A recently published study by an international team of scientists from China and Australia found that over the past 20 years (2001 to 2020), countries in the Southern Hemisphere have experienced accelerated drying compared to the Northern Hemisphere. The work, published in the journal Science, links this process to the periodic El Niño phenomenon, which affects surface water temperatures in the Pacific Ocean.
The researchers used satellite data and streamflow measurements to estimate fluctuations in water balance, which is defined as the difference between precipitation and water loss through evaporation and transpiration from plants. The findings indicated significant declines in water resources in parts of South America, Africa and Australia, with vegetation at risk and the likelihood of fires increasing in tropical forests.
The study also highlights that increased aridification in southern latitudes could lead to dramatic environmental and climate changes, with average temperatures possibly rising to critical levels over the next 80 years. Such changes threaten the sustainability of South American agriculture, which is an important supplier of agricultural products to the world market, increasing tensions in global food systems.
According to the authors, the stability of water supply in the Northern Hemisphere may remain unchanged due to the widespread introduction of human activities such as irrigation, dam construction and intensive agriculture, which is especially important given the concentration of much of the world’s population in this region.