Extreme heat kills people, crops and morale in Northwest India
The invisible killer hunts the more susceptible prey
Hey Chuggers,
If you’re still around, I apologize for the silence on this channel. In the last six months, I defended my PhD dissertation, moved to Florida, spent 7 weeks back home in India, married my love, moved to New Jersey and started a new job at Princeton University. Pretty intense in hindsight, but I’m back and hoping to write more frequently.
Why heat extremes? The evidence is crystal clear. Heat extremes lead to more excess deaths and agricultural yield fluctuations than any other natural extreme condition. It’s a no brainer that we need better integration of heat forecasts into our everyday activities, outdoor worker behavior and policies, and cyclical agricultural activities. While this is true for large regions around the globe, the risk across Northwest India is severe and daunting. I’m chugging along on a larger goal to tackle climate risk and protect agriculture and health in Northwestern India. This piece covers the past observed and future projected threat of extreme heat over India - my hope is that the risk over Northwest India will reveal itself to the reader.
A comprehensive analysis of heat risk was performed by Saumya Singh, R K Mall, Nidhi Singh (Dept of Science and Technology DST, India) in 2020. They reveal a lingering scary situation - India has become a hotspot for heat-related mortality. Deaths tolls due to heat waves between 1978-1999 were estimated at 5330. However, the recent extreme heatwaves in 2003 and 2015 alone led to 3054 and 2248 deaths respectively (Chaudhury et al., 2000; Ratnam et al., 2016). We’ll cover more about what this means for agricultural yield and its quality. This study used the standard criteria of IMD (Indian Meteorological Dept) and temperature data recorded at 395 stations across India to calculate how often heatwaves and severe heatwaves have occurred in the past. Say whatever you want about people’s tolerance and adaptation to hot environments, but the base threshold that IMD uses to define a heatwave over the Plains of North India is ridiculously high - 45 degC or 113 F! Nevertheless, here’s one key result from the study to put the heat risk into perspective.
The trend of heatwave and severe heatwave events during March-July of 1956-2016
The red colors mean that during the years of 1956-2016, there has been a significant increase in heatwaves (days > 45 degC) and severe heatwaves (days > 47 degC) in the Spring and Summer seasons. While these trends are based on dry temperature alone (as opposed to Humid temperature, but more about that later), they reflect that Northwest India has been battling with increased risk of extreme heat over the past decades.
What does this mean going forward? Well, our best guess is that it’s only going to get worse. Researchers from MIT (the one in Massachusetts, not the one in Manipal) conducted state-of-the-art calculations on what the climate change projections mean for the Indian subcontinent in terms of extreme heat events. They focused on humid heat (or wet bulb temperature), and all you have to know about humid heat is this - hot air exerts stress on the human body to cool itself down but the humidity in the air reduces the capacity of the human body to cool itself down. High heat is bad; combined with high moisture, it is worse. Here’s what the study conducted by Eun-Soon Im, Jeremy Pal and Elfatih Eltahir in 2017 revealed about the past and future heat extremes in the region.
Extreme heatwave occurrences in the past (1979-2015)
Three likely scenarios of highest projected wet bulb temperatures over the 21st century (wet bulb temp > 31 degC is deadly)
Clearly, the geographical locations of the most extreme projected heat waves lies in Northern India and coincides largely with locations of dense human populations, high economic output and intense agriculture. If you would like to know more about similar topics that are piquing my interest these days, subscribe and read up.
It’s a disturbing exercise to document the misfortune faced by people due to anomalously hot weather (more on the damage in future letters), especially because most of that damage can be contained with existing accessible technology and improved communication within warning systems. While there is a case to be made to improve the forecast system and the dissemination of information, the true reasons that prevent the integration of state-sponsored weather/climate information into agricultural practices are largely undocumented. A system can only be improved if there is feedback, and feedback is generated when users reveal the flaws through repeated usage of the system. I can’t blame IMD Agrimet division, in all honesty they have built a fantastic portal and a phone application that issues climate advisory for farming. However, if the integration is lacking, how do you improve a system? This isn’t just a meteorological problem anymore, it’s a social behavior problem. I’m gonna leave it at that and continue the reconnaissance. Stay cool and hydrated, and pay attention to heat warnings! Later chuggers.