THE PHENOMENON OF BUSHFIRES

They are grassfires (similar to forest fires in India).

Since the Australian continent is semi-arid, it has a large expanse of grasslands that provide readymade material for large fires.

Although 2019 bushfire has been exceptional in its devastation, it is a common phenomenon in Australia since
thousands of years.

They have burnt down one lakh square kilometer land in Australia in 2019.

If one studies the natural ecosystem of the Australian continent, it is easy to gauge the impact of bushfires on overall evolution.

THE CHARACTERISTICS OF BUSHFIRES 

Speed of Movement: 

Their speed is higher than that of forest fires.

High heat output: 

Which allows them to smolder for days and weeks after the fire has crossed a location. This ensures that the impact of fires is felt at a location for a very long time.

CAUSES OF BUSHFIRES 

The basic cause of massive bushfires in the presence of hot and dry conditions over a long time scale.

The main factor which leads to the creation of such condition is Indian Ocean Dipole which creates exceptionally dry conditions (Low Rainfall and High aridity), abnormally high Temperatures (positive Temperature
anomaly).

The actual trigger is provided by Arson or lightning strike.

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HOW DO BUSHFIRES CREATE THEIR OWN WHETHER SYSTEMS?

Intense fires generate smoke. But their heat can also create a localized updraft powerful enough to create its changes in the atmosphere above. As the heat and smoke rise, the cloud plume can cool off, generating a large, puffy cloud full of potential rain. The plume can also scatter embers and hot ash over a wider area.

Eventually, water droplets in the cloud condense, generating a downburst of rain. But the “front” between the calm air outside the fire zone and a pyrocumulonimbus storm cloud is so sharp that it also generates lightning and that can start new fires.


IMPACTS OF BUSHFIRES

Physical, direct impacts: 

Over 18 million hectares have burned in the Australian bushfire season 2019–2020 as of mid-January according to media reports, destroying over 5,900 buildings including over 2,800 homes. In addition to human fatalities, many millions of animals are reported to have been killed.

Ongoing ecological and biodiversity impacts: 

An estimated billion animals, and many more bats and insects, are likely to die in total over the coming weeks and months as a result of lost habitat and food sources.

This loss is part of a much bigger picture of a world where biodiversity is in steep decline.

Public Health :

Smoke and ash content into the air led to the worst air quality in major cities across Australia. The effects of smoke exposure and inhalation range from the eye.

and respiratory tract irritation to more serious disorders, including reduced lung function, bronchitis, exacerbated asthma and premature death.

According to the World Health Organisation, older people, people with cardiorespiratory diseases or chronic illnesses, children, and people who work outdoors are particularly vulnerable.

The impacts of the fires across borders: 

Smoke from wildfires can travel great distances. It is often pushed into the stratosphere by the heat from fires. Smoke from bushfires in Australia has drifted across the Pacific and may have reached the Antarctic, according to the World  
Meteorological Organization.

This has led to hazardous air quality in major cities throughout Australia and affected New Zealand and cities in South America after smoke reached both Argentina and Chile.

Mental health costs: 

Fires do not only cause physical harm; many people experience mental trauma from the experience of emergency evacuation and losing homes, pets, belongings, livestock or, other sources of livelihoods.

Economic costs: 

The actual economic costs of these bushfires are still being analyzed, but it’s clear that infrastructure has been damaged and that impacts extend to industries such as farming and tourism. Some businesses and institutions have been forced to close their doors during periods of excessive levels of air pollution.

Climate feedback loops (reduction in carbon stock): 

The bushfires have not only been made more likely and intense by climate change, but they also add to it. Until the 2019–2020 Australian bushfire season, the forests in Australia were thought to reabsorb all the carbon released in bushfires across the country. This would mean the forests achieved net-zero emissions.

However, global warming is making bushfires burn more intensely and frequently and the 2019–2020 bushfires
have already emitted 400 megatonnes of carbon dioxide into the atmosphere, according to the Copernicus monitoring program.

This is as much as Australia’s average annual carbon dioxide emissions in just the past three months. These will increase Australia’s annual greenhouse gas emissions, contributing to global warming, and heighten the likelihood of recurring mega-fires that will release yet more
emissions. This is a deeply concerning climate feedback loop.

Agricultural impacts: 

The bushfires have scorched pasture, destroyed livestock and razed vineyards, with regrowth and recovery likely to stretch water resources already challenged by drought. Reports indicate that the country’s dairy supply will likely be hit hardest.

Meat, wool, and honey output may also be impacted. About 13 percent of the national sheep flock is in regions that have been significantly impacted and a further 17 percent in regions partially impacted, according to Meat & Livestock Australia.

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