The wildfires in Australia and coral death

We have all seen how the wildfires in Australia have led to death and destruction. 28 people have died. More than 3,000 homes are gone or damaged. 100,000 square kilometers of forests is turned to ashes. And one billion animals have lost their lives or are injured: Koalas, kangaroos, wallabies, birds and other species that only live in Australia. Climate change is singled out as the main driver for the destructive wildfires.

The wildfires not only kills on land. Coral death is mainly over-looked.

Ash in the oceans

Huge wildfires ravaged Indonesia in 1997 and 1998. The smoke spread to the Philippines in the North, Sri Lanka in the West and Northern Australia in the South. Around 80,000 square kilometers burned. This was then the largest wildfires ever recorded and the damages were estimated to be close to 5 billion dollars.

Researcher Nerilie J Abram and her team wondered how these wildfires affected sea life. The researchers looked at living and fossile corals and studied chemical climate traces the last 7,000 years outside Indonesia.

They took into account the Indian Ocean Dipole. This is a natural phenomena that leads to temperature variations in the ocean. When the temperature is low in the Eastern parts and warmer in the Western the climate turns dry in the East with more precipitation in the West. This effect was particularly strong in 2019 and led to the drought in Australia and extreme rains in East Africa. The effect normally leads to more nutrients into the oceans, increased algae blooming which in turn leads to coral death.

From the traces the last 7,000 years this phenomena couldn’t fully explain the widespread coral death after the 1997 wildfires. There had to be something else in the equation and the researchers suspected the wildfires as a factor.

Ash is algae food

Ash brings iron and other nutrients into the ocean. This leads to increased algae blooming. When algae die bacteria break them down. This requires oxygen and with less oxygen the corals are choked.

The Indian Ocean Dipole is regarded as one of the causes of the wildfires in Australia. Many of the wildfires happened in the Northeast of Queensland close to the highly endangered Great Barrier Reef.

Climate Council published a report in July 2018 that documented how much of this reef is damaged and its condition is worse than previously thought. The damage is caused by higher ocean temperatures and the reef has suffered severe bleaching.

Coral bleaching is when the zooxanthellae algae is expelled by the coral. This happens when corals get stressed for instance when it gets too hot. Change in nutrition and sunlight may also cause this stress. The coral fades in color and if the temperature stays high, the algae won’t come back and the coral dies. One third of the Great Barrier Reef was damaged due to the mass bleaching in 2016-2017.

The Australian Climate Council published in July 2018 a report of the 2016-2017 bleaching. It found that the damage was even worse than what was reported initially. The report also warned that from 2030 this phenomenon is likely to happen every second year. This means that the entire Great Barrier Reef is about to die completely.

The report also warns that unless we reach the 1.5 degrees target, the reef has little chances to survive. By 2 degrees increase it is likely that all tropical coral reefs will collapse.

Although mass bleaching is not something new, it only occurred every 27 years on average before the climate change effects kicked in. Today is happens every 6 years. And even if the Great Barrier Reef does recover it will never get back its glorious days.

More research on the ashes impact on coral reefs is needed. The wildfire Thomas that ravaged California in December 2017 is also believed to have impacted ocean ecosystems. The wildfires in Australia, sadly enough, give ample opportunities to learn more about these effects.

Warmer oceans means more frequent dipoles

As the ocean temperatures increase the extreme dipoles will occur more often. From every 17 years to every 6 years.

The Red Cross published last year the report “The cost of doing nothing”. The report finds that 200 million people, almost a doubling of today, will need humanitarian assistance in 2050 if nothing is done to stop climate change. This will require 20 billion dollars annually The wildfires in Australia and the flooding in East Africa show us why.

Cover photo: A helicopter fighting wildfires in Victoria, December 30, 2019. Credit: Ninian Reid/State of Victoria.