Irrigation could be delaying monsoon in India, cautions IPCC study -TV Jayan
-The Hindu Business Line
But it could be helping to boost rainfall in the Horn of Africa
Is irrigation adversely affecting the monsoon in India and delaying its onset? Maybe, according to a report on climate change and land brought out by the United Nation’s Intergovernmental Panel on Climate Change (IPCC) last week.
“Irrigation in India occurs prior to the start of the monsoon season and the resulting land cooling decreases the land-sea temperature contrast. This can delay the onset of the monsoon and decrease its intensity,” the report said, quoting studies carried out in the past.
Beneficial for some
Irrigating farms in India may be having an unfavourable outcome within its national boundaries but it’s probably having some beneficial impact in faraway places.
According to a global modelling study published in 2016, irrigation in India is increasing rainfall in the Horn of Africa.
This IPCC special report, authored by over 100 scientists, looks mainly at how human use of land is driving climate change. According to the report, the use by humans is directly affecting about 70 per cent ice-free land surface on the planet.
One of the chapters in the report dealing with interactions between land and climate says the effects of irrigation on local, regional and global climate are very well studied. According to scientists, it is well established that irrigation increases total evapo-transpiration, increases the total amount of water vapour in the atmosphere, and decreases mean surface daytime temperature within the irrigated area and during the time of irrigation.
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