Absolute horrific images are coming out of Australia right now. There are still a few fires burning at emergency levels in various regions. The smoke is so extreme and so dense that it can be seen from space. Around 2,100 homes have been devastated. Six and a half million hectares of land scorched. The astounding toll on the nation’s wildlife has also been recorded. This is just heart-breaking. These record-breaking bushfires in Australia have been kicked off by things like lightning strikes, a few cases of arson and winds. But one of the biggest reasons they’ve become so extreme is the same reason East Africa is flooding.
Bushfires in Australia are a natural part of the country’s ecosystem. Their “fire season” varies across regions. Even New South Wales, the most populous state, is used to blazes breaking out. In the summer of 1974, fires burned 3.6 million hectares, and in 2003, another 2 million hectares were lost to fire. But the bushfires that took place in 2019 are even worse: 5 million hectares in New South Wales have charred by this time — and it’s only going to get even worse.
So why is this fire season so horrible?
To start with, the world is getting hotter day by day as a result of climate change, so is Australia. 2019 was its hottest year on record, with parts of the country reaching up to 45 degrees Celsius in December 2019, which also happens to be the driest. All over the year, other there are climatic forces at work that affect Australia’s weather and causing large scale bushfires. Nevertheless one of the most significant is the Indian Ocean Dipole or the IOD.
The IOD is a big temperature gradient that affects the surface water temperature in the Indian Ocean, from the edge of Africa to the edge of Australia. Meteorologists have been measuring these temperature shifts for decades in three phases: Positive, neutral and negative. When the IOD is neutral, the surface water in the Indian Ocean is evenly warm. A negative phase is when winds come in from the east and shift the warm water toward Australia. Warmer seawater means more evaporation and cloud formation resulting in heavy rains. So Australia receives more rain than normal, from time to time triggering floods. But the cooler water near East Africa translates to less rain and even droughts sometimes. A positive phase is what’s causing the bushfires in Australia and the flooding in East Africa now. Africa. The But 2019’s was extreme. The positive IOD was one of the most horrendous on record, with the water temperature difference between Africa and Australia being remarkably high. Henceforth, extreme weather in Australia, but also in Africa. The worst flooding in two decades. More than three times their annual rainfall in only four days. Scientists believe it’s linked to record temperatures in the Indian Ocean.
The good news is the IOD is already shifting to neutral which should bring some much-needed relief to Australia and Africa in early 2020. But as the planet continues to warm, some scientists are concerned about how that might affect weather phenomena like the IOD. One study predicts positive IODs, like what we’re seeing now, could happen more frequently as global temperatures rise and warm the Indian Ocean. Combine that with the rising overall temperature of Australia, and these kinds of devastating fires, fuelled by unusually dry vegetation, could become the new normal.