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Ledger 1 : 30 — For every dollar the world invests in protecting or restoring nature, thirty dollars are spent on activities that degrade it. (UNEP, State of Finance for Nature 2026)
Cases / Water use · Caspian Sea (Azerbaijan, Iran, Kazakhstan, Russia, Turkmenistan) · 2003–2025

Tehran Convention, its protocols and the Caspian states' declarations on the water level decline (2003–2025)

Short record: the main facts, with sources. A full case file has not been prepared.

Nature's voice · report
Things were done in my name here. No one has measured what reached me.
Did nature suffer? Not measured. Accounts differ ↓
Details not on record: 2 none on record · 1 insufficient · 2 not measured · 2 disputed See the gaps
Accounts of the harm differ
Whether cooperation among the Caspian states is adequate to the level decline
  • Government and regulators Ministers and Senior Officials of the five Caspian states (2024): Stress the urgent need for joint action and reaffirm collective responsibility; aim to establish a working group. Tehran Convention Secretariat
  • Researchers Court et al. (2025): The states have often prioritised national economic and political interests over transboundary cooperation; adapting requires a level of transboundary political cooperation beyond that achieved to date. University of Leeds / White Rose Research Online
  • Researchers Prange, Wilke and Wesselingh (2020): Governance for Caspian Sea-wide adaptation to the level decline was lacking; the Caspian Environment Programme assumed in 2011 only slight fluctuation. University of Bremen (author copy)

The five Caspian states adopted the Tehran Convention in 2003 (in force 12 August 2006) and four protocols between 2011 and 2018. On 18 November 2024 and 17 November 2025 their ministers adopted declarations on the water level decline, with an aim to form a working group and a 2025–2035 action plan in preparation; no amounts are stated, and Court et al. (2025) wrote that the states have often prioritised national interests over transboundary cooperation.

4 (a fifth, on monitoring, under negotiation)Protocols adopted under the Tehran Convention by 2018
Tehran Convention Secretariat protocols page; no amounts of money are stated in the convention, protocols or declarations reviewed.

Status As of November 2025: two protocols in force, a working group aimed at in 2024 and an action plan for 2025–2035 in preparation; no amounts or measured effects are on record.

What?
The five Caspian states adopted the Tehran Convention, four protocols and, in 2024 and 2025, declarations on the water level decline with an aim to form a working group and an action plan for 2025–2035. Tehran Convention Secretariat
Where?
Caspian Sea region; declarations adopted in Baku (COP29) and Belém (COP30); convention signed in Tehran. Tehran Convention Secretariat
When?
Convention signed 2003, in force 2006; protocols 2011–2018; declarations 18 November 2024 and 17 November 2025. Tehran Convention Secretariat
Who?
Gained
None on record
Lost
None on record
Harmed
Why?
The states acknowledged a long-standing and alarming trend in the level decline and its effects on ecosystems, biodiversity, coastal communities, fisheries, navigation, tourism and infrastructure. Tehran Convention Secretariat
How?
Framework convention with protocols, ministerial declarations at COP29 and COP30, a proposed working group and a draft 2025–2035 action plan; support from UN-system bodies sought. Tehran Convention Secretariat
6 of 6 questions (what, who, where, when, why, how) have an answer on record

What happened

The record, in order.

The Framework Convention for the Protection of the Marine Environment of the Caspian Sea (Tehran Convention) was signed in Tehran on 4 November 2003, according to the 2024 declaration, and entered into force on 12 August 2006, according to the Secretariat's page; its parties are Azerbaijan, Iran, Kazakhstan, Russia and Turkmenistan. The Secretariat lists four protocols: the Aktau Protocol on oil pollution preparedness and response (adopted 12 August 2011, in force 25 July 2016), the Moscow Protocol on land-based sources (adopted 12 December 2012; Kaspika reported it entered into force on 13 November 2023, the second protocol in force), the Ashgabat Protocol on biodiversity (adopted 30 May 2014) and the EIA Protocol on transboundary environmental impact assessment (adopted 20 July 2018; its ratification table shows all five states ratified, Iran on 30 July 2025). A fifth protocol on monitoring, assessment and information exchange was listed as under negotiation. The Secretariat page does not state entry-into-force dates for the Ashgabat and EIA protocols.

On the water level, Prange, Wilke and Wesselingh wrote in December 2020 that the intergovernmental Caspian Environment Programme had "assumed in 2011 that the Caspian sea level would fluctuate only slightly in the future" and that governance for Caspian-wide adaptation was lacking. On 18 November 2024, at COP29 in Baku, ministers and senior officials of the five states adopted a declaration that recognised the 2014 Astrakhan agreement on hydrometeorology, stated that the decline "is driven by a complex combination of climatic, hydrological, and anthropogenic factors", recorded an aim to establish a working group of the states, on the initiative of Azerbaijan's President, to identify the causes and develop measures to prevent further shallowing, and called on UN-system bodies for technical and financial support without naming an amount. At COP30 in Belém on 17 November 2025 a high-level event organised by Azerbaijan's ministry and the Secretariat ended with a further declaration that builds on the Baku text and welcomes preparation of a Caspian Sea Level Fluctuations Action Plan 2025–2035.

Court et al. (Communications Earth & Environment, 2025) wrote that since the early 1990s the Caspian states have made progress on legal frameworks under the Tehran Convention but "have often prioritised national economic and political interests over transboundary cooperation", and that adapting to the decline requires "a level of transboundary political cooperation beyond that achieved to date". Kazakhstan's Deputy Minister Mansur Oshurbayev presented the Interstate Programme and the draft Action Plan at a COP30 side event, according to Inbusiness.kz, with no financial figures. No output of the working group was found in the sources reviewed.

  1. 2003Tehran Convention signed (4 November)
  2. 2006Convention enters into force (12 August)
  3. 2011Aktau Protocol adopted (12 August); in force 25 July 2016 per the Secretariat (COP6 text gives 26 June 2016)
  4. 2012Moscow Protocol adopted (12 December); in force 13 November 2023
  5. 2014Ashgabat Protocol adopted (30 May); hydrometeorology agreement signed in Astrakhan (29 September)
  6. 2018EIA Protocol adopted in Moscow (20 July)
  7. 2024Baku declaration on the Caspian water level decline (18 November, COP29)
  8. 2025Iran ratifies the EIA Protocol (30 July), per the Secretariat table
  9. 2025Declaration adopted at a COP30 event in Belém (17 November)

What was said

Claims, in the words of those who made them.

“The Sides acknowledge the long-standing and alarming trend in the Caspian Sea level decline.”

“have often prioritised national economic and political interests over transboundary cooperation”

Where accounts differ

Each party's account, side by side, with its source. The record does not settle these points; it shows them.

Whether cooperation among the Caspian states is adequate to the level decline
Government and regulators
Ministers and Senior Officials of the five Caspian states (2024)

Stress the urgent need for joint action and reaffirm collective responsibility; aim to establish a working group.

Tehran Convention Secretariat
Researchers
Court et al. (2025)

The states have often prioritised national economic and political interests over transboundary cooperation; adapting requires a level of transboundary political cooperation beyond that achieved to date.

University of Leeds / White Rose Research Online
Researchers
Prange, Wilke and Wesselingh (2020)

Governance for Caspian Sea-wide adaptation to the level decline was lacking; the Caspian Environment Programme assumed in 2011 only slight fluctuation.

University of Bremen (author copy)

How it looked

What was shown, beside what was recorded.

Shown

  • The Tehran Convention described as the foundation of collaborative efforts to protect the marine environment of the Caspian Sea and as the key regional legal framework.
    Ministers and Senior Officials of the five Caspian states, Baku Declaration · Tehran Convention Secretariat

Recorded

  • Convention in force 12 August 2006; Aktau Protocol in force 25 July 2016; Moscow Protocol in force 13 November 2023.
    Kaspika Caspian Seals Conservation Agency
  • A 2019 depositary note (Iran) records the Aktau Protocol in force on 25 July 2016 and the Ashgabat Protocol ratified then only by Turkmenistan; the COP6 ministerial statement of 21 October 2022 gives 26 June 2016 for the Aktau Protocol and records ratifications of the Ashgabat Protocol by Turkmenistan, Iran and Kazakhstan.
    Tehran Convention Secretariat
  • COP6 (Baku, 19–21 October 2022) noted progress in negotiating a protocol on monitoring, assessment and information exchange.
    Tehran Convention Secretariat
  • Deputy Minister Mansur Oshurbayev presented the Interstate Programme and the draft Action Plan 2025–2035 at a COP30 side event; the report gives no financial figures.
    Inbusiness.kz
  • EIA Protocol ratified by all five states by 30 July 2025 per the Secretariat table; entry-into-force date not stated on the page.
    Tehran Convention Secretariat
  • The Baku Declaration (18 November 2024) and the Belém declaration (17 November 2025) state no amounts of money.
    Tehran Convention Secretariat
  • No output of the working group announced in 2024 was found in the sources reviewed.

In nature's name

What was promised in nature's name, the money that moved, and what was measured.

Promised

  • “On the initiative of the President of the Republic of Azerbaijan the Sides aim to establish a working group of Caspian littoral states to identify the causes of this decline and to develop measures to prevent further shallowing.” — Ministers and Senior Officials of the five Caspian states, Baku Declaration (18 November 2024) Tehran Convention Secretariat

Benefit to nature: what was measured

Not measured

No source reviewed measures an effect of the convention, its protocols or the declarations on the Caspian level or ecosystems, and the level kept falling after the declarations were adopted. The declarations are the states' own statements.

Protocols in force
2 of 4 adopted
Aktau Protocol (2016) and Moscow Protocol (2023) Kaspika Caspian Seals Conservation Agency
EIA Protocol ratifications
all five states by 30 July 2025
Entry-into-force date not stated on the Secretariat page Tehran Convention Secretariat

Operation Ongoing · Action Plan 2025–2035 in preparation as of November 2025; working group aimed at in the 2024 declaration. Tehran Convention Secretariat

Findings on record

  • Own admission Ministers and Senior Officials of the five Caspian states (2024-11-18) · Baku Declaration on Strengthening Cooperation to Address the Caspian Sea Water Level Decline: “The Sides acknowledge the long-standing and alarming trend in the Caspian Sea level decline.” Tehran Convention Secretariat
  • Peer-reviewed study Court et al., Communications Earth & Environment (2025-04-10) · Communications Earth & Environment 6:261: “have often prioritised national economic and political interests over transboundary cooperation” University of Leeds / White Rose Research Online
  • Peer-reviewed study Prange, Wilke and Wesselingh, Communications Earth & Environment (2020-12-23) · The other side of sea level change: “assumed in 2011 that the Caspian sea level would fluctuate only slightly in the future” University of Bremen (author copy)

Who gained

Money that reached nature, beside money that stayed elsewhere.

Reached nature or the ground

Not published
No figure published.

Gained elsewhere

Not totalled
Currency: · Window: . All figures cover the same period. * Estimate built from cited figures.

Responses on record

  • Ministers and senior officials of the five Caspian states (18 November 2024; 17 November 2025): Adopted declarations on 18 November 2024 and 17 November 2025 reaffirming the Tehran Convention and aiming at a working group on the causes of the decline. · Tehran Convention Secretariat

In court and with insurers

Every proceeding and every insurer decision on record.

Lawsuits and rulings

No court case on record. No court has ruled on this case.

Insurers

No insurer decision on record.

What nature saw

Outcomes measured on the ground, and nature's note.

Nature's report opens this page. Below: further outcomes measured on the ground.

Protocols in force
2 of 4 adopted (Aktau 2016, Moscow 2023)
Kaspika, November 2023; Secretariat pages
Caspian level while the declarations were adopted
approximately 75 cm fall in 2022–2024
CASPCOM as cited by Court et al. (2025)

What we don't know

Undisclosed, unproven, untried: recorded as data.
Own admissionPeer-reviewed findingBenefit not measured

Nature

  • Not measured Harm to nature: The record holds no measurement of harm to nature.
  • Disputed Whether cooperation among the Caspian states is adequate to the level decline

Record

  • None on record Not stated: any budget, fund or amount for the Tehran Convention's work on the water level; the declarations call for technical and financial support without an amount.
  • None on record None on record in the sources reviewed: the working group's membership, meetings or results, and the text of the 17 November 2025 declaration.
  • Insufficient Not stated: entry-into-force dates of the Ashgabat and EIA protocols on the Secretariat page; the ratification table for the Ashgabat Protocol is incomplete.
  • Not measured Not measured: any effect of the convention, protocols or declarations on the Caspian Sea level; no evaluation was found.
  • Disputed Disputed: the entry-into-force date of the Aktau Protocol, 25 July 2016 (Secretariat pages and a 2019 depositary note) against 26 June 2016 (COP6 ministerial statement, 2022).

Did the harm stop?

The sources reviewed give no evidence that the decline has stopped; the declarations were adopted while the level kept falling.

Who paid?

No source reviewed states who pays for the working group or the action plan; the 2024 declaration calls on UN-system bodies for technical and financial support.

Sources

Voices on record: — Company or project— Government and regulators— Courts✓ Press and investigations✓ Communities and civil society✓ Researchers✓ International bodies

Press and investigations

Communities and civil society

  1. Moscow Protocol to the Tehran Convention Entered into Force
    Kaspika Caspian Seals Conservation Agency · 2023-11-13

Researchers

International bodies

  2. Tehran Convention (about the convention)
    Tehran Convention Secretariat ·

Connected cases

Related matters, and cases linked to this one through the same organisations, with the role each played in both.
Terms used on this page

Law and courts

Trustees (natural resource)
Government agencies that act on behalf of the public to recover and spend damages for harm to natural resources.
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