The natural system has long been in balance, but due to modern human activity and climate change, the system is no longer in balance.
A research team looked into how bias-corrected regional climate projections affected the seasonal variability of streamflow over Pakistan. The natural system has long been in balance, but due to modern human activity and climate change, the system is no longer in balance.
The disruption makes it more challenging for humans to predict the future because they depend on nature to survive. Additionally, developing nations are more susceptible to the social and economic harm brought on by climate change because they are less aware of it and have not made adequate preparations for it.
To better understand seasonal changes in the streamflow regime in Pakistan’s four main rivers in the middle and later decades of the twenty-first century, a research team from POSTECH recently corrected the biases of future regional climate model projection data.
The Upper Indus, Kabul, Jhelum, and Chenab River basins are Pakistan’s four principal river basins. The research team at POSTECH, led by Professor Jonghun Kam (Division of Environmental Science and Engineering) and post-graduate researcher Shahid Ali, evaluated past and projected changes in streamflow timing.
The research team made use of bias-corrected hydrological projections as well as observational data. The Journal of Hydrology recently published this study.
The use of surface water and the Earth’s water cycle are the main topics in hydrology. Instead of replicating in the lab, different assumptions, statistics, and mathematical techniques are used to study precipitation, runoff, infiltration, and streamflow and provide fundamental knowledge and data for the use of water resources as science explores the complexity of the natural water flow.
However, the water cycle itself is changing as a result of climate change and human activity, making it challenging to solve future issues using knowledge and data from the past.
Pakistan is a prime example of a nation where there are significant seasonal variations in streamflow, which results in a lack of water resources for agriculture.
To make matters worse, Pakistan’s downstream regions were submerged by the Indus River last year, devastating the local communities. But knowledge of upcoming seasonal changes in streamflow over Pakistan is still scarce.
The VIC-river routing model was simulated by the researchers and forced by runoff and surface data from six regional climate models. Later, they adjusted the seasonality and minimum biases using observational data.
They calculated the centre-of-volume dates (CVDs) from observed and bias-corrected simulated streamflow data, as well as half of the annual cumulative streamflows (HSCs) and the dates of reaching the first quartile (25th percentile), in order to quantify seasonal changes in the hydrologic regime.
The three river basins, with the exception of the Chenab River basin, showed a significant decreasing trend in CVD with a range between -4.5 and -12.6 days between 1962 and 2019. Hydrologic projections that had been bias-corrected indicated that during the observational period, CVD had decreased by 4.2 to 6.3 days.
The decreased CVDs ranged from 5 to 20 days in the near future (the average for 2050 to 2059) and from 11 to 37 days in the far future, according to the four study river basins (the 2090 to 2099 average).
Then, Professor Kam said, “The rate at which Pakistan’s mountainous regions melt snow in late winter can affect the amount of water that will be available for spring crop planting.
This study highlights the diversity of hydrologic responses to future climate projections of surface warming of a similar magnitude.” In order to adapt to climate change, he continued, “it is urgent to prepare basin-specific water resource management and policies.”
The Global Korea Scholarship (GKS) Program of the National Institute for International Education (NIIED), a division of the Ministry of Education in the Republic of Korea, as well as the Mid-Career Researcher Program of the National Research Foundation of Korea, provided funding for this study.