in its introduction. The link reopened briefly about 2.6 million years ago. What remains is salt water at about 12.8 parts per thousand on average, with more sulphate and less chloride than the ocean.

Does Azerbaijan have a coast at all

The sources disagree, and the disagreement is about definitions more than about measurement.

Britannica's point is practical: to reach the world's shipping lanes Azerbaijan, like any landlocked state, relies on a neighbour. The Factbook's zero is the same judgement expressed as a number, with the 713 kilometres relegated to a footnote. The two shoreline lengths, 713 and 800 kilometres, are both published and neither source says how it was measured, so both are given here. The Wikipedia figure for the widest stretch of the Azerbaijani section of the sea is 456 kilometres.

The Factbook also lists maritime border disputes with Turkmenistan, Kazakhstan, Iran and Russia. This catalogue records that the disputes exist and takes no position on them.

The shore has been worked for oil for more than two centuries. Baku stands on the southern side of the Absheron Peninsula, around a bay that the islands of the Baku Archipelago shelter from the sea and the peninsula shelters from violent northerly winds. In 1803 two oil wells were sunk in Bibi-Heybat bay, 18 and 30 metres from the shore; a storm destroyed them in 1825. On 24 August 1949 the first exploration well was spudded at Neft Daşları, where the water is 10 to 25 metres deep, and Britannica describes Greater Baku as including an island built on stilts about 100 kilometres out. The northern Caspian usually freezes completely by January, and in exceptionally cold years floating ice drifts south along the western shore as far as Absheron.

How three mountain systems close the central lowland

Britannica divides the territory by height. More than two fifths is lowland, about half lies between 400 and 1,500 metres, and a little more than a tenth rises above 1,500 metres. Wikipedia puts the share covered by the three mountain systems at approximately 40%.

The crest of the Greater Caucasus forms part of the northern boundary, and Bazardüzü stands on it, shared with Russia. The Wikipedia geography article gives its height as 4,466 metres in one paragraph and 4,485 in another; the record and Britannica both use 4,466. Shahdag, at 4,243 metres, is the summit the Factbook lists as lying wholly inside Azerbaijani territory. Deep gorges cut the spurs and ridges on the southern side, and Britannica notes that the range lies in a zone of high seismic activity.

The Lesser Caucasus enters from the south-west as the Shahdag, Murovdag and Zangezur ranges and the Karabakh Upland. Lake Göygöl lies among them at 1,566 metres. The Karabakh Range runs from its crest down to the margin of the Kura lowland, and Britannica traces its vegetation in one descent: steppe on the plain, oak, hornbeam and beech on the lower slopes, then birch and alpine meadow.

The Talysh are three parallel ranges. At their foot the Länkäran Lowland, an extension of the Kura-Aras Lowland, runs along the coast to the Iranian border near Astara.

Elevation changes over short distances everywhere. The shore at 28 metres below sea level and the summit of Bazardüzü are separated by roughly 4,500 metres of relief inside a country of 86,600 square kilometres.

Where Azerbaijan's rivers run and where they stop

Wikipedia counts 8,350 streams, of which only 24 are longer than 100 kilometres, and every one of them drains to the Caspian. Most are not navigable. The hydrography of the whole country belongs to one basin.

The Kura, or Kür, is the spine of it. Wikipedia gives its length as 1,515 kilometres. Its main right-bank tributary, the Aras, forms part of the border with Iran and meets the Kura at the centre of the lowland, a short distance before the joined river builds its delta into the sea. The lowland takes both names. The Shirvan, Mil and Mugan plains are parts of it, on grey soils and saline solonchaks, with solonetz and chestnut soils on the higher ground.

Every large reservoir in the country is on the Kura. The Mingachevir Reservoir, in the west, covers 605 square kilometres by Wikipedia's figure and 606 by Britannica's, with a maximum depth of 75 metres. It generates electricity and feeds the canals. The Upper Karabakh Canal runs 172 kilometres from the Aras to the reservoir, irrigates more than 100,000 hectares, and sends water back into the Aras in dry summers. The Upper Shirvan Canal runs 122 kilometres and irrigates about 100,000 hectares more. Sarysu lake covers 67 square kilometres, about a ninth of the reservoir's surface.

Irrigation is where the water goes. The Factbook put irrigated land at 14,250 square kilometres in 2010, and total freshwater withdrawal at 12.21 cubic kilometres a year, of which 78% went to agriculture, 18% to industry and 4% to households. Renewable water resources stood at 34.68 cubic kilometres in 2011.

How much of this land counts as farmland depends on the definition. The Wikipedia geography article says about 15% is arable in its prose and 22.95% in its Factbook table, an estimate for 2012; the main Wikipedia article gives agricultural land as 54.9%.

How the Caucasus divides Azerbaijani weather

Wikipedia records nine of eleven climate zones as present in the country. The mechanism is the Greater Caucasus, which blocks the cold air masses that arrive from the north and leaves most of the foothills and plains subtropical.

The central and eastern lowland is dry subtropical. Britannica describes a mild winter and a summer of four to five months averaging about 27 °C, with maxima reaching 43 °C. Baku, on the coast, averages 4 °C in January and 25 °C in July.

Rain falls far more heavily in the south than on the peninsula where the capital stands. Länkäran, under the Talysh, receives 1,600 to 1,800 millimetres a year according to Wikipedia, and Britannica gives the humid south-east 1,200 to 1,400 millimetres, most of it in the cold months. Absheron, where Baku is, receives 200 to 350. A daily fall of 334 millimetres was observed at the Bilieser station in 1955.

Nakhchivan has the continental extremes. Its climate is dry continental, with cold winters and dry hot summers at altitudes of 700 to 1,000 metres, and both the absolute minimum of minus 33 °C and the absolute maximum of 46 °C were observed in its districts of Julfa and Ordubad.

Above about 3,000 metres the climate is upland tundra, and frost and heavy snow close the passes at those heights for three or four months each year.

How Khinalig herders use two altitudes in one year

In the Greater Caucasus the height of the land sets the herding year. In 2023 UNESCO inscribed the Cultural Landscape of Khinalig People and "Köç Yolu" Transhumance Route, which joins the high village of Khinalig in the Greater Caucasus to winter pastures in the lowland plains of central Azerbaijan by a seasonal route about 200 kilometres long. Köç Yolu means "Migration Route".

The Khinalig people are semi-nomadic. They spend summer on high pastures called yaylaqs, beside agricultural terraces cut into the mountain, and winter on lowland pastures called qishlaqs. The property includes the route itself and what grew along it: camping sites, springs and wells, irrigation systems, bridges, mausoleums, mosques and cemeteries. UNESCO records that animal husbandry remains the dominant economy, and that a Council of Elders still decides the timing of the migration, the turns for grazing and the shared use of water and pasture. The State owns most of the summer pastures, all the winter pastures and the route.

The two ends of the route sit in different vegetation zones. Britannica sets steppe and semidesert across the lowlands and foothills, beech, oak and pine forest on the mountain slopes, and alpine meadow above them. The animals follow the same ladder. Gazelles, jackals and hyenas are recorded in the lowlands; Caucasian deer, roe deer, wild boar, brown bear, lynx, wisent and chamois in the mountains, with the leopard rare.

Why an old forest survives on the Talysh slopes

The wet south-east holds a relict forest. The Hyrcanian Forests are a belt of broad-leaved forest about 1,000 kilometres long on the southern and south-western shores of the Caspian, running from south-eastern Azerbaijan east into Iran. UNESCO dates their history to 25 to 50 million years ago, when forests of this kind covered most of the northern temperate zone. They retreated during the glaciations of the Quaternary and survived here, cut off between the Caucasus and the semi-desert to the east.

Iran's component parts were inscribed in 2019. In 2023 the site was extended to two component parts in Azerbaijan, Dangyaband and the İstisuchay valley, both inside Hirkan National Park in the Lenkoran and Astara districts. UNESCO records more than 3,200 vascular plant species across the Hyrcanian region, 180 species of forest birds and 58 mammals, including the Persian leopard, the wolf and the brown bear. The oldest trees are 300 to 400 years old and some may be 500. The Talish people who live in the park hold traditional rights to use land in its buffer zone.

The same corner is where rural settlement is thickest: Britannica names Länkäran and Masallı.

For the country as a whole Wikipedia records more than 4,500 species of higher plants, 66% of the species that grow anywhere in the Caucasus, and four ecoregions. Forest covered 1,131,770 hectares in 2020, up from 944,740 hectares in 1990, and 305,570 hectares of the 2020 figure was planted.

What lies under the Absheron Peninsula

The peninsula that carries Baku is dry, low and full of gas. It receives 200 to 350 millimetres of rain a year, and Britannica describes it as the most densely populated part of the country: Greater Baku, divided into 11 districts, takes in almost the entire peninsula, and the city had 2,300,500 inhabitants on 1 January 2021.

Wikipedia states that nearly half the mud volcanoes counted on Earth are in Azerbaijan. The ravines of Gobustan, south-west of Baku, hold mud volcanoes and mineral springs together. The Lökbatan mud cone has been on Azerbaijan's UNESCO Tentative List since 1998. The Gobustan reserve, established in 1966, surrounds a rock-art landscape inscribed in 2007 and carrying more than 6,000 petroglyphs.

The same shallow hydrocarbons reach the surface as fire. Yanar Dag, a hillside near Baku, burns continuously where gas escapes through a thin, porous layer of sandstone, and the shallow oil deposits of Absheron produced natural fires that Zoroastrians treated as sacred. By the 15th century oil for lamps was being taken from surface wells here.

The Wikipedia geography article, drawing on the Factbook, records the other side of that inheritance. Refineries and chemical plants still ran with Soviet-era inefficiency in the early 1990s. Soil on the peninsula and in the cotton lands carries DDT, which was applied through the 1970s and 1980s after it had been banned, and defoliants used in cotton production. Britannica adds that sturgeon stocks in the Caspian are being depleted by pollution.

How Nakhchivan sits apart from the rest of Azerbaijan

The Nakhchivan Autonomous Republic is separated from the main territory by a strip of Armenian land. It borders Armenia, Iran and a short stretch of Türkiye, and it has no shore on the Caspian, so the country's only landlocked part in every definition is its exclave.

The border figures depend on who measured them, and the two published sets differ by 180 kilometres in total.

The Factbook's Iranian border totals 1,132 kilometres against Wikipedia's 756, and neither source explains the gap. The Aras runs along much of it, and the river line was fixed by the Treaty of Turkmenchay in 1828. The Treaty of Kars, signed on 13 October 1921, placed Nakhchivan inside the Azerbaijan SSR.

The exclave sits on the continental side of the country's climate range, at 700 to 1,000 metres, dry and exposed. Julfa and Ordubad, both within it, hold the country's recorded temperature extremes at either end.