What is going on with India’s weather?

It is worth keeping in mind that these trends are annual and are influenced by extremes all year round. However, monthly trends in the frequency of Indian temperature extremes for May, which can be found on the CLIMDEX climate database, show an increase over the past 60 years.

Based on local station data, the Indian Meteorological Department reported that many northern states experienced an average of eight heatwave days each March-July between 1961-2010. Trends in “normal” and “severe” heatwaves increased over this time, and in particular over the last decade of the analysis.

Some Indian regions also tended towards longer and more intense heatwaves after an El Ni?o, and northwestern states of India, where Phalodi is located, tend to experience more intense events anyway. Trends in the intensity of extreme temperatures are less clear and vary across the country.

Different spatial and temporal scales and methods of quantifying extreme temperature hamper a direct comparison of the two studies described above. However, they both document an increase in the frequency of extreme temperatures over India, which is consistent with many other regions worldwide. Heatwave indices and the hottest yearly temperature have only increased significantly in a relatively small region of western India.

What will the future bring?

Most climate models do not do a great job of capturing observed trends in heatwaves over India, because large-scale models struggle to accurately represent the localised effect of aerosols.

It is therefore difficult to use them in great detail for future projections, particularly if pollution levels continue or even increase. However, if air pollution is reduced, temperatures will rise with a vengeance. We know this from experience over Europe, where summer temperature trends were virtually zero up to the 1980s and very strong afterwards, once air pollution was controlled.

Even though this is the hottest time of the year for the region, the recent weather should not be dismissed as regular. It is feasible that India’s pollution problem has been “hiding” extreme heat spikes.

While any clean-up activities will have many positive local health impacts, these are likely to cause more intense heatwaves in future. This will be amplified by background warming due to climate change, which is also likely to drive increases in the frequency of temperature extremes.

Last year India and neighbouring Pakistan suffered similarly atrocious conditions, killing thousands of people. This year’s death toll is already in the hundreds, with numbers sure to rise further.

India is already highly vulnerable to the health impacts of oppressive heatwaves and, as climate change continues, this vulnerability will grow. It is therefore imperative that heat plans are put in place to protect the population. That’s a difficult prospect in places that lack communications infrastructure or widespread access to air conditioning.

In the longer term, this episode shows that the global warming targets agreed in Paris have to be taken seriously, so that unprecedented heatwaves and their deadly impacts don’t become unmanageable in this part of the world.