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.

How does lightning work?

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.

Is lightning a climate indicator?

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.