What SSP Global Climate Change Scenario is the Caspian Sea Region Following? Part 1: Air Temperature Analysis

Aleksander V. Bocharov; Andrey G. Kostianoy; Sergey Lebedev; Lyudmila I. Kolomeec; Pavel N. Kravchenko

doi:10.2205/2025ES001075

VAK Russia 1.6 UDC 55 CSCSTI 37.00 Russian Classification of Professions by Education 05.00.00 Russian Library and Bibliographic Classification 26 Russian Trade and Bibliographic Classification 63 BISAC SCI CSCSTI 38.00

8 more Collapse

WHAT SSP GLOBAL CLIMATE CHANGE SCENARIO IS THE CASPIAN SEA REGION FOLLOWING? PART 1: AIR TEMPERATURE ANALYSIS What SSP Global Climate Change Scenario is the Caspian Sea Region Following? Part 1: Air Temperature Analysis

АА Аа

Published in Russian Journal of Earth Sciences · Volume 25, Issue 6 · ELocator: ES6006 · Rubric: Special Issue: “Advances in Environmental Studies, from the VIII International Scientific and Practical Conference ‘Fundamental and Applied Aspects of Geology, Geophysics and Geoecology Using Modern Information Technologies’ ”

DOI: https://doi.org/10.2205/2025ES001075 · EDN: XXXHMN

Received: 10.09.2025 Accepted: 10.11.2025 Published: 10.12.2025 Language of publication: ENG

Authors

Aleksander V. Bocharov

ORCID

Andrey G. Kostianoy

ORCID

Sergey Lebedev

ORCID Scopus SPIN

Lyudmila I. Kolomeec

ORCID

et al.

Pavel N. Kravchenko

ORCID

Aleksander V. Bocharov

Tver Stare University Tver

Shirshov Institute of Oceanology, Russian Academy of Sciences Russian Federation

Geophysical Center, Russian Academy of Sciences Russian Federation

Maykop State Technological University Russian Federation

ORCID

Andrey G. Kostianoy

P.P.Shirshov Institute of Oceanology of the Russian Academy of Science Moscow

Geophysical Center, Russian Academy of Sciences Russian Federation

Maykop State Technological University Russian Federation

S. Yu. Witte Moscow University Russian Federation

ORCID

Sergey Lebedev

Academic degree: doctor of physical and mathematical sciences

Science rang: professor

Geophysical Center of Russian Academy of Sciences Russian Federation

Maikop State Technological University Maikop

National Research University of Electronic Technology Moscow

Shirshov Institute of Oceanology, Russian Academy of Sciences Russian Federation

ORCID Scopus SPIN

Lyudmila I. Kolomeec

Institute of Radar Meteorology Russian Federation

Saint Petersburg State University Russian Federation

Russian State Hydrometeorological University Russian Federation

The Voeikov Main Geophysical Observatory Russian Federation

ORCID

Pavel N. Kravchenko

Shirshov Institute of Oceanology, Russian Academy of Sciences Russian Federation

S. Yu. Witte Moscow University Russian Federation

ORCID

ABSTRACT

The paper’s aim is to study the impact of global and regional climate change on the state of the Caspian Sea. Determining the most probable climate scenarios for different coastal zones is an important step in predicting the change in the Caspian Sea level and developing plans for the region's adaptation to future climate change. This study assessed the Shared Socioeconomic Pathways (SSP) climate scenarios obtained using the CMIP6 global climate models (GCMs) by comparing the simulated data with actual measurements of surface air temperature (tas) at 72 weather stations in a 200-km buffer zone of the Caspian Sea. The analysis covered the period from 2015 to 2025. The research focuses on air temperature as the most reliably predicted parameter. The study used four main SSP scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5) calculated based on six climate models (AWI-CM-1-1-MR, CMCC-CM2-SR5, CNRM-CM6-1-HR, EC-Earth3, MPI-ESM1-2-HR and INM-CM5-0). The quality of the modeling was assessed using a number of indicators: mean error (ME), correlation coefficient (r), coefficient of determination (𝑅2), root mean square error (RMSE), Nash–Sutcliffe efficiency (NSE) and Kling–Gupta efficiency (KGE). The results showed a high degree of agreement between the models and observations for temperature, with correlation coefficients ranging from 0.85 to 0.96. However, systematic biases are observed (from −12.9 to +6.5 °C), with modeled data generally overestimated for lowland areas and underestimated for mountainous areas. The choice of the “best” SSP scenario varies depending on the metric used: based on RMSE and NSE, the most consistent with the actual mean temperature data (2015–2025) is the SSP5-8.5 scenario, while based on KGE, the SSP3-7.0 scenario better reproduces the variability and structure of the time series.

KEYWORDS

Caspian Sea, air temperature, weather stations, SSP, CMIP6, global climate models

Funding

The research was done with the support of the RSF Grant 23-77- 00027 “Investigation of the climate variability of thermo-hydrodynamic regime of the Caspian Sea based on remote sensing data”, https://rscf.ru/en/project/23-77-00027/.

Text

Text (PDF)

Read Download

1. Court R., Lattuada M., Shumeyko N., et al. Rapid decline of Caspian Sea level threatens ecosystem integrity, biodiversity protection, and human infrastructure // Communications Earth & Environment. — 2025. — Vol. 6, no. 1. — https://doi.org/10.1038/s43247-025-02212-5.

2. Eyring V., Bony S., Meehl G. A., et al. Overview of the Coupled Model Intercomparison Project Phase 6 (CMIP6) experimental design and organization // Geoscientific Model Development. — 2016. — Vol. 9, no. 5. — P. 1937– 1958. — https://doi.org/10.5194/gmd-9-1937-2016.

3. Gupta H. V., Kling H., Yilmaz K. K., et al. Decomposition of the mean squared error and NSE performance criteria: Implications for improving hydrological modelling // Journal of Hydrology. — 2009. — Vol. 377, no. 1/2. — P. 80– 91. — https://doi.org/10.1016/j.jhydrol.2009.08.003.

4. Hoseini S. M., Soltanpour M. and Zolfaghari M. R. Projected changes in Caspian sea level under CMIP6 climate change scenarios: probabilistic and deterministic approaches // Climate Dynamics. — 2025. — Vol. 63, no. 1. — https://doi.org/10.1007/s00382-024-07548-w.

5. IPCC. Climate Change 2023: Synthesis Report. Contribution of Working Groups I, II and III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, H. Lee and J. Romero (eds.)]. IPCC, Geneva, Switzerland. / ed. by H. Lee and J. Romero. — Geneva, Switzerland : Intergovernmental Panel on Climate Change (IPCC), 2023. — https://doi.org/10.59327/ipcc/ar6-9789291691647.

6. Kostianoy A. G., Malinin V. N. and Frolov A. V. Main Reasons for Changes in the Caspian Sea Level // Izvestiya, Atmospheric and Oceanic Physics. — 2025. — Vol. 61, S1. — S101–S115. — https://doi.org/10.1134/s0001433825701178.

7. Kostianoy A. G. and Pesic V. Advances in Environmental Monitoring of the Caspian Sea // Ecologica Montenegrina. — 2024. — Vol. 76. — P. 201–210. — https://doi.org/10.37828/em.2024.76.12.

8. Lavrova O. Yu., Ginzburg A. I., Kostianoy A. G., et al. Interannual variability of ice cover in the Caspian Sea // Journal of Hydrology X. — 2022. — Vol. 17. — P. 100145. — https://doi.org/10.1016/j.hydroa.2022.100145.

9. Nash J. E. and Sutcliffe J. V. River flow forecasting through conceptual models part I - A discussion of principles // Journal of Hydrology. — 1970. — Vol. 10, no. 3. — P. 282–290. — https://doi.org/10.1016/0022-1694(70)90255-6.

10. National Centers for Environmental Information (NCEI). — 2024. — URL: https://www.ncei.noaa.gov/ (visited on 08/26/2025).

11. O’Neill B. C., Tebaldi C., Vuuren D. P. van, et al. The Scenario Model Intercomparison Project (ScenarioMIP) for CMIP6 // Geoscientific Model Development. — 2016. — Vol. 9, no. 9. — P. 3461–3482. — https://doi.org/10.5194/gmd-9-3461-2016.

12. Raspisaniye Pogodi Ltd. Weather for 241 countries of the world. — 2004. — URL: https://rp5.ru/ (visited on 08/26/2025).

13. Riahi K., Vuuren D. P. van, Kriegler E., et al. The Shared Socioeconomic Pathways and their energy, land use, and greenhouse gas emissions implications: An overview // Global Environmental Change. — 2017. — Vol. 42. — P. 153– 168. — https://doi.org/10.1016/j.gloenvcha.2016.05.009.

14. Semenov S. M. and Gladilshchikova A. A. Scenarios of anthropogenic changes in the climate system in the 21st century // Fundamental and Applied Climatology. — 2022. — Vol. 8, no. 1. — P. 75–106. — https://doi.org/10.21513/2410-8758-2022-1-75-106. — (In Russian).

15. VNIIGMI-WDC. Main meteorological parameters (urgent data). — 2024. — URL: http://meteo.ru/data/basic-parameters/ (visited on 08/26/2025).

16. Zonn I. S., Kostianoy A. G., Kosarev A. N., et al. The Caspian Sea Encyclopedia. — Berlin, Heidelberg, New York : Springer Berlin Heidelberg, 2010. — https://doi.org/10.1007/978-3-642-11524-0.

This work is licensed under Creative Commons Attribution 4.0 International

PDF JATS XML

Chief Editor

Alexei Gvishiani

rjes@wdcb.ru

Deputy Chief Editor

Boris Dzeboev

rjes@wdcb.ru

Managing Editor

Ernest Kedrov

ernest.kedrov@ya.ru

Responsible Secretary

Natalya Kareva

rjes@wdcb.ru

2212

downloads

This work is licensed under Creative Commons Attribution 4.0 International Creative Commons

GOST

Bocharov A. V., Kostianoy A. G., Lebedev S. A., Kolomeec L. I., Kravchenko P. N. What SSP Global Climate Change Scenario is the Caspian Sea Region Following? Part 1: Air Temperature Analysis // Russian Journal of Earth Sciences. 2025. no. 6. ES6006. DOI: https://doi.org/10.2205/2025ES001075. EDN: XXXHMN. (Date of access 20.10.2026).

MLA

Aleksander V. Bocharov, Kostianoy A. G., Lebedev S. A., Kolomeec L. I., Kravchenko P. N.. "What SSP Global Climate Change Scenario is the Caspian Sea Region Following? Part 1: Air Temperature Analysis." Russian Journal of Earth Sciences 25.6 (2025): ES6006. DOI: https://doi.org/10.2205/2025ES001075. EDN: XXXHMN.

APA

Bocharov A. V., Kostianoy A. G., Lebedev S. A., Kolomeec L. I., Kravchenko P. N. (2025). What SSP Global Climate Change Scenario is the Caspian Sea Region Following? Part 1: Air Temperature Analysis. Russian Journal of Earth Sciences, 25(6), ES6006. https://doi.org/10.2205/2025ES001075 EDN: XXXHMN.

Chicago

Aleksander V. Bocharov, Kostianoy A. G., Lebedev S. A., Kolomeec L. I., Kravchenko P. N.. "What SSP Global Climate Change Scenario is the Caspian Sea Region Following? Part 1: Air Temperature Analysis." Russian Journal of Earth Sciences 25, no. 6 (2025): ES6006. https://doi.org/10.2205/2025ES001075. EDN: XXXHMN.

WIKI

{{cite journal | author = Bocharov A. V., Kostianoy A. G., Lebedev S. A., Kolomeec L. I., Kravchenko P. N. | title = What SSP Global Climate Change Scenario is the Caspian Sea Region Following? Part 1: Air Temperature Analysis | journal = Russian Journal of Earth Sciences | year = 2025 | volume = 25 | issue = 6 | pages = ES6006 | doi = 10.2205/2025ES001075 }} EDN: XXXHMN

Copy

Export: BibTeX EndNote RefMan RusMARC

WHAT SSP GLOBAL CLIMATE CHANGE SCENARIO IS THE CASPIAN SEA REGION FOLLOWING? PART 1: AIR TEMPERATURE ANALYSIS What SSP Global Climate Change Scenario is the Caspian Sea Region Following? Part 1: Air Temperature Analysis

Confirmation