Researchers of Global Change Programme (GCP) at Jadavpur University are predicting that climate change-induced stress on human health will create more morbidity and loss of productive workdays in Kolkata in coming years.

Taking into account the IMD data on temperature and humidity in Kolkata, the researchers found that months like March, April and May will be “no work months” if standards of World Health Organization (WHO) of heat stress is applied. Take for example the month of April 2009 in Kolkata, the temperature and the corresponding humidity level of 96.66 per cent days fell in the “Stop Work” zone as defined by the WHO. (See Box)

As against the average rise of temperature across the globe per decade, which is 0.8 degrees, Kolkata has witnessed the decadal rise of 1 degree temperature. “Since heat stress parameters are based on both temperature and humidity people at workplaces will experience more heat-related stress and health disorders,” says Joyashree Roy, head of GCP.

Roy, who was one of the principal co-drafters of Intergovernmental Panel for Climate Change (IPCC) Report in 2007, that fetched the panel Nobel Peace prize argues that even a minimum rise in temperature for Kolkata (0.01 degrees) could multiply the heat stress several times due to relatively high levels of humidity in summer months.

“Even at 28 degree Celsius coupled with 75 per cent humidity level, the WHO standard based calculations produce stop work alert,” Roy adds.

The GCP-JU researchers measured long-term temperature trends of the city and carried out actual measurements in various work places by occupational categories.

“We interviewed a number of construction workers, and street vendors, drivers who were exposed to heat stress and felt lazy and loss of desire to work,” says one of the researchers.

“The worst sufferers are rickshaw pullers, those joining noon shift schools, policeman on the street and so on,” the research points out.

The researchers have also come up with adaptation strategies to address increasing heat stress.

Researchers say that by choosing comfortable dress codes, shades, air-conditioning, better wind circulation, productivity loss can be reduced. For example, 25 per cent loss reduction can be achieved through better ventilation, shades, dress codes while 50 per cent loss can be avoided by banning any outdoor activity in hot summer months. Combining rest hours with work hours at regular intervals will reduce productivity loss by 75 per cent. In case, one wants to achieve zero productivity loss then the entire work place has to be fully air-conditioned.

What is the standard for work condition

The WHO index that relates working condition with the prevailing climatic condition is called WBGT (Wet Bulb Glow Temperature) Index or Work Rest Balance Index. It is calculated on the basis of humidity, temperature, work ambience, clothing and a number of other factors