Context: 

Lightning strikes have been a significant cause of wildfires in Canada which has impacted the air quality of New York City.

About Lightning:

• Lightning is a natural atmospheric electrical discharge that occurs during thunderstorms. 
• It is a visible and powerful flash of light accompanied by a sudden release of energy. 
• Lightning is caused by the buildup and discharge of electrical charges within a thundercloud or between a thundercloud and the ground.

Mechanism of Lightning:

• Lightning happens when there is a big spark of electricity in the sky during a thunderstorm.
  • Thunderclouds: During a thunderstorm, there are clouds in the sky. Inside these clouds tiny water droplets and ice particles bump into each other. 
  • Electric Charges: When these particles collide, they create an imbalance of electrical charges. Some parts of the cloud become positively charged, and other parts become negatively charged. 
  • Charge Separation: The positive charges gather at the top of the cloud, and the negative charges gather at the bottom. This creates a strong electric field between the top and bottom of the cloud. 
  • Lightning Formation: When the electrical field becomes very strong, it can make a path for electricity to flow. It’s like a big spark traveling through the air. 
  • Flash of Light: When the lightning bolt moves, it heats up the air around it. This makes the air glow brightly, and that’s why we see a flash of light. 
  • Thunder: After the lightning bolt, we hear thunder. Thunder is the sound made by the rapid expansion  and contraction of air caused by the intense heat of the lightning. 

Impacts of Lightning:

• Wildfires: Lightning strikes can cause wildfires, which can lead to the destruction of vegetation, ecosystems, and property. 
• Power Outages: Lightning strikes can damage power lines, transformers, and electrical equipment, resulting in power outages. 
• Safety Hazards: Lightning poses a significant safety hazard to humans. Direct strikes can cause severe injuries or fatalities. 
• Atmospheric processes: Lightning plays a crucial role in the Earth’s atmospheric processes. 
• Nitrogen Fixation: Lightning contributes to nitrogen fixation, a process where atmospheric nitrogen is converted into forms that can be utilized by plants and other organisms. 

Incidence of Lightning:

• A report by the Centre for Science and Environment (CSE) and Down to Earth last year found that India witnessed 18.5 million lightning strikes between April 2020 and March 2021 – a 34% rise as compared to the same period in the previous year.
• According to a recent study by scientists at the Indian Institute of Tropical Meteorology. 
  • ‘Lighting flash density’ has increased – a measure of the frequency of lightning strikes – between 2009 and 2011 over the Indian subcontinent.
• State Risk management analysis shows that states like Odisha and Andhra Pradesh can bring down deaths by almost 70% in a “short time”.

Is Lightning an indicator of Climate change?

• The World Meteorological Organisation recognises lightning as an essential climate variable that critically contributes to the characterisation of the earth’s climate.
• As global warming increases the earth’s surface temperature, lightning activity is also predicted to increase.
• However, lightning-­climate relationships based on data for short periods, and different regions, in the present climate cannot always be used as a proxy for future global warming.

Way Forward:

• Lightning risk management strategy: A Lightning risk management strategy has to be customized for each state/region, taking into account seasonality, intensity and frequency of lightning.
• Lightning microzonation: Lightning microzonation within states can also help in handling the risks posed by strikes.
• The National Disaster Management Authority has also set up a protocol for early warning dissemination on thunderstorm and lightning in July 2021, which also specifies the ideal requisites of such a system including a mechanism to disseminate this information below district level.

News Source: The Hindu