Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2019 Feb 6;9(1):1464.
doi: 10.1038/s41598-018-38071-8.

The future of extreme climate in Iran

Saeid Ashraf Vaghefi  1 , Malihe Keykhai  1 , Farshid Jahanbakhshi  1   2 , Jaleh Sheikholeslami  1 , Azadeh Ahmadi  3 , Hong Yang  1   4 , Karim C Abbaspour  5
Affiliations

The future of extreme climate in Iran

Saeid Ashraf Vaghefi et al. Sci Rep. .

Erratum in

Abstract

Iran is experiencing unprecedented climate-related problems such as drying of lakes and rivers, dust storms, record-breaking temperatures, droughts, and floods. Here, we use the ensemble of five high-resolution climate models to project maximum and minimum temperatures and rainfall distribution, calculate occurrences of extreme temperatures (temperatures above and below the historical 95th and 5th percentiles, respectively), analyze compound of precipitation and temperature extremes, and determine flooding frequencies across the country. We found that compared to the period of 1980-2004, in the period of 2025-2049, Iran is likely to experience more extended periods of extreme maximum temperatures in the southern part of the country, more extended periods of dry (for ≥120 days: precipitation <2 mm, Tmax ≥30 °C) as well as wet (for ≤3 days: total precipitation ≥110 mm) conditions, and higher frequency of floods. Overall, the combination of these results projects a climate of extended dry periods interrupted by intermittent heavy rainfalls, which is a recipe for increasing the chances of floods. Without thoughtful adaptability measures, some parts of the country may face limited habitability in the future.

PubMed Disclaimer

Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
Climate map of Iran showing the location of province capitals. This figure is shared under a CCBY 3.0 Share-Alike 3.0 Unported license and no changes were made to the original figure. https://creativecommons.org/licenses/by-sa/3.0/deed.en).
Figure 2
Figure 2
Maximum temperature distribution (°C). (A) illustrates the historical distribution. (B,C) are the differences between averages of historical and the 5 GCM ensembles. Increases of 1.1 to 2.75 °C are seen across the country. (D,E) illustrate the coefficient of variation of the 5 models. The larger the coefficient of variation, the larger the disagreement between the 5 models in each scenario. The models agree more in the central and southeastern parts of Iran across all climate zones.
Figure 3
Figure 3
Extreme hot days for the historical and future periods. (A) is the 95th percentile of historical maximum daily air temperature (Tmax) (°C) (1980–2004). The shown temperatures in (A) have occurred an average of 18 days per year. (B,C) show the number of days per year in the future (2025–2049) where extreme Tmax exceeds the historical value of 18 days. Most regions in Iran may experience longer extreme hot days of up to 2 months per year.
Figure 4
Figure 4
Extreme cold days for the historical and future periods. (A) is the 5th percentile of historical minimum daily air temperature (Tmin) (°C) (1980–2004). The shown temperatures in (A) have occurred an average of 18 days per year. (B,C) show the number of days per year in the future (2025–2049) where extreme Tmin is less than the historical value of 18 days. Most regions in Iran may experience fewer extremely cold days per year.
Figure 5
Figure 5
Rainfall distribution (mm). (A) illustrates the historical average annual rainfall distribution (1980–2004). (B,C) show the differences between the historical rainfall and the averages of the 5 GCMs. (D,E) illustrate the coefficient of variation in the 5-model ensemble. RCP4.5 shows high agreement between the models, while in RCP8.5 models agree more in the northern part of the country.
Figure 6
Figure 6
Compound analysis for dry periods where (for ≥120 consecutive days, rainfall <2 mm day−1 and Tmax ≥30 °C). (A) shows the frequency of such conditions in the past (1980–2004). (B,C) illustrate the difference between the historical and the future (2025–2049) frequencies of the events. Increasing extreme dry periods are predicted for Hot Dry Desert and Hot Semi-Desert areas, while Caspian Sea Mild and Wet zone may experience fewer extreme dry conditions in both scenarios.
Figure 7
Figure 7
Compound analysis for wet periods where (for ≤3 consecutive days: the total amount of rainfall ≥110 mm). (A) shows the frequency of such conditions in the past (1980–2004). (B,C) illustrate the difference between the historical and the future (2025–2049) frequencies of the events. Increasing extreme wet periods are predicted for most regions except the Hot Dry Desert climate zone. Western provinces along Zagros Mountain in Hot Coastal Dry and Cold Mountain zones may be most vulnerable to wet-period conditions.
Figure 8
Figure 8
The top figure shows the 6 regions we considered for analysis in this paper for the period of (2025–2049) (see also Table 1). Blue areas in the map show the basin and red areas show the location of floods. Frequency of floods are shown in: (B) Ajabshir in East Azerbaijan province, (C) Azad-Shar county in Gorgan province, (D) Iran-Shar county in Sistan & Balouchestan province, (E) Firooz-Abad county in Fars province, (F) Abarkouh county in Yazd province, and (G) Bushehr county in Bushehr province. The largest increase is seen in the Lorestan province, which falls in the Mediterranean with Spring Rain climate zone.
See this image and copyright information in PMC

References

    1. Trenberth KE, Fasullo JT, Shepherd TG. Attribution of climate extreme events. Nature Climate Change. 2015;5:725–730.
    1. Trenberth KE, Dai A, Rasmussen RM, Parsons DB. The Changing Character of Precipitation. Bulletin of the American Meteorological Society. 2003;84:1205–1218.
    1. Lenderink G, van Meijgaard E. Increase in hourly precipitation extremes beyond expectations from temperature changes. Nature Geoscience. 2008;1:511–514.
    1. Schuur EAG, et al. Vulnerability of Permafrost Carbon to Climate Change: Implications for the Global Carbon Cycle. BioScience. 2008;58:701–714.
    1. Vuille M, et al. Climate change and tropical Andean glaciers: Past, present and future. Earth-Science Reviews. 2008;89:79–96.

LinkOut - more resources