How does a forest fire happen?
Hundreds of years ago, forest fires were only started as a result of thunderstorms and lightning, in the absence of rain. There were also other rare natural phenomena, such as volcanic eruptions or earthquakes occurring in specific regions, which could cause the fire.
Nowadays, Human activities play a key role in increasing occurrence of natural disasters. For instance, Greenhouse gas emissions have a clear impact on rising temperatures. Extreme dryness which worsens fire seasons, extreme bursts of fire weather and behavior and the spread of fire across the country all align with scenarios painted by climate change projections. Recent studies show that extreme temperatures fueling historic bushfires were four times more likely to have happened because of human-caused climate change.
Which areas in Australia are affected?
Australia has always had bushfires, but early bushfire season last year, devastated several states. Wild fires burnt hundreds of thousands of hectares and destroyed hundreds of properties with some life losses.
Blazes have torn through bushland, wooded areas, and national parks like the Blue Mountains. Fires have damaged homes in the outer suburbs of large cities including Melbourne and Sydney and thick plumes of smoke have blanketed the urban center. However, with more than 1.65m hectares razed, New South Wales has been hit the most severely. That is an area significantly larger than suburban Sydney. At one point in NSW, firefighters were battling a fire front about 6,000km long, equivalent to a return trip between Sydney and Perth.
Seven districts in South Australia were rated as being at catastrophic risk of fire on as temperatures soared into the 40s. In Victoria, 100km/h winds fanned more than 60 blazes during an unprecedented heatwave.
As well as Eastern Australian states like Queensland where 20 homes have been lost and about 180,000ha burned, Western Australia has also experienced early bushfires in several regions. A code red, which is the most extreme warning, was issued for the north-western and central regions.
In total, more than 7.3 million hectares (17.9 million acres) have been burned across six states of Australia and thousands of residents have lost their homes.
What are the side effects?
Loss of biodiversity
Threatened species in Australia can number in the hundreds and Australia is the only home for many species. This year, areas that rarely burn in every year’s bushfires went up in flames. This is what makes the threat to their habitat particularly worrisome. As reported by scientists, the fires have pushed at least 20 threatened species closer to extinction.
According to a conservative estimate, about half a billion animals have been affected by the fires only in NSW, with millions likely dead. In total, an estimated 1 billion animals have been killed so far across the country. The estimate excludes invertebrates like insects, earthworms, and snails which could be dying by the trillions, along with bats and frogs. So, the number of total animals affected is almost certain to be much higher.
Many animals couldn’t outrun the blazes fanned by drought and high temperatures because the wildfires moved quickly and burned hotter than normal. In New South Wales alone, almost a third of koalas may have been killed and a third of their habitat has been destroyed in the fires.
Nonetheless, lucky animals which could survive face a new crisis: Their habitat is devastated and food sources have gone up in smoke. Hungry predators are another risk to survivors.
Threatened water supplies
Bushfires are capable of degrading water quality and altering the dynamics of stream ecosystems. Rain and cooler temperatures could help tamp down the blazes. However, too much rain falling too heavily could spell disaster for Australia’s water supplies.
Heavy rain can wash ash and eroded soil from the fires into waterways, affecting drinking water supplies downstream. Ash, soot, and charred vegetation could clog up streams, dams, and beaches, leading to blooms of algae and threatening water quality.
As well as quality, Blooms suck up oxygen available in the water column, strangling fish and other life. So, Fish and other aquatic life will be at the mercy of the rains. Moreover, Particles of ash could also lodge themselves in the gills of fish or gag filter feeders like mussels.
Bushfires can damage water supply infrastructure along with water catchments which leads to impeding the treatment processes that normally make our water safe to drink. In some cases, water treatment plants are bypassed completely, due to damage, power loss or an inability to keep pace with high volumes of water required for firefighting.
Untreated river water is usually not safe for drinking. Various types of bacteria, as well as the parasites giardia and cryptosporidium, could be found in water if river water has not been properly disinfected with chlorine. In cases where water may be contaminated with chemical substances rather than microorganisms, boiling is usually not effective.
Air pollution, Carbon emission and global warming
All fires emit a combination of thousands of compounds, including climate-warming greenhouse gases and smoke. Australian bushfires have already pumped hundreds of millions of tons of air pollutants like carbon dioxide, carbon monoxide and nitrous oxide into Earth's atmosphere which can harm the health of residents nearby. fine particulate pollution called PM2.5, is another byproduct of burning. It measures less than 2.5 micrometers across and can be transported long distances. As a result of recent fires, fine particulate pollution spiked to over 200 micrograms per cubic meter on average which is considered hazardous to older people, the very young and people with compromised immune systems.
Large pyrocumulonimbus storms above the fires in Australia acted like chimneys and shut smoke high into the air as if they were volcanic eruptions or nuclear explosions. Smoke billowing from the fires has made its way around the planet, injecting aerosols in the upper atmosphere and increasing carbon dioxide emissions. Satellite images from the National Oceanic and Atmospheric Administration show a haze from the deadly fires spreading over South America.
Another consequence of the fires is soot rain on the glaciers. New Zealand’s glaciers are already dwindling because of warming temperatures. In general, white snow has a high albedo and reflects sunlight at a relatively high rate. Darker snow colors lead to a lower albedo dipping which makes the glacier absorb more heat and melt faster. The fires had rained soot on New Zealand’s glaciers, which was reported by Australian as ashy snowfields and caramelized snow.
The bushfires in Australia are a never-ending story of loss, tragedy, and record-setting moments. With dozens of people killed, thousands of home destroyed, countless animals dead, and the fact that bushfire season still has about 2 months to go, Australia’s road to recovery may be long.