Just over a year ago Delhi was in the grips of an unbearable heatwave. It’s citizens experienced ten continuous days of relentless heat. Record-breaking temperatures peaked at over 47˚C with little relief overnight as temperatures sustained at an average of nearly 29˚C. That year power supplies failed to keep up with cooling demand and there were reports of social unrest in the north of India as substations were set on fire and power workers held hostage. The unrest was linked to a perception of there being political preference for distribution of scarce resources, at a time when resources were of greatest need to all citizens.
Fast-forward to 2015 and Delhi has again endured the searing heat of an Indian heatwave, with parts of the country having experienced sustained temperatures of 47˚C day after day. The number of deaths attributed to the heatwave has ranged from over 1,000 to well over 2,000, with accusations of false reporting following the introduction of a government compensation scheme for affected families. Whichever way you look at it, the latest heatwave is being reported as the deadliest in recent decades based on historic mortality data held by the Ministry of Home Affairs and the Indian Meteorological Department (IMD).
Turning up the heat
A 2014 research study presented the first projections of future heat waves in India based on the latest IPCC projections (CMIP5). The study found future heat waves to become more intense, with longer durations and occurring at a higher frequency and earlier in the year. Southern India, currently not impacted by heat waves, is expected to be severely affected by the end of the 21st Century. In northern India, the average number of days in a year with extreme heat stress conditions was expected to reach 30.
The Urban Heat Island Effect in cities is a well-known and studied phenomenon. But the impacts are not limited to the confines of a city. Studies have shown that cities can increase the heat in faraway places by affecting global air flows and disturbing jet streams in the northern hemisphere. These jet streams distribute heat and circulate cool air, and when intercepted by hot air can be pushed northwards, allowing warmer air from the equator to move farther north.
Although a number of complex factors contribute to the timing and arrival of much needed Indian monsoons, jet streams play a vital role and warming cities may become more of an influencing factor in the future. Coupled with India’s economic progression and expansion of cities as vital economic centres, the potential for heatwaves increasing in frequency and magnitude provides a clear and worrying message of far reaching implications in terms of physical, socio-economic and political risks.
The supply chain risk
Cities like Delhi are vital nodes in any country’s domestic and international supply chain. A city at risk not only has wide ramifications within its own country, but can also impact a country’s ability to trade successfully in an international arena.
Risks can manifest themselves at many levels, creating additional stressors and compounding effects in both the vertical and horizontal markets that a city operates within: health and productivity impacts on citizens and workforce, demand for water and power outstripping supply, melting of roads and buckling of rails, to name a few.
Coupled with poverty and low adaptive capacity, the less advantaged, who are also fundamental to the day-to-day operability of cities such as Delhi, are particularly vulnerable. As witnessed in India in 2014, sustained climatic stresses can result in unrest amongst those that feel disadvantaged, leading to further political and economic instability.
Some climatic events, such as elevated temperatures, can affect wide areas which are well beyond the physical parameters of a city. These areas may also be important inputs to a city’s supply chain, and may already be under stress from other existing factors. The Punjab is often described as the bread basket of India having some of the country’s most fertile agricultural land and a major contributing state to the nation’s food security. Yet, despite this, Punjab already suffers from water and power competition with other sectors, and on a wider scale with other, more economically progressive parts of the country. These existing stressors themselves are at additional risk from a changing climate and increased competition for resources between citizens, agriculture and industry.
In recent years, the issue of groundwater depletion has also become a major concern in both agricultural and urban areas in India. Research by the Columbia Water Center reported that water tables in Punjab have been dropping at alarming rates: from 1982-87, the water table in Central Punjab fell at an average rate of 18 cm per year, accelerating to 42 cm per year from 1997-2002, and heading to 75 cm per year during 2002-06. Considering that Punjab is a government mandated rice district and primary source for national reserves, this has clear implications for national food security and unrestricted supply to expanding city populations.
Delhi itself is also at risk from groundwater depletion. 62% of monitoring points show a declining trend with the State government stepping in to declare parts of Delhi as notified areas with a ban on groundwater extraction. Other parts of Delhi districts have been declared as ‘over-exploited areas’, with a clear signal that continued abstraction is at risk. Factors for groundwater depletion include inadequate piped supplies resulting in unauthorised drilling of boreholes, and the rapid pace of urbanisation resulting in reduced natural recharge of aquifers. Levels in parts of Delhi have declined between 2 and 20 metres compared to historic levels, and this in a city that requires over 3Ml of water per day, but can only supply in the region of 2Ml.
Although climate change may in itself not cause outright failure of city systems and processes, its gradual erosion over time of operational, environmental and comfort margins may bring cities, their inhabitants and infrastructure ever closer to breaching safety margins. When finally tipped over the edge by extreme events, this may occur more often and for longer periods of time than designed for, especially where these are designed to a past, stationary climate.