Bangalore is now warmer by one degree

Bangalore is now warmer by one degree

Divya Gandhi and Deepa Kurup
Traffic, concrete and loss of tree cover have made ‘air-conditioned city’ a heat island
— Photo: K. Murali Kumar

Hotter days ahead: Experts say the increase in Bangalore’s average temperature is ‘very significant’ in terms of global warming.
Bangalore: For old-time Bangaloreans who insist that the city is getting hotter, the Meteorological Centre has the evidence: a “trend chart” shows that Bangalore’s average temperature has risen by one degree over the last 45 years (1963 to 2008). One degree may not sound like much, but is “very significant” in terms of global warming, explains A. Muthuchami, Director of the centre.

The annual average maximum temperature, which in 1963 was 28.9 degrees Celsius, rose to 29.9 degrees Celsius by 2008.

“This translates into a 0.25 degree rise in temperature every decade,” he added. “If this trend continues, we can expect an increase of 2.5 degrees by 2050, which will probably imply the need for remedial intervention by the Government in terms of power and water supply,” said Mr. Muthuchami. These worrying statistics are just a confirmation of the fact that Bangalore is fast becoming a “heat island”, with weather conditions rather different from its immediate surroundings, said T.V. Ramachandra, Associate Professor, Centre for Ecological Sciences at the Indian Institute of Science (IISc.)

The reasons are not unexpected: the proliferation of heat-trapping, concrete-glass-chrome buildings; the razing of hundreds of avenue trees to widen roads to make way for the annual addition of a staggering three lakh vehicles; and of course, the greenhouse gases emitted by these vehicles. Bangalore has seen an unprecedented change in its landscape in the last few decades: a 466 per cent increase in built up area between 1973 and 2007, with a corresponding decline in the area under water bodies by 70 per cent in the same period and a 63 per cent reduction of vegetation from 2002 to 2007 alone, according to a research paper on Bangalore’s urban sprawl co-authored by Mr. Ramachandra.

Startling figures
And so, when the city’s Met Centre opened an office at the international airport in Devanahalli nearly a year ago, some startling figures began to come in: the readings at Devanahalli (which retains much of its original landscape) have been consistently three to four degrees lower than the city centre.

At the other end of town too, at the old airport, temperatures are on average at least two degrees lower than at the city centre, observed Mr. Muthuchami.

“In fact even within the city, wherever there is green cover and water bodies such as in the IISc., the temperature can be a good two to three degrees cooler than at the city centre,” Mr. Ramachandra explained.

Conversely, areas such as ITPL where there is “concentrated growth” and a propensity for paving and for glass and chrome buildings, the average temperature is higher by two degrees, he added.

Going haywire
The city is growing faster than the planning process, believes J. Srinivasan, professor at the Centre for Atmospheric and Oceanic Sciences, IISc., and Chairman of the Divecha Centre for Climate Change: “Some of the older parts of Bangalore — such as Jayanagar — are well planned with enough open area and parks. Several newly-developed areas of Bangalore, including IT parks, are often not planned and built with little regard to local environmental conditions,” he said.