What temperature in Bengaluru tells about global warming

Temperature in Bengaluru was the highest ever in 2015. And February was the hottest. Do we need more proof of global warming?

An article on New York Times says 2015 was the hottest year on earth so far. Just as 2015 made way for 2016, we have another article from Washington Post that says February 2016 was the hottest month for entire Earth!

What’s going on? Is global warming coming true? What was it like, in Bengaluru?

This February had one of the warmest days in its history

February 23rd, 2016, recorded a maximum temperature of 35.5 degree C, which is the highest temperature in Bengaluru for February since 2005. However, all-time record for February goes to a day in 2005. According to IMD officials, the hottest day in the month of February in last 148 years was 17th February 2005 – the temperature had hit 35.9 degree celsius.

Sundar M Metri, a director at the Indian Meteorological Department in Bengaluru, says that increased cloud cover reduces the maximum possible temperature, but increases the minimum temperature. The minimum temperature for February was 19 degree C, as opposed to the standard average for February, 17.2. The maximum was 35.5, as opposed to the average of 30.2. The average for each month is taken from Climatological table.

All time minimum temperature for February was 9.4 degree C, recorded in 1884.

Is temperature in Bengaluru increasing each year?

A tool compiled by New York Times shows that temperature in Bengaluru was 0.9 degree C warmer than the average normal. Average for Bengaluru is 24.7 degrees, while the tool shows an average of 25.6 degree Celsius.

Temperature graph from New York Times for 2015.

While temperature in Chennai was 0.8 degree C below normal, Delhi was only 0.5 degrees above normal. Colombo in Sri Lanka was 1.2 degree warmer than the normal in 2015.

Another graph from Accuweather shows that both maximum and minimum temperatures were constantly higher than average in February 2016.

Graph from Accuweather for February 2016.

We couldn’t verify the phenomenon through IMD data, because the data is not open to all.

What is Climatological table?

Indian Meterological Department makes use of climatological tables. Climatological table is a table of average temperature for a 30-year time band, that has maximum and minimum temperature averages for all 12 months of the year calculated by taking into consideration the timeband between the years considered. The timeband used by IMD-Bangalore is 1971-2000. Next scale, ranging from 1981 to 2010 is expected to be released by IMD, till which time the data will have to be tallied with the old scale.

Will this timeband be relevant for today’s Bangalore? It may not be, say the sources in IMD. The landscape and green cover in Bengaluru saw much changes in the years, with the city expanding constantly, more and more areas being built up and more and more greenery making way for buildings and roads.

Google Earth comparison of landscape of core Bangalore area between 2000 and 2015.

How is temperature measured by IMD?

The Bengaluru branch of Indian Meteorology Department (IMD) was set up in 1867, 10 years after the Sepoy Mutiny. The weather data is recorded here with the internationally accepted standards and techniques, specified by the World Meteorological Organisation.

Sources in Climatology section of IMD say that the temperature is recorded at 4 feet height, using a thermometer. The thermometer is placed in Stevenson’s screen. (Stevenson screen, as defined by Wikipedia, is a meteorological screen meant to shield instruments against precipitation and direct heat radiation from outside sources, while still allowing air to circulate freely around them. It forms part of a standard weather station.)

Related Articles

It’s rainiest November in Bengaluru since 1916; more to come!
Data from 100 years reveals the rainiest months in Bengaluru

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Similar Story

Bengaluru’s street vendors are the first to be impacted by climate change: Lekha Adavi

Lekha Adavi, member of AICTU, says the nature of street vending has changed in the city due to the impact of climate change.

(This is part 1 of the interview with Lekha Adavi on the impact of climate change on Bengaluru's street vendors) On May 1st, while the world celebrated Labour Day, Bengaluru recorded its highest temperature in 40 years. With temperatures continually on the rise, one of the most affected groups are street and peripatetic vendors (vendors who operate on foot or with push carts). In this interview, Lekha Adavi, member of the All India Centre of Trade Unions (AICTU), talks about the effect of climate change on street vendors. Excerpts: Lekha Adavi, member of the All India Centre of Trade Unions…

Similar Story

Smothered by smog: Struggle of vegetable vendors in Delhi’s Keshopur Mandi

Delhi's air pollution affects every resident, but for the urban poor, like vegetable vendors of Keshopur Mandi, it is much worse.

Halfway through our interview, vegetable vendor Rekha asked me point blank, “Isse kya hoga,” and at that moment, I could not think of an answer. She was right and had every reason to be hopeless. Much has been written about air pollution and much energy has been spent on expert committees and political debates and yet nothing has changed.  “Hum toh garib log hai, hum kisko jakar bole, hamari sunvai nahin hoti” (We are poor people, to whom do we go, nobody listens to us),” says Rekha Devi, who sells vegetables in the Keshopur Mandi. Keshopur is a large retail…