Lightning Strikes in India

News: Recently, thirty people were killed in separate incidents of lightning in various parts of the country. Lightning is the biggest contributor to accidental deaths due to natural causes.

Background:

  • As many as 18.5 million lightning strikes were recorded in India between April 2020 and March 2021, according to India’s second annual report on lightning released by Lightning Resilient India Campaign (LRIC) recently.
  • LRIC is a joint initiative of Climate Resilient Observing-Systems Promotion Council (CROPC), National Disaster Management Authority, India Meteorological Department (IMD), Union Ministry of Earth Science, World Vision India, UNICEF among others.
  • The campaign aims to reduce the number of deaths to less than 1,200 a year by 2022. This is an increase of 34% compared to previous year; at least 13.8 million strikes were recorded between April 2019 and March 2020.

What is lightning?

  • Lightning is a very rapid — and massive — discharge of electricity in the atmosphere, some of which is directed towards the Earth’s surface.
  • These discharges are generated in giant moisture-bearing clouds that are 10-12 km tall.
  • The base of these clouds typically lies within 1-2 km of the Earth’s surface, while their top is 12-13 km away.
  • Temperatures towards the top of these clouds are in the range of minus 35 to minus 45 degrees Celsius.
  • As water vapour moves upward in the cloud, the falling temperature causes it to condense.
  • Heat is generated in the process, which pushes the molecules of water further up.
  • As they move to temperatures below zero degrees Celsius, the water droplets change into small ice crystals. They continue to move up, gathering mass — until they are so heavy that they start to fall to Earth.
  • This leads to a system in which, simultaneously, smaller ice crystals are moving up and bigger crystals are coming down. Collisions follow and trigger the release of electrons — a process that is very similar to the generation of sparks of electricity.
  • As the moving free electrons cause more collisions and more electrons, a chain reaction ensues.
  • This process results in a situation in which the top layer of the cloud gets positively charged, while the middle layer is negatively charged.

Climate Change and Lightning:

  • An increase of one degree Celsius would increase the frequency of lightning strikes by 12% , warned California University in a study published 2015.
  • A study published in Geophysical Research Letters in March 2021, too, has established links between climate change and rising incidences of lightning in the Arctic region.
  • The number of lightning strikes recorded during the summer months between 2010 and 2020 shot up from around 18,000 at the start of the decade to more than 1,50,000 by 2020. Therefore, even the Indian Institute of Tropical Management (IITM) concludes that the increase in lightning incidents may be directly related to the climate crisis, and the availability of more moisture over land due to global warming.
  • IITM in Pune is the only institution in India that works full-time on thunderstorms and lightning.