14th June 2023 (7 Topics)
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What is causing large-scale wildfires in Canada?
Context
According to the Canadian Interagency Forest Fire Centre, there are 426 active fires in the country as on June, 2023.
What is causing the wildfires in Canada?
- The Reuters report stated that Wildfires in Canada’s British Columbia and Alberta province have been caused by lightning. It is the main precursor of natural wildfires.
- Observation: Laboratory experiments and field observations have indicated that continuing electrical currents in lightning flowing for more than some tens of milliseconds (so-called Long-Continuing-Currents, or LCC) are likely to produce fires.
What does the report imply about global lightning and global LCC?
- According to the study, simulations suggest an increase in total global lightning and global LCC by the 2090s.
- The simulated globally averaged surface temperature increases by about 4 Kelvin (since Kelvin and Celsius have a linear relationship, this equals to an increase by about 4 degrees Celsius), and thus we obtain an increase in total lightning activity of 11% per Kelvin.
- The estimated increase of LCC lightning over land by 47% indicates a higher risk of lightning-ignited wildfires in the future.
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Lightning is a giant spark of electricity in the atmosphere between clouds, the air, or the ground. In the early stages of development, air acts as an insulator between the positive and negative charges in the cloud and between the cloud and the ground. |
How does lightning work?
- During a storm, water droplets from warmer air and ice crystals from cooler air come together to form thunderstorm clouds. Contact between these water droplets and ice crystals produce a static electrical charge in clouds.
- When opposing negative and positive charges in clouds build up, the insulating capacity of air between the charges as well as between the cloud and the ground breaks down, leading to a rapid discharge. This is what we call lightning. It can occur between opposite charges within the thunderstorm cloud, or between opposite charges in the cloud and on the ground.
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.
- According to American Geophysical Union’s magazine Eos, lightning also produces nitrogen oxides. These react with other gases in the atmosphere and produce ozone, which is a strong greenhouse gas that traps earth’s outgoing heat and retains it in the atmosphere, altering climate and weather patterns.
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Low snowfall and dry spring are also the reasons behind uncontrolled wildfires in Canada. |
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