Wildfires in Canada
Context:
According to the Canadian Interagency Forest Fire Centre, there were 426 active fires in the country as of June 8, 2023.
Causes of wildfires in Canada:
- Lightning: Lightning strikes have been a significant cause of wildfires in Canada.
- Continuing electrical currents in lightning, known as Long-Continuing-Currents (LCC), have been observed to have a higher probability of starting fires.
- The study also found that LCC lightning activity increased by around 47% over land, implying a higher risk of lightning ignited wildfires in the future.
- Human activities: Reports indicate that human activities have also contributed to the occurrence and severity of the wildfires.
- Cloud Formation: During a storm, water droplets in warmer air and ice crystals that condensed in cooler air coalesce together to form thunderstorm clouds (usually cumulonimbus clouds).
- Lightning Flash:
- Contact between these droplets and crystals produces a static electrical charge in the clouds.
- The negative and positive charges in the clouds build up. Over time, the voltage difference becomes high enough to surmount the resistance presented by the air, leading to a rapid discharge of electric charge.
- Occurrence: It can occur between oppositely charged surfaces within a thunderstorm cloud or between such surfaces in the cloud and on the ground.
- The World Meteorological Organisation recognises lightning to be an essential climate variable that contributes critically to the way the earth’s climate is characterised.
- Lightning also produces nitrogen oxides, which react with oxygen in the air to form ozone, which is a strong greenhouse gas.
- However, lightning-climate relationship based on data for short periods, and different regions, in the present climate cannot always be used as a proxy for future global warming.