Historical Evidence of Compound Heatwave and Extreme Precipitation in Pakistan, 1980-2024

The anthropogenic shifts in the climate have triggered an unprecedented rise in climate extremes which have impacted millions of lives and caused trillions of dollars’ worth of damage. The climate drivers that cause these high impact events are usually spatially or temporally compounded. These compound climate extremes are extreme events that occur simultaneously, in close succession or due to drivers that are not implicitly extreme but become extreme when combined. The impact depends on the vulnerability and exposure of the stakeholders that define the risk. Compound climate extremes are exemplified through hot-dry such as compounding heatwaves and drought or hot-wet extremes such as compounding heatwaves and extreme precipitation. Pakistan is not a new to the occurrence of heatwaves and extreme precipitation however, the compounding of these extremes is a relatively novel field of study.

Pakistan’s climate adaptation and disaster management strategies predominantly focus on these extremes in isolation while compound climate extremes have been overlooked. To assess the scientific gap, we quantified the historical occurrences and intensities of these compounding extremes, we assessed sequential heatwaves and extreme precipitation in Pakistan from 1980 to 2024 over 47 meteorological stations across the country by employing daily observational datasets for daily maximum temperatures (˚C) and precipitation (mm).

The analysis recorded a total of 599 events for the study period. A rise in the frequency of these compounding extremes was recorded since 1980 for extreme precipitation following heatwaves events within 7 days, 5 days, 3 days and 1 day. These events are consolidated in the North and Northeastern stations of Pakistan. The highest duration for these events is recorded for 7 day interval event.

These compounding extremes are especially high risk as compared to isolated extreme events because of the smaller gap between their occurrences which leaves little to no time to respond. Moreover, these events not only cause heatwave associated morbidities and losses and damages but also lead to pluvial and flash flooding. The occurrence of these events especially in southern provinces, as depicted by the study, highlights the potentially high risk of impact as a consequence of the large population, underdevelopment, pervasive poverty, social inequalities, and crippling infrastructure which increases the exposure and vulnerability of the people to such events.