By Okoro Uchechukwu
Over the past week, the internet was flooded with images of the orange-tinted skylines of cities located around in the western United States. Many of us wondered what could cause the skyline to appear so apocalyptic. Well, the answer is ‘smoke’.
White light refracts as it passes through a medium. Certain materials or surfaces will cause light to refract light more than others. This refraction is responsible for the colours we perceive from a material. The size of particles also determines the type of light that passes through a medium. For example, our atmosphere primarily consists of nitrogen and oxygen which refracts blue light (hence the blue skies). Larger particles such as smoke particles scatter blue light allowing red-yellow light pass through leaving the now-familiar orange tint. Vast swathes of the western United States have been engulfed in flames for weeks now.
Recipe for a Wildfire
The smoke which has obstructed the atmosphere in recent weeks have been from wildfires. Wildfires are unplanned and uncontrolled fires that burn vegetation and grassland. They usually occur in rural and sparsely populated areas.
For an uncontrollable wildfire to occur, two main things are necessary; a warm climate that dries out vegetation overtime (turning it to kindling) and a source of ignition (the spark). In some cases, wildfires are started by nature, with the ignition coming from lighting strikes. But in many cases, they are caused by anthropological factors such as the smoke from a gender reveal party that started the fire in California last week. In many rural communities, wildfires are started by farmers and are used to clear an area for planting or to convert forests to pasture for animal grazing. In recent years, the potency and extents of these fires have increased and are now a cause for alarm, why?
Climate Change as an Accelerant
With increasing climate change the intensity of wildfires has increased over the years. Climate change affects wildfires by increasing the risk of fires and extending the length of fire seasons. A hotter and longer dry spell results in drier vegetation which can easily catch fire as well as a longer period of burning.
With altered weather patterns; such as prolonged drought and intense heatwaves, the effects of climate change have increased the severity of wildfires. Evidence of this can be seen in recent fires, from the Amazon rainforest fire last year to the Australian wildfires earlier this year and now the California wildfires. This year has produced one of California’s worst wildfire seasons on record as over 3 million acres of land has been burned compared to an average California wildfire season only about 300,000 acres are burnt. It is no coincidence that 6 of the largest wildfires in California have been recorded this year alone.
In addition to indirect activities that contribute to global warming, direct activities of humans are also responsible for the increased fires being witnessed. Change in human land-use is another factor that has led to increased wildfires. Deforestation in the Amazon rainforest has directly been linked to increased fire activity. Rainforest burning is usually the last stage in deforestation as it presents a cheaper alternative to clearing land and providing ash for pastures.
It needs not to be said that global warming presents the biggest threat to our existence. We must collectively come together to battle this threat because the next time we may be forced to wear protective masks may not be due to a deadly virus rather it will be to prevent smoke inhalation as our planet burns.