Abstract
We analyse an ensemble of statistically downscaled Global Climate Models (GCMs) to investigate future water availability in the Upper Indus Basin (UIB) of Pakistan for the time horizons when the global and/or regional warming levels cross Paris Agreement (PA) targets. The GCMs data is obtained from the 5th Phase of Coupled Model Inter-Comparison Project under two Representative Concentration Pathways (RCP4.5 and RCP8.5). Based on the five best performing GCMs, we note that global 1.5 °C and 2.0 °C warming thresholds are projected in 2026 and 2047 under RCP4.5 and 2022 and 3036 under RCP8.5 respectively while these thresholds are reached much earlier over Pakistan i.e. 2016 and 2030 under RCP4.5 and 2012 and 2025 under RCP8.5 respectively. Interestingly, the GCMs with the earliest emergence at the global scale are not necessarily the ones with the earliest emergence over Pakistan, highlighting spatial non-linearity in GCMs response. The emergence of 2.0 °C warming at global scale across 5 GCMs ranges from 2031 (CCSM4) to 2049 (NorESM) under RCP8.5. Precipitation generally exhibits a progressive increasing trend with stronger changes at higher warming or radiative forcing levels. Hydrological simulations representing the historical, 1.5 °C and 2.0 °C global and region warming time horizons indicate a robust but seasonally varying increase in the inflows. The highest inflows in the baseline and future are witnessed in July. However, the highest future increase in inflows is projected in October under RCP4.5 (37.99% and 65.11% at 1.5 °C and 2.0 °C) and in April under RCP8.5 (37% and 62.05% at 1.5 °C and 2.0 °C). These hydrological changes are driven by increases in the snow and glacial melt contribution, which are more pronounced at 2.0 °C warming level. These findings should help for effective water management in Pakistan over the coming decades.
| Original language | English |
|---|---|
| Article number | 147759 |
| Journal | Science of the Total Environment |
| Volume | 788 |
| DOIs | |
| State | Published - Sep 20 2021 |
Funding
This work is supported by the project of Asia-Pacific Network for Global Change Research (APN) titled “Towards robust projections of climate extremes and adaptation plans over South Asia: CRRP2018-04MY-Ali” and Hydro-geochemistry Laboratory, Department of Environmental Sciences, Quaid-i-Azam University, Islamabad. We also acknowledge the support of Dr. Hyung-Il Eum, Environmental Monitoring and Science Division Canada, in downscaling process. M. A. was supported by the National Climate-Computing Research Center, which is located within the National Center for Computational Sciences at the ORNL and supported under a Strategic Partnership Project, 2316-T849-08, between DOE and NOAA. This manuscript has been co-authored by employees of Oak Ridge National Laboratory, managed by UT Battelle, LLC, under contract DE-AC05-00OR22725 with the U.S. Department of Energy. The publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). This work is supported by the project of Asia-Pacific Network for Global Change Research (APN) titled “Towards robust projections of climate extremes and adaptation plans over South Asia: CRRP2018-04MY-Ali” and Hydro-geochemistry Laboratory, Department of Environmental Sciences, Quaid-i-Azam University , Islamabad. We also acknowledge the support of Dr. Hyung-Il Eum, Environmental Monitoring and Science Division Canada, in downscaling process. M. A. was supported by the National Climate-Computing Research Center , which is located within the National Center for Computational Sciences at the ORNL and supported under a Strategic Partnership Project, 2316-T849-08 , between DOE and NOAA. This manuscript has been co-authored by employees of Oak Ridge National Laboratory, managed by UT Battelle, LLC, under contract DE-AC05-00OR22725 with the U.S. Department of Energy. The publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ).
Keywords
- Global Climate Models
- Hydrological modeling
- Paris Agreement
- Upper Indus Basin
- Water availability