The future of droughts in Iran according to CMIP6 projections

Abstract

Anthropogenic climate change is exerting immense pressure on water resources in Iran. This study investigates future precipitation and meteorological droughts across the country considering performances of 41 General Circulation Models (GCMs). The findings indicate a significant increase in Long-term Average Annual Precipitation (LAAP) across Iran with an overall north-to-south increasing gradient, particularly in areas prone to extreme events. However, focusing solely on LAAP is misleading. Projected precipitation reveals substantial inter-annual variability, impacting both the severity and duration of meteorological droughts. For instance, 100-year return period droughts are expected to intensify in severity (SSP1-2.6: 4-91%, SSP8-5.5: 46-204%) and duration (SSP1-2.6: 19-76%, SSP8-5.5: 40-127%) across most regions, except the Persian Gulf coastal zone, where droughts may become less severe (SSP1-2.6: 23%, SSP8-5.5: 23%) and shorter in duration (SSP1-2.6: 27%, SSP8-5.5: 10%). Additionally, bivariate frequency analysis suggests that major droughts could become significantly more frequent in the future.

Keywords:

• climate change
• Earth system models
• precipitation indices
• extreme events

Disclaimer

As a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also.

Acknowledgments

We express our thanks to the data providers.

Disclosure Statement

There are no real or perceived financial conflicts of interests for the authors.

Data Availability Statement

All data described in the main text are available. The observed dataset of synoptic stations is available from Iran’s meteorological organization website (https://data.irimo.ir/). All climate model simulations are from CMIP6 and are publicly available, and are hosted on various servers including the Copernicus datasets (https://cds.climate.copernicus.eu/cdsapp#!/dataset/projections-cmip6?tab=form).

Additional information

Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.