Extreme heat has once again gripped large parts of India and Pakistan, impacting hundreds of millions of people in one of the most densely populated parts of the world. The national meteorological and hydrological departments in both countries have working closely with health and disaster management agencies to save lives, in line with the WMO drive to strengthen early warnings and early action.
The heat has been prolonged and widespread. On 15 May, the India Meteorological Department said that numerous observing stations reported temperatures of between 45°C (113°F) and 50°C (122 °F). This followed a heatwave at the end of April and early May, at which temperatures reached 43-46 °C.
Temperatures also neared 50°C in worst hit areas of Pakistan. The Pakistan Meteorological Department said that daytime temperatures are likely to be between 5°C and 8°C above normal in large swathes of the country. It said the hot dry weather posed a risk to water supplies, agriculture and human and animal health.
It warned that in the mountainous regions of Gilgit-Baltistan and Khyber Pakhtunkwa, the unusual heat would enhance the melting of snow and ice and might trigger glacial lake outburst floods or flash floods in vulnerable areas, as well as river levels.
“Heatwaves have multiple and cascading impacts not just on human health, but also on ecosystems, agriculture, water and energy supplies and key sectors of the economy. The risks to society underline why the World Meteorological Organization is committed to ensuring that multi-hazard early warning services reach the most vulnerable,” said WMO Secretary-General Prof. Petteri Taalas.
“It is premature to attribute the extreme heat in India and Pakistan solely to climate change. However, it is consistent with what we expect in a changing climate. Heatwaves are more frequent and more intense and starting earlier than in the past,” he said.
The Intergovernmental Panel on Climate Change, in its Sixth Assessment Report, said that heatwaves and humid heat stress will be more intense and frequent in South Asia this century.
India’s Ministry of Earth Sciences recently issued an open-access publication about climate change in India. It devoted a whole chapter to temperature change.
- The frequency of warm extremes over India has increased during 1951-2015, with accelerated warming trends during the recent 30 year period 1986-2015 (high confidence). Significant warming is observed for the warmest day, warmest night and coldest night since 1986.
- The pre-monsoon season heatwave frequency, duration, intensity and areal coverage over India are projected to substantially increase during the twenty-first century (high confidence).
The heatwave was triggered by a high pressure system and follows an extended period of above average temperatures.
India recorded its warmest March on record, with an average maximum temperature of 33.1 ºC, or 1.86 °C above the long-term average. Pakistan also recorded its warmest March for at least the past 60 years, with a number of stations breaking March records.
In the pre-monsoon period, both India and Pakistan regularly experience excessively high temperatures, especially in May. Heatwaves do occur in April but are less common. It is too soon to know whether new national temperature records will be set. Turbat, in Pakistan, recorded the world’s fourth highest temperature of 53.7°C on 28 May 2017.
Both India and Pakistan have successful heat-health early warning systems and action plans, including those specially tailored for urban areas. Heat Action Plans reduce heat mortality and lessen the social impacts of extreme heat, including lost work productivity. Important lessons have been learned from the past and these are now being shared among all partners of the WMO co-sponsored Global Heat Health Information Network to enhance capacity in the hard hit region
The South Asia Heat Health Information Network, SAHHIN, supported by GHHIN, is working to share lessons and raise capacity across the south Asia region.
India has established a national framework for heat action plans through the National Disaster Management Authority which coordinates a network of state disaster response agencies and city leaders to prepare for soaring temperatures and ensure that everyone is aware of heatwave Do’s and Don’t’s.
The city of Ahmedabad in India was the first South Asian city to develop and implement a city-wide heat health adaptation in 2013 after experiencing a devastating heatwave in 2010. This successful approach has been expanded to 23 heatwave-prone states and serves to protect more than 130 cities and districts.
Pakistan has also made strides towards protecting public health. In the summer of 2015, a heatwave engulfed much of central and north-west India and eastern Pakistan and was directly or indirectly responsible for several thousand deaths. That acted as a wake-up call and led to the development and implementation of the Heat Action Plan in Karachi and other parts of Pakistan.