Context: Soaring global temperatures could lead to more “hot lightning” strikes in many parts of the world, according to a new study published in the journal Nature Communications.
What are the Important Highlights of the Study?
- Lightning-induced wildfires: According to the study, lightning is a major cause of triggering wildfires and is responsible for producing the largest wildfires in some regions of the world.
- Impacts: Lightning-caused wildfires are dangerous as they spread rapidly before a strong response can be implemented and release substantial amounts of carbon, nitrogen oxides and other trace gases into the atmosphere.
- Hot lightning strikes: The latest study is the first to examine the connection between increasing global temperatures and the occurrence of “hot lightning” strikes.
- The study has also examined how the hot lightning strikes might affect the incidents of wildfires across the world.
- Most vulnerable regions: According to the study, the areas that might witness a significant increase in wildfires triggered by the LCC strikes are Southeast Asia, South America, Africa, Australia, North America and Europe.
- Decrease of wildfires in Polar Regions: Many northern Polar Regions might see a decrease in wildfires as rainfall is projected to increase while “hot lighting” rates remain constant, the study said.
What are ‘Hot Lightning’ Strikes?
- “Hot lightning” strikes, also known as long continuing current (LCC) are a type of lightning that has a higher temperature and longer duration than regular lightning.
- This type of lightning strike can last from around 40 milliseconds to nearly a third of a second.
- Why “hot lighting” has more potential of triggering a wildfire than typical lightning?
- Lightning with continuing currents can transport more energy from cloud to ground than typical lightning.
- When lightning with continuing currents attach to ground or vegetation, they produce more Joule heating and higher temperature than typical lightning, increasing the probability of ignition.
- Climate change and ‘hot lightning strikes or LCC strikes’:
- With the help of computer simulations, the study has observed that as the atmosphere warms, there might be an increase of41 per cent in the incidents of LCC strikes by 2090.
- This means that the rate of such lightning flashes could jump from three strikes per second globally to four strikes per second.
What is Lightning and how does it occur?
- Lightning is a rapid and massive electrical discharge that takes place between storm clouds and the ground, or within the clouds themselves.
- Mechanism of lightning:
- Scientists believe that for lightning to occur, positive and negative charges must separate within a cloud.
- This happens when the water droplets in the bottom part of the cloud are moved upwards, where the much colder atmosphere freezes them into small ice crystals.
- As these small ice crystals continue to go up, they gain more mass and eventually become so heavy that they start to fall down to Earth.
- This causes a system in which ice crystals going down collides with the water vapours coming up, leading to the accumulation of positive charges on the top of the cloud and negative changes gathering at the base, while the atmosphere between them in the cloud acts as an insulator.
- When the positive and negative charges grow large enough, their strength overpowers the insulating properties of the properties. As a result, the two kinds of charges meet with each other and produce lightning.
- Climate Change & 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.
- Increased Lightning Strikes in India:
- 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).
- 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, and 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.
- 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).
