Megadroughts Could Hit Australia and Last for Over 20 Years, Resulting in Future Rainfall Declines [Study]

Megadroughts are defined as extremely long-lasting drought events covering a large area that can last for years or even decades. In human history, previously recorded megadroughts have caused widespread ecological, environmental, and societal impacts. Amid extreme dry conditions and warmer temperatures, the said climatic phenomenon also serves as fuel for wildfires, especially in tropical and subtropical regions of Earth.

In previous years, scientists have determined the continuance of megadrought events in the 21^st century, including the Southwest United States megadrought that started in the year 2000. Now, a recent study revealed in March 2024 that Australia could be hit by unprecedented, decades-long megadroughts. Based on the study's new climate model, the megadroughts in Australia may last for more than 20 years.

What Classifies a Megadrought?

Megadroughts is exceptionally, multi-year drought events in terms of duration, severity, or spatial extent relative to other droughts of the last 2,000 years, according to the National Oceanic and Atmospheric Administration's (NOAA) National Integrated Drought Information System (NIDIS). Unlike severe or extreme drought, megadroughts can cause catastrophic disturbances in natural habitats and human population centers.

In a 2022 report posted on the NIDIS website, it was found that severe droughts have impacted many regions of the world, including western North America, Europe, East Africa, and China in recent years. Some of these events were dubbed by media and scientific literature as "megadroughts" to refer to almost significantly impactful drought event. Despite this designation, there is weak scientific consensus about when a drought becomes a megadrought.

Regardless, drought impacts are known for their notorious repercussions to the environment such as lack of rainfall, dried up water reservoirs, increased illnesses, and heightened mortality rates. In previous droughts, mass animal deaths have been reported. Some of the common causes of these fatalities are dehydration due to lack of access to water resources or hunger due to less food, as well as sufficient cover against the scorching heat.

Australia Megadroughts

Last month, researchers from the Australian National University and the ARC Center of Excellence for Climate Extremes predicted the occurrence of the decades-long Australia megadroughts. The findings were published in the journal Hydrology and Earth System Sciences on March 27, suggesting that climate change could worsen the consequences of a megadrought should it happen in Australia today.

The Australian research team arrived at their conclusion by using multiple climate models to simulate droughts that transpired over the past millennium, particularly from the year 850 to 2000. The models were also used to determine how future droughts might change in the future. The potential for "historically unprecedented Australian droughts" shows that it is no longer a matter of if but when, the study implies.

In 2019, drought has been reported to be responsible for killing millions of kangaroos in eastern Australia, which experienced several years of dry spell.