Warming Arabian sea sparks extreme rainfall and landslides in Kerala, climate scientist warns

New Delhi: A senior climate scientist has highlighted that the warming of the Arabian Sea is contributing to the formation of deep cloud systems, which in turn is leading to extreme rainfall in Kerala and an increased risk of landslides. This warning follows a series of devastating landslides in the Wayanad district of Kerala early Tuesday, which have claimed at least 45 lives, with many feared trapped under the debris.

S. Abhilash, Director of the Advanced Centre for Atmospheric Radar Research at Cochin University of Science and Technology (CUSAT), explained that the heavy rainfall in districts such as Kasargod, Kannur, Wayanad, Calicut, and Malappuram has been a result of an active monsoon offshore trough affecting the Konkan region over the past two weeks. The soil in these areas had become saturated from the prolonged rain.

On Monday, a deep mesoscale cloud system formed off the Arabian Sea coast, leading to intense rainfall in Wayanad, Calicut, Malappuram, and Kannur. This heavy rain triggered localised landslides in these hilly areas. Abhilash noted that the cloud systems were notably deep, comparable to those observed during the catastrophic Kerala floods of 2019.

According to Abhilash, scientists have observed a trend of increasingly deep cloud systems developing over the southeast Arabian Sea. These systems sometimes intrude into the land, as seen in 2019. He pointed out that the warming of the southeast Arabian Sea has led to atmospheric instability above the region, including Kerala. This instability facilitates the formation of deep clouds, which is linked to climate change. Previously, such intense rainfall was more common in the northern Konkan region, north of Mangalore. However, with climate change, the rain-bearing belt with deep clouds is shifting southward, which is contributing to the recent extreme rainfall events.

Abhilash's research, published in the 2022 edition of npj Climate and Atmospheric Science journal, indicates that rainfall over the west coast of India is becoming increasingly convective. Another study by Abhilash, along with scientists from IITM and IMD, published in Elsevier in 2021, found that the hotspot for heavy rainfall in the Konkan region has shifted southward, which could have severe consequences. The study suggested that increased rainfall intensity raises the likelihood of landslides in the high and mid-land slopes of the Western Ghats in eastern Kerala during the monsoon season.

The India Meteorological Department (IMD) reported that several automatic weather stations in Thrissur, Palakkad, Kozhikode, Wayanad, Kannur, Malappuram, and Ernakulam recorded rainfall between 19 cm and 35 cm. Most IMD stations in the region reported rainfall exceeding 24 cm in 24 hours, with some farmer-installed stations recording more than 30 cm.

The Met Office has also warned of the possibility of very heavy rainfall in some areas of Kerala over the next two days. PTI