6 days ago
Reduced green cover, urban heat island effect make Kochi sweat: Study
Kochi: With several healthy trees being felled to convert open spaces into concrete structures, urban heat island (UHI) area is expanding in the city, thereby increasing the land surface temperature (LST).
Kochi Metro Rail Ltd's move to lay interlocking tiles on medians along the metro stretch is a case in point. According to a study, anthropogenic factors and urbanisation have resulted in the city getting warmer than nearby rural parts. UHI has expanded by 66% over nine years in Kochi during winter. UHI was experienced in 14sq km in 2014 and it rose to 41sq km in 2023 during winter.
The study, "Seasonal Analysis of Land Surface Temperature and Urban Heat Island Dynamics: A Comparative Study of Kochi and Fairbanks" conducted by Nansen Environmental Research Centre and Kerala Agricultural University, also shows a rising trend in LST (temperature on earth's surface in a particular area).
The total rise in LST was around 1.7Celsius over the past 23 years in summer, with an annual increase of around 0.07C in Kochi.
The study noted that the increase of 1.7C occurred in the peak summer month of March.
In contrast, it was 1.9C during the same period in winter, with an annual increase of 0.08C. The study found that moderate UHI intensities rose from 17.74sq km in 2014 to 31.3sq km in 2023 during summer.
With the city experiencing a significant warming trend, especially in winter, the study warns that it might also exacerbate the UHI effect in the years to come.
It attributes severe UHI and increased temperature events to ongoing uncontrolled urbanisation and reduced green cover in Kochi.
"With rising UHI, life in the city will become harsher. City dwellers experience UHI more at night because the heat remains contained within the city limits. Outer areas of the city have more vegetation and fewer concrete structures, thus helping temperature dip sooner. However, due to high impervious structures, roads and less vegetation in the city, temperature doesn't come down easily," said Chandu P J, senior project fellow at the research centre.
"Even during winter, temperature in urban areas doesn't reduce, while the outskirts show a more cooling effect. The increase in heat will have huge ramifications for both macro and micro-organisms. When heat rises people install air conditioners, which in turn increases greenhouse gases that raises temperature further, causing climate change," he added.
The observed trends in Kochi, alongside intensified UHI effects, underscore the need for adaptive strategies to mitigate the adverse effects of rising temperatures, the study finds.
Chandu suggested increasing vegetation in the city and implementing vertical gardens in high-rise buildings to reduce rising temperatures.
Box
Effects of Rising Temperature
*Leads to high energy consumption
*Water scarcity and drought situation
*Sea level rise due to melting of glaciers
*Increased risk of heatwave
*Adverse effects on ecosystem
*Impacts health of organisms
*Takes a toll on economy
Mitigation
*Planting more trees
*Reduce greenhouse gas emissions
*Sustainable urban planning with more thrust on conservation of water and biodiversity
*Implementation of climate resilient actions
