A recent study has revealed that the Earth's southern hemisphere has been drying more compared to the northern hemisphere from 2001-2020. The study's authors think that El Niño could be the primary cause.
Drying Southern Hemisphere
These findings are grounded on satellite data and stream and river flow measurements. These allowed the researchers to calculate and model water availability changes. Water availability refers to the net difference between the quantity of water supplied to a landscape and the water taken away to the atmosphere via evaporation or plant leaves.
Despite only containing a quarter of the planet's land area, the southern hemisphere greatly affects global water availability more than the northern hemisphere.
The new analysis shows a significant plummet in water availability across central and northwestern Australia, most of Africa, and South America. However, there are certain regions, such as southern South America, that may have more water availability.
However, amidst the great inter-regional variations, the study posits that water availability across the northern hemisphere is relatively balanced. This is partially due to great human influences, including food production, dams, and irrigation. These factors are more relevant across the Northern Hemisphere, as this region houses 90% of the global population.
Implications of the Drying Out of the Southern Hemisphere
Now, how exactly does the drying out of the southern hemisphere affect the northern hemisphere and the entire planet? A part of the answer can be found in the regions that are more likely to go through heightened drying.
Part of South America's terrain is the Amazon rainforest, which plays a key role in climate change and is a globally crucial species habitat and indigenous community home. Drying in the rainforest would hamper vegetation and boost fire risk. This would be bad news not just for humans and animals as it may also boost the risks of releasing billions of tons of carbon that are locked in the rainforest.
South America is also a significant exporter of sugar, soybeans, coffee, fruits, and meat for the world market. With this, water availability changes could globally affect food systems.
Drying across most of Africa also poses great concerns, as this continent contains several socioeconomic contrasts and climatic zones. Great pressures on habitats and food systems will stress the continent, which faces various concerns linked to inflation and the Ukrainian war.
As for northwestern Australia, it is considered one of the greatest wildernesses in the country. However, it would be wrong to consider the entire region empty and insignificant when drying up. Drying will affect the patterns of vegetation and boost temperature increases.
At the same time, drying across central Australia could also affect the climate and weather in coastal regions where the majority of the population and cities of Australia are situated. Drying trends are also seen in the southeastern and southwestern parts of the country. This leads to stresses and changes in habitats, wildfires, human health impacts, and depleted rivers.
Regarding climate change, the specific scale and nature of the impacts are difficult to gauge or model locally or regionally. Nevertheless, the study notes clear differences in patterns and climate processes across the southern hemisphere. This would affect water availability, especially when El Niño hits.
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