Why is Istanbul flooding and is extreme rainfall becoming more common?

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1. 1

   Exploring Spatio-Temporal Precipitation Variations in Istanbul: Trends and Patterns from Five Stations across Two Continents

   Atmosphere (Kara et al.)Published Apr 28, 2024Checked Oct 15, 2026

   “Apart from dry conditions, “moderate” precipitation is the most frequently observed type across all stations. However, “extreme” events occur significantly more often (6%) during the warm season compared to the cold season (2%). Long-term anomalies in terms of annual precipitation totals have shown similarity between stations in the north and south, which has also been observed in longitudinally close stations. Despite the longer duration of the cold season and stronger temperature gradients, extreme rainfall events are more frequent during the warm season, primarily due to thunderstorm activity. While trend analyses revealed limited significant trends in precipitation intensity categories and extreme indices, the study highlights the importance of comprehensive examination of extreme rainfall events on both station-based and regional levels, shedding light on potential implications for regional climate change. Lastly, during the cold season, the inter-station correlation in terms of annual total precipitation amounts has been considerably higher compared to the warm season.”

2. 2

   Long-Term Variations of Temperature and Precipitation in the Megacity of Istanbul for the Development of Adaptation Strategies to Climate Change

   Advances in Meteorology (Toros et al.)Published Jan 1, 2017Checked Oct 15, 2026

   “A notable increase in temperatures has started after the 1940s, which is in parallel with the beginning of industrialization era in Istanbul. This warming is associated with an extensive population growth and accompanied the decrease in vegetation cover. Increasing in minimum series of temperature is more evident than maximum values and the rising rate of temperature values has been more pronounced during recent decades. The first significant upward trend in precipitation series has periodically started in 1920s, while there has been a stable trend from 2001 till today. The daily average of rainfall amount increased with a mean value of 58 mm during the total study period. Rising rate of daily maximum precipitation has been more evident in the last 3 decades, which is shown by the increased frequency of heavy rainfall. In this regard, both of the temperature and precipitation series had higher mean values (13.9°C and 878 mm) for the final period (1965–2016) compared to the mean values (13.6°C and 799 mm) belonging to the first period (1912–1964).”

3. 3

   Analysis of the occupancy rates of İstanbul Dams and optimum water management strategies against climate change effects.

   PeerJ (Akiner)Published Sep 16, 2025Checked Oct 15, 2026

   “The inequitable distribution of water resources was measured using the Gini coefficient, and a value of 0.65 indicated a striking imbalance in the current system. Geographical analysis revealed that dams located in the north have stable occupancy rates, while dams closer to the city center and under urban pressure exhibit erratic and underperforming conditions. Time series analyses revealed distinct seasonal fluctuations across dams. These patterns reflect the dams' responses to different climatic and spatial conditions, and no direct assessment has been made of factors such as climate change. The study revealed that the occupancy fluctuations and inequalities exhibited by the İstanbul dam system over time vary significantly depending on the dam's location, basin characteristics, and operational conditions. This suggests that the current dam structure is far from a spatially homogeneous entity and that management approaches should consider this diversity. This study aims to contribute to developing sustainable and climate-adapted water policies for megacities like İstanbul through a data-driven governance approach.”

4. 4

   Climate Change Projections for Turkey: Three Models and Two Scenarios

   Turkish Journal of Water Science and Management (Demircan et al.)Published Jan 31, 2017Checked Oct 15, 2026

   ““A scenario is a coherent, internally consistent and plausible description of a possible future state of the world”. The name “representative concentration pathways – RCP’s” are referred to as pathways in order to emphasize that their primary purpose is to provide time-dependent projections of atmospheric greenhouse gasses (GHGs) concentrations. In this study, it is intended to reveal the possibilities of future climate change for Turkey and its surrounding region. HadGEM2-ES, MPI-ESM-MR and GFDL-ESM2M Global Circulation Models’ RCP4.5 and RCP8.5 scenarios outputs were used in the study. Temperature and precipitation projections were produced from these outputs, based on domain with 20 km resolution, covering period between 2016 and 2099 and using regional climate model RegCM4.3.4 and with dynamic downscaling method. According to the models results, it is expected that an increase between 1°C and 6°C in mean temperatures of Turkey. In generally precipitation amount shows a decreasing except winter season. Although there is no regular decreasing or increasing trend throughout projection period, it attracts more attention irregularity of precipitation regime.”

5. 5

   The effects of climate change on historical and future extreme rainfall in Antalya, Turkey

   Hydrological Sciences Journal (Yilmaz)Published Jul 22, 2014Checked Oct 15, 2026

   “There is increasing concern that flood risk will be exacerbated in Antalya, Turkey as a result of global-warming-induced, more frequent and intensive, heavy rainfalls. In this paper, first, trends in extreme rainfall indices in the Antalya region were analysed using daily rainfall data. All stations in the study area showed statistically significant increasing trends for at least one extreme rainfall index. Extreme rainfall datasets for current (1970–1989) and future periods (2080–2099) were then constructed for frequency analysis using the peaks-over-threshold method. Frequency analysis of extreme rainfall data was performed using generalized Pareto distribution for current and future periods in order to estimate rainfall intensities for various return periods. Rainfall intensities for the future period were found to increase by up to 23% more than the current period. This study contributed to better understanding of climate change effects on extreme rainfalls in Antalya, Turkey.”