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[ISLAMABAD] Aridity has gripped over 60 per cent of Pakistan, say researchers who made a long-term (1901–2016) study of precipitation (rain, snow, sleet, dew and hail) and potential evapotranspiration (evaporation from soil and by plant transpiration) over the country’s 80 million hectares of landmass.
“Our study findings show that declining precipitation has remained a key cause of aridity in most of the country”
Shamsuddin Shahid, Universiti Teknologi Malaysia
Researchers from China, Malaysia and Pakistan, who published their work in Hydrology and Earth System Sciences this month (19 July), say aridity increased mostly in the southern parts of the country, where rains have shown a declining pattern over the past century.
The study shows that a major shift in aridity and rainfall occurred between 1971 and 1980 and that average annual evapotranspiration rates in most parts of the country are much higher than precipitation rates, resulting in rising aridity.
“Warming temperatures and consequent evapotranspiration have been long believed to be key causative forces of aridity. But our study findings show that declining precipitation has remained a key cause of aridity in most of the country,’’ says Shamsuddin Shahid, an author of the study and associate professor at the hydrology department, Universiti Teknologi Malaysia.
Shahid tells SciDev.Net that a large area in the northeast of Pakistan became wetter during the study period 1901–2016. Most of the country’s southern half is witnessing rising aridity trends while the upper half of the country, especially the northeast, is becoming less arid.
Consequently, agriculture in the central and southern part of the country, where rice, sugarcane, wheat and cotton are grown, is threatened by high evapotranspiration rates while farming in the upper half of the country, which mostly grows maize, potato, onion and other vegetables, is in a better situation, Shahid says.
Aridity is fast emerging as the gravest risk to Pakistan’s agriculture, which is the mainstay of the economy, says Amjad Tahir Virk, who led the first phase of the five-year UNDP-funded Desertification in Pakistan project that ended in 2013.
“Surging aridity in Pakistan’s south, which contributes 70 per cent of the total agriculture productivity and farm-related jobs, means [a] hike in overall food insecurity, rural poverty and significant loss of farm-based jobs,” Virk, who specialises in science-based aridity management, tells SciDev.Net.
Declining precipitation patterns in the country’s southern parts means more frequent droughts even in irrigated areas, says Virk. On the other hand, growing precipitation trends in the northern regions means these areas will suffer more riverine and flash floods in the coming years, he adds.Saeed Gulzar, assistant professor at the Pir Mehr Ali Shah Arid Agriculture University, says adaptation measures in agriculture, forestry, water management and water infrastructure sectors are vital to aridity mitigation.
“Increasing vegetation cover to help reduce evaporation and strengthen water holding capacity of the soil, enhancing rainwater storage and introducing drought-resilient crop varieties are critical measures for tackling aridity,” Gulzar says.
This piece was produced by SciDev.Net’s Asia & Pacific desk.