In August, Pakistan broke damaging rainfall records, averaging more treble than usual for the August monsoon season. As a result, it leads to record monsoon flooding. However, the figure was seven to eight times the national average in Sindh and Balochistan, two provinces in the south. Around 1,500 individuals died due to the disaster, which also caused more than 30 million people to lose their homes.
Is this something that a warmer environment is supposed to have influenced? The World Weather Attribution team swiftly conducted its routine analysis of this query and published the findings on Thursday. They employ standardized analysis of both historical weather data and climate model simulations as part of their peer-reviewed methodology for these quick investigations. A specific weather pattern will be examined to determine whether Global warming is causing monsoon flooding.
Numerous aspects – this phenomenon was more sophisticated than anything like a brief heatwave because it happened in waves over several weeks and was based on drastically changing monsoon flooding patterns. Monsoon rains are caused by Seasonal movements of moist air across land and an uplift that cools the air and removes moisture. This pattern is hit-or-miss in Pakistan since it typically originates over eastern India and turns northward before reaching Pakistan.
But this summer, eight monsoon depressions have neatly traced east-to-west across India and Pakistan, partly because the year’s early record warmth kept the low-pressure system in place and attracted the systems. This has impacted more of Pakistan’s south. However, late in August, rain also fell in Pakistan’s north due to a dip in the jet stream.
Pakistan’s Department of Meteorology In addition to these large-scale geographical trends, warm water in the eastern Indian Ocean boosted the moisture content of the air migrating onshore. As a result, the previous flooding record was reached in 2010, another La Nia year, and we can partially blame the present La Nia for that. This year, the impact of La Nia was amplified by the Indian Ocean Dipole oscillation.
Researchers need a precise characterization of the region and period to examine meteorological events. They were forced to accept two in this situation. They looked at the 60-day average precipitation during the monsoon flooding season for the Indus River Basin and the five-day average rainfall for just the southern provinces of Sindh and Balochistan. According to the research, “these two criteria best capture the implications of the storm, covering both the brief period of heavy precipitation in the southern provinces and the prolonged stretch over Pakistan.”